Planning Water Supply and Sanitation Projects in Developing Nations

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the water. According to Wuhrmann, the dominant reaction product between the phosphate ion and the ferric ion at pH above 7 is believed to be FePO4, with a solubility product of about 1023 at 25°C. The colloidal particle size of the FePO4 requires a sufficient excess of ferric ion for the formation of a well-flocculating hydroxide precipitate, which includes the FePO4 particles and acts as an efficient adsorbent for other phosphorous compounds.It has been reported that for efficient phosphorus removal (85 to 95%), the stoichiometric amount of 1.8 mg/l Fe required per mg/l P should be supplemented by at least 10 mg/l of iron for hydroxide formation. Also, the use of anionic polymer is considered desirable in order to produce a clear supernatant (Wukash, 1968).Lime Lime reacts with the bicarbonate alkalinity of waste-water to form calcium carbonate, which precipitates, under normal conditions: Ca(OH)2  Ca(HCO3)2 → 2CaCO3 ↓  2H2O (8)Normally, 70 to 90% of the phosphorus in domestic sewage is in the form of orthophosphates or polyphosphates that may hydrolyze orthophosphates. The remaining phosphorus is present in the form of organic-bound phosphorus. The removal of phosphorus can be achieved by direct adsorption on the surface of calcium carbonate particles. Orthophosphates can also be precipitated in the alkaline range by reaction with cal-cium salts to form hydroxyapatite, according to the following reaction:10Ca(OH)2  6H3PO4 → 10Ca  (PO4)6(OH)2 ↓  18H20 (9)Schmid and McKinney (1969) observed that hydroxyapatite was present in soluble form at a pH value above 9.5. They also found that at pH values of 9.5 or less, phosphorus was adsorbed onto the growing faces of calcium-carbonate par-ticles, thereby inhibiting their growth. Buzzell and Sawyer (1967) have shown that at pH levels of 10 to 11 in the primary sedimentation tanks, BOD removal of 55 to 70%, nitrogen removal of 25%, phosphate removal of 80 to 90%, and coli-form removal of 99% can be expected. Bishop et al. (1972) have reported that precipitation of domestic wastewater with lime removed approximately 80% of the TOC, BOD, and COD; 91% of the SS; 97% of the total phosphorus; and 31% of the total nitrogen. Phosphates from secondary effluent have been removed successfully at Lake Tahoe by precipitation with lime (Slechta and Culp, 1967). Albertson and Sherwood (1967) found that by recirculating calcium-phosphate solids, previously formed due to the addition of lime, it was possible to reduce the lime dosage by about 50%.Galarneau and Gehr (1997) present experimental results of their studies on phosphorous using aluminum hydroxide. de-Bashan and Bashan (2004) present an extensive review of recent advances in phosphorous removal from wastewaters and its separation for use as a fertilizer or as an ingredient in other products.In wastewater-treatment practices, it is detrimental to form large floc particles immediately in the flocculation step because it reduces the available floc surface area for adsorp-tion of phosphorus. Therefore, it is essential to maintain fine pinpoint flocs in order to get a maximum phosphate removal by surface adsorption, and this can be achieved by minimizing the time of their flocculation. This is not the case if the goal is one of colloidal-solids removal, as is often the case in water treatment.The process of coagulation and flocculation in wastewater treatment can be summarized in the following three steps: 1. As the coagulant dissolves, positive aluminum and ferric ions become available to neutralize the negative charges on the colloidal particles includ-ing organic matter. These ions may also react with constituents in solution such as hydroxides, car-bonates, phosphates, sulfides, or organic matter to form complex gelatinous precipitates of colloidal dimensions that are termed “microflocs.” This is the first stage of coagulation, and for greatest effi-ciency a rapid and intimate mixing is necessary before a second reaction takes place. 2. After the positively charged ions have neutralized a large part of the colloidal particles and the zeta potential has been reduced, the resulting flocs are still too small to be seen or to settle by gravity. The treatment, therefore, should be flocculation, slow stirring so that very small flocs may agglomerate and grow in size until they are in proper condition for sedimentation. Some evidence suggests that aggregation of microflocs with dispersed waste con-stituents is the most important mechanism affecting coagulation in water treatment (Riddick, 1961). 3. During the third phase, surface adsorption of parti-cles takes place on the large surface area provided by the floc particles. Some of the bacteria present will also become entangled in the floc and carried to the bottom of the tank.Electrocoagulation Electrocoagulation is a process in which the coagulating ions are produced by electrolytic oxidation of sacrificial electrodes. This technique has been successfully used in the removal of metals, suspended particles, colloids, organic dyes, and oils. An interesting review of this technique is presented by Mollah et al. (2001). In it the advantages and disadvantages of electrocoagulation are presented as well as a description and comparison with chemical coagulation. His group studied its use in the treatment of a synthetic-dye solu-tion with a removal of 99% under optimal conditions (Mollah, Morkovsky, et al., 2004). Another publication (Mollah, Pathak, et al., 2004) presents the fundamentals of electrocoagulation and the outlook for the use of this process in wastewater treat-ment. Lai and Lin (2003) studied the use of electrocoagulation for the treatment of chemical mechanical polishing wastewater, obtaining a 99% copper removal and 96.5% turbidity reduction in less than 100 minutes.C016_005_r03.indd 976 11/22/2005 11:25:16 AM

977Sedimentation Sedimentation basins are important compo-nents in water- and wastewater-treatment systems, and their performance greatly depends upon proper design. In chemical treatment of wastewater, the separation of chemically coagu-lated floc depends on the characteristics of the floc in addition to the factors normally considered in the design of conven-tional primary and secondary clarifiers. Field experience indi-cates that the usual values for surface overflow rates used in separating chemical floc in water-treatment plants must be reduced in order to obtain a good efficiency in the removal of floc from chemically coagulated wastewater (Weber et al., 1970; Convery, 1968; Rose, 1968; Kalinske and Shell, 1968). In wastewater-treatment practices, the recommended overflow rate for removal of alum floc is 30 m/day, while with use of lime or iron salts, it can be increased up to 40 m/day.FiltrationFiltration of wastewater can be accomplished by the use of (1) microscreens, (2) diatomaceous earth filters, (3) sand fil-ters, (4) mixed media filters, or (5) membranes. The filtration of sludges, on the other hand, is achieved by sand beds or vacuum filters.The filtration characteristics of the solids found in a bio-logical treatment plant effluent are greatly different from those of the floc formed during chemical coagulation for the removal of organic matter and phosphates. Tchobanoglous and Eliassen (1970) have noted that the strength of the bio-logical floc is much greater than that of the flocs resulting from chemical coagulation.Accordingly, biological flocs can be removed with a coarser filter medium at higher filtration rates than can the weaker chemical flocs, which may shear and penetrate through the filter more readily. Lynam et al. (1969) had observed that the chemical floc strength can be controlled, to some degree, with the use of polymers as coagulant aids. Their experi-ments yielded higher SS removal by filtration when 1 mg/l of anionic polymer A-21 was used along with alum.The filterability of solids in a conventional biological plant effluent is dependent upon the degree of flocculation achieved in the biological process. For example, filtration of the effluent from a trickling-filter plant normally cannot yield more than 50% removal of the SS due to the poor degree of biological flocculation in trickling filters. On the other hand, the activated sludge process is capable of a much higher degree of biological flocculation than the trickling-filter pro-cess. The degree of biological flocculation achieved in an activated sludge plant was found to be directly proportional to the aeration time and inversely proportional to the ratio of the amount of organic material added per day to the amount of SS present in the aeration chamber (Culp and Hansen, 1967a). It has also been reported that up to 98% of the SS found in the effluent from a domestic sewage-treatment plant after a 24-hour aeration time could be removed by filtration without the use of coagulants (Culp and Hansen, 1967b).Microscreening Microscreens are mechanical filters in which flow is passed through a special metallic filter fabric placed around a drum. The filter traps the solids and rotates with the drum to bring the fabric under backwash water sprays fitted to the top of the machine, in order to wash the solids to a hopper for gravity removal to disposal. The rate of flow through the microscreen is determined by the applied head, normally limited to about 150 mm or less, and the concentration and nature of the SS in the effluent.Extensive tests at the Chicago Sanitary District showed that microscreens with a 23 µm aperture could reduce the SS and BOD of a good-quality activated sludge effluent, 20–35 mg/l SS and 15–20 mg/l BOD, to 6–8 mg/l and 3.5–5 mg/l, respectively (Lynam et al., 1969). It was noted that the microscreens were more responsive to SS loading than to hydraulic loading and that the maximum capacity of the microscreens was reached at the loading of 4.3 kg/m2/day at 0.27 m/min.Diatomaceous Earth Filtration Diatomite filters found their widest application in the production of potable waters, where the raw water supply was already of a relatively good quality, i.e., of low turbidity. Operating characteristics of diatomite filters can now be predicted under a wide range of operat-ing conditions by utilizing several mathematical models (Dillingham et al., 1966, 1967). Several investigators have studied the filtration of secondary effluent by diatomite filters whose ability to produce an excellent-quality effluent is well established (Shatto, 1960; R. Eliassen and Bennett, 1967; Baumann and Oulman, 1970). However, the extremely high cost and their inability to tolerate significant variations in SS concentration limit the usage of diatomite filters in sewage-treatment practices.Sand Filtration Sand filters have been operated as slow sand filters or as rapid sand filters made with one or more media. A slow sand filter consists of a 150- to 400-mm-thick layer of 0.4-mm sand supported on a layer of a coarser mate-rial of approximately the same thickness. The underdrainage system under the coarser material collects the filtrate. The rate of flow through the filter is controlled at about 3 m/day. This rate is continued until the head loss through the bed becomes excessive. Then the filter is thrown out of service and allowed to partially dry, and 25 to 50 mm of the sand layer, which includes the surface layer of sludge, is manually scraped from the top for washing. Disadvantages of slow sand filtration system are: (1) the filters may become inoper-ative during the cold winter weather, unless properly housed; (2) slow sand filters may not be effective due to the rapid clogging of filters (the normal frequency of cleaning filters varies from once to twice a month; Truesdale and Birkbeck, 1996); (3) the cost of slow sand filtration is three times the cost of rapid sand filters and twice the cost of microscreens (anonymous, 1967); and (4) the large space requirement.Rapid sand filters consist of about a 400-mm-thick layer of 0.5- to 0.65-mm sand supported on coarser gravel. The rate of filtration ranges between 80 and 120 mm/min. At this high filtration rate, the filter beds need backwashing when the head loss becomes excessive.C016_005_r03.indd 977 11/22/2005 11:25:17 AM
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Lynam et al. (1969) reported results of detailed tests con-ducted on filtration of secondary effluent from an activated sludge plant of the Chicago Sanitary District. They used a filter bed of 0.85-mm-effective-size sand in a 280-mm depth and a filtration rate of 120 mm/min, and analyzed the data in terms of both hydraulic and SS loadings. Poor correlations were obtained between effluent quality and hydraulic load-ing, effluent quality and solids loading, and solid removal and hydraulic loading. However, an excellent correlation existed between SS loading and SS removals. It was also observed that the sand filtration of alum-coagulated solids was no better than that of uncoagulated solids, and the opti-mum SS removal was obtained by alum and polymer coagu-lation in combination with sand filtration.A review of the retention of pathogenic bacteria in porous media is presented by Stevik et al. (2004). The review includes the factor affecting bacteria retention and the factors that effect elimination of bacteria from porous media. The authors also suggest priority areas of research in this field.Multimedia Filtration The limitation of the single medium rapid sand filter follows from its behavior as a surface filtra-tion device. During filter backwashing, the sand is graded hydraulically, with the finest particles rising to the top of the bed. As a result, most of the material removed by the filter is retained at or very near the surface of the bed. When the secondary effluent contains relatively high solids concen-trations, the head loss increases very rapidly, and SS clog the surface in only a few minutes. One approach to increase the effective filter depth is to use dual-media beds consisting of a discrete layer of coarse coal placed above a layer of fine sand.More recently, the concept of mixed-media filters has been introduced in order to achieve a filter performance that very closely approaches an ideal one. In this case a third layer of a very heavy and fine material, garnet (with specific gravity of 4.2) or illmenite (with specific gravity of 4.5), is placed beneath the coal and sand. Conley and Hsiung (1965) have suggested the optimum design values for these filters. The selection of media for any filtration application should be based on the floc characteristics. An example of a typical dual-media filter is shown in Figure 2.Moving-Bed Filters These types of filters were put on the market by the Johns-Manville Corporation in the late 1960s. It is a continuous sand filter in which influent wastewater passes through the bed and becomes product water. Solids trapped on the filter face and within the bed move with the filter media, countercurrent to the liquid. Solids and small amounts of filter media regularly removed from the filter face are educted to the filter media tower without stopping operations. Solids are scrubbed from the media and dis-charged as a waste sludge, while the washed media is fed back into the bed.The filter medium usually used is 0.6- to 0.8-mm sand with a maximum sand-feed rate of 5 mm/min and maxi-mum filtration rate of 85 m/day (2100 U.S. gal/day/ft2). The advantages claimed for this system are (1) automatic and continuous operation, (2) that the filter allows much higher and variable solids loadings than is permissible with a sand bed, and (3) that through an efficient use of coagulant chemi-cals, the system has the flexibility to reduce turbidity, phos-phorus, SS, and BOD to the desired level (Johns-Manville Corporation, 1972).Membrane Filtration Membrane filtration is being applied more extensively as membrane materials are becoming more resistant and affordable. Fane (1996) presents a description of membrane technology and its possible applications in water and wastewater treatment. An extensive study on microfiltra-tion performance of membranes with constant flux for the treatment of secondary effluent was published by his research group in 2001 (Parameshwaran et al., 2001). Kentish and Stevens (2001) present a review of technologies for the recy-cling and reuse of valuable chemicals from wastewater, par-ticularly from solvent-extraction processes.A feasibility study on the use of a physico-chemical treatment that includes nanofiltration for water reuse from printing, dyeing, and finishing textile industries was per-formed by Bes-Pia et al. (2003). In this work jar tests were conducted for flocculation using commercial polymers fol-lowed by nanofiltration. Their results show that the combina-tion reduces COD from 700 to 100 mg/l. Another treatment approach by the same authors (2004) uses ozonation as a pretreatment for a biological reactor with nanofiltration as a final step. A combined approach is presented by Wyffels et al. (2003). In this case a membrane-assisted bioreactor for the treatment of ammonium-rich wastewater was used, showing this to be a reliable technology for these effluents.Galambos et al. (2004) studied the use of nanofiltration and reverse osmosis for the treatment of two different waste-waters. For their particular case the use of reverse osmosis was more convenient due to the high quality of the effluent, but the permeate of the nanofiltration can only be released into a sewer line or would have to be treated, resulting in an eco-nomic compromise. A comparison between a membrane bio-reactor and hybrid conventional wastewater-treatment systems at the pilot-plant level is presented by Yoon et al. (2004).The removal of volatile organic compounds (VOCs) using a stripper-membrane system was studied by Roizard et al. (2004). Their results show that this hybrid system can be used for the removal of toluene or chloromethane with a global efficiency of about 85%.Vildiz et al. (2005) investigated the use of a coupled jet loop reactor and a membrane for the treatment of high-organic-matter-content wastewater. The main function of the membrane is the filtration of the effluent and the recycle of the biomass to the reactor. One advantage of the system is its reduced size as compared with traditional treatment systems, as well as a better-quality effluent.A comprehensive review on the use of nanofiltration membranes in water and wastewater use, fouling of these membranes, mechanisms of separation, modeling, and the use of atomic force microscopy for the study of surface mor-phology is presented by Hilal et al. (2004). The future of C016_005_r03.indd 978 11/22/2005 11:25:17 AM

979membranes and membrane reactors in green technology and water reuse was published by Howell (2004). In it, water problems in different regions of the world are discussed, different membrane systems are presented, and different approaches for new research are introduced.Reverse Osmosis There are several reverse-osmosis units cur-rently in use to produce freshwater from seawater. With recent improvements in membranes, this process is also being used for purification of wastewater. Substantial removal of BOD, COD, total dissolved solids, phosphate, and ammonia by this process has been reported (Robinson and Maltson, 1967).In a reverse-osmosis process, wastewater containing dis-solved materials is placed in contact with a suitable semi-permeable membrane in one of the two compartments of the tank. The pressure on this compartment is increased to exceed the osmotic pressure for that particular waste in order to cause the water to penetrate the membrane, carrying with it only a small amount of dissolved materials. Therefore, the dissolved material in the wastewater gets concentrated con-tinuously, while highly purified water collects in the other compartment.The performance of the reverse-osmosis process depends mainly on (1) the membrane semipermeability or its effi-ciency to separate dissolved material from the wastewater, and (2) the membrane permeability or the total amount of water that can be produced with appropriate efficiency for the removal of dissolved materials. It has been reported that the conventional cellulose-acetate membranes give adequate separation efficiency, but the flow rate of water is too small to be of practical interest. However, cellulose-acetate mem-branes allow a much higher flow rate of product water, at the same separation efficiency, which makes it applicable in wastewater-treatment practices (Goff and Gloyne, 1970).The operating pressure, as well as the rejection perfor-mance of the membrane, is dependent on the membrane porosity. Rejection performances of three graded mem-branes with secondary sewage effluent were investigated by Bray et al. (1969).Merten et al. (1968) evaluated the performance of an 18.9 m3/day pilot reverse-osmosis unit in removing small amounts of organic material found in the effluent of carbon columns treating secondary effluent. With a feed pressure of 2760 kPa and water recovery of 80 to 85%, 84% removal of COD present in the carbon column effluent, averaging 10.8 mg/l, was achieved. Problems of clogging have occurred when operating with waters containing high concentrations of bicarbonate, and as such, adjustment of pH to prevent calcium-carbonate precipitation is normally required.Sadr Ghayeni et al. (1996) discuss issues such as flux control and transmission in microfiltration membranes and biofouling in reverse-osmosis membranes in their use for the reclamation of secondary effluents. The process used for the study consisted of a microfiltration membrane fol-lowed by a reverse-osmosis membrane. The performance of this combined system was evaluated by Sadr Ghayeni et al. (1998b), as was the study of the adhesion of bacteria to reverse-osmosis membranes (1998a).EffluentTransfer pipeStoragecompartmentFiltercompartmentCollectionchamberAirUnderdrain nozzlesRecycleBackwashEqualization tankDrainSumpCoalSandFilterbackwashPolymerThree-wayvalveWater levelAlumInfluentFilterBackwashFIGURE 2 Typical dual-media filter (From Eckenfelder, 2000. Reprinted with permission from McGraw-Hill.)C016_005_r03.indd 979 11/22/2005 11:25:18 AM
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A study on the processing of composite industrial effluent by reverse osmosis was published by Sridhar et al. in 2003. The effluent used in the study was from combined bulk drug and pharmaceutical companies, obtaining a removal of 88% of dissolved solids, COD, and BOD, with reasonable water recovery. They also present a comparison between aerobic and reverse-osmosis treatment for this effluent.A physical-chemical process for the treatment of chemi-cal mechanical polishing process wastewater is presented by Lin and Yang (2004). In it the authors used chemical coagula-tion using different coagulants followed by reverse osmosis, obtaining water capable of being reused in the process due to its characteristics.Electrodialysis Electrodialysis involves the removal of inorganic ions from water by creating an electrical potential across two electrodes dipped in water. One of the two strips serves as a cathode and the other as an anode. The treatments that can be achieved by electrodialysis include: 1. Removal of inorganic ions: Under the effect of applied potential, cations and anions migrate to the cathode and anode, respectively. By alternat-ing membranes, a series of concentrating and diluting compartments can be created. For a long run and better efficiency, it is essential that turbid-ity, SS, colloids, and trace organics are removed from the wastewater before it enters the electrodi-alysis unit. 2. Effective bacteria reduction in wastewater: Most of the municipal wastewaters contain a high con-centration of chloride ions. Oxidation of chloride at the anode produces chlorine, hypochlorite, or chloramines, depending on the nature of the wastewater. Chlorine in these forms is a good dis-infectant and also provides an effective means of reducing soluble BOD.In order to reduce the operating cost of the electrodialysis pro-cess, the eroding anodes made of aluminum or iron are now being replaced by nonconsumable noble anodes, which appear to have more potential in wastewater treatment (Culp and Culp, 1971). The cost of disinfection by electrodialysis is reported to be 0.053 $/m3 of wastewater as compared to 0.095 $/m3 for the conventional chlorination (unpublished proposal, 1970). However, some other sources have reported that the cost of electrolytic treatment of wastewater was too high for the removal of a large percentage of secondary effluent COD.Grimm et al. (1998) present a review of electro-assisted methods for water purification, including electrodialysis. Fukumoto and Haga (2004) applied this technique for the treatment of swine wastewater with removal rates for NO3− and PO4−3 ions of 99% and an average color reduction of 58%.Gas StrippingIn domestic wastewaters, most of the nitrogen that gets converted to ammonia during biological degradation is present either as ammonia or in organic form. When the carbon concentration in wastewater becomes low and the nitrifying bacteria are populous, this ammonia can be oxi-dized by bacteria to nitrites and nitrates in the presence of dissolved oxygen. The stripping process can be employed either before or after secondary treatment for removing high levels of nitrogen that is present as ammonia. If it is to be used as pretreatment prior to a biological system, enough nitrogen, N:BOD  5:150, must be left in the efflu-ent to satisfy the nutritional requirement (Eckenfelder and Barnhart, 1963).In wastewater, ammonium ions exist in equilibrium with ammonia and hydrogen ions: NH4 ↔ NH3 ↑  H (10)At pH levels of 6 to 8, ammonia nitrogen is mostly present in the ionized form NH4. Increasing the pH to above 10 changes all the nitrogen to ammonia gas, which is remov-able by agitation. The stripping of ammonia from wastewater is carried out with air. In this operation, wastewater is agi-tated vigorously in a forced-draft countercurrent air-stripping tower when the ammonia is driven out from the solution and leaves with the air exhausted from the tower. The efficiency of ammonia removal in the stripping process depends upon the pH, airflow rate, tower depth, and hydraulic loading to the tower.Slechta and Culp (1967) have shown experimentally that the efficiency of the ammonia-stripping process is dependent on the pH of the wastewater for pH values up to 10.8. However, no significant increase in ammonia removals was achieved by elevating the pH above 10. Kuhn (1956) had come to the same conclusion. It has also been reported that the efficiency of the ammonia-stripping process depends on maximizing the air–water contact within the stripping tower. Higher ammo-nia removals and lower air requirements were obtained with a 40  50-mm packing than with a 100  100-mm packing. Increased tower depth, which provides additional air–water contact, results in greater ammonia removals and lower air requirements. Ammonia removals of 90%, 95%, and 98% were obtained at airflow rates of 1875, 3000, and 6000 m3 per cubic meter of wastewater, respectively.Gas stripping is also used for removal of H2S and VOCs from wastewater.Ion ExchangeThe ion-exchange process has been adopted successfully in wastewater-treatment practice for removing most of the inorganic dissolved salts. However, the cost of this method for wastewater treatment cannot be justified unless the efflu-ent water is required for multiple industrial municipal reuse. One of the major applications of this technique is the treat-ment of plating-industry wastewater, where the recovery of chrome and the reuse of water make it an attractive choice (Eckenfelder, 2000).Gaffney et al. (1970) have reported that the modified DESAL process, developed for treating acid mine drainage C016_005_r03.indd 980 11/22/2005 11:25:18 AM

981waters, can be applied successfully to the treatment of sec-ondary sewage effluent. This process consists of passing secondary sewage-plant effluent upflow through an ion-exchange unit filled with a weak base anion exchange resin, Amberlite IRA-68, operated on a bicarbonate cycle. The effluent with a pH of 6.0 is then treated with a small quan-tity of bentonite and cationic flocculant, Prima floc C-7, fol-lowed first by aeration to drive out carbon dioxide, and then lime softening in proportion to its hardness concentration. A dosage of 30 mg/l of bentonite, 3 to 5 mg/l of polyelec-trolyte, and normal lime levels are required. The effluent that is partially desalinated and essentially free of nitrates, phosphates, chlorides, alkyl benzene sulfonate (ABS), and COD can be produced. If the salinity is too high, it may be reduced further by passing a portion of the effluent through a weak acid cation, Amberlite IRC-84. It has been observed that IRA-68 can remove much of the organic contents and COD, thereby eliminating or markedly reducing the need for carbon treatment.Slechta and Culp (1967) tested a cationic resin, Duolite C-25, for the removal of ammonia nitrogen from the carbon column effluent that was containing ammonia nitrogen in the range of 18 to 28 mg/l as nitrogen. A 100-mm-diameter Plexiglas cylinder filled to a depth of 700 mm with the resin served as the pilot ion-exchange column. The rate of appli-cation of influent waste to the ion-exchange column was 0.4 m3/min per cubic meter of resin. Following breakthrough of the ammonia nitrogen to 1 mg/l, the bed was backwashed and the resin was regenerated. On the average, about 400 bed volumes of carbon column effluent had been passed through the ion-exchange resin prior to a breakthrough to 1 mg/l ammonia nitrogen. However, considering the operating and capital costs, they concluded that the ammonia-stripping process was more efficient.Nitrate nitrogen, present in the effluent from the acti-vated sludge process, has been removed by anion exchange regenerated with brine by R. Eliassen and Bennett (1967). This ion-exchange process also removes phosphates and some other ions; however, pretreatment by filtration is essential. The resin is restored by treatment with acid and methanol.The removal of heavy metals with Mexican clinoptilo-lite was studied by Vaca Mier et al. (2001). In this study the interactions of lead, cadmium, and chromium competed for the ion-exchange sites in the zeolite. The authors also stud-ied the influence of such factors as the presence of phenol and the pH of the solution to be treated.AdsorptionApplication of adsorption on granular active carbon, in columns of counterflow fluidized beds, for the removal of traces or organic pollutants, detergents, pesticides, and other substances in wastewater that are resistant to biological deg-radation has become firmly established as a practical, reliable, and economical treatment (Slechta and Culp, 1967; Weber, 1967; Parkhurst et al., 1967; Stevens and Peters, 1966; Presecan et al., 1972).Adsorption can also be accomplished with powdered carbon (Davies and Kaplan, 1964; Beebe and Stevens, 1967), which is mixed in wastewater, flocculated, and ultimately settled. However, there are certain problems associated with the use of powdered carbon. These are: (1) that large quanti-ties of activated carbon are needed in wastewater treatment, because it is used only on a once-through basis, and han-dling of such large quantities of carbon also creates a dust problem, and (2) problems in disposal of precipitated carbon unless it is incinerated along with the sewage sludge.Carbon-Adsorption Theory Less polar molecules, includ-ing soluble organic pollutants, are removed by adsorption on a large surface area provided by the activated carbon. Smaller carbon particles enhance the rate of pollutant removal by providing more total surface area for adsorption, partial deposition of colloidal pollutants, and filtration of larger particles. However, it is almost always necessary to remove finely divided suspended matter from wastewater by pretreatment prior to its application on a carbon bed.Depending on the direction of flow, the granular carbon beds are either of the downflow-bed type or upflow-bed type. Downflow carbon beds provide the removal of suspended and flocculated materials by filtration beside the absorption of organic pollutants. As the wastewater passes through the bed, the carbon nearest the feed point eventually becomes sat-urated and must be replaced with fresh or reactivated carbon. A countercurrent flow using multiple columns in series is considered more efficient. The first column is replaced when exhausted, and the direction of flow is changed to make that column the last in the series. Full countercurrent operation can best be obtained in upflow beds (Culp and Culp, 1971).Upflow carbon columns for full countercurrent opera-tions may be either of the packed-bed type or expanded-bed type. Packed beds are well suited to treatment of wastes that contain little or no SS, i.e., turbidity less than 2.5 JTU. However, the SS invariably present in municipal and indus-trial wastewaters lead to progressive clogging of the carbon beds. Therefore, expanded-bed upflow columns have certain potential advantages in operation of packed-bed adsorbers for treating wastes that contain SS. In expanded-bed-type adsorbers, water must be passed with a velocity sufficient to expand the bed by about 10%, so that the bed will be self-cleaned.Experiments conducted by Weber et al. (1970) have shown that expanded-bed and packed-bed adsorption sys-tems have nearly the same efficiency with regard to the removal of soluble organic materials from trickling-filter effluent, under otherwise similar conditions. The packed-bed system was found to be more effective for removal of SS, but the clogging that resulted from these solids required higher pumping pressure and more frequent cleaning of the carbon beds. Because of the time elapsed in cleaning, the expanded-bed production was about 9% more than the packed-bed production.The Lake Tahoe Water Reclamation Facilities, described by Slechta and Culp (1967), included pretreatment of second-ary effluent by chemical clarification and filtration, thereby C016_005_r03.indd 981 11/22/2005 11:25:19 AM
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providing a highly clarified feed and permitting an extended operation of carbon beds. Carbon beds were of the upflow full-countercurrent columns and were usually operated as packed types since the turbidity of the applied water was always less than 0.3 JTU. The columns were also operated at times as expanded beds by drawing 10% of the carbon.The efficiency of carbon bed treatment depends on: 1. Contact time between the carbon and the wastewater 2. The pH of the wastewater (below pH of 9.0, the rate of adsorption of organics in wastewater increases with decreasing pH) 3. Temperature of the wastewater 4. Quality of the influent.Carbon-Bed Design The following are the important design parameters used in the design of activated-carbon beds: 1. Properties of filtering material: The two most common sizes of granular carbon normally used for wastewater treatment are 8  30 mesh and 12  14 mesh; 8  30 mesh carbon is preferable, although its surface area is less, because it reduces losses during regeneration, head loss is less, and the operation of the filter becomes easier. Culp and Culp (1971) have reported the desirable physical properties for granular activated carbon for use in wastewater treatment. 2. Depth of carbon bed: 3 to 10 m. 3. Flow rates: 140 to 700 m3/min per square meter of column cross-sectional area. For optimum per-formance of the bed, the actual depth and rate of flow should be determined by a dynamic pilot-plant test in the laboratory. 4. Activated carbon contact time: 15 to 35 mm, depending on the objective of treatment and the impurities to be removed from the wastewater.A diagram of a carbon-gas-adsorption process is presented in Figure 3.In the 1970s, over 30 granular activated-carbon plants were designed in the United States for use at municipal wastewater-treatment plants (DeJohn and Edwards, 1981). Thirteen of the plants are classed as physical-chemical and 15 as tertiary treatment plants, and 4 use carbon to dechlori-nate. According to the authors, there have been some prob-lems encountered at certain physical-chemical and tertiary treatment plants, but in their opinion, granular activated carbon is a viable treatment alternative when applied under proper conditions (Grieves et al., 1964).One of the changes in conventional treatment technology is the use of the PACT (Powdered Activated Carbon Treatment) process using powdered carbon in the aeration tank of an activated sludge system (Meidl, 1981). The development Backwash effluentreturnBackwasheffluentsumpColumn1Column2Column3Column4From storagereservoirRaw waterfeed pumpVirgincarbonmakeupSlurrymixingtankRegeneratedcarbonreturnRegeneratedcarbonstorageUtilitywaterHigh-pressurewaterEductorQuenchtankSpentcarbontankEductorHigh-pressurewaterWetscrubberMultiple-hearthregen-erationfurnaceEductorHigh-pressurewaterUtilitywaterFinal effluentEffluentretentionsumpBack-washsumpBackwashpumpFIGURE 3 Carbon-adsorption process diagram (From Eckenfelder, 2000. Reprinted with permission from McGraw-Hill.)C016_005_r03.indd 982 11/22/2005 11:25:19 AM

983of PACT in municipal wastewater treatment resulted from the inability of the physical-chemical treatment process to adequately treat wastewater. This process has been used successfully to treat domestic wastewater from a residential population of 30,000 in Vernon, Connecticut, and many other plants have been under construction. Similar applications of combined powdered-carbon and activated-sludge treatment to various industrial wastewaters, particularly coal-gasification wastewaters, are shown to be successful.Miyake et al. (2003) studied the adsorption equilib-rium isotherms of trichloroethylene (TCE) vapor stripped from TCE-polluted waters. These results can be used for wastewater treatment of waters with the same pollutant. A combined Al(III) coagulation/carbon adsorption process for the treatment of reactive dyes in synthetic wastewater was proposed by Papic et al. (2004). This process achieved 99.9% reduction of the dyes in the wastewater as well as 95.7 and 91.3% COD reduction for the two waters used. They conclude that the proposed process has many advan-tages, such as high efficiency, low use of coagulant, mini-mal sludge production, and high-quality product water with reuse potential.Adsorption of Pollutants on Biomaterials A review of potentially low-cost adsorbents for heavy metals was pre-sented by Bailey et al. (1999). Minamisawa et al. (2004) investigated the adsorption of cadmium and lead ions on different biomaterials, concluding that this is a promising alternative for the removal of these ions. Another review was published in 2004 by Gardea-Torresdey et al., concluding that Cd, Cu, Ni, Cr, and other ions have been successfully removed from solutions using different biomaterials. Gong et al. (2005) studied the use of peanut hull as a biosorbent for the removal of anionic dyes in a solution, obtaining sorp-tion capacities of between 13.99 and 15.60 mg per gram of biosorbent for three different dyes.FlotationSurface-active contaminants, if present in wastewater, will produce foam upon aeration. This foam rises to the surface of the wastewater and can be separated and concentrated. Moreover, as the foam generates and rises, certain sus-pended impurities also get removed by entrainment. Thus, the foam-separation process can be developed to provide a selective removal of soluble and colloidal pollutants in vari-ous concentrations from water or wastewater. The process may either utilize the surface-active impurities present in the wastewater or may require the addition of a specific surface-active agent prior to aeration; soluble or colloidal impurities of interest may be precipitated to improve their removal.Factors affecting the efficiency of the process of foam separation are: 1. Airflow rate/surface-active agent or airflow-rate-to-waste-flow-rate ratio (the removal efficiency increases when increasing the airflow rate, but yields wetter foam) 2. Air-bubble size (fine-bubble aeration improves the efficiency of foam separation, whereas coarse bubbles or deck aeration are not efficient) 3. Nature and concentration of surface-active agents 4. Foam stability 5. pH of the wastewater 6. Detention period (a short aeration time, 5 minutes or so, is considered sufficient) 7. Surface-to-volume ratio (a large surface-to-volume area is conducive to higher efficiency)The process of foam separation has been used successfully in a number of waste-treatment applications. These include (1) removal of surface-active materials such as ABS from sec-ondary effluent sewage (Klein and McGauhey, 1963; Grieves et al., 1964; Brunner and Lemlich, 1963; Fldib, 1963); (2) removal of radioactive ions from dilute aqueous solutions by the addition of anionic surface agents (Schoen and Mazella, 1961; Schoen et al., 1962; Schnepf et al., 1959); (3) removal of specific surfactants from refining and petrochemical waste-waters (Grieves and Wood, 1963); (4) foam fractionation of phenol (phenolate) from aqueous solutions using a cationic surfactant, ethyl hexadecyl dimethylammonium bromide, as the foaming agent (Grieves and Aronica, 1966); (5) the treat-ment of cyanide and acid chromate wastes (cyanide is precipi-tated with ferrous ions, and the ferrocyanide precipitates are floated with a cationic surfactant in a pH range of 5 to 7; acid chromate is reduced and precipitated as Cr(OH)3, and these precipitates are floated with an anionic surfactant [Grieves, 1972]); (6) the treatment of liquid wastes from the scrubbing of phosphate and fluoride from air-pollution emissions of the phosphoric-acid-manufacturing industry (these include pre-cipitation by lanthanum (III), followed by flotation with an anionic surfactant [Grieves, 1972]); (7) clarification of turbid raw water supplies by microflotation-activated carbon process (Grieves, 1972); and (8) physical separation of SS and coag-ulated dissolved organic impurities from wastewaters. ABS serves as activator for bubble attachment in flotation treatment of sewage (Klein and McGauhey, 1963). Other applications include the treatment of mine-drainage wastes combined with secondary sewage effluents and removal of H2S from sour wastes.An overview on flotation in wastewater treatment was published by Rubio et al. in 2002. The authors explain the process, present conventional and emerging flotation tech-niques and processes, and discuss the applications of the technique to different compounds. An example of a dissolved air flotation (DAF) process is presented in Figure 4.Chemical ProcessesAn extensive review on catalytic abatement of water pol-lutants was published by Matatov-Meytal and Sheintuch in 1998. In it they present the oxidation and reduction pro-cesses involved as well as a discussion on catalyst support and deactivation. A discussion on the use of iron for waste-water treatment was published by Waite (2002). This article presents the research challenges and the new possibilities in C016_005_r03.indd 983 11/22/2005 11:25:20 AM
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this area. A review on the use of ferrate (VI) salt as a coagu-lant and oxidant for water and wastewater treatment is pre-sented by Jiang and Lloyd (2002). In this paper the authors demonstrate the advantages of this approach in the treatment of microorganisms, heavy metals, and SS, as well as present the difficulties associated with this technique.Ghoreishi and Haghighi (2003) propose a combined bisulfite catalyzed sodium borohydride reduction followed by activated sludge for the treatment of nonbiodegradable textile effluent, reposting reductions of BOD, COD, and TSS of 74–88%, 76–83%, and 92–97% respectively. Lin and Wang (2004) investigated the performance of a proposed granulated activated carbon bed combined with ozonation and preceded by chemical coagulation, obtaining interest-ing results. Akcil (2003) discusses the advantages of using biological methods for the treatment of cyanide in gold-mill effluents as compared to well-established chemical meth-ods. Chung et al. (2003) evaluated the performance of a combined chemical absorption–biological oxidation system for the removal of H2S from gaseous streams such as those produced by livestock wastewater-treatment plants. They demonstrated the potential of this technique and obtained reductions on the order of 85%. Another combined approach is presented by Libra and Sosath (2003). In this case they used ozonation followed by a biological process for the treat-ment of textile wastewater, comparing two configurations of treatment processes, concluding that the most attractive alternative is the simplest: ozonation followed by aerobic treatment as compared to anaerobic, aerobic, ozonation, and aerobic treatments for their effluent and conditions.A comprehensive review on the properties of alumina, the chemical reactions involved in its use in water treatment, and adsorption and catalysis using alumina was published by Kasprzyk-Hordern in 2004. An interesting review on the enhancement of biodegradability of industrial wastes by chemical-oxidation pretreatment is presented by Mantzavinos and Psillakis in 2004. This exhaustive review includes many different pollutants, trends, and process schemes used as segregation by effluent type; evaluation of the pretreatment steps; and modeling of the individual steps involved.Aiyuk et al. (2004) propose a chemically enhanced pri-mary treatment followed by a UASB reactor for the treatment of domestic wastewater. The chemical pretreatment consisted of the addition of FeCl3 or Al2(SO4)3 and polymers in a mixing tank, and a posttreatment of the biologically treated water was achieved by zeolite adsorption for NH4 removal. Another combined solution was proposed by Bressan et al. in 2004. This approach includes the use of an enhanced Fenton process followed by biological treatment of olive-mill wastewater.Oxidative, Photochemical, and Electron-Beam ProcessesOxidizing agents like chlorine, ozone, hydrogen peroxide, potassium permanganate, and ultraviolet irradiation have been used successfully in oxidizing and stabilizing certain impu-rities like hydrogen sulfide, phenol, cyanide, and selected refractory organic substances. The reaction of chlorine with certain organic matter present in wastewater to form a more harmful persistent chemical has raised a serious question of continuing the use of chlorine for disinfection of waste-water effluents. Ozone is gradually becoming more popular, because it has strong oxidizing and disinfecting capacity and leaves no harmful residuals. It has been shown that ozone in combination with photochemical oxidation economically removed inorganic, organic, and toxic refractory species and effectively destroyed phenol in a bubble column or a stirred cell (Wall, 1980; Otake, 1979). Ganes and Staubach (1980) have reported the kinetics of the reaction between ozone and nitrilotriacetate in water and the effects of pH, metal content, and natural organics on the rate and extent of degradation.In 1993, Legrini et al. published an extensive review on photochemical processes for water treatment, including UV, H2O2/UV, ozone/UV, O3/H2O2/UV, TiO2/UV, vacuum UV, photochemical electron-transfer processes, and energy- transfer processes. In 1999, Andreozzi et al. published studies on the use of O3/UV and O3/H2O2 for the treatment of mineral-oil-polluted wastewaters, performing different experiments and achieving an 80 to 90% reduction of COD for the O3/UV treatment (Andreozzi et al., 1999). A discussion of the different advanced oxidation processes (AOP), as well as experimental apparatus and working procedures for the study of the applica-tion of this technique, is presented in Andreozzi et al. (2000).An extensive review on photocatalytic degradation was presented by Bhatkhande et al. (2001). In it they include a description of the process, the mechanisms implied, the compounds that can be degraded with it, and the variables that can affect this technique. Another review was pub-lished by Kabra et al (2004), concluding that this process can be used to treat industrial wastewater for the removal of metal ions and nonbiodegradable organics. Another con-clusion is that the costs of this method are slightly higher than for conventional methods, but that future research can make a competitive option. An interesting article on the evaluation of the use of peracetic acid for the disinfection of the effluent of Montreal’s wastewater-treatment plant was FIGURE 4 Conventional DAF unit with water recycle to the saturator (From Rubio et al., 2002, with permission from Elsevier).C016_005_r03.indd 984 11/22/2005 11:25:20 AM

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985published by Gehr et al. in 2003. In this study the authors presented and evaluated the different alternatives (with the exception of chlorine, due to environmental regulations) arriving at the conclusion that using the current process, the economically viable alternative is UV, while if some changes are made upstream, the use of peracetic acid could be a viable alternative.A study on the application of different AOPs to the treat-ment of textiles, Kraft bleaching, photoprocessing, and phar-maceutical wastewaters was published by Balcoglu et al. in 2003. They conclude that the efficiency of the AOP process used for a particular application depends upon the pretreat-ment used, and concentrations and types of pollutants present in the influent.Adesina (2004) investigated the use of photocatalysis for the treatment of spent industrial Bayer liquor and detox-ification of paper-mill effluents, among others. The use of sunlight as an energy source is also discussed. A compari-son of different AOPs and chemical-treatment options was conducted by Azbar et al. (2004) for the reduction of color and COD from an acetate- and polyester-dyeing process. They conclude that AOPs have better performances than chemical-coagulation methods for the parameters stud-ied. They also found that UV/H2O2 achieved 99% and 96% COD and color removal, respectively. Their choice from the economic point of view was the Fenton’s reagent process. The removal of the drug diclofenac by means of UV/H2O2 was studied by Vogna et al. (2004), showing that the proposed treatment was effective for the degradation of the drug. The behavior of the process Fe(III)/Air/UV was studied by Andreozzi and Marotta (2004) by using ben-zoic acid as the molecule to be treated, with the goal of developing kinetic models for this process. A study on the treatment of cork-processing wastewater was published by Acero et al. in 2004. They evaluated the use of different combinations of UV, H2O2, and O3 and Fenton’s reagent and photo-Fenton processes for the effluent under study and concluded that the best options that produce reusable water are those involving ozone.Broad reviews on oxidation technologies at ambient conditions and on hybrid methods for wastewater treatment were published by Gogate and Pandit (2004a, 2004b). Tabrizi and Mehrvar (2004) present an interesting article on the inte-gration of AOPs and biological processes, including recent developments, trends, and advances in this field. A review on the degradation of chlorophenols via AOP was published by Pera-Titus et al. in 2004. Among their conclusions is that although photocatalytic processes show higher half reaction times, they do not require oxidants or further separation of byproducts after the reaction.Ding et al. (1996) present a review of catalytic oxi-dation in supercritical water, including the reactions involved, the processes available, a comparison with sub-critical water oxidation, and an extensive review of the catalysts available. Kritzer and Dinjus (2001) published an interesting evaluation of the problems of supercritical water oxidation, with discussion and suggestions for its improvement.Ultrasound Ultrasound is being studied as an alternative solu-tion for environmental problems. This process works by gen-eration of highly reactive oxidizing species, such as hydroxyl, hydrogen, and hydroperoxyl radicals as well as hydrogen per-oxide by means of ultrasound waves (Vajnhandl and Majcen Le Marechal, 2005). In their review they include the use of ultrasound in the textile industry and its wastewaters.Electrochemical Oxidation Panizza and Cerisola (2004) published results on a series of experiments using an elec-trochemical cell for the treatment of synthetic-tannery wastewater using two different electrodes under various experimental conditions, concluding that electrochemical methods can be effectively applied for the final treatment of these effluents, achieving total COD, tannin, and ammo-nium removals.Electron-Beam Wastewater Treatment Water irradiation with ionizing radiation generates several very reactive ions and molecules. Getoff presents a review and the state of the art for radiation-induced degradation of water pollutants (1996). His group has studied the use of radiation for disin-fection and decomposition of pollutants in water and waste-water for years. Among the experimental factors proposed to affect the efficiency of this process in pollutant degradation are: form of radiation, energy, absorbed dose and dose rate, pollutant concentration, pH, temperature, effect of oxygen and ozone, presence of ozone and TiO2, and molecular struc-ture of the pollutants (2002).Pikaev et al. (2001) applied electron beams followed by coagulation for the treatment of mixed distillery and munici-pal wastewater; they conclude that the proposed scheme can treat the effluent at lower cost than the biological and sedi-mentation processes. In 2002 his group published pilot-plant experiments using electron-beam and biological oxidation for the treatment of dyeing wastewater. In this research they conclude that the proposed method reached the desired efflu-ent characteristics in about 8 hours of treatment, as compared to 17 hours for biological treatment alone (Pikaev, 2002). In collaboration with researchers from Korea, he also used electron beams combined with coagulation, flocculation, and biological processes for the treatment of paper-mill effluents. This research concluded with the design of a commercial plant for the treatment of 15,000 m3/day of wastewater with 80% of water reuse (Shin et al., 2002). In a final publication, Pikaev (2002) presents data on the treatment of different pollutants, including carboxylic acids, distillery slops, and petroleum products. In this work the author presents an eco-nomic evaluation of a commercial plant, concluding that the treatment costs for the proposed technology are about half of conventional methods.REFERENCESAcero, J.L., Javier Benitez, J. F., Heredia, J.B.D., and Leal, A.I. (2004). Chemi-cal treatment of cork-processing wastewaters for potential reuse. Journal of Chemical Technology and Biotechnology, 79(10), 1065–1072.Adesina, A.A. (2004). Industrial exploitation of photocatalysis: progress, per-spectives and prospects. Catalysis Surveys from Asia, 8(4), 265–273.C016_005_r03.indd 985 11/22/2005 11:25:21 AM
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Aiyuk, S., Amoako, J., Raskin, L., van Haandel, A., and Verstraete, W. (2004). Removal of carbon and nutrients from domestic wastewater using a low investment, integrated treatment concept. Water Research, 38(13), 3031–3042.Akcil, A. (2003). Destruction of cyanide in gold mill effluents: biological versus chemical treatments. Biotechnology Advances, 21(6), 501–511.Albertson, O.E. and Sherwood, R.J. (1967). Phosphate extraction process. Paper presented at the Water Pollution Control Federation meeting, Yakima, Washington, October.Andreozzi, R. and Marotta, R. (2004). Removal of benzoic acid in aque-ous solution by Fe(III) homogeneous photocatalysis. Water Research, 38(5), 1225–1236.Andreozzi, R., Caprio, V., Insola, A., and Marotta, R. (1999). Advanced oxidation processes (AOP) for water purification and recovery. Cataly-sis Today, 53(1), 51–59.Andreozzi, R., Caprio, V., Insola, A., Marotta, R., and Sanchirico, R. (2000). Advanced oxidation processes for the treatment of mineral oil-contaminated wastewaters. Water Research, 34(2), 620–628.Anonymous (1967). Renovation and reuse of wastewaters in Britain, published by Water Pollution Research Laboratory.Azbar, N., Yonar, T., and Kestioglu, K. (2004). Comparison of various advanced oxidation process and chemical treatment methods for COD and color removal from a polyester and acetate fiber dyeing effluent. Chemosphere, 55(1), 35–43.Babbit, H.E., Donald, J.J., and Cleasby, J.L. (1962). Water Supply Engi-neering. McGraw-Hill Book Company, New York.Bailey, S.E., Olin, T.J., Bricka, R.M., and Adrian, D.D. (1998). A review of potentially low-cost sorbents for heavy metals. Water Research, 33(11), 2469–2479.Balcoglu, I.A., Alaton, I.A., Ötker, M., Bahar, R., Bakar, N., and Ikiz, M. (2003). Application of advanced oxidation processes to different industrial wastewaters. Journal of Environmental Sciences and Health, Part A—Toxic/Hazardous Substances and Environmental Engineering, A38(8), 1587–1596.Baumann, E.R. and Oulman, C.S. (1970). Sand and diatomite filtration practices. Water Quality Improvement by Physical and Chemical Pro-cesses, Water Resources Symposium No. 3, University of Texas Press, Austin and London, 104.Beebe, R.L. and Stevens, J.I. (1967). Activated carbon system for wastewater renovation. Water and Waste Engineering, 4(1), 43.Bes-Pia, A., Iborra-Clar, A., Mendoza-Roca, J.A., Iborra-Clar, M.I., and Alcaina-Miranda, M.I. (2004). Nanofiltration of biologically treated textile effluents using ozone as a pre-treatment. Desalination, 167, 387–392.Bes-Pia, A., Mendoza-Roca, J.A., Alcaina-Miranda, M.I., Iborra-Clar, A., and Iborra-Clar, M.I. (2003). Combination of physico-chemical treat-ment and nanofiltration to reuse wastewater of a printing, dyeing and finishing textile industry. Desalination, 157(1–3), 73–80.Bhatkhande, D.S., Pangarkar, V.G., and Beenackers, A.A.C.M. (2001). Photo-catalytic degradation for environmental applications—a review. Journal of Chemical Technology and Biotechnology, 77(1), 102–116.Bishop, D.F., O’Farrell, T.P., and Stanberg, J.B. (1972). Physical-chemical treatment of municipal wastewater. Journal of the Water Pollution Con-trol Federation, 44, (3), 361.Bray, D.T., Merten, U., and Augustus, M. (1969). Chemical Engineering, 76(4), 60.Bressan, M., Liberatore, L., d’Alessandro, N., Tonucci, L., Belli, C., and Ranalli, G. (2004). Improved combined chemical and biological treat-ments of olive oil mill wastewaters. Journal of Agricultural and Food Chemistry, 52(5), 1228–1233.Brunner, C.A. and Lemlich, R. (1963). Foam fractionation: standard sepa-rator and refluxing columns. Industrial Engineering Chemistry, 2, 297–300.Buzzell, J.C. and Sawyer, C.H. (1967). Removal of algal nutrients from raw wastewater with lime. Journal of the Water Pollution Control Federa-tion, 39(10), R16.Chung, Y.-C., Ho, K.-L., and Tseng, C.-P. (2003). Hydrogen sulfide gas treatment by a chemical-biological process: chemical absorption and biological oxidation steps. Journal of Environmental Science and Health, Part B—Pesticides, Food Contaminants, and Agricultural Wastes, 38(5), 663–679.Conley, W.R., Jr. and Hsiung, K. (1965). Design and application of mul-timedia filters. Journal of the American Water Works Association, 57(10), 1333.Convery, J.J. (1968). Phosphorus removal by tertiary treatment with lime and alum. Paper presented at the FWPCA Symposium on Nutrient Removal and Advanced Waste Treatment, Tampa, Florida, November 15.Culp, R.L. and Culp, G.L. (1971). Advanced Wastewater Treatment. Van Nostrand Reinhold Company, New York.Culp, G.L. and Hansen, S.P. (1967a). Extended aeration effluent polishing by mixed media filtration. Water and Sewage Works, 114(2), 46.Culp, G.L. and Hansen, S.P. (1967b). How to reclaim wastewater for reuse. American City, June, 96.Davies, D.S. and Kaplan, R.A. (1964). Activated carbon eliminates organ-ics. Chemical Engineering Progress, 60(12), 46.de-Bashan, L.E. and Bashan, Y. (2004). Recent advances in removing phos-phorus from wastewater and its future use as fertilizer (1997–2003). Water Research, 38(19), 4222–4246.DeJohn, P.B. and Edwards, R.W. (1981). Application of GAC to municipal wastewaters. Proceedings of the International Conference on the Appli-cation of Adsorption to Wastewater Treatment, Vanderbilt University, Nashville, Tennessee, 109–127.Dillingham, J.H., Cleasby, J.L., and Baumann, E.R. (1966). Optimum design and operation of diatomite filtration plants. Journal of the American Water Works Association, 58(6), 657.Dillingham, J.H., Cleasby, J.L., and Baumann, E.R. (1967). Diatomite filtra-tion equations for flat and cylindrical septa. Journal of the Sanitary Engi-neering Division, American Society of Civil Engineers, 93(2) (SA1), 41.Ding, Z.Y., Frisch, M.A., Li, L., and Gloyna, E.F. (1996). Catalytic oxidation in supercritical water. Industrial and Engineering Chemistry Research, 35(10), 3257–3279.Eckenfelder, W.W. (1966). Industrial Water Pollution Control. McGraw-Hill Book Company, New York.Eckenfelder, W.W. (2000). Industrial Water Pollution Control. McGraw-Hill Book Company, New York.Eckenfelder, W.W. and Barnhart, E.L. (1963). Performance of high rate trickling filter using selected media. Journal of the Water Pollution Control Federation, 35(12), 1535.Ecodyne (1972). Physical-chemical sewage treatment plant for the village of Rosemount. Environmental Currents News, Environmental Science and Technology, 6(4), 306.Eliassen, K. and Bennett, G. (1967). Anion exchange and filtration techniques for wastewater renovation. Journal of the Water Pollution Control Fed-eration, 39(10), R81.Eliassen, R. and Bennett, G.E. (1967). Renovation of domestic and industrial waste water. Paper presented at the International Conference on Water for Peace, Washington, DC, May.Fane, A.G. (1996). Membranes for water production and wastewater reuse. Desalination, 106(1–3), 1–9.Fldib, L.A. (1963). Renovation of wastewater by foam fractionation. Paper presented before the Division of Water and Waste Chemistry, American Chemical Society, 143rd National Meeting, Cincinnati, Ohio, January 15.Fukumoto, Y. and Haga, K. (2004). Advanced treatment of swine waste-water by electrodialysis with a tubular ion exchange membrane. Animal Science Journal, 75(5), 479–485.Gaffney, J.G., Junin, R., and Downing, D.G. (1970). Ion exchange for industrial water. Water Quality Improvement by Physical and Chemi-cal Processes, Water Resources Symposium No. 3, University of Texas Press, Austin and London, 258.Galambos, I., Mora Molina, J., Jaray, P., Vatai, G., and Bekassy-Molnar E. (2004). High organic content industrial wastewater treatment by mem-brane filtration. Desalination, 162, 117–120.Galarneau, E. and Gehr, R. (1996). Phosphorus removal from wastewaters: experimental and theoretical support for alternative mechanisms. Water Research, 31(2), 328–338.Ganes, L.M. and Staubach, J.A. (1980). Reaction of nitrilotiacetate with ozone in model and natural waters. Environmental Science and Technology, 14, 571.Gardea-Torresdey, J.L., dela Rosa, G., and Peralta-Videa, J.R. (2004). Use of phytofiltration technologies in the removal of heavy metals: a review. Pure and Applied Chemistry, 76(4), 801–813.C016_005_r03.indd 986 11/22/2005 11:25:21 AM

987Gehr, R., Wagner, M., Veerasubramanian, P., and Payment, P. (2003). Dis-infection efficiency of peracetic acid, UV and ozone after enhanced primary treatment of municipal wastewater. Water Research, 37(19), 4573–4586.Getoff, N. (1996). Radiation-induced degradation of water pollutants—state of the art. Radiation Physics and Chemistry, 47(4), 581–593.Getoff, N. (2002). Factors influencing the efficiency of radiation-induced degradation of water pollutants. Radiation Physics and Chemistry, 65(4–5), 437–446.Ghoreishi, S.M. and Haghighi, R. (2003). Chemical catalytic reaction and biological oxidation for treatment of non-biodegradable textile effluent. Chemical Engineering Journal, 95(1–3), 163–169.Goff, D.L. and Gloyne, E.F. (1970). Reverse osmosis development. Water Quality Improvement by Physical and Chemical Processes, Water Resources Symposium No. 3, University of Texas Press, Austin and London, 312.Gogate, P.R. and Pandit, A.B. (2004a). A review of imperative technologies for wastewater treatment I: oxidation technologies at ambient conditions. Advances in Environmental Research, 8(3–4), 501–551.Gogate, P.R. and Pandit, A.B. (2004b). A review of imperative technologies for wastewater treatment II: hybrid methods. Advances in Environmental Research, 8(3–4), 553–597.Gong, R., Ding, Y., Li, M., Yang, C., Liu, H., and Sun, Y. (2005). Utilization of powdered peanut hull as biosorbent for removal of anionic dyes from aqueous solution. Dyes and Pigments, 64(3), 187–192.Grieves, R.B. (1972). Water and wastewater treatment applications of the foam separation process. Paper presented at the Second Annual Environ-mental Engineering and Science Conference, University of Louisville, Louisville, Kentucky, April 20–21.Grieves, R.B. and Aronica, R.C. (1966). Foam separation of phenol with a cationic surfactant. Air and Water Pollution International Journal, 10(1), 31–40.Grieves, R.B., Crandall, C.J., and Wood, R.K. (1964). Foam separation of ABS and other surfactants. Air and Water Pollution International Jour-nal, 8(8–9), 501–513.Grieves, R.B. and Wood, R.K. (1963). Continuous accumulation in foam for the treatment of refining and petrochemical wastes. Chem. In Can., 15, 13–15.Grimm, J., Bessarabov, D., and Sanderson, R. (1998). Review of electro-assisted methods for water purification. Desalination, 115(3), 285–294.Han, B., Ko, J., Kim, J., Kim, Y., Chung, W., Makarov, I.E., Ponomarev, A.V., and Pikaev, A.K. (2002). Combined electron-beam and biological treat-ment of dyeing complex wastewater: pilot plant experiments. Radiation Physics and Chemistry, 64(1), 53–59.Harriger, R.D. and Hoffman, F.L. (1970). Phosphorous Removal Tests—Two Rivers, Wisconsin. for Black and Veatch Consulting Engineers. Technical Service Department, Allied Chemical Corporation, Indus-trial Chemical Division, Syracuse, New York.Harriger, R.D. and Hoffman, F.L. (1971). Phosphate Removal Tests—Springfield, Ohio. for Black and Veatch Consulting Engineers, Tech-nical Service Department, Allied Chemical Corporation, Industrial Chemicals Division, Syracuse, New York.Hilal, N., Al-Zoubi, H., Darwish, N.A., Mohammad, A.W., and Abu Arabi, M. (2004). A comprehensive review of nanofiltration membranes: treat-ment, pretreatment, modelling, and atomic force microscopy. Desalina-tion, 170(3), 281–308.Howell, J.A. (2004). Future of membranes and membrane reactors in green technologies and for water reuse. Desalination, 162, 1–11.Jiang, J.-Q. and Lloyd, B. (2002). Progress in the development and use of ferrate(VI) salt as an oxidant and coagulant for water and wastewater treatment. Water Research, 36(6), 1397–1408.Johns-Manville Corporation (1972). Moving bed filter system. Water and Sewage Digest, May–June, 47.Kabra, K., Chaudhary, R., and Sawhney, R.L. (2004). Treatment of hazardous organic and inorganic compounds through aqueous-phase photocataly-sis: a review. Industrial and Engineering Chemistry Research, 43(24), 7683–7696.Kalinske, A.A. and Shell, G.L. (1968). Phosphate removal from waste effluent and raw wastes using chemical treatment. Paper presented at the Phosphorus Removal Conference sponsored by the FWPCA, Chicago, Illinois.Kasprzyk-Hordern, B. (2004). Chemistry of alumina, reactions in aqueous solution and its application in water treatment. Advances in Colloid and Interface Science, 110(1–2), 19–48.Kentish, S.E. and Stevens, G.W. (2001). Innovations in separations tech-nology for the recycling and re-use of liquid waste streams. Chemical Engineering Journal, 84(2), 149–159.Klein, S.A. and McGauhey, P.H. (1963). Detergent removal by surface strip-ping. Journal of the Water Pollution Control Federation, 35(1), 100.Kritzer, P. and Dinjus, E. (2001). An assessment of supercritical water oxi-dation (SCWO): existing problems, possible solutions and new reactor concepts. Chemical Engineering Journal, 83(3), 207–214.Kuhn, P.A. (1956). Removal of ammonium nitrogen from sewage effluent. MS Thesis, University of Wisconsin, Madison.Lai, C.L. and Lin, S.H. (2003). Electrocoagulation of chemical mechanical polishing (CMP) wastewater from semiconductor fabrication. Chemical Engineering Journal, 95(1–3), 205–211.Legrini, O., Oliveros, E., and Braun, A.M. (1993). Photochemical processes for water treatment. Chemical Reviews, 93(2), 671–698.Libra, J.A. and Sosath, F. (2003). Combination of biological and chemi-cal processes for the treatment of textile wastewater containing reac-tive dyes. Journal of Chemical Technology and Biotechnology, 78(11), 1149–1156.Lin, S.H. and Yang, C.R. (2004). Chemical and physical treatments of chemical mechanical polishing wastewater from semiconductor fabri-cation. Journal of Hazardous Materials, 108(1–2), 103–109.Lynam, B., Ettelt, G., and McAloon, T. (1969). Tertiary treatment at Metro Chicago by means of rapid sand filtration and microstrainers. Journal of the Water Pollution Control Federation, 41(2), 247.Mantzavinos, D. and Psillakis, E. (2004). Enhancement of biodegradability of industrial wastewaters by chemical oxidation pre-treatment. Journal of Chemical Technology and Biotechnology, 79(5), 431–454.Matatov-Meytal, Y.I. and Sheintuch, M. (1998). Catalytic abatement of water pollutants. Industrial and Engineering Chemistry Research, 37(2), 309–326.Meidl, J.A. (1981). Application of PACT to municipal wastewater. Proceed-ings of the International Conference on the Applications of Adsorption to Wastewater Treatment, Nashville, Tennessee, 357–383.Merten, U., Nusbaum, I., and Miele, R. (1968). Organic removal by reverse osmosis. Paper presented at the American Chemical Society Sympo-sium on Organic Residue Removal from Wastewaters, Atlantic City, New Jersey, September.Minamisawa, M., Minamisawa, H., Yoshida, S., and Takai, N. (2004). Adsorption behavior of heavy metals on biomaterials. Journal of Agri-cultural and Food Chemistry, 52(18), 5606–5611.Miyake, Y., Sakoda, A., Yamanashi, H., Kaneda, H., and Suzuki, M. (2003). Activated carbon adsorption of trichloroethylene (TCE) vapor stripped from TCE-contaminated water. Water Research, 37(8), 1852–1858.Mollah, M.Y.A., Morkovsky, P., Gomes, J.A.G., Kesmez, M., Parga, J., and Cocke, D.L. (2004). Fundamentals, present and future perspectives of electrocoagulation. Journal of Hazardous Materials, 114(1–3), 199–210.Mollah, M.Y.A., Pathak, S.R., Patil, P.K., Vayuvegula, M., Agrawal, T.S., Gomes, J.A.G., Kesmez, M., and Cocke, D.L. (2004). Treatment of orange II azo-dye by electrocoagulation (EC) technique in a continuous flow cell using sacrificial iron electrodes. Journal of Hazardous Mate-rials, 109(1–3), 165–171.Mollah, M.Y.A., Schennach, R., Parga, J.R., and Cocke, D.L. (2001). Elec-trocoagulation (EC)—science and applications. Journal of Hazardous Materials, 84(1), 29–41.Otake, T. (1979). Photo-oxidation with ozone. Journal of Chemical Engi-neering of Japan, 12, 289.Panizza, M. and Cerisola, G. (2004). Electrochemical oxidation as a final treatment of synthetic tannery wastewater. Environmental Science and Technology, 38(20), 5470–5475.Papic, S., Koprivanac, N., Loncaric Bozic, A., and Metes, A. (2004). Removal of some reactive dyes from synthetic wastewater by combined Al(III) coagulation/carbon adsorption process. Dyes and Pigments, 62(3), 291–298.Parameshwaran, K., Fane, A.G., Cho, B.D., and Kim, K.J. (2001). Analysis of microfiltration performance with constant flux processing of second-ary effluent. Water Research, 35(18), 4349–4358.C016_005_r03.indd 987 11/22/2005 11:25:22 AM
988
Parkhurst, J.D., Dryden, F.D., McDermott, G.N., and English, J. (1967). Pomona activated carbon pilot plant. Journal of the Water Pollution Control Federation, 39(10), R70.Pera-Titus, M., García-Molina, V., Banos, M.A., Gimenez, J., and Esplugas, S. (2004). Degradation of chlorophenols by means of advanced oxida-tion processes: a general review. Applied Catalysis B: Environmental, 47(4), 219–256.Pikaev, A.K. (2002). New data on electron-beam purification of wastewater. Radiation Physics and Chemistry, 65(4–5), 515–526.Pikaev, A.K., Ponomarev, A.V., Bludenko, A.V., Minin, V.N., and Elizareva, L.M. (2001). Combined electron-beam and coagulation purification of molasses distillery slops: features of the method, technical and economic evaluation of large-scale facility. Radiation Physics and Chemistry, 61(1), 81–87.Pokhrel, D. and Viraraghavan, T. (2004). Treatment of pulp and paper mill wastewater—a review. Science of the Total Environment, 333(1–3), 37–58.Presecan, N.L., Touhill, J.C., and Shuckrow, A.J. (1972). Cleveland west-erly physical chemical wastewater treatment plant. Paper presented at the Second Annual Environmental Engineering and Science Confer-ence, University of Louisville, Kentucky, April 20–21.Rich, L.G. (1963). Unit Processes of Sanitary Engineering. John Wiley and Sons, New York.Riddick, T.M. (1961). Zeta potential and its application to difficult waters. Journal of the American Water Works Association, 53(8), 1007.Rizzo, J.L. and Schade, R.E. (1969). Secondary treatment with granular activated carbon. Water and Sewage Works, 116(8), 307.Robinson, W.T. and Maltson, R.J. (1967). A new product concept for improvement of industrial water. Paper presented at Annual Meeting, Water Pollution Control Federation, New York.Roizard, D., Teplyakov, V., Favre, E., Fefilatiev, L., Lagunstsov, N., and Khotimsky, V. (2004). VOC’s removal from water with a hybrid system coupling a PTMSP membrane module with a stripper. Desalination, 162, 41–46.Rose, J.L. (1968). Removal of phosphorus by alum. Paper presented at the Phosphorus Removal Conference sponsored by the FWPCA, Chicago, Illinois.Rubio, J., Souza, M.L., and Smith, R.W. (2002). Overview of flotation as a wastewater treatment technique. Minerals Engineering, 15(3), 139–155.Rudolfs, W. and Trubnick, E.H. (1935). Activated carbon in sewage treat-ment. Sewage Works Journal, 7(5), 852.Sadr Ghayeni, S.B., Beatson, P.J., Schneider, R.P., and Fane, A.G. (1998a). Adhesion of waste water bacteria to reverse osmosis membranes. Journal of Membrane Science, 138(1), 29–42.Sadr Ghayeni, S.B., Beatson, P.J., Schneider, R.P., and Fane, A.G. (1998b). Water reclamation from municipal wastewater using combined micro-filtration-reverse osmosis (ME-RO): preliminary performance data and microbiological aspects of system operation. Desalination, 116(1), 65–80.Sadr Ghayeni, S.B., Madaeni, S.S., Fane, A.G., and Schneider, R.P. (1996). Aspects of microfiltration and reverse osmosis in municipal wastewater reuse. Desalination, 106(1–3), 25–29.Schmid, L.A. and McKinney, R.E. (1969). Phosphate removal by a lime-biological treatment scheme. Journal of the Water Pollution Control Federation, 41(7), 1259.Schnepf, R.W., Gaden, E.L., Mirocznik, E.Y., and Schonfield, E. (1959). Foam fractionation: metals. Chemical Engineering Progress, 55, 42–46.Schoen, H.M. and Mazella, G. (1961). Foam separation. Industrial Water Wastes, 6, 71–74.Schoen, H.M., Rubid, E., and Ghosh, D. (1962). Radium removal from ura-nium mill wastewater. Journal of the Water Pollution Control Federa-tion, 34(10), 1026.Shatto, J. (1960). Aerobic digestion and diatomite filter. Public Works, December, 82.Shin, H.-S., Kim, Y.-R., Han, B., Makarov, I.E., Ponomarev, A.V., and Pikaev, A.K. (2002). Application of electron beam to treatment of wastewater from papermill. Radiation Physics and Chemistry, 65(4–5), 539–547.Shuckrow, A. (1971). Battelle’s northwest laboratories. American Society of Civil Engineers Newsletter, August, 4.Slechta, A.F. and Culp, G.L. (1967). Water reclamation studies at the South Tahoe Public Utility District. Journal of the Water Pollution Control Federation, 39(5), 787.Sridhar, S., Prasad, K.K., Murthy, G.S., Rao, A.G., and Khan, A.A. (2003). Processing of composite industrial effluent by reverse osmo-sis. Journal of Chemical Technology and Biotechnology, 78(10), 1061–1067.Stander, G.J. and Van Vuuren, L.R.J. (1969). The reclamation of potable water from wastewater. Journal of the Water Pollution Control Federa-tion, 41(3), 355.Steel, E.W. (1960). Water Supply and Sewerage. McGraw-Hill Book Com-pany, New York.Stevens, D.B. and Peters, J. (1966). Long Island recharge studies. Journal of the Water Pollution Control Federation, 38(12), 2009.Stevik, T.K., Kari, A., Ausland, G., and Hanssen, J.F. (2004). Retention and removal of pathogenic bacteria in wastewater percolating through porous media: a review. Water Research, 38(6), 1355–1367.Stumm, W. and Morgan, J.J. (1970). Aquatic Chemistry. John Wiley and Sons, New York.Tabrizi, G.B. and Mehrvar, M. (2004). Integration of advanced oxidation technologies and biological processes: recent developments, trends, and advances. Journal of Environmental Science and Health, Part A—Toxic/Hazardous Substances and Environmental Engineering, A39(11–12), 3029–3081.Tchobanoglous, G., Burton, F.L., and Stensel, H.D. (2003). Wastewater Engineering, Treatment and Reuse (4th ed.). McGraw-Hill Book Com-pany, New York.Tchobanoglous, G. and Eliassen, R. (1970). Filtration of treated sewage effluent. Journal of the Sanitary Engineering Division, American Soci-ety of Civil Engineers, 96(4) (SA2), 243.Truesdale, G.A. and Birkbeck, A.E. (1966). Tertiary treatment processes for sewage works effluents. Paper presented to the Scottish Center of the Institution of Public Health Engineers, March 28.Unpublished proposal to Clark County Sanitation District, prepared by Pacific Engineering and Production Co., Henderson, Nevada, 1970.Vaca Mier, M., Lopez Callejas, R., Gehr, R., Jiménez Cisneros, B.E., and Álvarez, P.J.J. (2001). Heavy metal removal with Mexican clino-ptilolite: multi-component ionic exchange. Water Research, 35(2), 373–378.Vajnhandl, S. and Majcen Le Marechal, A. (2005). Ultrasound in textile dyeing and the decolouration/mineralization of textile dyes. Dyes and Pigments, 65(2), 89–101.Van Hulle, S.W.H. and Vanrolleghem, P.A. (2004). Modelling and optimi-sation of a chemical industry wastewater treatment plant subjected to varying production schedules. Journal of Chemical Technology and Biotechnology, 79(10), 1084–1091.Villiers, R.V., Berg, E.L., Brunner, C.A., and Masse, A.N. (1971). Munici-pal wastewater treatment by physical and chemical methods. Water and Sewage Works, 118(8), R62.Vogna, D., Marotta, R., Napolitano, A., Andreozzi, R., and d’Ischia, M. (2004). Advanced oxidation of the pharmaceutical drug diclofenac with UV/H2O2 and ozone. Water Research, 38(2), 414–422.Waite, T.D. (2002). Challenges and opportunities in the use of iron in water and wastewater treatment. Reviews in Environmental Science and Bio-technology, 1(1), 9–15.Wall, A.E. (1980). Economically removed toxics. Water and Wastes Engi-neering, 17(2), 43.Weber, W.J., Hopkins, C.B., and Bloom, R. (1970). Physico-chemical treat-ment of wastewater. Journal of the Water Pollution Control Federation, 42(1), 83.Weber, W.J., Jr. (1967). Fluid-carbon columns for sorption of persistent organic pollutants. Advances in Water Pollution Control Research. Proceedings of the Third International Conference on Water Pollu-tion Research, Washington, DC, Water Pollution Control Federation, 1, 253.Wuhrmann, K. (1968). Objectives technology and results of nitrogen and phosphorus removal processes. Advances in Water Quality Improvement, University of Texas Press, Austin.Wukash, R.F. (1968). New phosphate removal process. Water and Wastes Engineering, 5(9), 58.C016_005_r03.indd 988 11/22/2005 11:25:22 AM

989Wyffels, S., Boeckx, P., Pynaert, K., Verstraete, W., and Cleemput, O.V. (2003). Sustained nitrite accumulation in a membrane-assisted biore-actor (MBR) for the treatment of ammonium-rich wastewater. Jour-nal of Chemical Technology and Biotechnology, 78(4), 412–419.Yildiz, E., Keskinler, B., Pekdemir, T., Akay, G., and Nuhoglu, A. (2005). High strength wastewater treatment in a jet loop membrane bioreactor: kinetics and performance evaluation. Chemical Engineering Science, 60(4), 1103–1116.Yoon, T.I., Lee, H.S., and Kim, C.G. (2004). Comparison of pilot scale performances between membrane bioreactor and hybrid conventional wastewater treatment systems. Journal of Membrane Science, 242(1–2), 5–12.Yuan, W.L. and Hsu, P.H. (1970). Effect of foreign components of the precipi-tation of phosphate by aluminum. Paper presented at the 5th International Water Pollution Conference, July–August.Zuckerman, M.M. and Molof, A.H. (1970). High quality reuse water by chemical-physical wastewater treatment. Journal of the Water Pollution Control Federation, 42(3), 437.ALESSANDRO ANZALONEPolytechnic University of Puerto RicoJ.K. BEWTRAUniversity of WindsorHAMBDY I. ALIAin Shams UniversityC016_005_r03.indd 989 11/22/2005 11:25:22 AM
990 PLANNING Planning is a field of study which encompasses a number of related physical development and social and scientific func-tions including land use analysis, transportation planning, housing policy, economic analysis, environmental planning, urban and rural development and redevelopment. The broad goal of planning is to provide thoughtful examination of physical development and related public policy initiatives. Planning has evolved from the early social concerns of 19th Century urban life—crowding, squalor and unhealthful living conditions focuses attention on such concepts as the public interest and on laws which protect the public health and safety. Controls on the location of unhealthful industrial uses such as slaughterhouses have evolved into land use planning and zoning controls. Concern for over crowding and provision of adequate light and air are now measured by housing analysis and population surveys. Planning is an inter-disciplinary field which brings an understanding of public health, legal and social issues, and architectural design principles to develop theories of the his-tory and future of development patterns. From principles of urban design appropriate street layout, open space and urban densities are derived which provide light and air. Traffic transportation planners identify the need for mass transit systems as well as traffic improvements. Standards in envi-ronmental planning provide a background to evaluate costs, benefits and impacts of new developments and initiatives. Planners are a diverse and loosely defined group who identify themselves by the branch of planning they engage in, thus land use planners, public health planners, economic planners, housing planners and transportation planners working side by side and within their own particular area of expertise in government and private industry. The advancement of the public interest and the protection of the public health, safety and welfare are two principles which continue to support a myriad of planning initiatives. The goals can be seen within the studies of environmen-tal planning: wetland management and other conservation efforts are viewed as controls which protect the public inter-est; air quality controls protect the public health, safety and welfare. Planners utilize academia as a home base, where the lessons of urban planning are taught, together with analyti-cal methods for the determination of social and scientific standards and criteria urban design and aesthetic principles. Professional planning societies also provide information and forums for discussion on planning issues. The American Institute of Certified Planners (AICP) offers a membership admittance test which serves to provide a roster of qualified professionals. Ethics standards promulgated by the AICP attempt to self-police the profession. Only two states, New Jersey and Michigan, license professional planners. The key analytical methods and models of planners include survey and sampling methods, ranking strategies, program evaluation, location planning, population forecast-ing and models for measuring impact of landuse actions including air quality analysis, transportation capacity, and employment, economic and fiscal impact. Land use planners utilize planning principles to determine appropriate locations for land uses within a specified area. The land use planner may be employed by a town or city to conduct long range planning and maintain and advance the master plan through day to day land use decision-making. Comprehensive plans provide forecasting tools for a variety of resources, popu-lation trends and social service needs, resource projections and utility and infrastructure investments as well as transportation planning, roadway improvements, and conservation lands and sensitive environmental lands. The role of government in planning in the United States is generally regarding as a local activity, for example, defin-ing the appropriate use for the abandoned industrial plant in your home town is a local decision-making process. However, planners are engaged at each level of government; that is, the federal, State and local level. From these broad perspectives the role of a planner shifts to reflects the chang-ing role of government. The federal government provides planning through public policy initiatives and laws and regulation. The two functions adhere to the two pronged principles of planning; the public interest and the public health safety and welfare. The public interest is served through programs which promote a particu-lar public policy initiative which is encouraged, such as open space or local park funding. Federal programs which admin-ister funding for state and local actions, such as Community Development Block Grants for urban redevelopment pro-mote the public interest. Promulgation and enforcement of regulations which protect the public health safety and welfare include the Clean Air Act, the Clean Water Act, and the Safe Drinking Water Act. The National Environmental Policy Act of 1969 is a key milestone within the federal government, aimed at promot-ing the general welfare, in that it requires federal actions to be subject to both inter-governmental and public review. The C016_006_r03.indd 990C016_006_r03.indd 990 11/18/2005 11:01:05 AM11/18/2005 11:01:05 AM
PLANNING 991intent of this law is to provide for a careful analysis of the likely effects of an action prior to use of federal funds. This law serves to open up the process of government decision-making to the public. In addition, the NEPA legislation pro-vides a model for similar environmental scrutiny at the state and local level, thus providing a network of environmental planning at all levels of government. In terms of land use decision-making, there is no central planning. The federal government role is confined to public policy, grants in aid and regulatory control (the environmen-tal controls placed on filling of wetland areas is an issue which most closely approximates central planning in that the effect of these regulations can often nullify development proposals which may be encouraged at the local level). Information gathering, such as census data provided by the Department of Commerce, is the key central planning function used universally by planners in all disciplines and sectors: statistics and forecasts are used by public agencies, private consultants and commerce and industry to under-stand and plan for communities with regard to population, transportation, housing, the economy and employment and a host of demographic and industrial data. At the State level, planning functions are both assumed from the federal government and conveyed to local govern-ments. State governments serve to administer federal pro-grams and assume responsibility for enforcement of some key planning and environmental responsibilities such as the Clean Air Act. Often, compliance with federal goals in one area forms the basis for government aid or funding of related public initiatives, for example, efforts to comply with air quality goals are often related to transportation funding. The State works closely with federal agencies as a conduit for policy and funding of government programs, often creating mirror agencies for administration of transportation, historic preservation and environmental protection. Also parallel and in association with the federal government, States provide for the collection and dissemination of statistical informa-tion such as the census and economic forecasting. The state government assigns and provides to local gov-ernments the authority to plan and zone. The power to plan in its narrow sense, land use control, is based upon the police power. Planning is seen to protect the health safety and gen-eral welfare of the public. The majority of planning work is done at the municipal level (a certain amount of master plan-ning and regional coordination is provided at the country and state level). The first element in municipal planning is the formulation of the Master Plan. The Master Plan or compre-hensive plan is an amalgam of public policy objectives and practical information for future planning such as existing demographic information and trends with projections of the future to the benefit of landuse plans, transportation plans, utilities, and education. The master plan should be a unique reflection of both the physical elements of the city and the people who live in it. Thus the master plan, which culmi-nates in a landuse map becomes the guide to the develop-ment regulations of a city. The zone plant sets forth the physical controls on uses and densities within the jurisdictional area. The physical layout of the city is assigned uses, densities and standards for development in a land use plan. A zone plan presents the regulations which carry out a given land use plan. The integ-rity of a zone plan is as strong as the development review boards. Planning Boards and Zoning Boards are charged with maintaining the integrity of the plan with the power to review subdivision, site plan and various requests. The site plan review process illustrates the typical plan-ning exercise and scope and range of municipal review powers. The site plan review, and variance requests, for example, a use variance, are subject to review and scrutiny from a municipal board with regard to the merits of the site plan, the need for the use, how the use is consistent with the master plan, how it advances planning goals of the commu-nity and what hardships or unique physical characteristics would justify a departure from set development standards and proscribed uses. Many municipalities have established environmental commissions, architectural or historical resource review boards all which serve to advise in the site plan review pur-suant to the general welfare. The environmental review at the municipal level should encompass the full range of rel-evant issues to asses the scope of the proposed activity and its likely impact on site and surrounding resources. ELIZABETH McLOUGHLIN PS & S Key Span C016_006_r03.indd 991C016_006_r03.indd 991 11/18/2005 11:01:05 AM11/18/2005 11:01:05 AM
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INTRODUCTION Planning for a major new facility must address the envi-ronmental impact of both the construction and operational phases of the project. It is essential to optimize alternatives, while evaluating performance relative to regulated emis-sions and ambient standards and to develop a cost effective permitting strategy. For large scale projects, Quig (1980) recommends a highly integrated project approach for environmental com-pliance early in the planning stage based upon historical siting, licensing, engineering and construction experience with similar sized plants. Strong emphasis on early process work is necessary to understand environmental impacts. This and other front-end engineering and planning should be executed in very close coordination with the staff charged with documenting the licensing effort. Extensive use of specialists is generally required. The major federal acts to be addressed are: 1) National Environmental Policy Act, (NEPA), 1969. 2) Clear Air Act Amendments, revised 1990. 3) Federal Water Pollution Control Act Amendments, 1972 (FWPCA). 4) Resources Conservation and Recovery Act (RCRA), 1976. 5) National Historic Preservation Act of 1966. 6) Historical and Archaeological Preservation Act of 1974. 7) Endangered Species Act, 1973. These federal and selected state environmental acts essentially address the following: Land Use Aspects (fuel storage, exclusion or buffer zones, waste disposal, zoning, and demography); Water Resources (availability and com-petitive uses, wastewater complexities and water quality, hazardous wastes, and waste heat); Air Quality/Meteorology (attainment/nonattainment areas, in terms of offset policy and lowest achievable emission rate; newsource perfor-mance standard for particulates; NO x and SO 2 ; prevention of significant deterioration in Class I, II, III; stack height credit; hazardous wastes; minor meteorologic changes); and Regulatory (multiple lead agency involvement, licens-ing strategy, feasibility of concept, permit requirements, and federal/state implementation). The environmental, health safety, and socio-economic impacts discussed above highlight the areas of concern which must be considered in the site characterization studies and subsequent reporting of the project compatibility with the proposed location. Baseline conditions must be identi-fied in the areas of potential impact. The characterization of the environment, the definition of the process operations and the identification of the potential impacts are the elements required for input to a comprehensive program of facility design for impact mitigation. As such, the development of an environmental statement of the project serves as feedback to the design effort with the result being a facility licensable from the environmental viewpoint. To illustrate the procedure we shall present a typical example, namely planning a new coal gasification plant. Technical details of gasification are discussed elsewhere in this Encyclopedia under Coal Gasification Processes. The example will focus on regulatory requirements and siting considerations. REGULATORY REQUIREMENTS The first step in any program of this nature is to define the regulatory requirements associated with the construction and operation of the proposed facility. This will define specific limitations and establish generally the study requirements for the program as they relate to the environmental, safety, health, and socioeconomic aspects of the development. AIR QUALITY RELATED REGULATORY REQUIREMENTS Federal Requirements At the Federal level, this project will be required to comply with the following air quality regulations and requirements. Primary and Secondary National Ambient Air Quality Standards (NAAQS) A demonstration showing compliance with NAAQS must be made to EPA for approval to com-mence construction. This would involve modeling the anticipated plant emissions and imposing the resultant con-centration increases on representative ambient air quality conditions and comparing these with NAAQS. Information necessary for this demonstration would include the facility emissions as discussed earlier and the ambient air quality C016_007_r03.indd 992C016_007_r03.indd 992 11/18/2005 11:01:29 AM11/18/2005 11:01:29 AM

993developed from a monitoring program or from representative data as available. New Source Performance Standards (NSPS) The proposed air quality control system (AQCS) for the facility must be designed to comply with existing NSPS for the coal prepara-tion facilities (e.g., particulates), the gas turbine component (e.g., NO x ) and the auxiliary boiler (e.g., SO 2 ) of the plant. Since NSPS do not exist for the coal gasification compo-nent, appropriate AQCS Best Available Control Technology (BACT) evaluations will be performed to select the con-trol system. In addition the AQCS design will have to be reviewed with the EPA for approval to construct. Prevention of Significant Deterioration (PSD) No con-struction can commence until the PSD permit has been obtained. The report and application for the permit would have to consider the following: the emissions from the total facility; a BACT review for any regulated pollutant (NAAQS, allow-able increments, NESHAP), which the plant emties above “de minimis” values, an air quality review for all pollutants emitted, after controls are applied, over the “de minimis” emis-sion rates unless it were demonstrated that the air impacts of those emissions would not exceed the air quality impact “de minimis” values. As part of these demonstrations ambient air quality monitoring would have to be conducted for the same pollutants for which BACT demonstrations would be required unless representative monitoring data are available. National Emission Standards for Hazardous Air Pollutants (NESHAP) The discharge to the atmosphere of pollutants regulated under NESHAP is not anticipated for this type of facility. However, tracking of EPA’s continued development of NESHAP should be carried out to ensure compliance with the regulations as they develop. New stationary sources and modifications to major sta-tionary sources are required by the Clean Air Act to obtain permits prior to construction of a new process facility. The stringency of permit requirements depends on the regional status of its compliance with ambient standards for particu-lar pollutants. For example, in zones having acceptable air quality referred to as “attainment areas” for a specific pollut-ant, the permits are of the prevention of significant deterio-ration (PFD) type. The code of federal regulations, US EPA Title 40 CFR, 51.166, specifies the set of minimum PSD air quality permit requirements to warrant approval by the US EPA. The primary objective of PSD is to insure new major sources and modifications of existing sources comply with NAAQS. Specific public notice requirements and subse-quent hearings allow for public comment to be part of the PSD review process. On the other hand, in a non-attainment area, NAA permits are required. NAA permits address area improvement of pollutant levels and falls under the state’s supervision, through a State Implementation Plan (SIP) enforced by the US EPA and DOJ. Either type of permit is subject to New Source Review (NSR). The physical change triggering regulation of pollutants is usually 100 or 250 tons per year, depending on the industrial source category. As of early 2005 the definition of major modification for coal fired power plants has come under dispute in the courts (see the discussion at the end of this article for further information). State Requirements The state may have air quality related requirements which will affect the proposed project. State requirements may include a permit to construct a facility if the construction of operation of the facility will release air contaminants into the atmosphere. The appli-cant must submit a completed application for Approval of Emissions and an Emission Inventory Questionnaire (along with a copy of the PSD Application) which show compli-ance with state air quality standards, toxic substance limita-tions and emission control requirements. WATER QUALITY RELATED REGULATORY REQUIREMENTS Federal Requirements At the Federal level, the major laws affecting the discharge of liquid effluents from the proposed facility are as follows: Clean Water Act (CWA) Under the CWA, the proposed project will require a National Pollutant Discharge Elimination System (NPDES) permit before commencing construction and operation. The application to the EPA for these permits would be based on the conceptual design of the wastewater control systems which could ensure compliance with effluent limita-tions and water quality standards. Where effluent limitations are not specified for discharges from certain facilities, limi-tations on discharges from similar operations would be used as a guideline for design of the wastewater control systems. These designs would be used to support the application for an NPDES permit. The NPDES permit and the work effort neces-sary for its preparation will also address the discharge of toxic pollutants listed on the Section 307(a) toxic pollutants list and any other toxics discharged from the plant. A section 404 permit is required by the Corps of Engineers for the discharge of dredge or fill material in the navigable waters of the United States. This permit is required for the river structures associated with the facility and would be prepared and obtained concurrently with the Section 10 permit required under Rivers and Harbors Act (see discus-sion below) and the NPDES permit. Application for either an NPDES permit from the EPA or a Section 404 permit from the Corps will trigger the NEPA review process and is the basis upon which the preparation of an environmental report (ER), in support of a Federal EIS, is considered necessary. Rivers and Harbors Act of 1899 (RHA) Under Section 10 of the RHA, any construction activity in a navigable waterway requires a permit from the Corps of Engineers. This permit will be required for the construction of the intact and discharge structures and the barge loading/unloading facilities. It would be submitted jointly as a common permit application with the Section 404 Dredge and Fill Permit application. State Requirements The state often has water quality related regulations and requirements which must be complied with before approval C016_007_r03.indd 993C016_007_r03.indd 993 11/18/2005 11:01:29 AM11/18/2005 11:01:29 AM
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to commence construction and/or operation of the proposed project can be obtained. They are typically as follows: A state regulatory agency may require that a certificate of approval be obtained prior to construction of a treatment facil-ity for handling industrial wastes. A report containing detailed information about the operation of the treatment facility must be developed and submitted prior to construction. Regulations may also require the submission of a permit application prior to discharge from an industrial source. The State may also issue a certification in accordance with the Clean Water Act which confirms that discharges from the facility will comply with effluent limitations and water quality standards. SOLID WASTE RELATED REGULATORY ACTIVITIES Federal Requirements The major Federal law governing the handling and disposal of solid waste is the Resource Conservation and Recovery Act of 1976 (RCRA). The most significant sections of RCRA are Subtitle C, which deals with Hazardous Waste Management and Subtitle D, which deals with Non-hazardous Waste Management. Regulations pursuant to Subtitle C of RCRA address identification and listing of hazardous waste, stan-dards applicable to generators, transporters, and owners and operators of hazardous waste treatment, storage and disposal facilities and permit requirements for treatment, storage or dis-posal of hazardous waste. The project will require a permit for disposal of any solid wastes determined to be hazardous by the criteria in Section 3001 regulations. Operation practices of the solid waste management facility are also regulated. In this regard the work necessary to determine the nature of the solid waste generated by this facility must be carried out. If the wastes are determined to be hazardous (Section 3001 Criteria) the applicable requirements of Subtitle C or RCRA must be incorporated into the facility design. Regulations promulgated under Subtitle D or RCRA establish criteria for the development of State plans for management of solid waste. No requirements are directly imposed at the Federal level. State Requirements State plans for the management of solid waste (Hazardous and Non-hazardous) may be at varying stages of develop-ment. An application for a permit to operate a hazardous waste management facility may be filed with the state’s DNR if any solid wastes to be generated at the proposed facility can be classified as hazardous. NATIONAL ENVIRONMENTAL POLICY ACT (NEPA) The major provision of NEPA which significantly impacts the planning and scheduling for major industrial facilities is the need for Federal agencies contemplating major actions, such as issuing permits, to prepare an environmental impact statement (EIS). In the case of this coal gasification facility, the requirement for a Federal EIS would be triggered by the application for an NPDES permit from EPA and/or a Section 404 or Section 10 permit from the Corps of Engineers for anticipated river structures. Upon designation of the lead agency based on discussions with the various Federal agencies and submit-tal of applications for permits, the EIS would be prepared according to CEQ final regulations. SITING THE PROJECT Geology, Topography, and Soils Geology studies should be performed to describe the soils, geologic and topographic setting of the site, particularly with respect to structural and topographic control of the local and regional groundwater flow systems. A secondary, albeit very important, purpose is the identification of potential geologi-cal hazards within the site area. Information sought includes physical and chemical soil characteristics, general topography, paleontology, and geological framework. Descriptions are sought for aquifer systems and characteristics including their name, thickness, depth, stratigraphy, and areal extent. Mineral production and unique geologic/geomorphic features will be documented. Pertinent data is summarized in tabular and/or graphic format. The results of the geology studies primarily define the soils, topographic, and geologic setting of the site. Potential impacts references these descriptive settings to evaluate impact magnitudes. The impact of plant site preparations and construction or localized site topography, soils and ero-sion characteristics, and site physical and economic geology are assessed. Geological hazards discussed include exces-sive slopes, unstable soils and fault zones. Groundwater Hydrology and Water Use The purpose of the groundwater studies is to understand the physical and chemical characteristics of the groundwater regime. This allows for an accurate assessment of groundwater impacts resulting from the proposed action in addition to for-mulation of mitigative measures to help alleviate these impacts. In addition, information necessary for the design of solid waste handling facilities as prescribed under RCRA is developed. Information sought includes general topography and geological framework, description of aquifer systems and characteristics including their name, thickness, depth, stra-tigraphy, and areal extent; seasonal groundwater levels, rate, and direction of flow; aquifer hydraulic properties including permeability, transmissivity, and storativity; surface water/groundwater inter-relationships; location of aquifer recharge and discharge areas; ground water quality; and domestic, industrial, and municipal groundwater well distribution and characteristics. Long and short term regional and site specific (within 5 miles of the site) data is sought. Special efforts are made to document the location of contaminated areas. C016_007_r03.indd 994C016_007_r03.indd 994 11/18/2005 11:01:29 AM11/18/2005 11:01:29 AM

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995 Groundwater sampling can be conducted in conjunction with surface water sampling. Samples are taken quarterly from monitoring wells. This information can then be evaluated in light of the projected facility emissions and demands on the area’s resources. The issues and concerns to be addressed include: 1) Use of groundwater by the plant, and the effects of lowering water levels or pressures for this reason or for construction purposes. 2) Changes in water quality, or effects on rocks/deposits, caused by accidental leaks or spills, efflu-ent discharge, slag or scrubber sludge pits, surface water and the like. The potential impacts identi-fied are evaluated in light of their magnitude and importance. Extra attention is paid to those judged significantly high in either value. By early identification of stresses that might affect the natu-ral systems, steps can be taken to minimize the impacts or alleviate them to an acceptable degree. Mitigative measures that can be taken during plant design, construction or opera-tion, such as adding clay liners, for example, can be evaluated and described. Using the results of plant design, the initial impact eval-uation and the adopted mitigative measures, a final evalua-tion is made of the effects of the construction and operation of the proposed plant and ancillary facilities on the natural environmental systems. This activity evaluates expected effects of the proposed plant both during and after construction of the groundwater hydrologic environment. Each effect is evaluated as to its unavoidable adverse effects and favorable effects. Surface Water Hydrology and Water Use The purpose of the surface water studies is to determine, develop and present the surface water quantity and quality characteristics of the site and its surrounding environs. These data and information are analyzed and evaluated in recognition of the proposed facility’s operation and construction related characteristics to determine and project potential effects and impacts on the surrounding surface water. Specifically, the objectives are: 1) To provide a quantitative description of the hydro-logic setting of the site and its vicinity including any stream flow characteristics (i.e., flood and low flow frequencies, seasonal ranges, averages, and historical extremes), and the physical and chemical water quality characteristics of source and receiving waters. Annual and seasonal ranges and averages are developed. 2) To identify the other water uses (withdrawals as well as discharges) and users including the loca-tion and quantities involved; 3) To identify the existing water quality criteria and regulations affecting plant discharges, and 4) To evaluate the impact of construction and opera-tion of the proposed plant on adjacent surface waters, with regard to the applicable water quality criteria, and related permit requirements. The data and information needed for the description of the hydrologic setting of the surface waters of the site and evalu-ation of the plant’s impact include the following: 1) Geographic and topographic maps of the site area containing varying degrees of local and regional details to delineate the drainage basin and its drainage patterns. 2) Watershed characteristics such as geometry, slope, vegetation types and density, and soil types to derive rainfall-runoff relationships (empirical runoff coefficient). 3) Records of rainfall events to estimate overland flow. 4) Records of stream flows from gaging stations on local water courses. These data are used in defin-ing statistical stream flow characteristics. 5) Meteorological data including air temperature, relative humidity, solar radiation, wind speed and evaporation data, and thermal plume calculations (as needed). 6) Records of various water users, locations of with-drawal, quality, and quantities involved. 7) Proposed plant site location map, grade elevation, drainage pattern, character of soil types, and cover. 8) The physical and chemical water quality charac-teristics of the surrounding surface waters. 9) The facility description and operational characteris-tics relating to the discharge quantity and quality. In addition, construction procedures, methods, sched-ules, and erosion control features are needed. In addition to a water quality characterization program, the required data is collected through existing sources. This would involve a thorough search, review, and compilation of the existing hydrological data base. Appropriate Federal, State, and local agencies are contacted and interviewed and published regulatory materials is reviewed to gain informa-tion regarding other water users and water laws affecting the plant construction and operation. A field monitoring program is carried out to obtain water quality characteristics of intake and discharge waters. Water quality samples are taken quarterly from selected stations. A hydrological assessment of the construction phase is undertaken to: 1) identify changes in drainage patterns and possible effects on flooding potential, 2) identify changes in riparian terrestrial habitat areas, 3) identify the potential for erosion and local soil losses. These impact areas are addressed, and mitigating measures are specified for their control. C016_007_r03.indd 995C016_007_r03.indd 995 11/18/2005 11:01:29 AM11/18/2005 11:01:29 AM
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For the operational phase, the various aqueous discharges from the plant are inventoried and evaluated. Results of plume analyses, if appropriate, are critiqued with respect to compliance with applicable water quality criteria and standards. Recommendations concerning the potential opti-mization of the plant water management plan are made to reduce or eliminate environmentally objectionable dis-charges. Consumptive water use for the plant is identified to determine the effects of plant operation on intake waters and downstream users. Recommendations concerning opti-mization of the plant water management plan and the use of alternate or supplemental sources of water are made, if warranted. Ecology The ecological studies are designed to generate and assemble pertinent data to determine the status of threatened and endangered species, and commercially or recreationally important wildlife species, and to identify and locate sen-sitive, unique, and critical aquatic, riparian, and terrestrial habitat areas in the site area. Additionally, the status of com-mercially or recreationally important fish in any site intake and discharge waters is determined. The biological setting is then analyzed in light of the proposed plant construction and operational characteristics to arrive at assessments of impact potential. Terrestrial Ecology In evaluating the impact of the project on the terrestrial environment, the work objective is to assess both construc-tion and operation of the facility utilizing “baseline” data developed and secured from field programs, literature, and agency contacts. Animal species, occurrence, abundance, distribution, and preferred habitat associations and principal ecological interactions are determined. Habitats are identi-fied and described as natural plant communities within the site. Additionally, discussions and data gathering activities focus on vertebrates and prominent otherwise important plant community components. Construction-related effects largely result from veg-etation and habitat removal, which often constitutes the major impact of a major industrial facility on terrestrial communities. Assessment of vegetation loss due to land clearing is based on previous identification and mapping of regionally productive rare, or otherwise important vegetation types. In this regard, the role of plants in soil stability warrants detailed consideration. Effects of facility construction on wildlife is also evaluated in terms of important habitat areas. Attention is focused on those species which appear sensitive to habitat loss (e.g., species already limited by factors relat-ing to habitat availability), which function as critical compo-nents of a community, or which are considered “important.” The latter category refers to wildlife designated uncommon, threatened or endangered, or wildlife of recreational or eco-nomic value. An assessment of project operation including existing and proposed effects on vegetation must consider stack and cooling tower emissions. Predicted ground-level concentra-tions of stack emissions and cooling tower salt are compared to exposure levels considered thresholds for possible injury or damage, and to exposure levels documented as injurious under filed conditions. Potential effects of facility operation (existing and pro-posed units) on wildlife from stack emissions, dust, increased human activities, and noise are evaluated. Additionally, the potential for bird collisions with plant components is evalu-ated. The magnitude of a potential bird-collision problem is evaluated from data compiled during field studies. Included in the impact assessment analysis is the use of the plant site by wildlife during station operation. Collecting ponds and other waste bodies provide habitat for waterfowl and amphibians, while areas cleared during construction and allowed to revegetate (or which are replanted) potentially provide habitat for a variety of species. Aquatic Ecology The aquatic ecology of the site intake and discharge waters as well as habitat removal associated with barge facilities is addressed, habitat and food web relationships of the system characterized and potential impacts to the system estimated. Data requirements are met by literature review, interviews, and discussions with local fishermen and scientists and field collections. While data gathering focuses on fish species, particularly the commercially or recreationally important species, other biotic elements of the lotic and lentic environ-ments are identified. Evaluation of potential impacts of the construction and operation of the proposed facility consist of projecting the effects of the various activities on the description of existing environmental conditions developed as a result of the field program, literature review and agency contacts described above. The primary construction impacts likely to affect the aquatic habitat are those associated with the construction of the intake facility and secondarily increased erosion due to construction. Impact assessment of construction activi-ties centers primarily on habitat lost or denied due to actual physical placement of structures and habitat degradation. Attention is focused on those species which appear sensi-tive to habitat loss; which function as critical components of the aquatic community; or are considered “important” (rate, threatened or endangered, or of commercial or recreational value). Assessment of operational impacts centers on the effects of water withdrawal and the associated losses to the fish commu-nity due to entrainment and impingement. Potential changes in the population structure all addressed. Losses are estimated from population densities and from the field sampling program. Entrainment losses are expressed as “adult-equivalents” if war-ranted for important species. Potential discharge effects (ther-mal and chemical) are based on information developed from the literature review and input of engineering parameters. C016_007_r03.indd 996C016_007_r03.indd 996 11/18/2005 11:01:29 AM11/18/2005 11:01:29 AM

997 Land and Waterway Use The purpose of the land and waterway use—demographics effort is to: 1) determine the existing land use of the site and existing and future land and waterway use pat-terns in the surrounding area in order to assess any conflicts which may exist and to evaluate any impacts on land use that may occur from the con-struction and operation of the plant; and 2) determine the population growth patterns of the area in order to assess the impact the plant will have on nearby towns and communities in the area. Based on the existing land uses, and the analysis performed by other disciplines such as terrestrial and aquatic ecology and air quality, impacts upon adjacent land uses caused by construction and operation are estimated. This impact assessment includes the impact of storage pond construc-tion, noise, dust, plant appearance, stack emissions, cool-ing tower fogging and salt depositions, and construction stage traffic activity on residential, recreational, agricul-tural, and other adjacent land uses in the area, as well as the compatibility of the proposed plant with local land use plans, aesthetics, and regulations. Specific attention is given to the type and relative value of the land uses to be preempted or adversely affected by plant construction and operation. The impacts of the increase in activities on a river if applicable is estimated including additional barge traffic staging in the area and the impact of these activities on exist-ing movements and facilities in the vicinity of the area. The demographic impact assessment consists of com-paring the population projections for the study area to the expected population influx to be caused by plant construc-tion and operation. The comparison is done by taking the estimated plant-related population influx as a percentage of the total projected population of the area to be affected by the incoming workers and families. Socioeconomics The purpose of the socioeconomics studies is to deter-mine and describe the existing socioeconomic base for the plant region and surrounding major towns and to assess the changes, either positive or negative, which would occur as a result of the construction and operation at the proposed site. The existing socioeconomic based is described for those areas likely to be impacted by the influx of construction and operational employment for the plant. Information required to describe the socioeconomic base of the area includes the following: 1) peak number of construction workers by craft during each year of plant construction; 2) estimate of the number of immigrant construction workers expected during construction of the plant; 3) existing and future capacity of the schools, hospi-tals, fire, sewer, etc., facilities in site area; 4) local government fiscal capabilities and local tax structure and tax bases; 5) employment and income statistics; and 6) economic base studies. Socioeconomic impacts can result from the influx of immigrant construction workers to the area around the plant. This occurs when the construction force required to build the plant is fairly large and there are a number of large construction projects competing for the labor supply in the area. The socioeconomic demand analysis qualitatively com-pares the demand for service facilities, and employment during the construction and operation of the plant with the baseline socioeconomic projections. Any perceived increases in demand for local facilities is qualitatively evaluated with respect to the cost of the facilities and the ability of local units to finance them. Impacts associated with plant operation to be assessed include an evaluation of the change in local tax structure as a result of a large influx of new tax revenues to the local governments and the impact associated with the relocation of plant operating personnel into the area. Noise The purpose of this effort is to sample the existing ambi-ent noise levels surrounding the proposed site, and to esti-mate the environmental noise impact produced by the plant operation. In order to properly assess the noise environmental impact, plant noise emissions should be evaluated in terms of any State or local noise regulations. Consequently, vari-ous State and local regulatory agencies are contacted to determine the status of the regulatory constraints that might be imposed on the plant operation and construction noise emissions. In the absence of any such constraints, US EPA’s guidelines for the protection of “Public Health and Welfare,” as indicated in the “Levels Document” (550/9-74-004) are followed. A literature review is conducted to assist in identifying the major sources of noise of the plant and in quantifying them. The search includes various professional journals, other environmental reports, and manufacturers’ publica-tions. Construction schedule, equipment list, general arrange-ment drawings, project description manual, and operational parameters of major plant equipment (Forced Draft Fans, Turbine Generator, Pumps and Motors) are obtained from the appropriate sources. The facility noise levels are then evaluated and assessed in terms of existing regulations or guidelines and any potential restrictive conditions in either the working environment or the general site environment are identified. In addition, potential limitations to equipment are identi-fied as are appropriate mitigative measures. C016_007_r03.indd 997C016_007_r03.indd 997 11/18/2005 11:01:30 AM11/18/2005 11:01:30 AM
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Cultural Resources Cultural resource studies involve a review of appropriate records, and site-related literature to identify sensitive archaeo-logical, historical, recreational, and aesthetic resources in the project area. Most of the information required for cultural resource studies is available from State and Federal cultural resource agencies and societies. An on-site survey is conducted to locate any cultural resources eligible for the National Register of Historic Places. Project components which affect significant cultural resources are identified and the magnitude of the impact evaluated. Mitigation alternatives are addressed. If seri-ous impacts are discovered they should be brought to the attention of the developers promptly so that policy deci-sions can be made at the earliest opportunity to rectify the situation. Air Quality/Meteorology The purpose of this program is to obtain and analyze Air Quality/Meteorology data so that: the site can be charac-terized; the air quality implications of the facility can be evaluated; mitigative and control measures can be devel-oped; and an Environmental Report and PSD application can be prepared. The data required for the Air Quality/Meteorological pro-gram work efforts relate to: (1) The air quality/meteorological characterization of the existing site and region; and (2) The facility’s atmospheric emissions and operating characteristics. Specifically, the existing site and region must be characterized in terms of the regulated pollutant such as SO 2 , Particulates, NO x , CO, Photochemical Oxidants, and the local meteorol-ogy, including winds, stability, and other physical charac-teristics. In addition, the facility’s emission characteristics including their quantity and quality must be developed so that their impacts can be established. To establish the required data base it is necessary to gather and update existing emission inventory information, collate meteorological and air quality data, review present and proposed PSD Class I and nonattainment areas, evaluate topographic influences and monitor the region’s air quality characteristics. The task of establishing adequate meteorological and air quality data bases includes evaluating any existing local meteorological and air quality data. The validity of the data and its representativeness with respect to the proposed site must also be assessed. As required, data from other sources is evaluated as a basis for comparison with local data, or as a supplement to local data where necessary. The objective is to establish meteorological and air quality data bases which are most representative of the proposed site. A report should be prepared to provide technical sup-port for a construction permit application under the PSD provisions of the Clean Air Act of 1977. Described in the report are the data bases, methodologies and models utilized in the analyses. The PSD report also includes appropriate maps, summary tables and figures necessary to display relevant information such as locations of plant sites, PSD Class I and nonattainment areas, and resultant pollutant concentrations. An atmospheric impact assessment of the proposed and alternative cooling tower types is included in the ER. Operational impacts of the tower to be considered include elevated visible plumes and deposition of cooling tower drift. Computer modeling is utilized to predict the impact of these occurrences. Ground level fogging/icing is also addressed. Computer modeling is utilized to predict the frequency and duration of ground level fogging and icing for the alternative cooling towers. The potential for interaction of the cooling tower and stack plumes must also be addressed. National Weather Service (NWS) data can be supplemented by any available meteorological data to the fullest extent pos-sible to develop the estimates of cooling frequencies, and salt deposition rates are given on an area basis and include more detailed information, as necessary, for any sensitive receptors. Health Implications The purpose of this work effort is to identify and evaluate the potential health concerns, including estimates of offsite exposures that may result from facility operation at the site. Once the concerns are identified, the need for controls and the feasibility of the gasification plant at a particular site from a public health perspective can be evaluated. Changes in coal type, process or waste treatment systems can be addressed if needed to mitigate a potential health concern. This allows and insures that alleviation of potential health problems is an integral part of the facility planning. The health implications to the offsite population are iden-tified and assessed. Specific analytical measurements from pilot plant studies, available information from similar indus-trial plants, and other existing studies regarding the health implications from coal conversion processes are used. The overall approach involves scaling the results of specific pilot plant runs and other study results to approximate a commer-cial size facility; applying standard air dispersion models and waste dilution criteria in order to predict exposure concen-tration; and evaluating the predicted concentration against known information on the toxicity of each contaminant. The identification of potential public health concerns requires not only the estimation of exposure levels but also the evaluation of the relative toxicity of each chemical species. Consequently, a review of the toxic properties of each iden-tified chemical substance or chemical group is required. At the conclusion of this evaluation each contaminant or chemi-cal group is categorized into one of four groups—potentially significant health problems, potentially minor health problem, no expected health problem, and those for which insufficient information is available. The results of this evaluation is then utilized to develop control systems and/or mitigative actions for the facility. In addition, the results are presented in the ER and discussed in terms of a cost/benefit framework. C016_007_r03.indd 998C016_007_r03.indd 998 11/18/2005 11:01:30 AM11/18/2005 11:01:30 AM

999 With regard to occupational health, worker exposure to toxic substances is a potentially serious problem which could significantly lessen and limit the benefits of alternative fuel technology. As such, its implications must be carefully eval-uated in the planning and design phases of this project. The Occupational Safety and Health Act (OSHA) contains basic worker protection guidelines and specific regulations which establish industry procedures for the protection of work-ers from exposure to potentially toxic or health impairing substances. However, the current regulations do not specifically address a coal gasification process and only limited operat-ing experience is available from existing gasification plants. Consequently, identification of potential occupational health problems must be done in an indirect manner through com-parison with other industries. This occupational hazard analysis yields identification of potential hazards, definition of possible control measures for as many of those hazards as possible, and identification of areas of concern where insufficient knowledge or control methodologies exist. In addition it provides input to: 1) design of worker protection programs to be imple-mented at the plant, 2) design of engineering controls to minimize work-er exposure to hazardous substances, for example, isolation of process steps, ventilation changes, pressure control, etc. Most of the procedural information, repeated from the arti-cle by Quig and Granger (1983) remains valid today. For a more quantitative treatment of the effluent emissions observed during plant operation the reader is referred to the study of Holt (1988) on the Cool Water plant and to the current Encyclopedia article, Coal Gasification Processes. PERMITTING FOR LANDFILL GAS ENERGY RECOVERY Purpose New York State Air Guide 41 (1996) provides guidance on the permitting of emissions from municipal solid waste landfills, including the use of landfill gas for energy recovery, flares and, also, passive venting, as per the following: Background Landfill gas (LFG) is generated by the decomposition of wastes in all municipal solid waste landfills, regardless of age or size. The total volume of gas generated is a direct function of the quantity of wet, decomposable refuse available; however, the rate of gas generation can vary greatly over time, depending on numerous factors (such as the volume of waste, the depth of the landfill and the amount of rain-fall the landfill receives), most of which are uncontrollable. Landfills the accept waste water treatment plant sludge for disposal tend to generate more LFG than those that do not. LFG is not generated until the available oxygen supply has been consumed and the decomposition process becomes anaerobic. The typical composition of LFG is essentially the same at all landfills and at all points within the landfill. The typical composition of LFG is: Methane 50–58% Carbon Dioxide 35–45% Hydrogen 1–2% Oxygen 1–2% Nitrogen 2–5% Non Methane Organic Compounds 3–5% (NMOCs) 1 LFG can, and should, be used for energy recovery. The energy content of LFG comes entirely from the methane component, which has a basic heating value of 1,000 Btu/standard cubic foot (scf). Since the nominal concentration of methane in LFG is approximately 55%, the heating value of raw LFG is approx-imately 550 Btru/scf, although this figure can, and will, vary somewhat. By comparison, natural gas is composed of 95% methane, giving it a basic heating value of 950 Btu/scf. At the majority of landfills in New York State, LFG is currently uncontrolled or passively vented to the atmosphere. Recovering and combusting such gas into useful energy will virtually eliminate harmful emissions from a fuel that is oth-erwise wasted. This also prevents the pollution associated with the use of fossil fuels (i.e., SO 2 ). If LFG is not com-busted, it will still escape to the atmosphere through the path of least resistance (diffused from landfill, vented or flared). Federal Regulations Air In accordance with the Clean Air Act, the U.S. Environmental Protection Agency (EPA) has proposed New Source Performance Standards (NSPS) under 40 CFR 60 Subpart WWW for municipal solid waste landfills. These NSPS will affect landfills that began construction or modifi-cation after the standard was proposed (5/30/91) or existing landfills that have accepted waste since November 8, 1987. It must be noted that this proposed rule is currently being developed. The rule is subject to change and it is possible that it will not be released. However, the guidelines contained in this proposed rule should be used in developing a permit for the use of landfill gas. Additional information regarding this proposed rule is included in Appendix A. In a recent Federal court case in Pennsylvania (Ogden Products Inc. vs. New Morgan Landfill Co.), the court ruled that the landfill in question is subject to New Source Review since it has the potential to emit more than 50 tons per year of volatile organic compounds. This decision, combined with the NSPS for landfills proposed by the EPA, will make all new landfills subject to the requirements of the CAA, partic-ularly if the landfill has the potential to emit volatile organic compounds at levels exceeding air quality standards. Hazardous Waste When LFG is recovered, it tends to cool, and some condensate is formed. It is stated in Section C016_007_r03.indd 999C016_007_r03.indd 999 11/18/2005 11:01:30 AM11/18/2005 11:01:30 AM
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124 of the Superfund Amendments and Reauthorization Act (SARA) of 1986 that if the aqueous or hydrocarbon phase of the condensate removed from the gas recovered from a landfill meets any of the characteristics of a hazardous waste (i.e., it fails the TCLP test), the condensate shall be considered hazardous waste and regulated accordingly. This section is an amendment to the Resource Conservation and Recovery Act (RCRA), but is not part of RCRA. Since this provision of SARA is not actually part of RCRA and there are no implementing regulations in 40 CFR, it may be bind-ing upon EPA, but RCRA-authorized states (such as New York) are not obligated to enforce its requirements. This issue could arise if LFG is to be recovered from a munici-pal landfill that meets the size and NMOC criteria cited in Appendix A and is included on the Superfund priority list of inactive hazardous waste sites. State Regulations Solid Waste 6 NYCRR Part 360 has requirements for the control of LFG during both the active life of the landfill and after the landfill is closed. While the landfill is in operation, the owner must periodically (i.e., quarterly) monitor for the presence of LFG at or above 25% of the lower explosive limit (LEL) at on-site structures and any off-site areas. When the landfill is closed, an LFG control system must be included in the closure plans to prevent the migration of concentrated LFG away from the site and to prevent damage to a landfill cap. LFG is lighter than air and will tend to rise causing the overlying cap to rise also. Generally the LFG is allowed to vent to the atmosphere through a porous gas vent layer that leads to gas vent risers spaced at approximately one vent per acre. Part 360-2.16 contains the regulations regarding LFG recovery facilities. These regulations require that anyone proposing an LFG facility obtain a permit to construct and operate the facility. The application for a permit must con-tain an engineering plan, engineering report and an opera-tion and maintenance plan. Hazardous Waste As cited above, some LFG condensate may exhibit hazardous waste characteristics. In an October 20, 1992 declaratory ruling applying to the Freshkills Landfill, the Department excluded landfill gas condensate from being regulated as a hazardous waste. This ruling was based on the grounds that the LFG was derived from a household waste and therefore excluded from hazardous waste regulation under New York State law. However, if the landfill received both munici-pal and industrial or hazardous waste, the condensate may be hazardous. The condensate would need to be analyzed using the TCLP method to determine if it is a hazardous waste. Air NYSDEC’s proposed Part 201 operating permit program (proposed to comply with the federal Clean Air Act Amendments of 1990) contains an exemption for LFG emissions vented directly (i.e., without a flare or energy recovery device) to the atmosphere that fall beneath major source thresholds as long as the facility is operating in compliance with 6 NYCRR Part 360. Such an exemption will not apply to landfills subject to NSPS or National Emissions Standards for Hazardous Air Pollutants. A number of landfills in New York State currently use flares or energy recovery for control of their LFG. These emission sources must have a permit from the Division of Air Resources. These permits are issued under 6 NYCRR Part 201. All energy recovery projects produce NO x in the combustion of the LFG. These projects must control NO x emissions as required under Part 227-2. For example, if a lean burn internal combustion engine running on LFG is used for energy recovery, the emission limit for NO x is 9.0 grams/brake horse power-hour (Part 227-2.4(f)). LFG recovery projects would be affected by either Prevention of Significant Deterioration (PSD) or New Source Review in Nonattainment Areas (Part 231) regu-lations depending on the location of the project. Projects in nonattainment areas are likely to be affected by NO x and CO requirements (Note: the entire state is nonattain-ment for VOC and NO x because the state is in the ozone transport region). This is because recovering energy with a combustion unit will create NO x and CO that often require emission offsets to be obtain and the installation of Lowest Achievable Emission Rate (LAER) technology. The EPA has issued interim guidance stating that sources may be exempt from New Source Review (NSR) provided that the project is environmentally beneficial and there are no adverse air quality impacts. This exemption from NSR is referred to as a pollution control project. The EPA presently expects to complete rulemaking on an exclusion from major NSR for pollution control projects by mid 1996. However, in the case of nonattainment areas, EPA believes that the state or the source must provide offsetting emission reductions for any significant increase in a non-attainment pollutant from a pollution control project. Presently, 6NYCRR Part 231 allows a Pollution con-trol project exemption only at existing electric utility steam generating units (25 megawatts of electrical output). Consequently, LFG projects which exceed the applicability thresholds, would have to obtain NO x offsets at a ratio of 1.3 or 1.15 to 1, depending on the location of the project (i.e., in a severe non-attainment area or in a moderate non-attainment area), and would be required to install LAER technology. Please note that this may change if the EPA determines that this type of project is eligible to become a pollution control project. Approach to Permitting—DAR When the economics of an energy recovery project using LFG are favorable, these projects are to be encouraged. The following is the hierarchy of preferred LFG uses: 1. Gas cleaning and upgrade to pipeline quality gas; 2. Energy recovery with gas pretreatment or conver-sion to a reusable chemical product; 3. Energy recovery without gas pretreatment; 4. Flares with high combustion efficiency (i.e., 98% or greater); 5. Vents, if no economically feasible use for the gas is available. C016_007_r03.indd 1000C016_007_r03.indd 1000 11/18/2005 11:01:30 AM11/18/2005 11:01:30 AM

1001 The following procedure will be used for permitting of energy recovery facilities that utilize LFG: If the LFG Is Pretreated (i.e., if the constituents other than methane are removed from the gas), then permit as a combustion source with no further emission testing or ambient modeling necessary to satisfy toxic concerns. The permit should address traditional combustion contaminants such as NO x and CO. However, the permit application for this type of option must include a detailed description of the method(s) to be used for gas pretreatment. LFG can contain up to 50%, by volume, CO 2 (35–45%) and air toxics (1–2%). The pretreatment employed must remove these compounds before the LFG can be permitted for just the traditional combustion contaminants. Note that gas pretreatment will minimize toxic products of incomplete combustion and minimize system corrosion. If the LFG Is Not Pretreated, then permit as a combus-tion source and use the total concentration of NMOC emit-ted to address toxic issues. Note that if the gas is burned, either by a flare or energy recovery process, generally the air toxics will be destroyed. It will be easier and more effi-cient to regulate the NMOC (or total VOCs) than trying to identify and regulate all contaminants of LFG emissions, since they can vary greatly depending on the waste dis-posed at the landfill. The permit should address traditional combustion contaminants such as NO x and CO. The EPA proposed standard of 20 ppmvd NMOC should be used as BACT for the control of untreated LFG used as a combus-tion source. Periodic stack testing of the emissions is rec-ommended at the discretion of the permit writer. With regard to compliance with Part 231, the LFG facility may need to obtain NO x and CO offsets at the ratio applicable to its location (i.e., 1.3 or 1.15 to 1). This requirement may change if the EPA decides that LFG-type facilities are eligible for a pollution prevention exclusion. The permit reviewer will need to exercise judgment to determine if the LFG facility is required to obtain these offsets. As stated above, an LFG facility can be used for energy recovery. While a combustion turbine or internal combustion engine is not normally considered add-on pol-lution control devises, they do serve the same function as a flare, namely to reduce VOC emissions at the landfill with the incidental benefit of producing useful energy (energy that would otherwise be produced using higher polluting fossil fuels). For an LFG facility the reviewer should pro-ceed as follows: 1. Verify that the NO x increase has been minimized to the extent practicable; 2. Confirm (through modeling or other appropriate means) that the actual significant increase in NO x emissions will not violate the applicable NAAQS, PSD increment or adversely impact any air qual-ity related value; 3. Apply all otherwise applicable SIP and minor source and permitting requirements and ensure that NO x offsets are provided in an area in which nonattain-ment review applies to NO x emissions increases. Coordination within the Department The use of LFG will require coordination of efforts between the Divisions of Air Resources (DAR) and Solid and Hazardous Materials (DSHM). If a landfill meets the criteria cited above and the emissions from the site must be controlled, the proposed plan for this control should be submitted to both Divisions. DSHM should focus their review of the proposal, based on the requirements of Part 360-2.16. DAR should focus their review on evaluating and permitting the combustion sources that utilize the LFG, as outlined in the previous section. Both Divisions must keep in mind that LFG can be a valuable resource for energy generation and that using this resource will conserve the use of other fossil fuels and permit the re-use of material otherwise considered waste. Further, the respective project managers handling a particular facility’s permit applica-tion should maintain communication to ensure that there are no unnecessary delays on developing a permit for an LFG facility. APPENDIX A OF AIRGUIDE 41 NSPS for Municipal Solid Waste Landfills In accordance with the Clean Air Act, the U.S. Environmental Protection Agency (EPA) has proposed New Source Performance Standards (NSPS) under 40 CFR 60 Subpart WWW for municipal solid waste landfills. These proposed NSPS will affect landfills that began construction or modi-fication after the standard was proposed (5/30/91) or exist-ing landfills that have accepted waste since November 8, 1987. It must be noted that this proposed rule is currently being developed. This proposed rule would require landfills to install active gas collection and control systems if they exceed both of the following criteria: • design capacity in excess of 2.500,000 Mg (2,700,000 tons); and • NMOC emission rate in excess of 50 Mg per year (50.05 tpy). Landfills closed prior to November 8, 1987 or having design capacities less than 2.5 million metric tons will be exempt once this rule is finalized. The NMOC emission rate is determined by the following equation: M NMOC = 2 L 0 R (1e– kt ) C NMOC (3.595  10– 9 ) where, M NMOC = mass emission rate for NMOC, Mg/yr L 0 = refuse methane generation potential, m 3 /Mg refuse (default value = 170 m 3 /Mg) R = average annual acceptance rate, Mg/yr k = methane generation rate constant, 1/yr (default value = 0.05/yr) t = age of the land fill in years C016_007_r03.indd 1001C016_007_r03.indd 1001 11/18/2005 11:01:30 AM11/18/2005 11:01:30 AM
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C NMOC = concentration of NOMOC, ppmv as hexane (default value= 4,000 ppm) 3.595  10 9 = conversion factor (Note: In the absence of site specific data, use the given default values to determine NMOC emission rate.) Each landfill of design capacity greater than or equal to 2,500,000 Mg must determine its NMOC emission rate, using the above equation. If the NMOC mass emission rate is less than 50 Mg/yr, the landfill owner would submit this information to the NYSDEC as part of the Part 360 permit. No further action regarding control of the landfill emission would be required. The emission rate will be recalculated annually, with a report submitted to the Department. This report must be submitted to the Department within 90 days of the issuance of a construction or operating permit or ini-tial acceptance of refuse, whichever is earlier. If the NMOC mass emission rate is greater than 50 Mg/yr, the landfill owner must submit a design for, and install a col-lection and control system at the landfill. This control system must be designed to reduce, in accordance with 40 CFR 60 Subpart WWW, the emission of NMOCs by 98% by weight. Wehland and Earl (2004) present the inconsistencies in legal and enforcement interpretations of the PSD requirement for NSR major modifications and hence the criteria by which to determine the need for a PSD permit and the installation of BACT. There is no need to install equipment if the modifi-cations are of the routine maintenance, repair or replacement without increase in unit capacity. For each of the four cases involving coal fired power plants in which decisions were reached prior to 2004, the court’s conclusions were different, and in some cases significantly different. In U.S. vs. Southern Indiana Gas & Electric Co. (S.D. Ind. 2003), the district court ruled that the utility had fair warning about EPA’s decision to review the records of the affected unit, only, in determining if the maintenance was routine, but deferred its final determina-tion to the more general NSR applicability. In U.S. vs. Ohio Edison (S.D. Ohio 2003), the court concluded that fair warning was given to the utility in the plain language of the CAA. The court gave weight to establishing the routine nature of the maintenance by analyzing the all of the factors below for the projects: (1) budgeting and accounting, (2) purposes and costs, and the (3) net emissions increase In U.S. vs. Duke Energy (M.D. N.C. 2003), the district court ruled that EPA’s past practices in other cases require that industry-wide rather than the individual unit’s past practices were the criteria to be followed. Also the court favored an increase in emissions analysis to be on a “Projected actual”, rather than on a “future potential” basis. They also indicated that when determining the applicability of a modification, the NSPS rule of not increasing the maximum hourly emis-sions rate should be followed. In the case, Tennessee Valley Authority vs. U.S. (11 th Cir. 2003), the decision by the circuit court side-stepped the pri-mary differences and ruled against the EPA because of its use of an administrative procedures that deprived TVA of its rights to a hearing. In October 2003 the EPA defined a rou-tine project as one that would cost less than 20% of the total cost of replacing an emitting unit. The new rules and lack of enforcement were being challenged as of 2004. An alter-native to the current regulations offered by the authors, “is to eliminate the NSR and incorporate plant-wide emission limits in operating permits.” They also recommend model-ing and employing maximum achievable control technology (MACT) when modeling results determine controls are nec-essary to protect the air quality. REFERENCES Holt, N.A., EPRI Report AP-5467, Feb. (1988). Quig, R.H., Chem. Eng. Prog., 76, 47–54, March (1980). Quig, R.H. and Granger, T., Encyc. Of Env. Sci. & Eng. Vol. 1, 103–113 (1983). NYS Department of Environmental Conservation, Albany, New York, Air Guide 41, p. 1–5, March (1996). USEPA TITLE 40 CFR 52.01–52.2, P. 9–55 US Government Printing Office, Washington DC: July 1, 2000. Ibid Title 40 CFR 51.166, p. 167–186 Wehland C. and L. Earl, Clearing the Air, Environ. Protection, p. 20–22, 66, June 2004. http://www.epa.gov/ttn/nsr/ gen/wkshpman.pdf ROBERT H. QUIG THOMAS GRANGER Ogden Products, Inc. EDWARD N. ZIEGLER Polytechnic University C016_007_r03.indd 1002C016_007_r03.indd 1002 11/18/2005 11:01:30 AM11/18/2005 11:01:30 AM
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INTRODUCTION It is estimated that over 1.5 billion people in the world are without adequate water supply and waste disposal facili-ties. 1 Waterborne diseases kill an average of 25,000 people every day, and millions suffer the debilitating effects of the diseases. 2 Concerned about the need for safe water supply and sanitation, the United Nations (UN) declared 1981–1990 as the International Water Supply and Sanitation Decade with the professed goal of supplying potable water for all the people of the world by 1990, and also of providing all people with the means to safe disposal of human excreta. This goal was highly optimistic in view of the fact the nearly 80 percent of the population in the developing countries does not have access to piped water supply, and even a large percentage lacks public sewers and household waste disposal systems. 3,4 At the end of the International Water and Sanitation Decade, it was estimated that almost 31 and 44 percent of the world population was lacking safe water supply and adequate human waste disposal, respectively. The global population being 5.28 billions, total population currently having inad-equate water supply and sanitation is therefore staggering. 5 – 7 Based on an assessment of the successes and failures of the Decade, it is believed that much has been accomplished, but progress is needed on all fronts: rehabilitation and operation of existing systems, training of personnel, financing, and new construction to achieve the goals of the Decade within a reasonable time in the future. In this article many factors that contribute to successes and failures of the Water Decade goals are reviewed. The discussion is divided into (1) under-standing of the needs, (2) appropriate technology for water supply and waste disposal, (3) commitment, (4) financial resources, (5) training of people to plan, design, build, oper-ate and maintain water and sanitary projects, and (6) role of developed nations. 8 – 10 UNDERSTANDING THE NEEDS Adequate supply of safe water and basic sanitation are the foundation of health. Water pollution and poor sanitation are probably responsible for 80 percent of the morbidity and mortality in the developing countries. It is estimated that over 900 million cases of diarrhea related illness occur each year, resulting in the death of over 3 million chil-dren. Common diseases associated with polluted water are grouped in Table 1. 11 Prevention of such diseases depends on the improvement of the quality of the water supply, personal hygiene, food handling and preparation; as well as the provi-sion of adequate sanitation, including sanitary facilities for human waste disposal. The importance of personal hygiene specially on the part of mothers and children is the key to beneficial results in dis-ease prevention. Therefore, more intensive activities directed to improve personal hygiene should be emphasized in the developing countries. Furthermore, a meaningful program of providing safe water supply in developing countries must also include safe disposal of human excreta, basic education, and improvement of sanitary conditions. The major constraints on the progress of the International Drinking Water Supply and Sanitation Decade have been operation and maintenance and rehabilitation of the systems that were built earlier. Broken-down and poorly functioning facilities waste money, are a threat to health, and discourage future investments. Also, inappropriate technology is at the root of many water supply and waste disposal problems in the developing countries. 12,14 APPROPRIATE TECHNOLOGY Water Supply The goal of the UN Water Decade was to provide “clean water and adequate sanitation for all by 1990”. It should be noted that this did not mean a tap and a flush toilet in every house. Reasonable access to safe water is usually understood to be within 500 m of the household; for many developing countries, adequate sanitation probably refers to some tech-nology intermediate between the water flush toilet and the simple pit latrine. The scope of the task of the UN Water Decade was truly enormous considering that the two pri-ority areas are the rural population (71%), who often have to travel long distances for water, and the crowded urban poor (25%), for whom water supply often is grossly inad-equate; 87% of rural population and 47% of urban fringe areas lack adequate sanitation. 12 Naturally, achieving uni-versal coverage would mean not only supplying almost one billion people currently without safe water supplies and the 1.7 billion people without sanitation, but matching popula-tion growth as well. Annual investment is currently in the range of 15 to 20 billion dollars per year—about 2 to 3 per-cent of gross investment in developing countries. If the share C016_008_r03.indd 1003C016_008_r03.indd 1003 11/18/2005 11:01:57 AM11/18/2005 11:01:57 AM
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remains constant over the next fifteen to twenty years, eco-nomic growth will allow investment to double in real terms, to 30–40 billion a year. 13 Therefore, selection of appropriate technology and service levels must be established in bring-ing down the capital costs of water supply and sanitation projects. It was also demonstrated in the first half of the Decade that the biggest priority is correcting the inadequate training of the operating personnel. 14 Selection of appropriate technology for use by the devel-oping countries requires (1) understanding of the cultural background, regional environmental conditions, and local needs; (2) selection of appropriate systems that will be within TABLE 1Common disease associated with contaminated water and poor sanitationDisease Common VehicleWater-borne diseasesAmoebic dysenteryBacillary dysenteryCholeraCriptospridiosisGastroenteritisGiardiasisHepatitisLeptospirosisParatyphoid feverSalmonellosisTyphoidDiseases transmitted by ingesting contaminated water and foodWater-washed diseasesConjunctivitisHookworm (Ankylostoma)LeprosyScabiesSkin sepsis and ulcersTrihcuriasisWhipworm (Enterobius)YawsLack of adequate quantity of uncontaminated water, and poor personal hygiene create conditions favorable for their spreadWater-based diseasesBilharziosisDracunculosisOncholersosisPhilariosisSchistosomiasisTreadwormDiseases caused by infecting agents by contact with or without ingestion of water. An essential part of the life cycle of the infection agent takes place in an aquatic animalFecal-disposal diseasesClonorchiasisDiphyllobothriasisFasciolopsiasisParagonimiasisDiseases caused by infecting agent mostly contracted by eating uncooked fish and other foodWater-related vectorsArbovirusBancroftianDengue feverEncephalitisFilariasisHemorrhagic feverMalariaDiseases transmitted by insects which live and breed close to water. Infections are spread by mosquitoes, flies, and insect biteAdapted in part from Ref. 11.C016_008_r03.indd 1004C016_008_r03.indd 1004 11/18/2005 11:01:57 AM11/18/2005 11:01:57 AM

1005the financial (minimizing initial investment cost as well as maintenance cost) and technical (minimizing operational failures) resources; (3) training paraprofessional rural water technicians (using available labor where possible instead of expensive imported equipment); (4) promoting complemen-tary activities to help people to obtain the most benefits from the systems (so that users will receive long-term benefits of these basic services); and (5) selection of the most appropri-ate water source and the most appropriate energy source for conveying water to its users. The different sources of small community water supply systems in developing countries can be categorized as fol-lows: (1) groundwater, (2) rain water, (3) springwater, and (4) surface water. Depending on the sources of water supply, many techniques have been found effective and applicable to the water and sanitation programs in the developing coun-tries. Some of these techniques are presented below . Groundwater In areas where groundwater is read-ily available at moderate depth, constructing a number of wells fitted with hand pumps is by far the cheapest means of providing a good water supply. 14 Although, community water systems piped under pressure to households and public standposts may be an ultimate goal, many areas will realisti-cally have to seek hand pumps as an interim if not an ulti-mate measure. The trouble with most hand operated water pumps used in developing countries is that they are not hardy enough and require frequent maintenance. Pump parts are usually expensive to buy and are difficult to make locally to fit the pump. Development work started at the Consumer Research Laboratory (CRL) in England has led to the snappy plastic pump: a simpler, cheaper and hardier device that has many beneficial features. A complete description of such hand pumps is given by Sattaur. 15 Additional information on other types of hand pump manufactured in developing coun-tries may be found in Ref. 15. Hofkes provides some other techniques and methods of groundwater withdrawal used by small water supply systems in developing countries. 11 Rainwater In developing countries rainwater is some-times used to supplement the other water supply sources. In some tropical islands rainwater is the only source of domestic water supply. Rainwater harvesting requires adequate provi-sion for the interception, collection and storage of the water. Generally, cisterns are built to collect the runoff from the roofs. Water quality preservation is very important and some basic measures should be followed to exclude bird drop-pings, insects and dirt from the stored water. Also, storage in cool conditions, exclusion of light, and regular cleaning is essential. Simple disinfection devices may be very useful. Rainwater catchments are relatively simple to construct and maintain. It is expected that these systems will be widely used in the future. In Kenya, concrete jars used as storage tanks are said to be the most popular appropriate technology. Their popularity is growing among the villagers in Thailand where the construction and maintenance of these units is undertaken by technicians of the Sanitation Division of the Department of Health. The technician directs the voluntary labor of villagers in constructing concrete storage tanks rein-forced with bamboo. The Villagers then repay the costs of the tanks in 12 monthly installments. The owners of these tanks, having contributed so much of their time and money into their construction are usually very keen to operate and maintain it properly. 16 Design details and economics of many cisterns, storage tanks, and other rainwater harvesting systems may be found in Refs. 17 – 21 Spring and Surface Water There are many situations in the developing world where water is available from a nearby stream or spring. Various devices have been constructed to utilize the energy available in flowing streams to pump the water to the point of use. The more successful devices, that will represent substan-tial savings in pumping water are the hydraulic ram pumps (hydram) and low-head turbine pumps. One converts pres-sure energy to mechanical work and the other converts kinetic energy to mechanical work. These two practical devices have been described and compared in detail by Schiller. 22 He observed that the hydram is easier to operate and maintain, but installation of the turbine pump is easier and simpler. Before the Water Decade program started the water qual-ity control was given least importance in developing coun-tries. Perhaps, the major reason was inappropriate operation and maintenance of the equipment. The primary goal of any water project started in the Drinking Water Decade was to provide a facility and system that can be operated, maintained and managed at local levels giving self sufficiency with proper personnel and financial needs. 23 Local capabilities for operation and maintenance must be developed through training local maintenance personnel, establishing a locally managed maintenance fund, selecting an easily maintained technology, and requiring capital contributions from the community to increase local sense of ownership and respon-sibility for the systems. 24 Finally, a successful drinking water program requires extensive local participation (materials and labor) and minimize dependence on overseas materials and equipment for construction and operation of facilities. 25 Human Waste Disposal Rapid growth of the urban populations (mainly because of migration from rural areas) has led to severe problems in providing human waste disposal systems. Only 32 percent of the population in the developing countries is directly con-nected to sewer systems. Therefore, the collection and dis-posal of human wastes constitute a serious environmental and health problem. 26 Several alternatives are available; each has its own limitations and constraints. Certainly there is no single option appropriate to all situations. The range of options described below is sufficient to cover the vast major-ity of the situations within the low income communities of the developing countries. One of the fundamental principles of community sanita-tion is to remove all putrescible matter, particularly human wastes. A satisfactory excreta disposal method must satisfy the following requirements: 26 1) Should not be accessible to flies or animals 2) Should not cause odors or unsightly conditions C016_008_r03.indd 1005C016_008_r03.indd 1005 11/18/2005 11:01:57 AM11/18/2005 11:01:57 AM
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3) Should be simple and inexpensive to construct and operate 4) Should not cause ground water or surface water contamination 5) Should not cause soil contamination. The appropriate technology for human waste disposal in developing nations fall into two major applications (1) rural, and urban areas without sewers, and (2) urban areas having municipal sewers. Appropriate technology for each of the above applications are discussed below: Rural and Urban Areas without Municipal Sewers The environmentally acceptable methods of human waste disposal in rural areas include various types of sewerless composting toilets. Common examples of such toilets are bored-hole latrine, pit privy, vault privy, septic privy, chemi-cal toilet, soil or composting toilet, methane forming toilet, and box-and-can privy. 26,27 These devices are simple and inexpensive to build and operate. Each of these devices is briefly discussed below. Bored-hole Latrine: Bored-hole latrines consist of a hole in the ground 25 to 60 cm in diameter, and 2 to 3 meters deep. The hole may be braced to prevent it from caving. A concrete slab with a hole cut in it may be placed over it, and the entire assembly is made into an outhouse. When the hole is filled, the structure is moved to another hole. Fly and odor problems are controlled by keeping the hole covered, and dropping dry soil in the hole on a regular basis. Deep bored-hole latrines present danger of ground-water pollution. 26 Pit or Vault Privy: Pit or vault privies can serve the needs of homes, schools or groups of homes. A concrete pit or vault is constructed in the ground and a toilet seat is located on the top. The seat cover must be kept closed to prevent flies from entering. Odor is a problem. A vent pipe raised over the roof has been helpful in odor control. In 3 to 4 months when the pit or vault becomes full, there is the unpleasant job of cleaning it. Some vaults have two compartments. When one compartment is full it is kept closed for 2 to 3 months while the other side is used. During this time, the excreta is decom-posed, and cleaning becomes less objectionable. Pit or vault privies with separate back covers have also been used. These back covers help in the cleaning operation. 26 Septic Privy: Septic privies utilize a liquefying tank similar to a septic tank. The waste is digested and overflow may be discharged into a percolation field. The toilet has a shallow trap. After use the toilet must be flushed by pouring 2 to 3 liters of water. 26 Chemical Toilet: Chemical toilets consist of a tank in which waste accumulates. The toilet seat is provided directly over the tank. Caustic soda (sodium hydroxide (NaOH)) is most commonly used to kill the bacteria and to liquefy the wastes. The caustic soda dosage is 1 to 2 kg of sodium hydroxide per month for a family of four. The tank is emptied periodically. If caustic soda is used the tank contents can be carefully applied over farming land. Many types of chemical toilets are available from various manufacturers. 26,28,29 Soil or Composting Toilet: This is dry toilet capable of being used indoors. The toilet consists of a wooden frame with toilet seat, and a bucket lined with a plastic bag. The toilet is started with a layer of dry soil 10 to 15 cm deep. Users must sprinkle several scoops of soil after each use. Once or twice a week, the bag is removed, tied and stored. After a decomposition of several weeks the contents are spread over farm land. 30 A more involved is the Clivus Multrum composting toilet. This toilet was developed and has been successfully used for some time in Sweden and is now manufactured in the United States. 31 The toilet is capable of composting toilet waste, kitchen wastes, and even leaves and grass. It has three sloping chambers and is started with a layer of peat moss four to five inches thick. Design and operational details may be obtained in Ref. 31. Another toilet similar to Clivus Multrum toilet is the Toa-Throne compost toilet also devel-oped in Sweden. Another dry composting toilet that has been proven highly successful in Vietnam, offers a suitable system for all developing nations. 32 The toilet consists of two-holer outhouse in which only one hole is used at any one time. There is no raised seat, instead each hole is placed in a squat-ting plate at floor level. The urine flows out and soaks into the ground outside the outhouse. The fecal wastes go into the other hole. The user must drop dry soil or ash after use. When the toilet is two-thirds full, the rest is filled with soil, and the vault is tightly sealed. The other side is started. After a composting period of approximately 45 days the contents are taken out and used over the farm as rich compost. 33,34 Methane Farming Toilet: In India small biogas plants are extensively built in rural areas. These biogas plants anaero-bically digest animal manure and other organic wastes, and the methane is used to light, heat, and power the farms. Singh gave the basic design and construction details of such toilet. 34 Other designs of anaerobic digesters utilizing human, animal and other organic wastes are used in Kenya and Brazil. 35 – 37 Morris developed a package unit for meth-ane generation from human wastes. 37 Khandelwal provided design and operational details on dome-shaped biogas plants used in India. 38 Eusebio and Rabino provided design of large biogas plants used in Philippines, India and Africa. 39 Box-and-can Privy: The toilet system consists of a wooden box, the lid and toilet seat. The can or pail is remov-able through the top or side of the box. The cans are removed manually under regular scavenger service, emptied, cleaned, and replaced. This system is most commonly used in cities that do not have a sewerage system. This type of system is associated with odors and serious fly problems if the lids are not tightly closed after use. For satisfactory operation there should be a regular scavenger service, preferably under a governmental supervision with ordinances covering types and size of box and can, method of emptying and cleaning of the cans, and ultimate disposal of the human waste. A speedy and convenient way is to use identical toilet boxes and cans for the entire community. The scavengers remover the can and place it in his vehicle without emptying, and replacing a clean can. The vehicle when full is taken to a central disposal facility for emptying, and replac-ing with clean cans. The disposal facility should be located in C016_008_r03.indd 1006C016_008_r03.indd 1006 11/18/2005 11:01:58 AM11/18/2005 11:01:58 AM

1007a remote area and should utilize anaerobic digesters whereby the recovery and sale of methane gas, and digested sludge as soil conditioner can be achieved. The central disposal facili-ties should be equipped with running water, hose, and chemi-cal solution for washing and cleaning the cans. Experience has shown that such systems based on pay-ments by the residents to private scavengers have been unsat-isfactory. The service is poor, irregular and wastes may be dumped uncontrolled upon land and in waters. The box-and-can system should be used only as a tempo-rary means of waste disposal with continued effort to replace it by other more acceptable methods. Furthermore, it should be carried out only under the supervision of trained person-nel and under strict governmental control. Urban Areas with Municipal Sewers The wastewater collected through municipal sewers contains large volumes of water. Therefore, treatment technology is much more complex than discussed above. Treatment schemes to achieve second-ary level of treatment (90% organics and total suspended solids removal) include screening, grit removal, primary sedimenta-tion, biological treatment (activated sludge or trickling filter), final clarification, and disinfection. Other physical, chemical and biological treatment processes may be added to remove phosphorus, nitrogen, and additional organics and suspended solids. The solids fraction (sludge) is digested aerobically or anaerobically. Although, such treatment technology may be desirable for the developed nations, their use in developing nations may not be appropriate. Such treatment processes are costly to build, and complex to operate. Desirable treatment meth-ods for developing nations may include the following: 1) stabilization pond followed by effluent reuse on farming lands, 2) Imhoff tanks followed by stabilization pond and effluent reuse on farming land, and 3) upflow anaerobic sludge blanket process. Imhoff tanks provide primary sedimentation, and anaero-bic digestion of settled sludge. The methane is collected for energy source and digested sludge is used as compost. The stabilization pond (oxidation pond or lagoon) is an earthen basin that retains the wastewater for sufficient time to stabilize the organic matter, and destroy large percentage of pathogens. The effluent is used for irrigation, or discharged into natu-ral waters. 40 – 43 The upflow anaerobic sludge blanket process (UASB) was developed in Netherlands and is extensively used and tested in the developing nations. 44 In this process the wastewater enters the bottom of the reactor and percolates up through the sludge blanket where organics are converted to methane and carbon dioxide by anaerobic organisms. The gas is collected, and treated effluent is drawn off from the top. 34 COMMITMENT The water supply and sanitation schemes in developing countries cannot be successful without the willingness of the government to commit the resources to undertake water supply and sanitation projects. Unfortunately, the govern-mental priority in this area is quite low. Most of the develop-ing countries set their priorities as follows: (1) agriculture, (2) industries, (3) energy resource development, (4) educa-tion, (5) commerce and transportation, (6) family planning, (7) housing and urban development, and (8) water supply, and sanitation, and environmental control. 45 Such priorities have been set on account of necessities. It is necessary that the developing countries give needed priority on water and sanitation. FINANCIAL RESOURCES The success of any program in any country depends upon the financial commitments of the respective governments. Developing nations (except for the oil exporting nations) are poor and have very limited funds. A 1975 study indi-cated that villagers if they have to pay more than 50 cents per month for water supply, they would not participate in the program. 45 Their ability to pay for water and sanitation is very limited. Success of the program will depend upon outside funds, and local labor. TRAINING AND MANPOWER DEVELOPMENT It is well recognized that the success of any program requires well trained people. Unfortunately, past experience has shown that many internationally supported training pro-grams were not successful because the emphasis was incor-rectly placed. Engineers from developing nations when trained in the western world generally learn the theory and design of most sophisticated unit operations and processes in water and wastewater treatment and environmental engi-neering. When they return to their countries, they are gen-erally eager to utilize such technologies, although in most cases these may be quite inappropriate. Furthermore, for-eign consultant’s unfamiliarity with the cultural and operat-ing competence of the people in developing countries have resulted in selection and design of technology that have not functioned. What is really needed is a program where training at all levels may be effectively provided. The includes training of central government officials and engineers; local govern-ment officials, residents and technicians; on-the-job training of operators; and users education. Government officials set the priorities and make funding decisions. Engineers have responsibility to evaluate, select and implement the appro-priate technology. Local officials participate and support the program. The technicians and operators have the responsibil-ity for continued operation and maintenance of the system. And finally, users education is essential as they are the ulti-mate beneficiary. In order to effectively provide such a complex training opportunity, programs must be developed in the develop-ing nations. Such training programs must be developed as C016_008_r03.indd 1007C016_008_r03.indd 1007 11/18/2005 11:01:58 AM11/18/2005 11:01:58 AM
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academic programs, short courses, seminars, and internships to address different audiences yet meet the specific needs of each. Brief discussion is given below. Academic Programs Academic programs include regular undergraduate and graduate programs at universities, and technology or voca-tional programs in polytechnics and colleges. Both programs have different objectives. University Programs Regular academic programs such as master’s and bachelor’s degrees in civil, sanitary or envi-ronmental engineering, biology, public health, and so on. have been modeled along the lines of western universities. These programs often may not be directly applicable to the needs of the developing nations. It is necessary to modify or develop new programs tailored for their national needs. As an example, graduates in civil, sanitary or public health engi-neering must also know community interactions, socio-eco-nomic implications, relationships between service levels and health and well-being, that dictate the success or failure of any water supply and sanitation projects, especially in rural and urban settings of developing nations. Technology Programs The technology or vocational programs should be directed towards training technicians, health inspectors, and community workers. Specialized train-ing is needed so that these personnel can undertake field work, organize the community, conduct training, and assist the com-munity in the selection and installation of water supply and sanitation facilities, and provide continued operation and maintenance of such facilities. Special training is needed for personnel to motivate people and implement the programs in rural areas where approximately 75% of the population lives. Short Courses and Seminars In corporation with the health ministry specialized short courses of one- or two-week duration should be conducted at universities, colleges, and high schools. These short courses should be designed to provide training to full-range of people including decision makers, engineers, operators and community workers. Decision Makers The government officials who have the responsibility for setting up priorities, and allocation of funds must be aware of the relationship between service levels and health and other benefits, cost of construction and operation, and short-range and long-range implications of the investments in water supply and sanitation projects. Engineers and Designers The intensive short courses designed for engineers and designers should cover the suc-cesses and failures of different projects, improvements needed in future systems, public education, and how to relate health conditions and project objectives in order to develop the most cost-effective system for the specific conditions. Operators and Community Workers Intensive short courses should be conducted for operators and community workers in basic topics ranging from chemistry, biology, vec-tors, communicable diseases, to metal working, equipment repairs, operation and maintenance, leak repairs, book keep-ing, to management of public works projects. On-the-job Training On-the-job training programs of varying periods with or without short courses should be developed to train field workers and inspectors and local people in construction techniques and operation of water supply and sanitation systems. Such practical training can be a powerful tool for manpower development. Primary Health Care Workers Health education or sanitation education should be provided at village level. Villagers, literate or illiterate, should be trained as primary health care workers, or barefoot doctors, whose training should be emphasized on prevention, and curative care. Six to 12 months intensive training could be provided at local high schools or through health education service. Users Education Training of villagers in water supply and sanitation must also be provided as part of user or adult education program. This can be achieved by mass campaigns by health education extension services. Health education must also be instituted in primary schools. This will provide the broadest, and most dependable coverage to younger groups. The program must include community sanitation; hygiene habits in home; fly rodent and other vector control; water con-tamination and use of water supply devices; and proper use and maintenance of various types of privies and latrines. Training and Educational Material, and Education of Trainers It is important that training, educational and technical material should be in the form of posters, technical books, manuals, photographs, slides, films and audio-visual aids. Audio-visual equipment has been highly successful in train-ing personnel, and illiterate population in rural areas. A porta-ble power generator may be necessary for rural areas without electrification. Educational material must be carefully prepared for the specific audience. General health related material covering disease transmission, vector control, water and food pro-tection, personal hygiene, should be prepared for general public with no education. Information on public use of water supply and sanitation devices should also be prepared for general audience. Technical and semitechnical information should cover the design and construction; and operation and maintenance of different types of water supply and sanita-tion devices presented earlier in this paper. The other most important of all training program activi-ties is the selection and training of instructors or trainers. Technicians and supervisors should be trained so that they can teach their colleagues, subordinates or interns on the job. Education of trainers should be provided in schools, through short courses, audio-visual aids, and job training. ROLE OF DEVELOPED NATIONS Developed nations can play a major role in helping the developing nations to achieve the original goals of the UN C016_008_r03.indd 1008C016_008_r03.indd 1008 11/18/2005 11:01:58 AM11/18/2005 11:01:58 AM

1009Water Decade. The assistance may come in the form of fund-ing of the international agencies (UN, World Bank, etc.) and international development agencies in their own countries. The technical assistance and transfer of know-how can also be achieved in the form of advisory services to the gov-ernments, utilities, and institutions. The assistance can be provided by short-term and long-term consultants for on-job training, development of educational material, and training of personnel and manpower development. REFERENCES 1. Kalbermatten, J.M. and F.W. Montanari, Water for the world: The scope of the challenge, Journal American Water Works Association, June 1980, p. 308. 2. Muyibi, S.A., Planning water supply and sanitation projects in devel-oping countries, Journal of Water Resources and Management, 118, July/August 1992, pp. 351–5. 3. Rao, S.V.R. and John A. Rasmussen, Technology of small commu-nity water supply systems in developing countries, Journal of Water Resources Planning and Management, July 1987, p. 485. 4. Witt, Vicent M., Developing and applying international water quality guidelines, Journal American Water Works Association, April 1982, p. 178. 5. Anonymous, Human Development Report 1991, UNDP, Oxford Uni-versity Press, New York. 6. Rural water supply, World Water and Environmental Engineer, June 1990, p. 46. 7. Theme Interaction, World Water, Journal American Water Works Asso-ciation, June 1988, p. 33. 8. The World Bank, “Development and the Environment”, World Devel-opment Report 1992, Oxford University Press, New York. 9. Churchill, A., Rural Water Supply and Sanitation: Time for a Change, World Bank Discussion Paper no. 18. Washington, D.C. 1988. 10. Bris, J. and D. de Ferrantis, Water for Rural Community: Helping People to Help Themselves, World Bank, Washington, D.C. 1988. 11. Hofkes, E.H., Small Community Water Supplies, Technology of Small Water Supply Systems in Developing Countries, John Wiley & Sons, Great Britain, 1983. 12. Schiller, E.J., The United Nations Water Decade and North American Engineers and Planers, Chapter 1, Water Supply and Sanitation in Developing Countries, Ann Arbor science, 1982. 13. The World Bank, “Development and the Environment”, World Devel-opment Report 1991. Oxford University Press, New York. 14. Wolman, Abel, The next five years, Journal American Water Works Association, June 1985, p. 12. 15. McJunkin and E.H.A. Hofkes, Hand-Pump Technology for the Devel-opment of Groundwater Resources, Chapter 4, Water Supply and Sanitation in Developing Countries, Ann Arbor science, 1982. 16. Sattaur, Omar, Developing countries switch to sanappy plastic pumps, New Scientist, November 26, 1987, p. 36. 17. Schiller, E.J., Rooftop Rainwater Catchment Systems for Drinking Water Supply, Chapter 7, Water Supply and Sanitation in Developing Countries, Ann Arbor Science, 1982. 18. Grover, B., Harvesting precipitation for community water supply, World Bank, Washington D.C., 1984. 19. Maddocks, D., An introduction to methods of rain water collection and storage, Appropriate Technology, 2, No. 3, 1975, pp. 24–25. 20. Maddocks, D., Methods of creating low cost membranes for use in the construction of rainwater catchment and storage systems, Intermediate Technology Publications, Ltd., London, 1975. 21. Watt, S.B., Rainwater storage tanks in Thailand, Appropriate Technol-ogy, 5, No. 2, 1978, pp. 16–17. 22. Schiller, E.J., Renewable Energy Pumping from Rivers and Streams, Chapter 5, Water Supply and Sanitation in Developing Countries, Ann Arbor Science, 1983. 23. Austin, John H. and James K. Jordan, Operation and maintenance of water systems in developing countries, Journal American Water Works Association, July 1987, p. 70. 24. Karp, Andrew W. and Stephen B. Cox, Building water and sanitation projects in rural Guatemala, Journal American Water Works Associa-tion, April 1982, p. 163. 25. Monk, Robert, Terry Hall, and Mohammed Hussain, Real world design: Appropriate technology for developing nations, Journal Ameri-can Water Works Association, June 1984, p. 68. 26. Ehlers, V.M. and E.W. Steel, Municipal and Rural Sanitation, McGraw-Hill Book Co., NY, 1965. 27. Ports, D.D., What’s in the future for composting toilet, Compost Sci-ence, Journal of Waste Recycling, 18, No. 4, July–August 1977, p. 16. 28. Qasim, S.R., Onsite wastewater treatment technology for domestic waste and special applications, The encyclopedia of Environmental Sci-ence and Engineering, Gordon and Breach, Science Publishers, Inc. New York, Third Edition, 1991, pp. 813–21. 29. Clark and Groff Engineers, Sanitary waste disposal for navy camps in polar regions, Final Report on Contract NBY-32205, Salem, Oregon, May 1962. 30. Leich, H.H., UN ignore waterless sanitation devices, Compost Science, Journal of Waste Recycling, 18, No. 3, May–June 1977, p. 7. 31. The Clivus Multrium Composting Toilet, Compost Science, Journal of Waste Recycling, 15, No. 5, Nov.–Dec. 1974. 32. Jounge, L.D., The Toa-Throne- A new compost toilet, Compost Sci-ence, Journal of Water Recycling, 17, No. 4, Sept.–Oct. 1976. 33. Leich, H.L. Sanitation for the developing nations, Compost Science, Journal of Waste Recycling, 18, No. 5, Sept.–Oct. 1977. 34. Singh, R.B., Building a biogas plant, Compost Science, Journal of Waste Recycling, 13, No. 2, March–April 1972, p. 12. 35. Methane farming in Kenya, Compost Science, Journal of Waste Recy-cling, 13, No. 5, Nov.–Dec. 1974, p. 15. 36. Company formed to advice our methane plant, Compost Science, Jour-nal of Waste Recycling, 15, No. 5, Nov.–Dec. 1974, p. 15. 37. Morris, G., Methane for home power use, Compost Science, Journal of Waste Recycling, 14, No. 6, Nov.–Dec. 1973, p. 11. 38. Khandelwal, K.C., Dome-shaped Biogas Plant, Compost Science, Jour-nal of Waste Recycling, 19, No. 2, March–April 1978. 39. Eusebio, J.A. and B.I. Rabiino, Research on biogas in developing coun-tries, Compost Science, Journal of Waste Recycling, 19, No. 2, March–April 1978. 40. Metcalf and eddy, Inc., Wastewater Engineering: Treatment, Disposal and Reuse, 3rd Edition, McGraw-Hill Book Co., New York, NY., 1991. 41. Viessman W. and M.J. Hammer, Water Supply and Pollution Control, 4th Edition, Harper & Row, Publishers, NY, 1985. 42. Qasim, S.R., Wastewater Treatment Plants: Planning, Design and Operation, Technomic Publishing Co., Lancaster, Pa., 1994. 43. Thery, Daniel, The biogas programs in India and China. Resource Man-agement and Optimization, 1, No. 4, Oct. 1981, Harwood Academic Publishers, NY. 44. Anaerobics attack tropical wastewaters, World Water, August 1988, p. 31. 45. Dallaire, Gene, UN Launches International Water Decade, US role uncertain, Civil Engineering, American Society of Civil Engineers, March 1981, p. 59. SYED R. QASIM The University of Texas at Arlington C016_008_r03.indd 1009C016_008_r03.indd 1009 11/18/2005 11:01:58 AM11/18/2005 11:01:58 AM
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INTRODUCTION During the past twenty-five years, man has subjected the earth to an ever increasing variety of chemical substances never before encountered by living organisms. Many of these foreign substances, which originated from industrial, agricultural and municipal sources, are seriously threaten-ing the natural environmental conditions established over geologic time by evolutionary processes. Organisms, includ-ing man, are finding it more and more difficult to escape the consequences of exposure to these compounds, many of which are known to interfere with life sustaining biochemi-cal and reproductive mechanisms. Little is known, however, concerning the effects the vast majority of these pollutants will have on plants and animals that inhabit this planet. The aquatic environment is the ultimate destination of most of these contaminants as a result of rainfall and runoff from the lands. The establishment of water quality requirements for the protection of fish life must, therefore, become an item of first priority. The task is complicated, however, by the fact that dif-ferent species of fish as well as different developmental states of the same or different species exhibit wide variations in their sensitivity or tolerance to foreign materials. In addition, the basic biochemical and physiological information needed to evaluate the harmful effects foreign substances have on organ-isms is severely lacking for fish and other aquatic organisms. It is the purpose of this chapter to briefly discuss the current state of knowledge in regard to the response of fishes to environmental contaminants. Because of the serious lack of information in the area of fish toxicology, † it is not pos-sible, nor is it within the scope of this discussion, to pre sent even an outline of the toxic effects of the many foreign sub-stances which fish encounter. Instead, representative com-pounds have been selected to illustrate the principles that are believed to play a major role in determining how fish respond to environmental contaminants. Unfortunately, these principles are based almost entirely on research per-formed over the last several decades dealing with the toxi-cologic responses of mammalian species, including man, to drugs and foreign compounds. Until equivalent research is performed on fishes, we will be forced to rely on these mammalian principles when attempting to evaluate the effects foreign compounds have on fish species. MECHANISMS OF TOXICITY Foreign substances can injure organisms through a vari-ety of mechanism but these can generally be grouped into two categories: specific and non-specific injury. Chemicals that produce non-specific injury usually do so at the site of exposure, such as skin, respiratory membranes, oral mucosa, and intestinal mucosa. Frequently, such injury is the result of the caustic or corrosive nature of the chemical with the cellular responses being directly related to the concentration of toxicant within the cell or tissue involved. Agents pro-ducing this type of injury are commonly referred to as “pri-mary irritants” because they induce local, minor to severe inflammatory responses and occasionally extensive necrosis (death) of cells. Excellent examples of these chemicals are acids, bases and aldehydes, all of which are strong irritants to mucous and gill membranes. Other compounds, unlike the non-specific action of the primary irritants, can have a high degree of specificity and act at low dose levels at certain receptor sites to produce pathological change in specific cells with subsequent altera-tion of the function of organ systems. The degree of injury is dependent on the efficiency of the repair mechanisms for the tissue involved. If a cell is not irreversibly damaged, func-tional and structural characteristics may return to normal. Cells that are permanently injured at usually replaced by fibrous (scar) tissue. Fibrosis can seriously impair the func-tional capability of the tissue or organ involved. Examples of substances that exhibit specific toxicologi-cal actions are those that produce mutations by interfering with the genetic machinery of germ cells. Mutation of a dominant gene may express itself immediately and produce fatal abnormalities (teratogenic effects) or early fetal death. Other mutations may not express themselves for several gen-erations and then suddenly appear creating serious abnor-malities for that individual and its offspring. Chemicals may be carcinogenic (e.g. diethylnitrosamine and aflatoxin) and initiate the growth of malignant tumors in fish and mammals (Stanton, 1965; Ashley et al. , 1964). Many toxicants directly or indirectly affect reproductive mechanism, gonadal growth and development, spawning behavior, and fry survival by specific toxicological actions. This can frequently result in a depletion or extinction of a susceptible species. † Toxicology is the scientific discipline that deals with the quantita-tion of injurious effects on living systems resulting from chemi-cal and physical agents that bring about alterations in cell or organ structure and function.C016_009_r03.indd 1010C016_009_r03.indd 1010 11/18/2005 1:12:29 PM11/18/2005 1:12:29 P

1011 FACTORS THAT INFLUENCE TOXICITY Several biological, physical and chemical factors play a part in determining the ultimate toxicological consequences of a foreign compound on an organism. To produce injurious effects, a toxicant must achieve an adequate concentration at its sites of action. The concentration attained at these sites in the animal obviously depends on the amount of foreign compound present in the animal’s environment. Equally important, however, are the extent and rate of the toxicant’s absorption, distribution, binding or localization in tissues, inactivation, and excretion. These factors are depicted in Figure 1 (Goodman and Gilman, 1970). The following sections discuss each of these aspects that play the major role in the response of organisms to foreign compounds. Absorption of the Toxicant Generally speaking, a compound with specific toxicologi-cal actions must first be absorbed and distributed (biological translocation) in an organism before it can reach its specific site of action and exert its toxic effect. The ease with which foreign substances are absorbed, therefore, is a significant factor in determining the toxicity of foreign compounds. Absorption of substances by fish occurs through the skin, oral mucosa, intestinal mucosa, and gills. Because it is nec-essary that gill surfaces be exposed to large volumes of water for the maintenance of adequate blood levels of CO 2 and O 2 , this organ is an especially vulnerable site for the absorp-tion of foreign materials. Fish are, therefore, exceptionally susceptible to toxicants that readily cross the gill epithe-lium. In addition, fish acquire many foreign substances from their diet by absorption across the gastrointestinal mucosa. It should be mentioned, however, that studies are severely lacking about this and other mechanisms of translocation of foreign substances in fishes. The biochemical and physicalchemical properties of a compound determine both its ability to cross biological membranes and its distribution within an organism. In gen-eral, the non-ionized, non-polar forms of compounds are significantly soluble in fat, i.e. lipid soluble, and are there-fore readily transported across the lipidal components which characterize animal-cell membranes (Whittaker, 1968). The chemical structure of a foreign compound also determines its ability to react with biological molecules as well as its susceptibility to biotransformation (metabolism) by organ-isms. The ability of an animal to metabolize foreign com-pounds is important to that organism because the products (metabolites) formed usually are less toxic (but occasionally greater) than the parent compound. A more detailed discus-sion of biotransformation mechanisms appears later in this chapter. Distribution of the Toxicant Once the toxicant is absorbed and has entered an organism’s blood or lymphatic system, it is readily transported and dis-tributed to sites of action, centers of metabolic breakdown or detoxication, storage, and excretion. Most toxicants are transported reversibly bound to blood proteins with only a small portion existing in the free or unbound state. Compounds must usually exist in this unbound state to react with biological molecules (receptors) and interfere with biochemical mechanisms. Therefore, the total amount of plasma protein available for the binding and transport of toxic substances plays an important role in the toxicological consequences of these compounds (Petermann, 1961). It is interesting to note that fish, when compared to mammals, have a distinct disadvantage in this regard since Locus of ActionReceptorFreeToxicantBoundToxicantPlasmaBoundToxicantMetabolitesExcretionAbsorptionFreeToxicantTissue DepotsBoundFreeBiotransformationFIGURE 1C016_009_r03.indd 1011C016_009_r03.indd 1011 11/18/2005 1:12:30 PM11/18/2005 1:12:30 P
1012
they have much less plasma protein. Compounds that have a high tendency to bind to plasma proteins may compete or displace one another from binding sites when they exist together in the blood. This may be the mechanism of danger-ous toxic interactions because plasma protein binding sites become so saturated that a greater percentage of unbound toxicant exists in the blood than would normally be present with only one toxicant. When the degree of plasma binding is high and the rate of release is low, plasma proteins can act as a storage depot for the bound substances. Storage depots also frequently result from a particular affinity a toxicant may possess for certain organs or tissues. Examples of this are the chlorinated hydrocarbon pesticides which are stores in body fat and heavy metals such as copper and mercury which are stored in the liver and kidney of fish (Life, 1969). Many foreign compounds are capable of producing a specific effect, that is, are selectivity toxic, on a specific bio-logical system or systems. These systems are said to be the site of locus of action of the chemical. The site may be con-fined to one anatomic location within the animal, or may be diffusely located throughout the animal. Two fundamental types of mechanisms are responsible for the selective action of chemicals on cells or cellular mechanisms. The first type is a result of factors that increase the con-centration of the toxicant at specific cell or tissue sites. This is accomplished in the organisms by mechanisms of selec-tive translocation and biotransformation. One good example is the renal tubular (kidney cell) injury produced in fish exposed to copper. Because copper is excreted by the kidney it accumulates at tubular cells. As the concentration rises injurious levels are reached and these cells are damaged or destroyed (Life, 1969). A second mechanism in the selective toxicity of chemicals on cells involves the presence of specific targets or receptor systems in exposed cells. In this case, the concentration of the toxicant is the same for all cells, but only certain cells are affected. This is due to the specificity of action of the toxi-cant on receptors that are normally occupied by endogenous hormonal or neurohormonal substances. Organophosphorus compounds such as parathion and malathion are good exam-ples of selectively toxic agents that act in this way. These cholinesterase inhibitors act to inhibit the enzyme respon-sible for hydrolysis of the neurotransmitter, acetylcholine. In this example cholinesterase is considered to be the receptor. Prevention of the hydrolysis of acetylcholine results in the continuous stimulation of post-synaptic sites throughout the central and peripheral nervous systems and rapid death due to respiratory paralysis is the usual outcome. Biotransformation and Excretion of the Toxicant The duration and intensity of injurious action of many for-eign compounds are largely determined by the degree and speed at which an organism can eliminate these compounds (Conney, 1967). The kidneys of both marine and fresh water fishes have been shown to share with mammalian kidneys the primary role of ridding an animal of potentially toxic compounds (Forster, 1961, 1967). The excretion of substances by the kidney is largely determined by lipid solubility characteristics of the com-pounds as they enter renal tubules. Molecules with a high degree of lipid solubility are readily re-absorbed from the renal tubule through lipoidal membranes back into the cir-culating blood and consequently are not excreted. It is only through certain specific biochemical transformations of these foreign compounds by the organism itself that lipid solubili-ties are altered and tubular excretion is successful (Brodie and Erdos, 1962). These reactions or transformations can be classified as oxidations, reductions, hydrolyses and synthe-ses (conjugation). Most animals, including fish, transform (metabolize) foreign compounds in two successive phases, the first phase consisting of a variety of oxidations, reductions, and hydro-lyses and the second phase of a limited number of synthe-ses or conjugations (Williams, 1967). Phase I reactions can result in: 1) The inactivation of a toxic compound; 2) The conversion of an initially inactive compound into a toxic compound; and 3) The conversion of a toxic compound into another toxic compound. The second phase of biotransformation, consisting of synthetic reactions, most often results in the conversion of toxic compounds into inactive excretory products. This con-cept of the metabolism of foreign compounds can be repre-sented as in Figure 2 (Williams, 1967). Biochemical reactions of both phases of metabolism are catalyzed by enzymes located in various organ systems, and it is from the study of the qualitative and quantitative variations in these enzymes that an evaluation of detoxifying capacities can be made for an organism (Williams, 1967). Phase I reactions are carried out by enzymes of normal metabolic routes and by enzymes which occur in the smooth endoplasmic reticulum of liver cells. When these cells are ruptured in the laboratory by homogenization the endoplas-mic reticulum undergoes fragmentation. High-speed cen-trifugation separates these fragments from the remaining cell constituents. These fragments are referred to as micro-somes and it is the microsomal enzymes that are involved in the metabolism of many drugs and foreign compounds. Microsomal enzymes do not generally act on lipid-insoluble compounds but rather convert lipid-soluble materials by oxi-dative and reductive processes to less lipid-soluble metabo-lites, which are more polar substances and, therefore, readily Phase IDrugActivation orinactivationOxidationreductionand/orHydrolysisproductsPhase IIInactivationSynthetic orconjugationproductsFIGURE 2C016_009_r03.indd 1012C016_009_r03.indd 1012 11/18/2005 1:12:30 PM11/18/2005 1:12:30 P

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1013excretable by the kidney. Without these biotransformations, the effects of some foreign substances on organisms would last for months (Brodie et al., 1965). Excretion of these lipid-insoluble metabolites can be achieved by active secretion at the tubules of the kidney or by passive transport across the glomerular membrane into the renal tubule (Forster, 1961, 1967). Since the metabolite has been transformed to a less lipid-soluble derivative, it will not diffuse back into the plasma for recirculation subsequent to passing through the glomerulus into the tubule. The microsomal enzymes were, until recently, thought to be concerned only with the metabolism of compounds which are normally regarded as foreign to the body. Conney (1967) has recently shown that steroid hormones and other normal body constituents are also substrates of the drug-metabolizing enzymes in liver microsomes and he suggests that this enzyme system may play a significant role in their regulation and physiological action. These enzyme systems are thought to operate by a mixed function oxidase mecha-nism whereby NADPH reduces a component in microsomes which reacts with molecular oxygen to form an “active oxygen” intermediate. The “active oxygen” is then trans-ferred to the drug or toxicant (Gillette, 1963). Key enzymes in the overall reaction are NADP-cytochrome c reductase, the flavin enzyme involved in the oxidation of NADP, cyto-chrome P-450, and NADPH cyctochrome P-450 reductase, which acts to reduce oxidized cytochrome P-450 (Gillette and Sasame, 1966). Many foreign compounds can alter these key enzymes and enhance or impair the ability of liver microsomal enzymes to metabolize other foreign compounds and ste-roids (Conney, 1967). Halogenated hydrocarbon insecti-cides have long been known to be potent stimulators of mammalian drug-metabolizing enzymes (Hart and Fouts, 1963; Hart, Shultice and Fouts, 1963). Buhler (1966) selectively induced drug-metabolizing enzymes in rain-bow trout by exposing these animals to DDT or phenyl-butazone. Organophosphate insecticides are unlike the halogenated hydrocarbons in that they inhibit, rather than stimulate, the metabolism of drugs and steroids by liver microsomes, when given chronically to rats (Rosenberg and Coon, 1958; Welch et al., 1967). Some heavy metals (Fe  , Cu , Zn  and Co  ) have also been shown to be inhibitory to drug metabolism in mice and rats (Peters and Fouts, 1970). Alterations in microsomal enzyme metabolizing capacities can substantially alter an animal’s response to foreign compounds as well as its ability to hydroxylate steroid hormones and other normal body con-stituents (Conney, 1967). Altered steroid metabolism can directly affect the animal’s ability to cope with environ-mental stresses as well as seriously impair reproductive mechanisms. Other than Buhler’s (1966) work on rainbow trout, little is known about the effects foreign compounds have on the microsomal drug metabolizing capacities of fishes. In addition, the current state of knowledge dealing with metabolism of foreign compounds in fishes is, at best, scanty (Adamson, 1967). THE TOXICITY OF COMPLEX EFFLUENTS Most industrial effluents contain mixtures of two or more substances. These complex effluents present special prob-lems in evaluating their toxicities to fish and other organisms. In some cases two agents with similar pharmacologic actions can produce a response that is equal to the summation of the effects of the individual agents or greater than the summa-tion of the independent effects of the two agents. The latter response is called “potentiation” and represents the condition whereby one compound is made more toxic in the presence of another compound which alone may produce minimal or no pharmacologic effect. Potentiation poses a special problem for the aquatic environment as well as the terrestrial environ-ment for it is possible that a certain combination of relatively harmless substances may result in an unpredictable high level of toxicity that would seriously threaten the existence of one or many species. Usually, however, the effect of two agents is the summation of responses to each agent. Occasionally, the effect of a toxic substance is reduced on the addition of another substance, a phenomenon referred to as antagonism. In some cases the antagonistic substance may or may not be toxic when present by itself. Synergism (potentiation and summation) and antagonism are poorly understood phenomena and greatly confuse the understanding and prediction of the toxic effects of industrial effluents. The majority of toxicological studies conducted in this and other countries on both mammals and fish deal with the effects of single substances on organisms; only a few stud-ies are currently investigating the responses of organisms to complex mixtures of substances. Synergism and antagonism are worthy of further investigation, for little is known about the basic mechanisms governing these processes. RESISTANCE OF FISH TO TOXICANTS Resistance of animals to chemicals has been known to exist for some time now and has posed serious obstacles in the control of insects and bacteria. While the mechanisms of resistance remain thus far a mystery, we know that they are genetically based. Most susceptible populations of animals have an occasional individual which exhibits resistance and it is this member that provides the genetic material for selec-tion pressures to act upon. Resistance has best been demonstrated with various pesticides in several natural populations of fishes (Ferguson et al., 1964, 1966), but these findings have attracted little attention. Many biologists have, in fact, believed this phe-nomenon to be beneficial to these animals, especially since they are useful to man. Recently, some disturbing evidence has emerged sug-gesting that pesticide-resistant vertebrates pose a major hazard in natural ecosystems and that they may be creating serious toxicological problems for man (Ferguson, 1967). The reason for this is some resistant animals carry massive residues of unaltered pesticides in their tissues and aggra-vate the already serious problem of biological magnification. 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Animals whose resistance is due to enhanced abilities to metabolize toxic substances to inactive metabolites do not, however, contribute to biological magnification. Biological magnification results when a foreign sub-stance enters plants and small animals and is then passed rapidly along food chains to larger animals. As this happens the substance becomes more and more concentrated until it reaches dangerous levels in the large predacious fish, many of which are consumed by birds and mammals including man. Clearly, the more resistance a fish has for the particu-lar toxicant in its tissues the greater the likelihood it will be consumed by animals living on the land. Unfortunately, these animals may not have equivalent levels of resistance and may be unable to adequately deal with these toxicants. CURRENT METHODS OF EVALUATING TOXICITY IN FISHES The establishment of water quality standards for concentra-tions of toxic pollutants that will be safe for fish has recently become a major concern of Federal and State Governments in pollution control (Water Quality Criteria, 1968). Efforts in this regard have centered around determining lethal limits of toxicants by establishing a TLm (tolerance limit, median) of various species exposed to toxicants for periods of time up to 96 hr (Sprague, 1969). These short term studies have been valuable in defin-ing the upper limits of toxicity but have not considered the subtle deleterious effects of foreign compounds which may not be evident for weeks, months, or longer (Water Quality Criteria, 1963). These responses to toxicity may manifest themselves in appetite changes, metabolic alterations, dis-orders of the nervous system, reproductive changes, behav-ioral abnormalities, or alteration of vital functions which are not immediately lethal. For this reason, investigations have only recently been conducted to measure toxicity in terms of survival, growth, and reproductive alterations resulting from long-term exposure to sublethal levels of pollutants (Water Quality Criteria, 1968). The concept of a “maximum accept-able toxicant concentration (MATC)” has originated from these studies and is defined as the highest continuous con-centration of a toxicant that does not significantly decrease the laboratory fish production index; an index developed by Mount and Stephen (1967) which takes into account sur-vival, growth, reproduction, spawning behavior, viability of eggs, and growth of fry. Because the toxicity of most pollutants varies with water characteristics and fish species, Mount and Stephen (1967) proposed the use of an “application factor,” (calculated by dividing the MATC of the 96-hr TLm value), to determine safe concentrations of toxic pollutants which, when deter-mined for one species of fish in one type of water, may be applicable to other waters and other species. Studies are currently underway to test the practicality of this approach (Mount, 1968; Mount and Stephen, 1969). The “application factor” approach may improve upon present methods of estimating safe concentrations of toxicants. At best, however, this approach requires considerable time for collection and evaluation of data and measures only the end result of a multitude of biochemical, physiological, metabolic, pharmacological and pathological responses to toxicants. Little definitive information is gained concerning the mechanism which produces the gross changes upon which the “application factor” is based. Because of the virtual impossibility of thoroughly assess-ing the individual, cumulative, synergistic and antagonistic effects of the numerous substances continually being intro-duced into our environment, it is imperative that we know the basic metabolic, physiologic and toxicologic responses of fish to compounds representative of broad categories of foreign substances. Only then will we be in a position to predict intelligently the biological effects of toxicants and regulate their concentrations to assure protection of this very important biological resource. If fish toxicologists continue to consider only the effect of a substance on the labora-tory fish production index without understanding causative mechanisms, they will severely limit the amount of informa-tion available for making meaningful decisions so desper-ately needed in water pollution control programs. Investigations of the disposition of foreign compounds in fish will shed valuable information on the evolution of enzymes that metabolize drugs, on drug metabolic pathways and excretion, and on factors affecting the biological half-life of foreign compounds in their lower species as well as higher vertebrates including man (Adamson, 1967). The edi-tors refer the reader to numerous studies which have noted the collection of fishes with fin erosion or other deformities. A few concentrated on fresh water streams (Reash and Berra, 1989; Sindermann, 1979) whereas a preponderance focused on marine or estuarine environments with and without pol-lution (see Cross, 1985; Skinner and Kandrashoff, 1988) for example. Reash and Berra found that the incidence of fish erosion was significantly greater at polluted stream sites compared to unpolluted sites. REFERENCES Adamson, R.H. (1967) Fed. Proc., 26, 1047. Ashley, L.M., J.E. Halver and G.N. Wogan (1964) Fed. Proc., 23, 105. Brodie, B.B., G.J. Cosmides and D.P. Rall (1965) Science, 148, 1547. Brodie, B.B. and E.G. Erdos (1962) Proceedings of the First International Pharmacological Meeting, 6 , Macmillan, New York. Buhler, D.R. (1966) Fed. Proc., 25, 343. Conney, A.H. (1967) Pharm. Rev., 19, 317. Cross, J.N. (1985) Fish Bull. , 83, 195. Ferguson, D.E. (1967) Trans. Thirty-Second North Am. Wildlife and Natu-ral Resources Conf. Ferguson, D.E., D.D. Culley, W.D. Cotton and R.P. Dodds (1964) Bio Science, 14, 43. Ferguson, D.E., J.L. Ludke and G.G. Murphy (1966) Trans. Am. Fish. Soc., 95, 335. Forster, R.P. (1961) Kidney cells, in The Cell, Ed. by J. Brachet and A.E. Mirshy, 5 , pp. 89–161. Academic Press, New York. Forster, R.P. (1967) Renal transport mechanisms, in Proceedings of an International Symposium on Comparative Pharmacology. Ed. by E.J. Cafruny, pp. 1008–1019. Fed. Am. Soc. Expt. Biol., Bethesda, Maryland. Gillette, J.R. (1963) Prog. Drug. Res., 6 , 13. Gillette, J.R. and H.A. Sasame (1966) Fed. Proc. , 25, 737. C016_009_r03.indd 1014C016_009_r03.indd 1014 11/18/2005 1:12:30 PM11/18/2005 1:12:30 P

1015 Goodman, L.S. and A. Glman (1970) The Pharmacological Basis of Thera-peutics, Chapter 1, Macmillan, London. Hart, L.G. and J.R. Routes (1963) Proc. Soc. Exp. Biol. Med., 114. Hart, L.G., Shultice and J.R. Fouts (1963) Toxicol. App. Pharmacol. , 5, 371. Life, J.S. (1969) Metabolism and pharmacodynamics of copper in the goldfish ( Carassium Auratus ), Ph.D. dissertation, The University of Michigan. Mount, D.I. (1968) Water Res., 2 , 215. Mount, D.I. and C.E. Stephan (1967), Trans. Am. Fish. Soc., 96, 185. Mount, D.E. and C.E. Stephan (1969), J. Fish. Res. Bd. Canada 26, 2449. Petermann, M.L. (1961) Med. Clin. North Am., 45, 537. Peters, M.A. and J.R. Fouts (1970) Biochem. Pharmacol., 19, 533. Reash and Berra (1989) Air, Water Soil Poll. , 47, 47. Rosenberg, P. and J.M. Coon (1958) Proc. Soc. Exp. Biol. Med., 98. Sindermann, C.J. (1979) Fish Bull., 76, 717. Skinner, R.H. and W. Kandrashoff (1988) Water Res. Bull., 24, 96. Sprague, J.B. (1969) Water Res., 3 , 793. Stanton, M.F. (1965) J. Nat. Cancer Inst., 34, 117. Water Quality Criteria (1963) Federal Water Pollution Control Administration. Water Quality Criteria (1968) Federal Water Pollution Control Administration. Welch, R.M., W. Levin and A.H. Conney (1967) J. Pharmacol. Exp. Therap., 155, 167. Whittaker, V.P. (1968) Br. Med. Bull., 24, 101. Williams, R.T. (1967) Fed. Proc., 26, 1029. JOHN E. BARDACH University of Michigan C016_009_r03.indd 1015C016_009_r03.indd 1015 11/18/2005 1:12:30 PM11/18/2005 1:12:30 P
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INTRODUCTION All forms of mining cause some impact on the aquatic envi-ronment, just as any other earth disturbance will impact the local hydrology. Sometimes this impact is very adverse, in which case there is usually a considerable disruption of the natural life cycles in the affected water. Other, and less noted cases may even improve the local waters. Unfortunately, the adverse impacts greatly outnumber the advantageous cir-cumstances so that the result of mining is to severely degrade the aquatic environment. A generalized characterization of the impact of mining on water is rather difficult, as almost any specific change in the chemical qualities of the affected waters may be found at some specific point. In almost all cases, however, there is an increase in the total dissolved solids in the mine drain-age waters. Additionally, the acidity of mine drainage is increased above normal ground water levels for the area, and the level of dissolved metal is increased. In some areas, however, the alkalinity levels are increased by mining. Many forms of mining also increase the suspended solids content of water. Coal mining has received the greatest amount of atten-tion as the mining which causes water pollution. This is perhaps deserved as the mining of coal has been a major operation for many years and more coal has been mined than any other single mineral. Water pollution from coal mining was known in medieval England and the mines in Wales were known to make the creeks run red. This fact was important to the exploration of the North American continent, as early explorers deduced the presence of large deposits of coal from the natural color and character of some of the streams and creeks. Similar conditions were some-times noted in relation to other mineral deposits in the US. As the outcrop materials come into contact with the atmo-spheric conditions, oxidation and solubilization take place and the products are transported into the streams. Hence, the natural production of some mine drainage is a natural phenomena which has existed almost from the beginning of time. Coal mine drainage may vary from waters pure enough to drink without treatment to waters containing more than 20,000 mg/l acidity with commensurate amounts of iron and other dissolved solids. Drainage from metal mines may vary over almost equally wide ranges of acidity but often con-tain substantial amounts of dissolved heavy metals. In most respects the acid drainages from metal mines are similar to acid coal mine drainages. This similarity is so great that most of the treatment processes and prevention mechanisms developed and applicable to coal mine drainage can also be applied to metal mine drainage. ORIGIN OF ACID MINE DRAINAGE The earth strata associated with and superjacent to coal and many other minerals almost always contain the iron sul-fide mineral pyrite (FeS 2 ). Oxidation of the acidforming pyritic material associated with mining is necessary for the formation of mine acids and as oxygen is a necessary part of the oxidation of these materials, there can be no signifi-cant amount of oxidation until these are exposed to air. The process of mining greatly increases the exposure of these materials to atmospheric oxidation. Oxidation of the sulfide mineral begins as soon as it is exposed to the air and contin-ues at a rate characteristic of the geologic and atmospheric conditions. Usually this oxidation causes spalling of the mineral substance with a progressive increase in the amount of surface area available for oxidation. Time then becomes a significant factor in the amount and rate of formation of acid mine drainage. The exact nature of the pyritic mineral which oxidizes so rapidly and causes the acid drainage from mining has been sought for many years. In appearance, the mineral is often grey like marcasite, and its oxidation rate is even more rapid than that of marcasite. X-ray diffraction stud-ies of the sulfide material associated with coal, however, have confirmed by the crystal structure that the material is pyrite rather than some other crystalline form of iron sulfide. The intricate mechanism of oxidation of this pyrite and the formation of acid drainage has been the subject of many learned discussions and research efforts extending back over fifty years or so. The reaction will occur at normal room temperature and humidity conditions with the release of SO 2 into the atmosphere. Under more humid conditions, the reac-tion results in all of the sulfur being converted into sulfate. Typical reactions depicting some of the several paths pos-sible for the reaction of the iron sulfide, air, water and alkali materials are listed. This list is typical rather than all-inclusive to cover all possible reaction routes. C016_010_r03.indd 1016C016_010_r03.indd 1016 11/18/2005 11:03:03 AM11/18/2005 11:03:03 AM

1017 FeS 3O FeSO SO2FeS 7O 2H O 2FeSO 2H SO4FeSO 2H S22 4 2222 42442⫹⫹⫹⫹ ⫹⫹→→OO O 2Fe (SO ) 2H O4FeSO O 2H O 4Fe(OH)SOFe (SO )42 243 242 2 424⫹⫹⫹⫹→↓→↓332 4 2422 4 4 322H O 2Fe(OH)SO H SOCa(HCO ) FeSO CaSO Fe(HCO )4⫹⫹⫹⫹→↓→FFe(HCO ) O 2H O 4Fe(OH) 8COCa(HCO ) Fe (SO ) 4H22 2 2 3 222 2 43⫹⫹ ⫹⫹⫹→↓↑224322422 2 4 4OCaSO 2Fe(OH) 2CO 2H SOCa(HCO ) H SO CaSO 2CO→↓↑→⫹⫹⫹⫹⫹222 2H O.↑⫹ There has been a continuing debate among the scientific community over the role which bacteria may play in the for-mation of acid mine damage. Bacteria of the Ferrobacillus ferroxidans family are almost always found in large pools of acid mine drainage. The bacteria have been shown to have the capability of oxidizing ferrous iron to the ferric state. However, they thrive in a very limited pH range (approxi-mately pH 3.5) and there is no evidence to indicate that they contribute directly to the primary oxidation of the pyretic substance. Ferric ion can oxidize sulfide sulfur and this could possibly provide a mechanism for the bacteria to increase the rate of oxidation of pyrite in some circumstances. Other recent studies have shown that the transfer of oxygen from the atmosphere to the pyrite surface is the rate limiting factor of the reaction, making moot arguments put forth as to whether bacterial or chemical oxidation is the principal mechanism of acid drainage formation. Bacteria may play a significant role in the oxidation of the ferrous to ferric ion in mine drainage. This fact can be of considerable importance in the treatment of mine drainage as ferrous iron tends to retard the rate of neutralization reac-tions. It almost appears that this is Nature’s first step in the neutralization of acid drainage. The bacterial oxidization of iron allows the alkalinity of the associated earth strata and of diluting waters to be more readily reacted with the acid-ity of the mine drainage waters. This concept is rather radi-cally at variance with former concepts that considered the sterilization of a mine as a possible method of reducing or eliminating the formation of acid drainage. Bacteria has been used deliberately as a step in the treatment of mine drain-age. This process allows the ferrous iron to be oxidized and accelerate the neutralization of the acid salts. The formation of acid drainages from surface and under-ground mines is essentially the same process, and the two drainages are indistinguishable on the basis of the chemi-cal qualities of the waters. In general the iron contained in drainage from surface mines and also from coal refuse piles is in the ferric state. The drainage from surface mining may contain very substantial amounts of suspended solids or sedi-ment. Because many of the drainage problems of strip and deep mines are directly interrelated there is almost no rational way of separating the treatment or preventive measures which may be applied to the two types of mining. EXTENT OF ENVIRONMENTAL IMPACT The problem of environmental degradation caused by mine drainage is widespread and serious. Some form of mining occurs in each of the fifty states and many states are exten-sively mined. The aquatic degradation caused by coal mining in the eastern and Appalachian region is best known and has been best documented. For this reason, most statements of the damages caused by mine drainage cite only the degra-dation in the Appalachian area. The Appalachian Regional Commission reported that some 10,500 miles of streams in that region are affected by mine drainage and acid drainage continually pollutes nearly 5700 stream miles. Since data are not available in many mining areas, particularly in the Rocky Mountain and western areas, firm total statements of the extent of the problem cannot be made. However, enough information is available to indicate that it is very substantial. The extent and amount of degradation which may be caused by the presence of mine drainage, and the environ-mental and economic impacts which may be felt, vary, of course, with the type of mine, the strata surrounding it, and other localized conditions. For example, coal mine drainage, which is usually acidic, kills fish and other forms of aquatic biota by lowering the pH of the water and also may have an adverse economic effect upon the human population. The acidity accelerates the cor-rosion of bridges, culverts, boats and navigational facilities, making replacement at shorter intervals necessary. High cost water treatment may be required to make the local water supply potable or suitable for industrial use. Water contact sports may not be possible in the area, causing a loss of potential tourist industry revenues. Although metal mining may cause the same adverse effects, it usually occurs in less densely populated regions. Additionally, metal mine drainage may render the waters toxic to humans as well as aquatic life by the presence of heavy metals. REMEDIES FOR MINE DRAINAGE POLLUTION In the past a substantial number of investigators have simply discussed the problem and observed its extent so that more is known about the nature of the problem than about the mech-anisms which may be applicable to correcting or mitigating it. Mine drainage may be characterized on the basis of its source and possible remedies considered by this categoriza-tion even though the chemical nature and biological impact of the drainage from the several sources is identical. For the purposes of this discussion let us consider three types of mine drainage by the source: drainage from active or operat-ing mines, drainage from non-operating (sometimes called abandoned) mines and drainage which will be generated in the future from mines which have not yet begun operation. C016_010_r03.indd 1017C016_010_r03.indd 1017 11/18/2005 11:03:04 AM11/18/2005 11:03:04 AM
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Separating surface and underground mines is not feasible as they frequently occur together and interact to add to the problem. Presently operating mines have certain characteristics which differentiate mines them from other mines. Primarily because they are now in operation a responsible owner or operator can be located and people, equipment, machinery and power are available at the mine site. This allows con-sideration of procedures to treat the mine drainage as well as procedures to reduce or minimize the amount of pollut-ants discharged both during the remainder of the mine’s life and after mining has been terminated. Procedures pres-ently available may be employed to minimize the amount of mine drainage pollution which issues from an operat-ing mine, but no procedures are now available which can totally eliminate it. Non-operating, or abandoned mines, generally do not have any responsible person readily available, or any other resources such as personnel and machinery, which makes abatement techniques more expensive for this type of mine than for one which is operating. When a mine is still in the planning stage, it is easier to plan for future prevention of pollution and thereby reduce it. For instance, provisions can be pre-planned for a mine to have rapid and complete drainage during the mining opera-tion, thereby reducing the pollutional discharges which other-wise may need to be treated. Additionally, improved mining methods can provide for minimum void spaces after mining; also water level control after mining ceases can be provided only during the mine pre-planning stages. The methods for alleviating mine drainage may be divided into the two basic categories of treatment of mine drainage, and prevention of the formation of discharge of pollutants. Treatment removes pollutants by physical/chemical means and generally results in only specific pollutants being removed or reduced. The process must continue for as long as the source produces pollution and usually in the case of mine damage this is tantamount to “treatment in perpetuity.” Disposal of wastes and constant usage of power or chemicals made such treatment unduly consumptive of both human and physical resources. Treatment methods for coal mine drain-age are summarized in Table 1 and many of the methods are applicable to other types of mine drainage pollution. Prevention is the total cessation or massive reduction of the formation or discharge of pollutants during and after the operating life of the mine. Prevention of all forms of pollution, including dissolved and suspended materials, is obviously more desirable than simple treatment of pollution with its attendant problems. Provisions for prevention of the formation of pollu-tion cab be planned into a mine while it is still on the drawing board. Specific techniques for prevention and correction of pollution from mines, both operating and non-operating, are shown in Table 2. TABLE 1Summary of treatment techniquesPollutants removedaNeutralization and aerationMicrobial iron oxidationReverse osmosis Ion exchange Flash distillationdElectro-dialysisProduct recovery Silt basinsAcidityXXX NA XX XcXX XeXfNAIron XX XX XXX XcXXX ? XfNAAluminum XXX NA XXX XcXXX XeXfNAManganese XbNA XXX XcXXX XeXfNACopper XX NA XXX XcXXX XeXfNAZinc XbNA XXX XcXXX XeXfNAHardness — NA XXX XcXXX XeXfNASuspended solids X NA NA NA NA NA XfXDissolved solids — NA XXX XcXXX XeXfNAState of artgCU PP PP R, PP, FSOcFSD ReR R, CUCost, $/1000h0.05–4.55 UK 0.30–2.57 0.30–2.53 0.33–3.25 0.52–2.52 UK 0.02–1.0Waste productjS S B B, R B B S,B,R Sa NA—Not applicable, ? Questionable, X-degree to which removed, the greater number of “X”s the higher the removal.b Must be raised to very high pH.c Various ion exchange techniques are under evaluation. Their effectiveness and which pollutant is removed depends on the technique.d 5 mgd plant is under construction in Pennsylvania. Techniques has only a limited potential.e Technique will not operate where iron is present in water.f Various product recovery schemes are under consideration; however, all are still in research stage.g R—Research, PP—Pilot Plant, FSD—Full Scale Demonstration, CU—Common Usage.h Cost depends on the degree of pollution, size of plant, pre- and post-treatment requirements. UK—Unknown.j Each treatment process has a waste product that must be disposed of and creates additional problem. S—insert sludge, B—highly mineralized brine, R—regenerate.C016_010_r03.indd 1018C016_010_r03.indd 1018 11/18/2005 11:03:04 AM11/18/2005 11:03:04 AM

1019TABLE 2Cost and effectiveness of various at-source prevention and corrective techniquesControl techniquesEffectiveness %Cost RemarksSurface mine reclamation25–90 $300–3000/acre Includes backfilling, regarding, contouring, and water control structures. Prevents acid formation, erosion control, runoff of dissolved soils. Cost and effectiveness controlling factors are nature of surface and overburden, slope of land, and proposed use of land.Mine sealing (air) 0–50 $1000–5000/seal. Additional cost of $5000–100,000/seal may be required to control entrance of air through subsidence holes, boreholes, outcrop, etc.Sealing of an underground mine to prevent entrance of air. Prevents acid formation. Cost of effectiveness depend on the ability to locate and seal all air paths to the mine, type and condition of mine operating and type of seal. Most mines cannot be airsealed.Mine sealing (flooding) 75–99 $1000–20,000/seal. Additional costs of $5000–20,000 may be required to control drainage through bore holes, outcrop, etc.Sealing of an underground mine to completely and permanently flood the working. Prevents acid formation and sometimes all discharges. Cost and effectiveness depend on the ability to seal all discharges, size of mine, dip of seam, outcrop condition, condition of mine opening, type of seal, and amount of grouting required. Is not applicable to all mines.Drainage diversion 25–75 $200–20,000/acre The prevention of water from entering the mine area. Prevention of siltation and flushing of pollutants. Cost and effectiveness depend on ability to divert as much water as possible in properly designed structures.Impoundment 50–95 $350–1000/acre-ft Flooding of surface mine pits. Prevents acid production. Cost and effectiveness depend on complete and permanent flooding of the material responsible for acid production.Refuse pile reclamation (reject material from mining and processing)25–75 $1000–3000/acre Stabilizing a refuse pile with soil, chemicals, vegetation, etc. Prevents acid production and siltation. Cost and effectiveness depend upon the availability of the land in which the refuse piles can be filled and also upon the availability of impervious materials such as clay, fly ash, or limestone for compaction over the surface of the filled area.Reject tailing pond (reject material from mining and processing in slurry form)25–95 $300–2000/acre Stabilizing of tailings by flooding, soil covering, chemicals, vegetation, etc. Prevents air pollution and discharge of suspended and dissolved solids. Cost and effectiveness depend upon the size, location.Revegetation 5–25 $70–700/acre Establishment of vegetative cover on reclaimed surface mines, reject piles, and pond. Prevents erosion. Cost and effectiveness depend on the type of cover, soil conditioning, and thickness of cover required.Controlled pumping and drainage25–75 $0.190.23/1000 gallon Involves rapid removal of water from a mine before it gets contaminated or discharge of contaminated water at regulated rate so that dilution provides minimum contamination effects. Cost and effectiveness depend upon the characteristics of the material in the mine, contact time between water and exposed materials, rate of pumping, pumping head, and amount of dilution water available.Inert gas blanket Under research and development Filling of an underground mine with an inert gas to prevent acid production. Control of the bacteria in a mining environment. Prevents acid production. Technique does not show merit at this time.Sterilization Under researchInternal sealing Under research and development Internal sealing of underground mine to prevent acid production and/or mine drainage discharge.Longwall mining Under research and development Allows complete removal of the coal in an underground mine. Mine roof collapses behind the working face, eliminating “breathing” of the mine.Daylighting Under research and development Strip mining of a previously mined underground seam. Removes pillars left before. Surface must be reclaimed.C016_010_r03.indd 1019C016_010_r03.indd 1019 11/18/2005 11:03:04 AM11/18/2005 11:03:04 AM
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It can be seen from Table 2 and Figure 1 that the cost of creating or preventing the formation of mine drainage is a wide ranging variable, dependent on the method(s) selected for use. The estimated costs for the limestone neutralization treatment of mine drainage are shown in Figure 1 as a func-tion of acidity and quantity to be treated. As can be seen in the figures, the number of methods of alleviation and control of mine drainage which are highly effective are few, and most treatment processes produce undesirable by-products, as well as being expensive over the long run. It would be highly desirable to lessen the sources of mine drainage and to be able to treat it effectively with a gain in desirable by-products. New techniques for the prevention of pollution from mines are presently in the development and demonstration stage. For example, a new technique known as “daylight-ing” is being demonstrated. This procedure will use strip mining techniques to remove the residual coal from shal-low, non-operating mines and consolidate the overburden to prevent the continued discharge of acid drainage. A variety of abatement techniques related to surface mine reclama-tion are being demonstrated in the Appalachia region. Also there are two major efforts directed toward the development of non-pollutional mining techniques. These are the mining of coal under oxygen free conditions within the mine to 1 2 3 4 5 6 7 8 9 101112131415$1.00.90.80.70.60.50.40.30.20.10.09.08.07.06COST PER 1000 gal.ESTIMATED LIME NEUTRALIZATION TREATMENT COST - COAL MINE DRAINAGEO.I MGD1 MGD2–4 MGD6–7 MGDFIGURE 1 Estimated costs for treatment of coal mine drainage waters based upon a composite of published laboratory, pilot plant, and actual plant data. The estimate for the 0.1 MGD plant is preliminary and based upon limited information.prevent the oxidation of pyrite and the formation of acid drainage and the application of a new mining technique called “longwall stripping.” Longwall stripping will apply longwall mining techniques to shallow cover coals, which are now strip mined, to remove the coal without inverting or dismantling the overlying earth strata. LITERATURE REFERENCES Most discussions of this type are buttressed by an impressive listing of reference documents citing sources of the many facts contained therein. To the casual reader, these references are useless, except for their creation of an impression of author-ity. The serious worker will demand to have even more refer-ences and documentation. The field of coal mine drainage is somewhat unique in that the literature of the field is regularly collected, abstracted and these abstracts published. This pub-lication, entitled “Mine Drainage Abstracts, a Bibliography” is prepared by the Bituminous Coal Research, Inc. for the Commonwealth of Pennsylvania. Copies may be purchased from B.C.R., Monroeville, Pennsylvania. A listing of the reports of the research in this field may be obtained from the Publications Branch, Office of Research and Monitoring, Environmental Protection Agency, Washington, DC 20460. C016_010_r03.indd 1020C016_010_r03.indd 1020 11/18/2005 11:03:04 AM11/18/2005 11:03:04 AM

1021 REFERENCES 1. Ramsey, D.L. and D.G. Brannon, Predicted Acid Mine Drainage Impacts to the Buckhannon River, West Virginia, Water, Air and Soil Pollution, 39, 1, 1988. 2. Sobek, A.A., M.A. Bambenck, and D. Meyer, Soil Sci. Soc. Am. J., 46, 1982. 3. Sullivan, P.J., S.V. Mattigo, and A.A. Sobek, Dissociation of Iron Sulfates from Pyritic Coal Wastes, Environ. Sci. Tech., 20, 10, 1986. ERNST P. HALL Environmental Protection Agency POLLUTION LAW: see ENVIRONMENTAL LAW POLLUTION METEOROLOGY: see AIR POLLUTION METEOROLOGY POLLUTION OF GROUNDWATER: see GROUND WATER RESOURCE PRIMARY TERRESTRIAL CONSUMERS: see ECOLOGY OF PRIMARY TERRESTRIAL CONSUMERS PROTECTION OF THE ENVIRONMENT: see ENVIRONMENTAL LAW C016_010_r03.indd 1021C016_010_r03.indd 1021 11/18/2005 11:03:05 AM11/18/2005 11:03:05 AM
1022 PREVENTION OF TOXIC CHEMICAL RELEASE Purging of process vessels, tanks and piping before startup and after shutdown is imperative for pilot plants and large-scale plants in the process industries or wherever combusti-ble gases and vapors are handled. Gases most often used for purging are nitrogen, carbon dioxide, or gases derived from the combustion of hydrocarbons. The reader is referred to the sections on Vapor and Gaseous Pollutant Fundamentals and to Fossil Fuel Cleaning for unit operations and incinera-tion procedures involved in hazardous gas removal. To show how the purging procedure can be “mapped” a typical purg-ing chart will be constructed and the salient points explained (see Appendix). Inert gases such as nitrogen have the property of not only depressing or narrowing the explosive range of a combus-tible gas or vapor, but also of preventing the formation of explosive mixtures with air when these inert gases are mixed in suitable proportions with either air or with the combus-tible gas or with an explosive mixture of both. By displacing or mixing air contained in a vessel, tank or piping system to be placed into gas service, with a suitable amount of an inert gas such as nitrogen, a combustible gas may subsequently be introduced without the formation of an explosive mix-ture. Similarly, by displacing or mixing the combustible with a suitable amount of nitrogen, air may later be introduced without causing an explosive mixture to develop. During the purging procedure constant sampling of contents must be pursued using standard accepted methods of chemical analysis. GAS FLAMMABILITY LIMITS A flammable mixture of a gas, such as acetylene and air, may be diluted with one of the constituents (acetylene or air) until it no longer is flammable. The limit of flammability due to dilution is the borderline composition: a slight change in the direction will support burning, while in the other direction combustion cannot be supported and maintained. At the ends of these two extremes there are well defined limits within which self-propagation of flame will take place on ignition. These are known as “upper” and “lower” limits as defined in terms of the percentage by volume of com-bustible gas present in a mixture of the gas and air. Table 1 below lists these limits for some of the more common gases and vapors for conditions of atmospheric pressure and temperature. Within these limits, the combustible gas and air mix-ture liberates sufficient energy to continue to propagate flame from one mixture layer to the other. Mixtures above the upper limit may burn on contact with external air, since these layers are formed in the zone where gases mix. Certain conditions effect a shift in the two limits, either increasing or decreasing the spread between them as we will note later. These conditions include: ignition source, ignition inten-sity, direction of flame propagation (upward, downward, or across), size and shape of container, vessel, or piping orien-tation, temperature, pressure and humidity in the containing vessel, oxygen content and turbulence. EXPLOSIONS When a chemical reaction is accompanied by the libera-tion of heat, as the reaction progresses, it is followed by an increase in the amount of heat, which in turn helps to accel-erate the reaction. Thus the two advance together, both in highly intimate connection and mutually helpful, until the entire mass has been heated and chemically converted. When a burning substance, a match for instance, is placed in contact with the extreme outer limit of an explosive mix-TABLE 1Per cent gas or vapor in mixture—flammability limitsGas orvapor Lower UpperGas orvapor Lower UpperAcetylene 2.5 80.0Carbon monoxide 12.5 74.2 Acetone 2.6 12.8Hydrogen 4.0 74.2 Ethane 3.2 12.5Ethyl ether 1.9 48.5 Propane 2.4 9.5Carburetted 6.4 47.7 Butane 1.9 8.4Hydrogen sulfide 4.3 45.5 Benzene 1.4 8.8Methyl alcohol 6.7 36.5 Gasoline 1.5 6.2Coal gas 3.9 29.9 Turpentine 0.8 —Ethylene 2.8 28.6 Ammonia 16.0 27.0Pennsylvania 4.9 14.1 Ethyl alcohol 3.3 19.0Natural gas — — Methane 5.0 15.0Reference: G. W. Jones, Chemical review Vol. 22, 1938. pp. 1–26.C016_011_r03.indd 1022C016_011_r03.indd 1022 11/18/2005 1:12:55 PM11/18/2005 1:12:55 P
PREVENTION OF TOXIC CHEMICAL RELEASE 1023ture of gas and air, ignition takes place at the point of contact, i.e. incites chemical reaction. Combustion proceeds from the outside of the mixture towards the center, and thereby forms a plane of combustion which divides the gaseous mixture into two parts. On the one side are the highly heated products of combustion, and on the other, is the still unconsumed gas mixture. The velocity at which this plane advances in different for each gaseous mixture, and depends both on the compo-sition of the mixture and on the pressure to which it is sub-jected. The higher the velocity of propagation the greater the rise in temperature, and this latter, in turn, directly influ-ences gas expansion and the products of combustion, which thereby exert such a high pressure on their environment that any opposing medium, vessels, tanks, piping, walls, etc. is ruptured. APPLICABLE EXPLOSIBILITY DATA Not all explosibility data reported in the literature are appli-cable to purging problems. From the safety standpoint, it is desirable to select the widest explosive limits for the purge operation. In addition, an ample safety factor be applied, especially to the lower explosive limit. For acetylene-air mixtures, at atmospheric pressure and temperature, the published and accepted values for the lower explosive limit (LEL) and upper explosive limit (UEL) are 2.5 and 80.0% acetylene in air respectively. These are the widest limits recording. See Table 1. In every case involving combustible gas handling or processing, constant awareness of the inherent dangers to life and limb as well as property is imperative. In the case of acetylene, it is a well known fact that it has unstable characteristic at any pressure and whether or not a decom-position would take place depends on the intensity of the initial source of ignition. Higher pressures have the effect of lowering the initial energy necessary to initiate a decomposition. ACETYLENE—CASE STUDY Acetylene is inherently an unstable gas at any pressure and whether or not a decomposition would take place depends on the intensity of the initial source of ignition. Higher pres-sures have the effect of lowering the initial energy necessary to start a decomposition. Higher initial pressures will also result in an increase in the ratio of the maximum pressure developed in the decomposition to the initial pressure. As for acetylene-air mixtures, pretty much the same behavior is manifested. With decreasing ignition energies, the initial pressures must be correspondingly increased so as to bring the total gas mixture volume to decomposition. The size, shape and orientation of a process vessel as well as its material of construction have a profound effect on the ignition limits of combustible gas mixtures. The same applies to acetylene decompositions. It is a matter of heat balance during the combustion process. Even the relative position of the source of ignition. The widest explosive range is obtained for vertical cylindrical vessels or tanks when the ignition source is located at its base. The presence of water vapor and high humidity acts as a diluent and an inert gas. This effect is typical for all combus-tible gas–air mixtures. As for the effect on explosion limits, the ratio of vessel surface to cross-sectional area from a cooling or heat bal-ance point of view, long slender vessels (high ratio of surface to sectional area) narrow the limits of explosibility. It’s all a matter of the rate at which heat is removed from the gas mix-ture inside the vessel. As for the temperature effect, higher temperatures induce convection currents within the vessel and increase turbulence and widen the limits. Thus, only tests of actual operating setups can tell the effects on the widening or narrowing of the explosibility range. Then, once established, the LEL and UEL determined experimentally can be used to develop a purging graph here-inafter discussed and developed. EFFECT OF INERT GAS The effect of an inert gas on explosibility of combustible gases in air can be shown graphically on Figure 1 for acetylene–air mixtures. Once the conditions for actual operating condi-tions and configuration are determined experimentally, the graph can be set up as we shall see. As nitrogen is added to mixtures of the gas and air within the explosive range, a series of new mixtures are formed each of which has a different UEL and LEL than the pre-ceding mixture and the explosive range is narrowed along definite lines of demarcation. As the air and combustible gas contents are reduced by the addition of nitrogen, the line of LELs and the line of UELs converge and meet at a point, i.e., D. Here the range has degenerated to zero. No mixture of acetylene, air and nitrogen which contains less oxygen than the lowest point on the line LDU (point D ) is explosive in itself, but all mixtures within the areas bound by LUD are within the limits of explosibility and are therefore explosive. Again, in Figure 1, line ADE is drawn tangent to LDU at D. Any mixture represented by point X to the right of line DE and below the upper explosive limits DU is not explosive in itself. However, on dilution of that mixture with air, a new series of mixtures will be formed having compositions fall-ing along line X A which passes through the explosive area. Similarly, any mixture represented by a point to the left of line LD and DE will not form explosive mixtures on further dilution with air. Note line LD is not vertical but swings to the right as falls. APPLICATION OF GRAPH At startup when placing gas equipment into service purg-ing from air to inert gas, the object is to reduce the oxygen C016_011_r03.indd 1023C016_011_r03.indd 1023 11/18/2005 1:12:55 PM11/18/2005 1:12:55 P
1024 PREVENTION OF TOXIC CHEMICAL RELEASE1009080706050403020100z1009080706050403020100ZYX100908070 605040302010010 203040506070809010020181614121086420FDBE2197.5 %YSTART(LEL)ACombustible gas (Acetylene per cent by Volume)Inert gas (Nitrogen) per cent by Volume(Taking Equipment out of Service)XSTART(LEL)Line of LEL’SC20%Lower Limit 2.5 % C2 H2 pure and dry97.5% air dry0% N2 inert addedLine of flammabilitylimits from Fig.1C2 H2 and air onlyzero inertingnitrogenExplosion (2)rangenarrowedonaddition ofnitrogenLine of UEL’sUpper Limit 80% C2 H2 pure and dry20% Air dry0% N2 inert added2.54.8Inert Gas (Nitrogen) per cent by Volume(Putting Equipment into Service)Air per cent by Volume(Equivalents)Oxygen equivalent in air per cent by Volume(1)FIGURE 1 Acetylene-Air-Nitrogen purging chart (atmospheric temperature and pressure).C016_011_r03.indd 1024C016_011_r03.indd 1024 11/18/2005 1:12:55 PM11/18/2005 1:12:55 P
PREVENTION OF TOXIC CHEMICAL RELEASE 1025content of the air inside the equipment to a point that acety-lene (or other gas) may be subsequently introduced with-out forming an explosive mixture. From Figure 1 it may be observed that the safe condition will be reached when the oxygen content within the vessel or equipment has been reduced by the introduction of nitrogen to below approxi-mately 6.6% by volume, point F where FC drawn tangent to LDU at D intersects the vertical axis AB. Any mixture of this combustible gas, nitrogen and air having an oxygen content represented by a point below this line FC may be diluted with the combustible gas without forming an explo-sive mixture (see Appendix). WHEN SHUTTING DOWN Likewise, when shutting down or withdrawing equipment containing acetylene from service or when purging from combustible to inert gas, the object is to reduce combustible gas content to such a point that the air may subsequently be introduced without fear of forming an explosive mixture. Figure 1 shows that a safe condition will be reached when the combustible gas content within the equipment or piping has been reduced to below 4.8% by volume, denoted by point E. On occasions the mixtures of acetylene, nitrogen and air are to be diluted with a further quantity of inert gas so as to render them nonexplosive or incapable of forming explosive mixtures on later addition of air. Object here is to add suf-ficient nitrogen to convert the existing composition of the mixture to some composition corresponding to a point to the left of LD and DE. If we assume that the mixture is again denoted by point X , then on addition of nitrogen, successive mixtures will be formed along XB. Point where XB crosses DE denotes the safe endpoint composition. Then on the fur-ther addition of air (intentional or accidental) the line of mix-tures will fall to the left of LDE. In practice, it is desirable to decrease the proportions of oxygen and combustible gas below the determined values to provide a factor of safety. To prevent explosion in chemical processing, it is necessary to keep the air–gas or–vapor or mixture of the gases, air and nitrogen, below the LEL within the equipment most likely to be affected. An established safe practice is to keep the mixture well blended with air or inert gas so that calculated or experimental values never reach more than 25% of the LEL or other low limit as determined from Table 1 in temperatures below 250°F. Placing system into service or out of service should be done when system has been depressurized to atmospheric pressure. DEPRESSURIZING TO ATMOSPHERE More often than not, combustible-gas releases to atmosphere do not contain air. When handling acetylene in its pure state a maximum pressure of 15 psig is usually used. Thus on release to atmosphere large quantities of the gas may be emitted through pressure relief valves to flares or high stacks. Then again the gas may be returned to gas holder storage. If released to atmosphere, inert gas purging should be provided. An excellent reference on inert-gas purges of stacks on pressure releasing has been published * ; for process equipment see review. 12 SAMPLING OF MIXTURE CONTENTS During startup or shutdown of systems, sampling of mix-tures within equipment should be conducted downstream of the point of injection of nitrogen to ensure proper mixing of gases before sampling. Taking samples from stratified streams should be avoided. For piping systems sampling should be taken downstream of elbows and open valves. In anticipation of this elbows and turns as well as valves should be designed into the system originally. In actual testing it has been observed that form 6 to 10 volume changes are neces-sary to purge equipment or piping systems. Sampling should begin after this purge. Purging to a point below the LEL may be done using an explosimeter † that has been properly calibrated for the gas–air–nitrogen mixture. Laboratory testing procedures may also be used where samples are washed† with acetone and the volume of acetylene absorbed deducted from the entire sample to give volume of the remainder gases as air or nitrogen. Spark-resisting tools should be used to prevent sparking and possible ignition of combustible gas. Work shoes with rubber soles and so steel studs should be used. In addition, continuous sampling of the workroom atmosphere should be conducted using explosimeters built for that purpose. INERT GAS SUPPLY Where rigid purity of inerting gas is not a requirement, the use of inert gases obtained from the combustion of hydrocar-bon fuels may be used. This decision is one to be based on experience and processing needs. Gas analysis can now be accurately measured and con-trolled in tenths of a percent range. These inert gas genera-tors are provided with rugged instrumentation and controls for hazardous environments as found in desert and offshore installations. The analysis can even be accurately measured down to the ppm range where instrumentation maintenance is present. The same caliber of technician is needed whether or not the nitrogen source is cryogenic or hydrocarbon. Such inert gas generators are currently supplied with automatic trimmer control which analyzes the discharge gas and automatically controls the air-to-fuel ratio. For critical installations they are even equipped with inexpensive auto-matic vent and alarm systems. For more information and their technical manual, write to C.M. Kemp Manufacturing Company, Glen Burnie, Maryland 21061. † Explosimeters are available from Mine Safety Appliances Company, Pittsburgh, PA 15235 and Davis Emergency Equipment Company, Newark, New Jersey.C016_011_r03.indd 1025C016_011_r03.indd 1025 11/18/2005 1:12:55 PM11/18/2005 1:12:55 P