EPA/600/A-94/191 PILOT PLAHT INVESTIGATIOH OP ALTERNATIVE TREATMENT METHODS by Mark H. Griese Presented at the 82nd Annual Meeting of the Indiana Section American Hater Works Association, February 20-22, 1990, Indianapolis, Indiana Evansville Water and Sewer Utility Evansvilie, Indiana February, 1990 ------- PILOT PLANT INVESTIGATION OF ALTERNATIVE TREATMENT METHODS Mark H. Griese INTRODUCTION Not unlike every other utility within the State, the Evansville Waterworks Department is somewhat apprehensive about the impact which the Amendments to the Safe Drinking Water Act will have on it's Utility. In addition to those increased costs associated with the more stringent monitoring requirements, the promulgation of several specific regulations 'may necessitate significant and costly changes in Evansville's current treatment practices and treatment plant design. To more fully evaluate this impact and to determine the most cost effective approach toward insuring continued compliance, Evansville has initiated a treatment process study utilizing a pilot plant testing facility. Although some attention is being given to the optimization of all current unit processes, specific attention is being devoted to the evaluation of ozone and to increased chlorine dioxide capabilities for the further reduction of disinfection by-products. Evansville has already altered its disinfection scheme in its full-scale plant to meet existing tribalomethane regulations. More stringent impending regulations, however, require additional consideration of viable disinfection alternatives. The purpose of this paper is to describe the process by which Evansville implemented it's pilot plant project, to indicate the extreme degree of flexibility which a pilot unit affords a Utility in determining treatment alternatives, and to discuss some of the ------- preliminary data which Evansville has generated and how this data has altered the originally designed approach to the project. This process study is not Evansville's first experience with pilot plant application. In the late 70's and early 80's, the Evansville Utility engaged in a cooperative effort with the EPA to evaluate the use of chlorine dioxide and to determine the effectiveness of granular activated carbon for removal of organic compounds present in the source water as well as any formed after chlorine dioxide disinfection. The pilot plant selected for this earlier project was a single train 100 gpm Neptune Micro-Floe unit utilizing the conventional treatment processes of rapid mix, floceulation, settling, and filtration. Although rather large and lacking the flexibility required for the current study, this unit did produce water which compared remarkably well with our full- scale system. The data derived from this project convinced Evansville officials that pilot-plant results could be used to accurately project the effects of full-scale plant modifications. IMPLEMENTATION OF PROCESS STUDY As already indicated, increased speculation that more stringent disinfection byproduct regulations could be promulagated as early as 1992 led Utility officials to the conclusion that more information was needed concerning possible disinfection alternatives. Although.the low concentrations of chlorine dioxide currently used as a pre-treatment measure have proven valuable in maintaining Evansville's annual THM concentration well below 100 ug/L, this treatment methodology would not adequately insure ------- consistent compliance if this MCL is drastically reduced. It was the desire to address this issue and to obtain data concerning those byproducts associated with other disinfection alternatives that prompted the current project. Due to the fact that full-scale testing is inefficient, cost prohibitive, and could expose the public to a quality of water that is less than adequate, it was pre-determined that a major component of the process study would be a pilot plant evaluation of potential treatment changes or plant modifications. Specifications were developed for the procurement of the needed professional services necessary to evaluate the current treatment processes at Evansvilie's Hater Filtration Plant and to develop treatment and operational recommendations based upon present and proposed federal and state standards. After reviewing proposals by a number of qualified engineering firms with specialized experience relating to treatment process studies, the engineering firm of Camp Dresser & McKee was selected by the Utility. Based upon Evansville's objectives and Camp Dresser & McKee's recommendations, the following Project Approach was developed. * Review Raw Mater Quality data and Plant Operations Records * Raw Water Quality Characterization * Assess Future Treatment Requirements * Optimize Existing Treatment Processes * Evaluate Alternate Oxidants and Disinfectants * Implement Pilot Study * Evaluate Results and Develop Recommendations * Develop Conceptual Design and Cost Estimates ------- PILOT PLANT DESIGN To address what was believed to be the most critical component of these project objectives, a pilot plant was constructed by CD&M that would not only simulate Evansville's conventional methods of treatment, but would also provide the advantages of parallel treatment trains, ozonation capabilities, and multiple filtration columns for evaluating a variety of filter media combinations. Upon arrival in Evansville, the pilot plant was installed and a raw water connection was made to an existing low service main. Provisions were made to, utilize the chlorine dioxide, chlorine, and alum solutions employed within the full-scale plant. This was done to insure a representative comparison and to eliminate any inconsistencies which might occur by using dissimilar treatment chemicals. All water produced by the pilot system would be run to • waste. The pilot plant itself consists of a number of individual modules that may be interconnected in a variety of different ways. It was this feature that afforded the flexibility required for this project. A description of the individual modules comprising this pilot plant system follows. * The Electrical Distribution Module provides and distributes power to the rest of the Pilot Plant. * The Influent Module performs the function of dividing the raw water stream into two paths to supply the parallel treatment systems and is equipped with an in-line turbidimeter for continuous monitoring of the source water. * The Ozonation unit is self-contained and is comprised of an ------- ozone generator, supply-air drier and filter, ozone monitor, ozone destruct unit, and two 6-inch diameter contact columns. The system is counter-current with water entering at the top and ozone/air being introduced at the bottom of each column. The ozonated stream is then directed to the next downstream process. The availability of two columns permits multi-step ozonation for one treatment train or comparative testing in both treatment systems. * The two parallel Rapid Mix and Flocculation Modules are constructed entirely of Plexiglas and contain two rapid mix compartments and three flocculation chambers. Each of the five basins has its own independent mixer which provides the capability of achieving tapered flocculation. Injectors and a static mixer are provided prior to the rapid mix for chemical • pre-treatment. Provisions have also been made to feed chemicals between the individual basins if so desired. * Since sedimentation is one of the most difficult water treatment processes to model on a pilot plant scale, the Sedimentation Module uses tube settlers to achieve adequate turbidity removal. Utilizing this method of sedimentation for the 2 gpm flow which is characteristic of both treatment trains, the one hour detention of this module achieves settled water turbidities very representative of those in Evansville's full-scale plant. Like the raw water influent module, each of these units is equipped with a combination turbidimeter/recorder for continuous monitoring of treatment efficiency. * Settled water is pumped to four individual 4-inch diameter ------- filter columns. Each filter control module is equipped with a variable-speed pump which controls the flow through the filters and, like the other key treatment points throughout the system, a combination turbidimeter/recorder. Each filter is provided with taps located at various depths of filter media which may be used to monitor headless development and/or turbidity penetration. For Evansville's project, two filters were filled with sand and anthracite to simulate the full-scale plants present design. The other two filters contain granular activated carbon that can be operated in parallel with the dual media filters or in series with them as a final treatment measure. BENCH SCALE TESTING Prior to the initiation of pilot plant testing, bench scale testing was performed to determine if the current unit processes of mixing, coagulation, and flocculation in the full-scale plant were being performed with optimum results for both turbidity removal and THM precursor reduction. A variety of mixing rates, coagulant dosages, and coagulant types were tested with no significant improvement over existing full-scale plant production. In an attempt to gain some preliminary data concerning ozone and chlorine dioxide dosages and associated THM reduction, bench scale testing was also performed using various ozone and chlorine dioxide dosages and then monitoring the treated water for 3-day trihalomethane formation potential. Although the reductions in THMFP were somewhat less than expected for ozone, the results of ------- this test did confirm the effectiveness of both oxidants in reducing tribalomethane formation and gave some preliminary indication of the results which could be expected by utilizing various dosages in the pilot plant process.(Figures 1 & 2) PILOT PLANT TESTING PROGRAM With the pilot plant in place and preliminary bench scale testing completed, continuous flow pilot plant testing was initiated to further evaluate various treatment options. The initial testing period was timed to coincide with that time of year in which the highest trihalomethane formation potential is experienced by the Evansville Utility. The key objectives of this portion of the process study are to: 1. Attain Primary Disinfection 2. Minimize Disinfection Byproducts 3. Lower Annual Average THMs to < 50 ug/L 4. Select Secondary Disinfectant To accomplish these objectives, the following appeared to be Evansville1s treatment options: 1. Eliminate Chlorine Dioxide — Use Ozone 2. Keep Chlorine Dioxide — Add Ozone 3. Keep Chlorine Dioxide -- Add Granular Activated Carbon 4. Keep Chlorine Dioxide -- Add Ozone & Granular Activated Carbon ------- OZONE DOSAGES VS. THMEP EVANSVILLE - BENCH SCALE TEST //2 en CL b_ no 100 70 60 50 CO 0 0.5 1.5 OZONE DOSAGES (mg/L) ------- CHLORINE DIOXIDE DOSAGES VS. THMFP EVANSVILLE - BENCH SCALE TESTS #4 & #5 no 100 «M 0 0.5 1.5 CHLORINE DOSAGES (mg/L) ------- Chlorine dioxide had certainly proven advantageous in reducing THM concentrations in the full-scale system. Speculation, however, that the combined residual of chlorine dioxide and the byproduct ions of chlorite and chlorate would be regulated at a level significantly below the current rscommended maximum of 1 mg/L, indicated that increasing the current chlorine dioxide capabilities alone would not be adequate for addressing the key objectives. The increased chlorite ani chlorate concentrations resulting from elevated chlorine dioxide dosages would need to be effectively removed prior to entering the distribution system. Since a limited amount of information is available that indicates GAG is relatively effective in accomplishing this removal, it was believed that any treatment scheme utilizing chlorine dioxide alone as the primary disinfectant would have to also include GAC capabilities. The other options available would be to maintain the current chlorine dioxide levels and supplement pre- disinfection and pre-oxidation with ozone, or to eliminate chlorine dioxide entirely from the treatment scheme. With preliminary estimates that the addition of ozone or combined ozone and GAC capabilities could cost the Utility in excess of 10 million and 50 million dollars respectively, the reason for effectively reviewing and optimizing each treatment option was apparent. Each individual pilot plant test was designed to last from 3 to 5 days. With the wide variety of treatment options to be addressed, and the fact that a distinct impact would have to be observed by any one treatment combination to meet the desired objectives, this 10 ------- schedule would provide the roost optimum use of the pilot plant during that time of year when the DBF formation was greatest. Although not a surrogate for all disinfection byproducts, trihalomethane formation potential was selected as that parameter to be used to determine the preliminary "success" of each treatment option. In addition to trihalomethane reduction being one of the key objectives of the project, in-house analytical capability for this parameter would expedite data turn-around and the refinement of future scopes of work. Upon the generation of sufficient data to determine the most optimum methods of treatment, longer test periods would be implemented to verify earlier results, to optimize all unit processes involved in these particular methods, to gather data on other disinfection byproducts, and to determine the impact of raw water seasonal variations. Test No. 1 of the pilot plant study was a three day evaluation of THM precursor oxidation utilizing elevated levels of chlorine dioxide as a pre-oxidant. Current application of chlorine dioxide in Evansville's full-scale treatment system seldom exceeds 1.0 mg/L. This level of treatment has been selected because it is adequate for maintaining annual THM levels below the current MCL, and in consideration of minimizing residual chlorite and chlorate in the finished water. Since this dosage has proven inadequate for reducing annual average THM formation levels below the 50 ug/L level specified as a project objective, concentrations of 1.5 mg/L or higher would be applied during the process study. One treatment train of the pilot plant was pre-treated using an 11 ------- average dosage of 2 mg/L of chlorine dioxide while the second train was pre-treated with sufficient chlorine to maintain a free residual throughout the process. Finished water samples were collected from each of the two treatment trains, stored in the presence of chlorine for a period of three days at a temperature currently representative of the distribution system, and then analyzed for THM formation potential. A river water sample was also analyzed to monitor changing formation potential conditions. Figure 3 shows the results of Test fl. The three day THMFP for the river water was approaching 300 ug/L and the finished water from the pre-chlorinated train exhibited a formation potential of 174 ug/L. The sample collected from the pilot plant system utilizing pre-chlorine dioxide oxidation, however, showed a significant reduction in formation potential with a three day average of only 26.8 ug/L. This reduction apparently indicates a considerable oxidation of THM precursor material by the elevated chlorine dioxide dosage of 2 mg/L. Test No. 2 was designed to provide a direct comparison between a water treatment system using pre-ozonation and one using pre- chlorine dioxide addition. The raw water supplying one of the two pilot treatment trains was diverted through the ozonation module where it was treated with an average ozone concentration of 1.2 mg/L. The second pilot train was again pre-treated with chlorine dioxide. To provide a more direct comparison of the two preoxidants, the chlorine dioxide dosage was reduced to 1.5 mg/L. Figure 4 indicates the results achieved in Test 12. Although exhibiting a distinct reduction in formation potential as compared 12 ------- THM FORMATION POTENTIAL COMPARISON EVANSVILLE - PILOT PLANT TEST #1 L i_ E 300 250 200 150 100 50 0 RIVER PRE-CI2 PRE-002 SAMPLE TYPE ------- TIIM FORMATION POTENTIAL COMPARISON EVANSVILLE - PILOT PLANT TEST 350 300 250 200 150 100 50 0 RIVER o PRE-OZONE PRE-002 SAMPLE TYPE ------- to the earlier tested pre-chlorination process, the ozone treated water still exhibited a THM formation potential in excess of that water pre-treated with chlorine dioxide. The increase in THM levels in the chlorine dioxide system compared to those in Test 1 was more than likely due to both the increase in the raw water formation potential and the 0,5 mg/L dosage reduction. To again determine if the conventional treatment methods of coagulation and flocculation could be further optimized for the removal of THM precursors, Tests 3 & 4 of the pilot study were geared for a direct comparison of ferric chloride and the currently employed aluminum sulfate. Test 3 compared the two coagulants directly with pre-chlorination being practiced in both treatment trains. Nearly identical THM formation potential was observed for both systems. In Test 4, the water in both pilot treatment systems was pretreated with ferric chloride and the pre- disinfectant scheme utilized in Test 2 was repeated. As in Test 2, both systems exhibited significant reductions in THMFP as compared to the raw water. Although a slight improvement was noted for the system pretreated with ozone, the difference was minimal and it was determined that a significant reduction in DBP formation could not be expected by altering coagulants. The treatment applications used in Pilot Test No. 5 would again compare identical dosages of chlorine dioxide and ozone. In this test, however, ozone treatment would occur, not as a pretreatment measure, but after the treatment processes of coagulation, flocculation, and sedimentation. This study was designed to determine if the efficiency of ozone oxidation could be increased 15 ------- by altering its point of application. As can be seen in Figure 5, that treatment train being pre-treated with chlorine dioxide again exhibited the greatest reduction in disinfection byproduct formation potential. Although the THM levels of both systems were somewhat higher due to tie increasing formation potential of the raw water, pre-oxidation using chlorine dioxide still revealed the greatest efficiency in reducing this disinfection byproduct. Tests 6 & 7 compared chlorine dioxide treatment to a treatment system utilizing both pre- and settled ozone application. Due to a continued increase in raw water formation potential, both systems were treated with 2.5 mg/L of the respective disinfectants. The entire 2.5 mg/L dosage of chlorine dioxide was applied as pre-treatment while the ozone was applied as a pre- treatment measure and in the settled water at 1.5 mg/L and 1.0 mg/L respectively. Figure 6 shows the results of Test 7. The elevated raw water formation potential was impacting both treatment systems. By comparison, however, the chlorine dioxide treated system still revealed significantly lower THM levels. At this point in the project, it was beginning to appear that, at least for Evansville's raw water source, chlorine dioxide was going to be the pre-disinfectant of choice. The Evansville Utility had anticipated ozone oxidation to prove more efficient in reducing disinfectant byproduct formation. Although an estimated 10 million dollar capital investment would be needed to implement ozone treatment in Evansville's full-scale plant, this alternative was obviously more attractive than the 40 to 50 million that would be needed for GAG to remove the chlorite and chlorate associated 16 ------- THM FORMATION POTENTIAL COMPARISON EVANSVILLE - PILOT PLANT TEST #5 500 400 300 200 100 0 M U, RIVER SETTLED-OZONE PRE-CI02 SAMPLE TYPE ------- CL THM FORMATION POTENTIAL COMPARISON EVANSVILLE - PILOT PLANT TEST #7 500 400 500 200 100 0 vO CO RIVER TWO STAGE OZONE PRE-CD2 SAMPLE TYPE ------- with increased chlorine dioxide capabilities. Pilot Test No. 8 repeated the comparison made in Test 2 with ozone and chlorine dioxide both being applied as a pretreatment measure at the higher 2,5 mg/L level. This test was performed to reconfirm that single stage ozonation was as effective at reducing THMFP as was the dual stage application performed in the previous tests. As in Test. 2, chlorine dioxide again exhibited the greater reduction at a percentage similar to those in the previous test modes. Hot to be dissuaded from our original perception, one last attempt was made to improve those results obtained by ozone oxidation. A number of studies have indicated that small amounts of hydrogen peroxide used in conjunction with ozone application greatly enhance oxidation capabilities. To test the applicability of "Peroxone" technology in Evansvilie's process, Tests 9 & 10 directly compared a treatment system using pre-ozonation to one using pre-ozonation and hydrogen peroxide addition. Figure 7 reveals the results of Test 10 after the hydrogen peroxide dosage used in Test 9 was increased from 0.5 mg/L to a concentration of 1.0 mg/L. This test was performed for an entire week with every effort made to identify some improvement in the ozonation/peroxide process. As evident in Figure 7, no improvement was noted. Although both trains exhibited formation potential variations which compared remarkably well with those in the raw water, the numbers generated for both treatment processes were almost identical. 19 ------- TI-IM FORMATION POTENTIAL COMPARISON EVANSVILLE - PILOT PLANT TEST #10 jr~ ^. en Q. LJL. 500 400 300 200 100 0 RIVER 03 03 & H202 TEST DATES ------- NEW SCOPE OF WORK When the Pilot Plant study was still in its infancy, Evansville made a request to the EPA Research Center in Cincinnati, Ohio for supplemental analytical support for disinfection byproducts. In consideration of the EPA's plans for the development of regulations concerning these byproducts, it was believed that the data generated could assist the EPA in its regulatory development. As the data began to indicate the viability of chlorine dioxide for primary disinfection, the EPA informed Evansville of bench scale work being performed by Dr. Gil Gordon of Miami University in Oxford, Ohio on minimizing the amount of chlorite and chlorate in drinking water treated with chlorine dioxide. Dr. Gordon had discovered that sulfur dioxide could be used to quantitatively remove the chlorite ion concentration to below the 0.1 mg/L level. This process, coupled with the minimizing of chlorate concentrations by proper chlorine dioxide generation, would permit the use of higher concentrations of chlorine dioxide with the elimination and/or removal of chlorite and chlorate ion residuals. Evansville now had a fifth treatment option. Although this method of treatment, to our knowledge, has not been performed outside of the laboratory, the implications of this technology warrant our investigation. Because this research could determine the viability of chlorine dioxide as a Best Available Technology under the Disinfection Byproduct Rule, the EPA is now supporting Evansville both financially and analytically in this endeavor. In consideration of the previously generated data and the mutual benefits which could be derived by both Evansville and the OSEPA, 21 ------- a new scope of work was developed to fully evaluate the use of chlorine dioxide as a primary disinfectant and the reduction of its byproducts by sulfur dioxide application. Prior to the initiation of the revised scope of work, a number of additions were made to the Pilot Plant to better evaluate this treatment process. A 30 pound per day chlorine dioxide generator was donated to the Utility by Rio Linda Chemical Company to be used specifically for the pilot study. In tests 1 - 10, chlorine dioxide from the full- scale generation system had been transferred to a day tank for application to the pilot plant. Tests indicated that an increase in chlorate formation was occurring during this period that was probably due to the presence of a low level chlorine residual in the batch solution. Since control of the chlorate ion would need to be accomplished by optimizing the generation process and by removing the chlorite ion prior to post-chlorination, this new generator was installed with the majority of the production stream going to the full-scale plant and a small, but accurate, percentage going to the pilot plant. This "slip streaming" procedure was accomplished by utilizing chemical resistant variable-area flowmeters. Based upon the analytically determined concentration of the original chlorine dioxide solution, the proper milliliter per minute setting is made to achieve the desired disinfectant dosage. This method of chlorine dioxide application is more accurate than the previously employed procedure and it takes advantage of the newly installed generator's efficiency. 22 ------- Secondary settling basins have also been incorporated into the pilot plant to add an additional 90 minutes of settling and contact time to the treatment system. This treatment addition was made to more closely simulate Evansville's full-scale plant, to provide a location for pH adjustment if so desired, and to provide additional contact time for the chlorine dioxide prior to the addition of sulfur dioxide. This additional contact time would helf insure the bacteriological integrity of the water supply and assist in monitoring the presence of a chlorine dioxide residual beyond primary settling. A sulfur dioxide system is also being added to the Pilot Plant. Based upon the same principal as the chlorine dioxide system, precision rotometers will be utilized to "slip stream" a small percentage of an inductor generated sulfur dioxide solution. This stream will be added immediately prior to the dual media filters. The fourth and final addition to the Pilot Plant was the attachment of four 20 gallon clearwells to each filter effluent. These clearwells will permit post-chlorination for the removal of excess sulfur dioxide and sampling points representative of finished water quality. A fifth piece of equipment was installed, not in the Pilot Plant, but in the laboratory. An ion chromatograph for the detection, monitoring, and accurate quantitation of chlorite and chlorate has been obtained. Generating chromatorgrams similar to that produced in gas chromatography, this instrument can accurately detect both ions at levels below 0.1 mg/L. Since it was nearly impossible to monitor these types of levels with the previously employed 23 ------- amperometric measurements, this instrument was essential for determining the success of the new treatment process. With these additions in place, the revised scope of work was initiated. The revised scope of work consists of five basic components. 1- Optimize Generator Ifficienc^ - A sufficient number of analyses on the chlorine dioxide production stream will be performed to insure that the generator is producing chlorine dioxide with minimal chlorine and chlorate residuals. 2. Bench Scale Studies fjojr Reduction/Reroova 1 of. Chlorine Dioxide and Chlorite - Bench scale studies will be conducted by the EPA to determine optimum dosages of sulfur dioxide for achieving chlorite and chlorine dioxide removal. Other dechlorinating agents such as PAC and ferrous ion may be evaluated to determine their potential for accomplishing the same task. 3. Demonstrate the Best Method vs. GAC - The major operational scheme of this phase will consist of adding the sulfur dioxide prior to the dual media for reducing chlorine dioxide and chlorite. Post chlorination will then occur to remove any excess sulfur dioxide. This process will be compared to one utilizing the GAC columns for removal of the same constituents. 4. Comparison of Chlorine Dioxide and Ozone - Since chlorine dioxide and ozone are probably the only disinfectants that can be applied to the raw water and still meet the disinfection byproduct regulations, they will be evaluated in parallel in this phase. 24 ------- 5. Optimization of Unit Processes - The purpose of the Phase of the pilot study will be to optimize the most desirable application by varying other unit processes. The effects of alternative coagulants, varied pH ranges, and various points of disinfectant application are examples of those unit processes that will be examined during this study period. Throughout the project, formation potential using chlorine will be done on collected samples to determine the impact of post chlorination. Compounds and surrogates that will be evaluated include trihalomethanes, haloacetonitriles, haloacetic acids, chloral hydrate, chloropicrin, chloropropanone, total organic halide, and total organic carbon. Other byproducts, such as the aldehydes and ketones, will also be monitored and evaluated. Phases 1 and 2 of the Project are now ongoing. The EPA is currently involved in the bench scale evaluation while Evansville is optimizing the chlorine dioxide generation efficiency and installing the sulfur dioxide system. Completion of the project is expected by late summer. CONCLUSION In a rapidly changing regulatory environment, this project is viewed by the Evansville Utility as an investment in the future that could now potentially save the department millions of dollars. Although not applicable to everyone, the specific research being conducted by Evansville certainly underscores the flexibility which a pilot plant facility provides a water utility. 25 ------- Whether it is used to optimize a current treatment process, to determine the feasibility of retrofitting a new treatment technique into an existing plant, or to design and size a new facility, pilot plant testing certainly provides a utility with a cost-effective approach for addressing these issues. 26 ------- TECHNICAL REPORT DATA /Please read Instructions on the reverse be/ore comnletm 1 REPORT NO, EPA/600/A-94/191 4. TITLE AND SUBTITLE Pilot Plant Investigation of Alternative Treatment Methods 6. PERFORMING ORGANIZATION CODŁ 3. R 5. REPORT DATE 7. AUTHOR(S) Mark H. Griese 8, PERFORMING ORGANIZATION REPORT NO. 9. PERFORMING ORGANIZATION NAME AND ADDRESS Offic$ of Research and Development Drinking Water Research Division 10. PROGRAM ELEMENT NO. US EPA Cincinnati, Ohio 11. CONTRACT/GRANT NO. 45268 12. SPONSORING AGENCY NAME AND ADDRESS 13, TYPE OF REPORT AND PERIOD COVERED Risk Reduction Engineering Laboratory, Cincinnati,OH Office of Research and Development OS Environmental Protection Agency Cincinnati, Ohio 45268 Symposium Paper 14. SPOroscJMING AGENCY CODE :YC( EPA/600/14 15. SUPPLEMENTARY NOTES Presented at the 82nd Annual Meeting of the Indiana Section American Water Works Association, February 20-22, 1990, Indianapolis, Indiana PO=Ben1amin Lvkins 16. ABSTRACT TPgT^ZT^ (513) 559.7450 Describes the process by which Evansville implemented it's pilot plant project, to indicate the extreme degree of flexibility which a pilot unit affords a Utility in determining treatment alternatives, and t,Q~ discuss some of the preliminary data which Evansville has generated and how this data has altered the originally designed approach to the project. 17. KEY WORDS AND DOCUMENT ANALYSIS DESCRIPTORS b.lDENTIFIEHS/OPEN ENDED TERMS COSATI Fiefd/Group 18. DISTRIBUTION STATEMENT Release to Public 19. SECURITY CLASS (This Report} Unclassified 20. SECURITY CLASS (This page) Unclassified 21. NO. OF PAGES 2S_ 22. PRICE EPA form 2220-1 (R»». 4-77) PREVIOUS EDITION is OBSOLETE ------- |