v>EPA United States Environmental Protection Agency Municipal Environmental Research EPA-600/2-78-076 Laboratory June 1978 Cincinnati OH 45268 Research and Development Water Factory 21: Reclaimed Water, Volatile Organics, Virus, and Treatment Performance ------- RESEARCH REPORTING SERIES Research reports of the Office of Research and Development, U.S. Environmental Protection Agency, have been grouped into nine series. These nine broad cate- gories were established to facilitate further development and application of en- vironmental technology. Elimination of traditional grouping was consciously planned to foster technology transfer and a maximum interface in related fields. The nine series are: 1. Environmental Health Effects Research 2. Environmental Protection Technology 3. Ecological Research 4. Environmental Monitoring 5. Socioeconomic Environmental Studies 6. Scientific and Technical Assessment Reports (STAR) 7. Interagency Energy-Environment Research and Development 8. Special” Reports 9. Miscellaneous Reports This report has been assigned to the ENVIRONMENTAL PROTECTION TECH- NOLOGY series. This series describes research performed to develop and dem- onstrate instrumentation, equipment, and methodology to repair or prevent en- vironmental degradation from point and non-point sources of pollution. This work provides the new or improved technology required for the control and treatment of pollution sources to meet environmental quality standards. This document is available to the public through the National Technical Informa- tion Service, Springfield, Virginia 22161. ------- EPA-600/2-78-076 June 1978 WATER FACTORY 21: RECLAIMED WATER, VOLATILE ORGANICS, VIRUS, AND TREATMENT PERFORMANCE by Perry L. McCarty, Martin Reinhard, Carla Dolce, and Huong Nguyen Civil Engineering Department Stanford University Stanford, California 94305 and David G. Argo Orange County Water District Fountain Valley, California 92708 Grant No. EPA-S-803873 Project Officer John English Wastewater Research Division Municipal Environmental Research Laboratory Cincinnati, Ohio 45268 MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY OFFICE OF RESEARCH AND DEVELOPMENT U.S. ENVIRONMENTAL PROTECTION AGENCY CINCINNATI, OHIO 45268 ------- DISCLAIHER This report has been reviewed by the Municipal Environmental Research Laboratory, U.S. Environmental Protection Agency, and approved for publica- tion. Approval does not signify that the contents necessarily reflect the views and policies of the U.S. Environmental Protection Agency, nor does men- tion of trade names or commercial products constitute endorsement or recoin— mendation for use. 11 ------- FOREWORD The Environmental Protection Agency was created because of increasing public and government concern about the dangers of pollution to the health and welfare of the American people. Noxious air, foul water, and spoiled land are tragic testimony to the deterioration of our natural environment. The complexity of that environment and the interplay between its components require a concentrated and Integrated attack on the problem, Research and development is that necessary first step in problem solu- tion and It Involves defining the problem, measuring its Impact, and search- ing for solutions. The Municipal Environmental Research Laboratory develops new and improved technology and systems for the prevention, treatment, and management of wastewater and solid and hazardous waste pollutant discharges from municipal and community sources, for the preservation and treatment of public drinking water supplies, and to minimize the adverse economic, social, health, and aesthetic effects of pollution. This publication Is one of the products of that research; a most vital cóimnunications link between the re- searcher and the user community. This report describes the performance of Water Factory 21, a 0.66 m 3 /s advanced wastewater treatment plant designed to treat municipal wastewater so that it can be used to recharge a groundwater system. Through this project groundwater supplies are being replenished, saltwater—endangered aquifers are being protected, and water Is being reclaimed for future use. Francis T. Mayo, Director Municipal Environmental Research Laboratory 111 ------- ABSTRACT Water Factory 21 is a 0.66 rn 3 /s (15 mgd) advanced wastewater treatment plant designed to improve the quality of biologically treated municipal waste- water so that it can be used to provide the injection water for a seawater barrier system. Processes included are lime treatment, ammonia stripping, breakpoint chlorination, filtration, activated—carbon adsorption, reverse os- mosis, and final chlorination. Because of interest in the use of reclaimed water to augment the domestic water supply, this study was initiated to eval- uate the effluent quality and efficiency of treatment for inorganic, organic, and biological contaminants. This report covers the first one and one—half years of plant operation. Chemical clarification with lime at pH greater than 11.3 removed 60 per- cent of the influent COD, 99 percent of the phosphates, and greater than 50 percent of the barium, cadmium, chromium, copper, iron, lead, manganese, sil- ver, and zinc. Removal of mercury, selenium, and arsenic were minimal. Ammonia stripping with two towers in series removed an average 82 percent of the influent ammonia, and was highly effective in reducing the concentrations of a wide range of low molecular weight and non—polar organics such as one— and two—carbon halogenated organics, chlorinated benzenes, and hydrocarbons. These in general were not removed efficiently by other processes. Activated—carbon adsorption was effective not only for general COD re- moval, but also for the removal of a wide range of specific organic compounds such as chlorinated benzenes and aromatic hydrocarbons, many of which are of toxicological significance. This process in combination with the others re- sulted in an overall COD removal of 90 percent, producing an effluent with a mean COD of 15 mg/i. Breakpoint chlorination (9:1 weight ratio of Cl 2 to N11 3 —N) is effective in reducing ammonia nitrogen to 1 mg/i; however, it results in the production of relatively high concentrations of chlorinated organics, particularly the haiofornis, if carried out before carbon adsorption, and depresses pH if prac- ticed following carbon adsorption. The latter point of application is prob- ably best for breakpoint chlorination as it minimizes effluent organics and pH control is technically feasible. Pilot studies with reverse osmosis indi- cated removals of 95 percent for general inorganics and 93 percent for COD. However, haloforms, chlorinated benzenes, and other low molecular weight or— ganics were not removed. Most influent samples taken were positive for virus and the presence of over 25 different viruses was verified. However, of 77 effluent samples ana- lyzed, only one was positive for virus, and contained one plaque of Polio Type 2. This single incidence appears to have been associated with an occa- sional problem of activated—carbon fines in the effluent. iv ------- This report is a progress report submitted In partial fulfillment of Research Grant No. EPA—S—803873 by the Orange County Water District under sponsorship of the U.S. Environmental Protection Agency. This report covers the period of January 1, 1976, to July 31, 1977, and was completed January 1, 1978. V ------- CONTENTS Foreword Abstract Figures Tables Acknowledgments 111 iv viii ix x 18 18 19 19 28 48 55 55 55 56 57 60 60 64 66 71 1 2 4 5 5 8 10 10 10 10 15 1. Introduction 2. Conclusions 3. Recommendations 4. Water Factory 21 General Description . Process Description . 5. Sampling and Analytical Procedures Sampling General Inorganics and Heavy Metals Organics Viruses 6. Results Characteristics of Influent Water Treatment Plant Performance . . General Inorganics and Heavy Metals Organics Virus 7. Discussion Background General Inorganics Heavy Metals Organics Virus Plant Reliability References Appendices A. Major Design Criteria, OCWD 0.66 1n 3 /s Advanced Wastewater Treatment Plant B. Summary Analyses for General Constituents, Trace Inorganics, Radioactivity and Pesticides vii ------- FIGURES Number Page 1 Processes and sampling locations at Water Factory 21 . . . . 6 2 Variation in flow rate at Water Factory 21 during the two periods of this study 7 3 Haloform concentrations after October 1976 when breakpoint chlorination was initiated; upper: filtration effluent (Q6); lower: plant effluent (Q9) 33 4 Chromatograms of CLS extracts with simultaneous flame ionization and electron capture detection. A: Q2 taken 6/12—13/1977; B: Q9 taken 6/12—13/1977 (numbers refer to Table2S) 40 5 ECD—chromatogram (setting 337/2k) of Qi extract, internal standard 2.34 ig/l. 1: diethylphthalate; 4: dioctyl— phthalate; 3: retention time as lindane; 2: unknown . . . 41 6A Pesticide standard (ECD setting 337/2 ). 1: BHC isomers 260 pg; 2: lindane 260 pg; 3: heptachior 160 pg; 5: aidrin 160 pg; 7: dieldrin 160 pg; 8: DDE 194 pg; 9: endrin 170 pg; 10: TDE 500 pg; 11: DDT 240 pg; i.s.: internal stan- dard, 1170 pg; 4, 6: impurities 42 6B PCB arochior 1242 standard, 2.66 ng; internal standard, 0.464 ng. Detector 337/2k 42 7 Typical total ion chromatogram (computer reconstructed) of a CLS extract from Q2. Lower graph is independently normalized. Numbers refer to substances in Table 25 . . . 47 8 Probability plot of virus assay levels 50 9 Seasonal variation In natural viruses in Water Factory 21 influent 52 A—l Reverse osmosis plant flow diagram 70 V1i] ------- TABLES Number Page 1 Water Factory Sampling Schedule, January 1976 through June 1976 11 2 Water Factory Sampling Schedule, October 1976 through June 30, 1977 12 3 General Analytical Procedures 13 4 Summary of Virus Concentration Methods 16 5 Mean Characteristics of Secondary Effluent Treated at Water Factory 21 18 6 Mean Characteristics of Treated Water and Regulatory Requirements, January 1976 through June 1976 20 7 Changes in General Parameters by Chemical Clarification, January through June 1976 (Monthly Mean Values) 21 8 Chemical Clarification. Heavy Metals Removal, January through June 1976 21 9 Ammonia Removal by Stripping, January through June 1976 . . . 22 10 Heavy Metals Removal by Carbon Adsorption, January through June1976 23 11 Mean Characteristics of Treated Water and Regulatory Requirements, October 1976 through June 1977 24 12 Changes in General Parameters by Chemical Clarification, October 1976 through June 1977 (Monthly Mean Values) . . 26 13 Effect of Chemical Treatment on Heavy Metals, October 1976 through June 1977 27 14 Effectiveness of Ammonia Stripping Process, October 1976 through June 1977 27 15 Filter Performance for Turbidity Reduction, October 1976 through June 1977 28 ix ------- TABLES (continued) Number Page 16 Heavy Metals Removal by Activated Carbon, October 1976 through June 1977 29 17 COD Removal by Water Factory 21 30 18 TOC Removal by Water Factory 21 30 19 Haloforin Concentrations Prior to Breakpoint Chlorination, January 1976 through June 1976 31 20 Haloform Concentrations during Second Period, October 1976 through June 1977 32 21 Concentrations of Highly Volatile Constituents Other than Haloforms ( tg/l), October 1976 through June 1977 . . . . 35 22 Closed—Loop Stripping Analyses for Selected Organics, October 1976 through June 1977 36 23 Efficiency of Ammonia Stripping and Carbon Adsorption for Removal of Selected Trace Organics Based upon Paired Samples 38 24 PCBs and Phthalate Concentrations at Various Sampling Points, April 1977 through June 1977 43 25 Compounds in WF—2l Samples Analyzed by CLSA and Their TIC Peak Heights Relative to the Internal Standard, 1—C1—C8 . . 45 26 Substances Tentatively Identified in Hexane Extracts . . . . 46 27 Virus Concentration in Influent (Q1) 49 28 Viruses Identified in Water Factory 21 Influent (Qi) . . . . 51 29 Virus Concentration in Chemical Clarifier Effluent (Q2), November 1975 through June 1976 53 30 Variability of Inorganic Constituents in Water Factory 21 Effluent 61 31 Variability of Organic Constituents in Water Factory 21 Effluent 62 x ------- ACKNOWLEDGMENTS Ms. Betsy Martin, Orange County Water District, participated in field virus concentrations for this project. Dr. Lawrence Leong and Dr. Rhodes Trussell, Project Engineers with James N. Montgomery, Consulting Engineers, Inc., were responsible for viral assay and technical direction for this phase of the project, respectively. Appreciation is extended to the California Department of Public Health for their conducting the extensive virus assays for this project, and to David Dickson, Research Assistant, Stanford University, who assisted in anal- yses for organic constituents. In addition to the support provided by the Orange County Water District and the U.S. Environmental Protection Agency, project financial assistance was provided by OWRT, U.S. Department of the Interior through Grant 14—34— 0001—7503, the California Department of Water Resources through Grant No. B52353, and various member agencies of WaterCare. xi ------- SECTION 1 INTRODUCTION The Orange County Water District (OCWD) has constructed Water Factory 21 and a series of injection wells near the Pacific Coast in order to reduce sea- water intrusion into the groundwater supply by recharge of reclaimed waste— water (9). Water Factory 21 is a 0.66 m 3 /s (15 mgd) advanced wastewater treatment plant which was designed to improve the quality of biologically treated municipal wastewater so that it could be used to provide the injection water needed for the seawater barrier system. Processes included in this f a— cility are lime treatment for suspended solids and heavy metal removal, ammo- nia stripping and breakpoint chlorination for nitrogen removal, filtration and activated—carbon adsorption for organics and additional suspended solids removal, reverse osmosis for demineralization, and final chlorination for disinfection. Because of the high quality of water reclaimed by Water Factory 21, in- terest has increased in the potential of using the reclaimed and injected wastewater to augment the domestic water supply. However, inadequate knowl- edge of inorganic, organic and biological constituents remaining after ad— vanced wastewater treatment has caused concern among health agencies respon- sible for protecting the safety of groundwater supplies. Because of such concern, this study was undertaken to: (1) characterize the quality of Water Factory 21 effluent, (2) assess the reliability of treatment plant operation for removal of trace contaminants, and (3) evaluate the effectiveness of the individual processes and processes in combination for removing materials of public health concern. This report is a summary of the results of inorganic and organic analy- ses, viral assays, and an evaluation of the performance for the first one and one—half years of operation of Water Factory 21. 1 ------- SECTION 2 CONCLUSIONS The results of the first one and one—half years of operation of Water Factory 21 have indicated that the advanced wastewater treatment plant is capable of removing a variety of inorganic, organic, and biological contami- nants present in trickling filter treated municipal wastewater. Chemical clarification with lime at a pH greater than 11.3 resulted in more than 50 percent reduction in the concentration of trace heavy metals such as barium, cadmium, chromium, copper, iron, lead, manganese, silver, and zinc. Mercury, selenium, and arsenic were not removed significantly by this process. The lime process also removed 60 percent of the influent COD, only a portion of which was In suspended form, and 99 percent of the influent phosphates. Following lime clarification ammonia stripping with two towers operated in series removed an average of 82 percent of the influent ammonia. In ear— her studies with the towers operated in parallel, removal was only 56 per- cent. In addition, ammonia stripping resulted in a high degree of removal of a variety of low molecular weight organic compounds, many of which were not efficiently removed by the other processes in the treatment system, such as activated—carbon adsorption and reverse osmosis. Included in the compounds removed were several chlorinated organics. This indicates that air stripping can be an important complementary process for removal of trace organic mate- rials. Activated—carbon adsorption was effective not only for general COD re- moval but also for the removal of a wide range of specific organic compounds, many of which are of toxicological significance. This process in combination with the others resulted in an overall COD removal of 90 percent, producing an effluent with a mean COD of 15 mg/i. Breakpoint chlorination at a weight ratio of 9 parts chlorine to 1 part ammonia nitrogen was effective for reducing the ammonia nitrogen concentra- tion to 1 mg/i. However, this process also caused the production of high concentrations of chlorinated organics such as the haloforms, created prob— lems in pH control, and adversely affected the effectiveness of activated— carbon adsorption. These problems except p11 control are minimized if break- point chlorination is practiced after rather than before activated carbon. Virus were present In most samples of secondary treated wastewater re- ceived at Water Factory 21. The advanced wastewater treatment was effective In removal of the virus as only one was found in the 77 samples of final 2 ------- effluent analyzed. The appearance of this single virus appears to have been related to an operational problem which resulted in the escape of activated— carbon fines in the effluent. Pilot plant studies indicated that reverse osmosis was effective in re- moving about 95 percent of the total dissolved solids in advanced treated effluent. It also removed 93 percent of the organics as measured hy the COD test, although many trace organics with low molecular weight such as the haloforms were not removed by this process. The combined advanced wastewater treatment processes employed at Water Factory 21 are capable of meeting the regulatory requirements for injection water as needed for the seawater barrier system. They also show promise for producing a water which may satisfy public health concerns associated with mixing of the injected water with groundwater in an aquifer used for general municipal purposes. 3 ------- SECTION 3 RECOMMENDATIONS This study has provided extensive data which can be used to evaluate the effectiveness of advanced wastewater treatment for removing inorganic, organ1 , and biological materials of public health concern. Problems which require further evaluation are indicated in the following. The effect of breakpoint chlorination or a free chlorine residual on the capacity of activated carbon, and its potential for release of specific orga- nic materials from activated carbon needs further study. Breakpoint chlorination results in the formation of high concentrations of several chlorinated organics of public health concern. The low nitrogen requirement which necessitated the use of breakpoint chlorination should be reevaluated. The potential benefits from the required ammonia nitrogen con- centrations of 1 mg/l in the injection water are offset by a high cost for breakpoint chlorination, increased concentrations of chlorinated organics, and reduced treatment plant reliability. Also, operational procedures which will minimize chlorinated organic formation need to be developed. Activated—carbon fines cause problems when present In effluents from ad- vanced wastewater treatment systems including clogging of reverse osmosis membranes and well injection systems, as well as Increasing the potential for pathogen passage through the system. Methods for reducing activated—carbon fines need to be explored. The program for measuring trace organics needs to be modified to allow more frequent and precise quantification for those specific organics which are of health concern. For these materials, the individual treatment proces- ses should be more closely evaluated to determine the effect of operational variables on the efficiency of removal. Because of time and expense, this may necessitate modification of the routine monitoring program. Many organics are not measureable by currently available analytical tech- niques. In order to gain some Idea of the health risks associated with such materials, some method of biological testing of the organics, such as bac- terial mutagenicity should be instigated and the results should be compared with those from alternative supplies. 4 ------- SECTION 4 WATER FACTORY 21 GENERAL DESCRIPTION The wastewater reclamation plant was designed to treat 0.66 in 3 /s (15 mgc of municipal trickling filter effluent by the processes indicated in Figure 1. These Include lime clarification with sludge recalcining, ammonia stripping, recarbonation, breakpoint chlorination, mixed—media filtration, activated— carbon adsorption and carbon regeneration, post—chlorination, and reverse os— inosis (RO) demineralization. The plant operation covered in this report has been divided into two distinct periods. Plant operation began in January of 1976 and was main- tained continuously through June, 1976. During this period the water being treated was not injected, the plant was operated for the specific purpose of gathering data to determine treatment capability. Following a plant shutdown which occurred during July, August and September of 1976 for routine mainte- nance and modifications, operations were restarted in October and were main- tained continuously for the duration of the study period. Figure 2 illus- trates the variation in flow rate through the plant during these two periods of operation. Generally, plant flows were maintained in the 0.22 to 0.26 m 3 Is range. Water Factory 21 is composed of dual unit processes which allow the indi- vidual units to be operated near design capacity even when the total system was operated at reduced flow. Typical flow rates for the various processes are as follows: Process Normal Percent of Design Flow Rate Prior to October 1976 After October 1976 Lime Clarification 100 80 Ammonia Stripping 100 40 Recarbonation 50 80 Filtration 100 100 Carbon Adsorption 100 100 Final Chlorination 20 40 5 ------- CHLORINATION CHEMICAL CLARIFICATION ACTIVATED CARBON ADSORPTION Processes and sampling locations at Water Factory 21. 0 1 C l 2 08 109 EFFLUENT AIR LIME SLUDGE CO 2 AMMONIA STRIPPING RECARBONATION REVERSE OSMOSIS FILTRATION Figure 1. 6 ------- .4 .3 (I) E IJJ I- 0 -J 0 MONTH OF OPERATION Figure 2. Variation in flow rate at Water Factory 21 during the two periods of this study. ------- PROCESS DESCRIPTION The individual processes at Water Factory 21 are illustrated in Figure 1. The major design criteria for each process are listed in detail in Appendix A. A general description of each process is given in the following. Chemical clarification is accomplished in separate rapid mix flocculation and sedimentation basins. Lime is used as a primary coagulant and is added in slurry form to the rapid mix basin. Lime feed is automatically controlled to achieve an optimum pH of 11.3. A lime dose of 350 to 400 mg/l as calcium oxide is sufficient to maintain this pH. The three—stage flocculation basins are operated with G values of 100, 25, and 20 s_i in the first, second, and third flocculation basins, respectively. Detention time in the flocculation basin is approximately ten minutes in each compartment. An anionic polymer, Dow A 23, is used as a settling aid in the third—stage basin. A polymer dose of 0.1 mg/i is usually added as a settling aid to improve clarification. The water flows from the bottom of the third flocculation basin into a settling basin. The settling basin is also equipped with inclined settling tubes to improve clarification. This process has been found effective for reducing turbidity, phosphates and suspended solids. Following settling, ammonia stripping Is accomplished in a countercur- rent induced draft tower at an air to water ratio of 3000 m 3 /m 3 . The depth of the polypropylene splash bar packing is 7.6 m. Each tower was originally designed to operate Independently; however, due to poor initial ammonia re- movals, the towers were modified to operate in series. Performance prior to modification had Indicated ammonia removals of 50—65 percent. Fcllowing the tower modification, removals have been increased to 80—85 percent. Breakpoint chlorination has been practiced since October, 1976, for ni- trogen control. It was found that a chlorine to ammonia nitrogen weight ratio of 9 or greater was required to decrease ammonia nitrogen levels to 1 mg/i or less. Three different locations for breakpoint chlorination were evaluated: just after ammonia stripping, while pH is high; between first and second stage recarbonation; and in conjunction with final chlorination. Each location was found to have relative advantages and disadvantages. In the recarbonation process, carbon dioxide is added to lower pH to ap- proximately 7.5. The recarbonation basin also served as a chlorine contact chamber during some portions of this study to allow detention time for break- point chlorination reactions to occur. Following the recarbonation basin, the effluent passes through open gravity mixed—media filter beds designed for a hydraulic loading rate of 0.2 in 3 /m 2 —min. The filter media is 0.76 m deep and consists of layers of coarse coal, silica sand, and garnet. It is supported by a layer of silica and garnet gravel with a Leopold underdrain. Alum (11 mg/l) and polymer (0.05 mg/l) are added to improve clarification. The water is then pumped through packed—bed, upflow pressure contactors filled with Calgon Filtersorb 300 granular activated carbon. There are 17 8 ------- contactors each operating in parallel and with an empty bed contact time of 30 minutes. The hydraulic loading rate for each column is 0.2 m 3 /m 2 —min. Following activated—carbon treatment the effluent flows to the final chlorination basin for post—chlorination, followed by 30 minutes of contact time at the design flow of 0.66 m 3 /s. A 0.22 m 3 /s reverse osmosis plant will treat a portion of the reclaimed water following activated—carbon treatment, so that when blended with the re- maining portion, an adequate reduction in total dissolved solids can be ob- tained. During this study the full—scale reverse osmosis plant was under construction, but effluent was available for evaluation from a 0.9 m 3 /h pilot plant using spiral—wound membrane elements. The pilot RO plant was operated on either activated—carbon effluent or mixed—media filter effluent. A flow diagram of the full—scale reverse osmosis plant is shown in Appendix A Figure A—l. The plant incorporates feeding sodium hexametaphosphate as a scale precipitation inhibitor, 25 p cartridge filtration, prechiorination and pH control with sulfuric acid. 9 ------- SECTION 5 SAMPLING AND ANALYTICAL PROCEDURES SAMPLING Analyses for chemical oxygen demand (COD), total organic carbon (TOC), inorganic constituents, and heavy metals were conducted by the Water Factory 21 analytical laboratory. Viral analyses were conducted by James Montgomery Engineers, Pasadena, California. Specific organic constituents were analyzed in the Stanford Water Quality Control Research Laboratory. Grab and composite samples were stored under refrigeration prior to organic analysis. Composite samples were prepared by mixing equal volumes of nine grab samples taken at three—hour intervals over a 24—hour period. Samples analyzed at Stanford were shipped by air in insulated containers, and arrived on the same day. Specific methods used in sample preservation prior to analysis are given under the specific analytical procedures which follow. Sampling locations are desig- nated by numbers preceded by the letter Q in Figure 1. GENERAL INORGANICS AND REAVY METALS The sampling and analytical procedures for general inorganics and heavy metals are described for two distinct periods. First is the period prior to injection and encompasses January, 1976, through June 1976. The other period coincides with the start of injection, from October 1976, through June, 1977. Table 1 indicates the sampling schedule and frequency for all inorganic and heavy metals analyses prior to October, 1976, and Table 2 for the period after October, 1976. The major difference between the two schedules is a decrease in heavy metals sampling frequency from daily composites during the first pe- riod to weekly composites for the second period. Also, additional samples from the pilot RO unit were taken during the second period. All analyses were conducted in accordance with Standard Methods (1). Table 3 summarizes the particular procedures from Standard Methods used for each parameter. ORGANICS COD and MBAS were determined on composite samples using the standard procedures listed in Table 3. TOC was determined on composite samples using a Beckman 915A TOC analyzer. The characterization of trace organic substances in water was performed for a number of selected substances on a routine basis. A broad and detailed characterization was attempted with some of the samples. In the following, the three basic procedures for the routine analysis of or— ganics are described: VOA (volatile organic analysis), CLSA (closed—loop 10 ------- TABLE 1. WATER FACTORY 21 SANPLING SCHEDULE January 1976 through June 1976 — Parameter Sample Points Plant Clarifier Influent Effluent 1 Q2 Ammonia Tower ill Effluent Q3 Ammonia Tower //2 Effluent Q4 Recarb. Interned. Settling Q5A Recarb. Basin Effluent Q5 Filter Effluent Q6 Carbon Effluent Q8 Chlorine Contact Basin Effluent Q9 T.mperature 1 pit EC Turbidity NH 3 -N Total & Free Chlorine Res. TOC COD MBAS Phenol Cyanide Trace Elements 3 Alkalinity Calcium Mg Total Hardness Sodium Sulfate Chloride P0 4 —P TKN ORG—N F B Coliform Virus 4 Color 2G 26 2G OC DC PC PC PC Vc PC DC PC DC PG 2G 2G 20 26 20 DC DC DC PC DC PC DC PG C 26 20 PG 26 20 PG 26 26 PG PG 20 2G PG PG 26 DC vc PC DC PG 20 26 2 DC vc 2 vc 2 PC 26 (2G) (26) 2G 2G (PC ) (PC) (DC I DC ) ( DC ) (PC) ( DC) (PC ) ( DC) ( DC) PC PC (VGJ C DC — Daily composite (1 grab every 4 hr. 500 ml sample) 1 Air and water in and out. O — Grab sample 2 Each carbon column DG — Daily grab sample 3 26 — One grab every 2 hr. (day shift only) Trace elements include: arsenic, chromium (VI), CM — Once per month grab barium, copper, mercury, selenium, cadmium, silver, lead, zinc, Fe, Mn. LEGEND: Test by operations lab. 4 Te t by t b Sampli ’ ig and concentration on—site by B. Martin. analysis by Montgomery Engineers ------- TABLE 2. WATER FACTORY 21 SAMPLING SCHEDULE October 1976 through June 30, 1977 p,) Parameter Sample Points Plant Clarifier Influent Effluent Qi Q2 Ammonia Tower #1 Effluent Q3 Ammonia Tower 02 Effluent Q4 Recarb. Intermed. Settling Q5A Recarb. Basin Effluent Q5 Filter Effluent Q6 Carbon Effluent QS Chlorine Contact Basin Effluent Q9 HO Plant Influent Q2 IA RO Plant Effluent g2 1 5 pH EC Turbidity NH 3 -N Total Free Chlorine Has. TOC COD IIBAS Phenol Cyanide Trace Elements Alkalinity Calcium Hg Total Hardness Sodium Sulfate Chloride P0 4 -P TKN ORG—N F B Colifonu Virus ’ Color DC DC CA DC DC WC WC WC WC WC DC DC DC WC WG D C 20 DC CA 2C DC WC WC DC DC DC WC WG 26 20 20 DC 20 20 2G 26 20 CA DC DC WC WC WC WC SC WC WC WC DC 20 20 WC WC WC DC DC WC WG DC WC DC DC DC DC DC DC D C DG DC DC DC — Daily composite (1 grab every 4 hr. 500 ml sample) C — Grab sample DC — Daily grab sample 2G - One grab every 2 hr. (day shift only) CM - Once per month grab WC — 24 hr composite taken once per week CA — Control panel value — online instrument average WC — Grab sample once per week Trace elements include: arsenic, chromium (V I), barium, copper, meroury, selenium, cadmium, silver, lead, zinc, Fe, Mn. Sampling and concentration on—site by B. Martin, analysis by Montgomery Engineers. ------- TABLE 3. GENERAL ANALYTICAL PROCEDURES Parameter Method Page Number from Standard Methods (1),l4th Edition conductivity @ 25°C direct, specific conductance meter 71 pH direct, pH meter 460 total dissolved glass fiber filtration, water bath solids (TDS) (100°C) and oven drying (180°C) 92 calcium titration with EDTA 189 magnesium atomic absorption, flame 148 sodium atomic absorption, flame 250 potassium atomic absorption, flame 234 aluminum atomic absorption, graphite furnace 148 iron atomic absorption, graphite furnace 148 manganese atomic absorption, graphite furnace 148 silver atomic absorption, graphite furnace 148 arsenic atomic absorption, graphite furnace 148 barium atomic absorption, graphite furnace 148 cadmium atomic absorption, graphite furnace 148 chromium atomic absorption, graphite furnace 148 copper atomic absorption, graphite furnace 148 lead atomic absorption, graphite furnace 148 selenium atomic absorption, graphite furnace 148 zinc atomic absorption, graphite furnace 148 mercury flameless atomic allsorption 156 alkalinity as CaCO 3 , titration with H 2 S0 4 278 chloride titration with Hg(N03)2 304 fluoride specific ion electrode 391 sulfate turbidimetric 496 phosphate ascorbic acid 481 nitrate—nitrogen brucine sulfate 427 ammonia—nitrogen 1. Kjeldahl method 438 2. phenate method 416 organic—nitrogen Kjeldahl 437 boron curcumin 287 methylene blue active substance (MBAS) methylene blue 600 chemical oxygen demand (COD) dichromate digestion 550 silica molybdosilicate 487 hardness, total EDTA 202 phenol colorimetric (AAP) 582 dissolved oxygen iodometric, azide modification 443 dissolved sulfide methylene blue 503 coliform membrane filter 928 fecal coliform membrane filter 937 color visual comparison 64 cyanide distillation and colorimetric 361 Table 3 continued 13 ------- Table 3 continued Parameter Method Page Number from Standard Methods (l),l4th Edition residual chlorine odor radioactivity gross alpha gross beta 1. amperometric 2. DPD threshold procedure internal proportional count. internal proportional count. 322 332 * 648 648 *flMethods for Chemical Analysis of Water and Wastes,” page 287, EPA—625—6— 74—003 (1974). stripping analysis), and SEA (solvent extraction analysis). The procedures and findings of the detailed characterization are given in Section 6. VOA Organics with high volatility were determined by stripping, concentration on a porous polymer trap, and gas chromatography (Tracor MT—220) using a Hall electrolytic conductivity detector as described by Bellar and Lichtenberg (2), but as modified by Symons et al. (3). One ml of 0.1! sodium thiosulfate was added to 50—mi vials at the time of grab sample collection to reduce residual chlorine. Organics measured include most haloforms, and various other chlori- nated one— and two—carbon organics. Concentrations measured were 0.1 pg/l and higher. CLSA Closed—loop stripping by the Grob procedure (12) allows analysis for a broad range of volatile organics present in the ng/l range and above, such as solvents, petroleum products, and chlorobenzenes. However, it is not very ef- fective in quantitatively analyzing for haloforms in the pg/i range. Organics in 200 to 500 ml of composite sample were removed by recirculation for two hours of a small volume of air through the sample and over an activated char- coal filter. The filter was extracted with 20 p1 of CS 2 , approximately 10 p1 of which could be recovered. An aliquot of 2 p1 was used for high resolution gas chromatographic (CC) analysis (Finnigan 9610), using a glass capillary column (25 in UCON KB, Jaeggi Laboratory for GC, Trogen, Switzerland) and flame ionization detection (FID). The gas chromatograph was equipped with a Grob type injector (Brechbiihler AG, Urdorf, Switzerland). In May, an effluent stream splitter was introduced for simultaneous flame ionization and electron capture detection. For mass spectrometric (MS) identification (Finnigan 4000), a 3—Ui aliquot was used. Monochlorinated normal alkanes (l—Cl- 8, l—Cl—C12, i—Cl—C16) were added to samples for internal standards. The method was cali- brated with tetrachiorethylene, chlorobenzenes, and aromatic hydrocarbons, recoveries from 40 to 80 percent were measured. 14 ------- SEA Solvent extraction analysis was used for pesticides (including PCB’s) and non—volatile organics. Initially, GC with a packed column was used, following procedures outlined by the EPA (5). This permitted detection of pesticides In concentrations of 10 to 100 ng/l and above. From the beginning of October 1976 analyses were conducted with a GC system (same as above) with a glass capillary column (20 m SE 54, Jaeggi Laboratory), and equipped with a wide— range electron capture detector (ECD, Analog Technology Model 140). The spe- cially designed interface consists of a temperature—stabilized hea&ing block for preheating Argon/methane (95/5) pure gas and capillary column inlet. One—liter composite samples were extracted with 25 ml of hexane, dried with sodium sulfate, concentrated to 2 ml, and cleaned on a florisil column (15). Two .il were injected splitless onto the 90°C column, and after solvent elu— tion, the oven temperature was increased at a rate of 4°C/mm from 90°C to 230°C. This procedure allowed an improved peak separation. An internal stan- dard, l,4—bis—(trichloromethyl)—benzene (Aldrich Chemical Co.), was added for quantification of halogenated compounds. VIRUSES Virus monitoring was conducted by James N. Montgomery, Consulting Engi- neers, Inc., Pasadena, California (3MM). The concentration methods used are summarized in Table 4, which includes a brief description of each method, the amount and type of chemical added, the sample volume usually tested, methods of elution, detection limits, the location where the method was used, and the corresponding dates. These methods were developed from a pooling of the in- formation gathered by the San Diego County Health Department; Baylor Univer- sity; the Los Angeles County Sanitation Districts; the University of Califor- nia, Berkeley; the University of North Carolina, Chapel Hill; and James N. Montgomery. The various methods were employed in an effort to improve virus recovery and to reduce manpower requirements. The concentration of enteric viruses in the final concentrated eluate was determined by the plaque assay method employing either a Buffalo Green Monkey kidney continuous cell line (BGM) maintained at JNN or a Primary Afri— eaii Green Monkey kidney (PAG) cell line purchased commercially. The general method consisted of adding Earle’s Balanced Salts, Fetal Calf Serum (FCS), and antibiotics to the sample, incubating at 37°C for 90 mi diluting with 0.05M Tris Buffer, inoculating a 30— or 60—mi prescription bottle containing the attached cell line, incubating for 90 mm at 37°C (absorption), washing the cells with Phosphate Buffered Saline (PBS), overlaying them with agar, and incubating at 37°C. Plaques were counted on days 2 through 7. During the course of this study it was found that many of the apparent plaques were not caused by animal viruses, and hence confirmation of plaques was required in order to obtain a time count. For confirmation, cellular debris from all suspected plaques were passed to tubes containing a monolayer of BGM cells and maintenance media, placed on a roller apparatus, and incu- bated for 7 to 8 days. A small sample was then passed to a new tube of the same kind and these tubes were examined for cytopathic effects during 2 to 7 15 ------- TABLE 4. SUMMARY OF VIRUS CONCENTRATION METHODS Adsorption or K—27 filter Direct flocculation Direct flocculation Adsorption ot K—27 filter Adsorption ot K—27 and Cox Filter Adsorption ot K—27 and Cox Filter lycine H 11.5 utrienl roth )H 9.0 glycine ,H 11.5 utrienl Broth pH 9.0 Flocced, centri- fuged, eluted up glycine, 3 times, last pellet dis- solved and used to plaque. Same as A. Same as A. Flocced, centri- fuged, eluted twice with nutri- ent broth, pH 9.0, flocced atpH4.3, dissolved at pH 9.0 and plaqued. Same as A. 10/8/76— 11/23/76 12/3/76— 6/2/77 6/20/7 7— 7/21/ 77 12/1/75— 6/9/76 6/15/76- 7/16/ 7( 7/20/76- 7/29/7( 10/8/76- 6/2/7 6/20/ 77- 7/21/7; Final Detec— Loca- Sam- Chem— ample luant Eluant tion tion )ling icals To lume Tolume Reconcentration Volume Limit Sam— Period Meth. Description Added Amount gal 1ution ml — Method ml PFU/m 3 pled Used 1ycine II 11.5 I- 0• ’ 11/25/75 — 7/28/7 A. B. C. D. E. F. Al(III) O.0005M Acid pH 3.5 A1(III) O.003M Al (III) Al (III) Al(TII) O.0005M Acid pH 3.5 A1(III) O.005N Acid pH 3.5 Al(III) O.0005M Acid pH 3.5 50 1 2 2 1100 50 50 4000 200 200 500 8000 1500 1500 80 80 80 80 80 80 glycine 2xl0 2 Ql Qi 5x10 3 Q1 5xl0 3 Ql 2 Q2 Q3 Q4 2x10 2 Q9 2x10 2 Q9 Same as A. Same as C. ------- days thcubation. The positives were then recorded as confirmed plaques. Tubes determined as positive were then frozen at —70°C. All Q9 positives were identified as were a small percentage of the positive Qi samples byJNM. In addition, identifications were made by the California Department of Public Health. Virus identifications by 3MM were accomplished using the Lim—Belnish— Melnick cross—secting antisera. A microtiter system using a cytopathic effect (CPE) as a positive response was employed in some identifications and a plaque reduction method was employed for others. After an initial titering of the isolated virus, it is appropriately diluted to 100 TCID 50 /0.l ml mixed with the cross—secting antisera, incubated one hour at room temperature, and inocu- lated into inicrotiter dishes or plaquing bottles. Neutralization of the CPE from a plus four to a plus one or an 80% reduction of plaques is the criteria used for identification. 17 ------- SECTION 6 RESULTS CHARACTERISTICS OF INFLUENT WATER Water Factory 21 reclaims treated municipal wastewater obtained from the Orange County Sanitation District. This wastewater has received primary and secondary treatment by trickling filtration. The effluent characteristics as determined from this study are given in Table 5 for the two separate periods of operation of Water Factory 21. TARLE 5. MEAN CHARACTERISTICS OF SECONDARY EFFLUENT TREATED AT WATER FACTORY 21 First Period — Second Period — Entire Period— Jan. 1976 Oct. 1976 Jan. 1976 through through through Parameter June 1976 June 1977 June 1977 General, mg/i Na 209 218 212 Ca 102 110 104 Mg 25 24 25 Cl 231 258 239 SO 4 284 — — Alkalinity (CaCO 3 ) 306 — — Hardness (CaCO 3 ) N11 3 —N 358 43 374 37 363 39 Org—N 1.6 8.3 5.9 P0 4 —P 5.2 5.6 5.5 B — 1.0 — TDS — 1020 — COD 108 142 131 Other pH 7.6 7.5 7.5 EC (pS/cm) 1870 1850 1860 Turbidity (TU) 24 42 36 * Values 18 ------- TREATMENT PLANT PERFORMANCE Results of analysis for general inorganic and heavy metals, organics, and viruses are given in the following paragraphs together with an evaluation of the effectiveness of individual and combinations of processes in removing con- stituents of interest. In general, the results are divided into the two main periods of plant operation, that prior to October 1976 before injection was started, and that period after October 1976 when injection was initiated. GENERAL INORGANICS AND HEAVY METALS Detailed summaries of data obtained for general inorganics and heavy me- tals are tabulated in Appendix B for the period before October 1976, the pe- riod after October 1976, and the total period. These tables contain mean values, standard deviations (which assume normal distribution), ranges, and numbers of samples analyzed. The following comparisons are made primarily with mean values. January 1976 through June 1976 A comparison of the influent, effluent and regulatory requirements for inorganics and heavy metals for this period is given in Table 6. The results illustrate that inorganics and heavy metals are sufficiently removed by the advanced wastewater treatment processes to meet regulatory requirements. The mineral quality including ammonia in general exceeded regulatory limits. Since this was during a testing period of operation and prior to injection, no blending, demineralization, or breakpoint chlorination for ammonia removal was provided. Chemical Clarification—— Lime is used as the primary coagulant in the chemical clarification pro- cess. Lime is slaked and added as a slurry to the rapid mix basin, the water is then flocculated in three separate individual flocculation basins, where an anionic polymer is added to improve clarification. Lime addition is con- trolled automatically to achieve a treatment pH of 11.3, which corresponds to a dose of approximately 350—400 mg/l as calcium oxide. The flocculated water is settled in the sedimentation basins, which are equipped with settling tubes. Chemical clarification is effective in reducing turbidity, COD and phosphate concentrations. Operation of the chemical clarifier at pH of 11.3 or greater provides good removal efficiency. A monthly and period summary for some of the parameters monitored on a continuous basis is given in Table 7. Chemical clarification was also effective in reducing many of the heavy metals remain- ing in the secondary effluent. Lime treatment reduced arsenic, barium, cad- mium, Cr(VI), copper, iron, lead, manganese, silver, and zinc concentrations. The percentage removal for each metal is summarized in Table 8. Those metals which were not reduced by chemical treatment were mercury and selenium. Ammonia Stripping—— The effluent from the chemical clarifier had an average pH of 11.4 and was pumped to the top of the ammonia stripping towers. Tower No. 1 was op- erated until May 1, 1976, at full design capacity of 2.7 m 3 /rn 2 —h of packing 19 ------- TABLE 6. hEAR CHARACTERISTICS OF TREATED WATER AND REGULATORY REQUIRE}IENTS January 1976 through June 1976 Regulatory Chlorine Require— for Ammonia Contact Overall ment Plant Clarif. Tower Filter Carbor Basin Reduc— Blended Param— Infi. El flu Effi. Effl. Effi. El 11. tion Injection eter Inits Q1_ O2 Q4 Q6 Q8 Q9 Percent Alk tg/i 306 328 — — 137 55 — N11 3 —N g/l — 43 19 — 17 60 1.0 TKN g/1 — 44 — 0.5 0.9 96 1.0 B ig/l — — — 0.63 — 0.5 Ca ig/1 102 142 107 — — Cl ig/l 231 — 246 — 120 EC iS/cm 1870 — 1470 21 900 F g/1 — — 0.64 — 0.8 Mg ag/i 25 1.0 — 96 — pH 7.6 11.4 6.7 — 6.5—8.0 P0 4 —P ag/i 5.2 0.09 — 98 — Na ag/i 209 — 205 — 110 S04 ag/i 284 — 312 125 TH ig/i 358 359 — 271 — 220 Turb. ‘U 24 1.9 0.5 0.9 96 1.0 CN tg/l — — — — — — 200 COD ig/k 108 53 45 13 88 30* As tg/1 2.5 1.1 1.1 1.1 56 50 Ba Lg/1 81 41 32 33 59 1000 Cd ig/l 9 2.9 2.5 2.2 76 10 Cr ig/1 192 88 84 48 75 50 Cu ig/1 285 93 88 27 91 1000 Fe ig/l 179 17 40 45 75 300 Pb ig/i 40 23 22 26 35 50 Mn ig/1 38 1.5 2.3 4.1 89 50 Hg ig/i 1.2 0.9 1.2 4.9 0 5 Se ig/1 6.2 6.5 6.3 6.4 0 10 Ag ig/1 13 8 12 14 — 0 50 Zn ig/i 300 29 670 124 — 59 — Gross ctCi/1 — — — — 0.3 — Gross B pCi/i 28 — E.co li <2.0 <2.0 *Regtllatory requirement for effluent COD pertains to carbon effluent (Q8). area, corresponding to a 3000 1n 3 /m 3 air to water ratio at ambient air temper- atures. During this period, however, it was observed that significant air short circuiting occurred within the tower. Therefore, it is believed that the actual air to water ratios were only about 700 to 1500 m 3 /m 3 . From January through April, the average ammonia removal was only 54 percent. 20 ------- TABLE 7. CHANGES IN GENERAL PARAMETERS BY CHEMICAL CLARIFICATION January through June 1976 (Monthly Mean Values) Parameter Units Jan Feb Mar Apr May June Avg. COD Inf., Qi mg/i — 113 101 96 107 120 107 Eff., Q2 mg/i — 54 51 47 51 59 52 Reduct. % — 52 50 51 52 51 51 P0 4 —P Inf., Qi mg/i 5.7 5.9 4.9 5.8 4.3 4.7 5.2 Eff., Q2 mg/i 0.05 0.08 0.17 0.02 0.05 0.16 0.09 Reduct. % 99 99 97 100 99 97 98 Turbidity Inf., Qi mg/i 21 23 22 17 25 33 24 Eff., Q2 mg/i 1.3 2.3 1.5 1.6 1.7 2.2 1.8 Reduct. % 94 90 93 91 93 93 92 pH Inf., Qi units 7.6 7.7 7.7 7.7 7.7 7.6 7.7 Eff., Q2 units 11.5 11.4 11.4 11.4 11.3 11.3 11.4 Magnes iuni Inf., Qi mg/i 26 26 24 24 24 — 25 Eff., Q2 mg/i 2.0 1.1 1.3 0.8 0.7 1.2 Reduct. % 92 96 95 97 97 — 95 Calcium Inf., Qi mg/i L09 94 iii 105 106 98 104 Eff., Q2 mg/i 135 141 162 151 129 138 143 Increase Z 24 50 46 44 22 41 38 TABLE 8. CHEMICAL CLARIFICATION. HEAVY METALS REMOVAL January through June 1976 Parameter Units Plant Influent Qi Clarifier Effluent Q2 Percent Removed As ugh 2.5 1.1 56 Ba uig/1 81 41 49 Cd uig/l 9 2.9 68 Cr ig/l 192 88 54 Cu g/l 285 93 67 Fe ulg/i 179 17 91 Pb g/l 40 23 43 Mn g/l 38 1.5 96 Hg ag/i 1.2 0.9 25 Se j ig/i 6.2 6.5 no change Ag pg/l 13 8 38 Zn jig/i — 300 29 90 21 ------- Ammonia tower No. 2 was modified to reduce short circuiting and was placed in operation about Nay 1, 1976. During May and June ammonia removal increased to 63 percent as indicated in Table 9. Aimnonia—nitrogen influent concentrations varied from a high of 100 mg/i during May to a low of 27 mg/i during January, with a mean of 43 mg/i. Effluent ammonia—nitrogen concentra- tions averaged 18 mg/l during the entire six months. Since the water being treated at this time was not injected, no further nitrogen control was prac- ticed prior to October, 1976. Recarbonation—— Recarbonation was achievedby diffusing carbon dioxide gas into the flow in two stages with allowance for intermediate settling. The first stage re- duced pH between 9.5 and 10.3. Following intermediate settling, additional CO 2 was added in the second stage to reduce pH to about 7.0. The cool and compressed stack gases from the lime recalcining furnace provided the source of CO 2 . The purpose of two—stage recarbonation is to remove as much calcium as possible and thus reduce TDS. However, during actual operation the calcium carbonate fioc which precipitated in the intermediate settling basin was very fine and difficult to settle and so the performance of the recarbonation basin for removing TDS and calcium was poor. Mixed—Media Filtration—— Following pH adjustment in the recarbonation basin, the wastewater flows into open gravity—flow multimedia filters. Enhancement of turbidity removal is accomplished by the addition of alum (12 mg/i) and Dow A23 anionic polymer (0.05 mg/i). Typical filter runs averaged 20—22 hours at a mean effluent turbidity of 0.5 TU. Activated—Carbon Adsorption—— The activated—carbon adsorption process follows mixed—media filtration. The plant design includes 17 parallel carbon contactors, 16 can be operated in parallel, with one remaining unit available for carbon storage. Columns No. 3, 4, and 5 were used primarily during this period of operation. Results TABLE 9. AMMONIA REMOVAL BY STRIPPING January Through June 1976 Month Stripping Tower Number Mean NH3—N, mg/i Percent Removal Influent Q2 Effluent Q4 January February March April May June Average 1 1 1 1 2 2 38 49 45 43 44 38 43 18 22 21 18 16 14 18 53 55 53 58 64 63 58 22 ------- on organic removals by activated carbon are given later. Activated, carbon was effective in reducing the concentration of cadmium, chromium, copper, and zinc as listed in Table 10. The data also show that activated—carbon treat- ment resulted in significant increases in iron and manganese concentrations, although the resulting concentrations were below regulatory limits and re- sulted in no adverse effect. Data also show that activated—carbon treatment had little effect on arsenic, barium, lead, mercury, selenium, and silver at the low concentrations which were present in the influent. October 1976 through June 1977 During this period, breakpoint chlorination was Initiated to reduce the ammonia concentration to meet requirements for injection., One part of treated water was then blended with two parts of well water from a deep aquifer in order to reduce the mineral content as required by regulations. Injection of blended water was Initiated during this period. In addition, pilot studies were started with reverse osmosis treatment of reclaimed wastewater as an al- ternative method for reducing the mineral content to an acceptable level. A summary of water quality at different points in the treatment system and a comparison with the regulatory requirements is given in Table 11. Each volume of Water Factory 21 effluent is blended with two volumes of water ob- tained from deep wells to form blended injection water (QlO). The quality of this blended water is compared in Table 11 with the quality requirements for injection water as issued by the California State Water Quality Control Board ——Santa Ana Region. The regulatory limit of 1 mg/i of ammonia is presently under question. In addition, the need for demineralization is apparent and it is anticipated that with the completion of a new 0.22 m 3 /s RO plant, the overall reduction in EC required will be met in the future without the need to blend with groundwater. TABLE 10. HEAVY METALS REMOVAL BY CARBON ADSORPTION January through June 1976 Parameter Units Carbon Influ Q6 Col ent Carbon Ef flue Q8 Col nt Percent Removal As iig/l 1.1 1.1 no change Ba pg/i 32 33 no change Cd pg/l 2.5 2.2 12 Cr pg/l 84 48 43 Cu pg/l 88 27 69 Fe pg/i 40 45 increase Pb pg/i 22 26 no change Mn pg/l 2.3 4.1 increase Hg pg/i 1.2 4.9 increase Se pg/i 6.3 6.4 no change Ag pg/i 12 14 no change Zn pg/i 670 124 81 23 ------- TABLE 11. MEAN CHARACTERISTICS OF TREATED WATER AND REGULATORY REQUIREMENTS October 1976 through June 1977 Blended Injection Plant Clarif. Recarb. Filter Carbon eduction Water Mean Regulatory Param— Infi. Effi. Effi. Effi. Effi. Qi to Q8 Conc. Require— eter Units Qi Q2 Q5 Q6 Q8 Percent Ql0 metit Aik mg/i — — 116 — 121 — NR 3 _N* mg/i 45 37 — 3.3 93 0.9 1.0 NOD—N mg/i - - — - 1.0 - Org—N mg/i — - — - 0.7 — TKN mg/i 53 41 4.6 91 1.6 10 B mg/i 1.0 0.84 — — — 0.36 0.5 Ca mg/i 110 0 103 37 — Ci mg/i 258 — — 103 120 E Coil MPN/ 41x 106 16 < 2 < 2 100 mJ EC PS/cm 1850 2070 780 900 F mg/i — — 0.53 0.8 Mg mg/i 24 0.2 — 0.6 — pH 7.5 11.5 8.1 7.6 6.5—8.0 P0 4 —P mg/i 5.6 0.07 — — — Na mg/i 218 — — 127 110 SO 4 mg/i — — — — — 83 125 TH mg/i — — — — — 99 220 Turb. TU 42 .1.1 1.2 0.34 — — 0.42 1.0 COD mg/i 142 52 — 45 18 87 11 30** TOC mg/i — — — 14 6.7 — — — MBAS mg/i — — — — — — 0.05 0.5 As pg/i 3.3 2.5 — 1.8 2.4 27 2.6 50 Ba pg/i 81 36 — 31 31 62 14 1000 Cd pg/i 29 2.4 — 1.8 1.7 94 0.6 10 Cr pg/i 154 37 — 41 26 83 8.8 50 Cu pg/i 266 73 — 49 32 88 12 1000 Fe pg/i 325 40 — 207 66 80 71 300 Pb Pg/i 19 3.6 4.7 5.3 72 2.8 50 Mn Pg/i 35 4.4 6.2 4.9 86 4.6 50 Hg pg/i 9 2.6 3.6 6.7 26 2.4 5 Se pg/i <2.5 <2.5 <2.5 <2.5 — 1.8 10 Ag Pg/i 5.5 0.8 1.3 1.5 73 0.8 50 Zn Pg/i 380 239 412 162 57 160 — CN Pg/i — — — — — <0.01 200 Phejxl Pg/i — 1.3 — * Ammonia tower effluent (Q4) = 6.5. ** COD of 30 mg/i appiie to carbon effluent (Q8). 24 ------- Chemical Clarification-— The general performance of the chemical clarifier during the second pe- riod is given in Table 12. Chemical clarification continued to be effective for reducing COD, turbidity, phosphate, and magnesium when operated at pH val- ues of greater than 11.3. Chemical clarification also reduced several heavy metals concentrations as indicated by the summary in Table 13. The metals removed include barium, cadmium, chromium, copper, iron, lead, manganese, silver, and zinc. Ammonia Stripping—— During the operational period prior to October 1976, ammonia removal ef- ficiencies had averaged a maximum of 65 percent. In an attempt to improve the efficiency of this operation, the ammonia towers were modified during the plant shutdown and repiped so that two towers could be operated in series. The effect of this modification on the performance of ammonia stripping is indicated in Table 14. Overall performance was increased to achieve over 80 percent removal of ammonia nitrogen. During the summer months, ammonia nitro- gen removals exceeded 90 percent. The first stripping tower reduced ammonia concentrations from an average of 32 mg/i to 11.2 mg/i, for a reduction of 65 percent. The second tower then further reduced this concentration to a mean average of 5.7 mg/l or by an additional 49 percent. Influent ammonia nitrogen concentrations ranged from a high of 85 mg/i in November to a low of 13 mg/i during January. Recarbonation and Breakpoint Chlorination—— Since two—stage recarbonation had proven to be difficult to operate dur- ing the first evaluation period, it was decided to operate the recarbonation basin as a single—stage system. Thus sufficient carbon dioxide was added to reduce the pH from 11.3 to a range between 7.5 and 8.0. Since the residual ammonia remaining after stripping still exceeded the injection requirements, the District also began breakpoint chlorination in October. Large quantities of chlorine were required (9:1 chlorine to ammonia ratio) which reduced the pH. In order to prevent excessive pH decrease it was found desirable to use breakpoint chlorination in conjunction with recarbonation. At this point chlorination reduced the quantity of CO 2 needed for pH reduction and pH con- trol was easier. Addition of chlorine in the recarbonation basin provided sufficient contact time for ammonia oxidation and resulted in a reduction of ammonia nitrogen from an average of 5.7 mg/i to less than 1 mg/i, as well as reducing pH to an average of 8.3. As discussed in a subsequent section on organics, breakpoint chlorina- tion had an undesirable effect in that it resulted in the production of chlorinated organics, particularly various haloforms, and these were only partially removed by activated—carbon adsorption. For this reason, break- point chlorination at the recarbonation basins was discontinued in April 1977 and was attempted with effluent from the activated—carbon contactors. Here, pH control proved difficult and ammonia removal was less efficient. The requirement for 1 mg/l maximum ammonia nitrogen in the injection water has been questioned by the OCWD and they have appealed to have the limit raised. Some removal of ammonia through ion exchange is expected as the injected water moves through the aquifer. Also, the high costs for 25 ------- TABLE 12. CHANGES IN GENERAL PARM1ETERS BY CHEMICAL CLARIFICATION October 1976 through June 1977 (Monthly Mean Values) Parameter Units Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June Avg. COD Inf., Qi mg/i 142 138 142 127 130 122 130 122 208 142 Eff., Q2 mg/i 56 49 51 46 48 44 46 48 72 52 Reduct. 61 64 64 64 63 64 65 61 65 63 PO 4 —P Inf., Qi mg/i 5.9 5.3 6.0 6.1 5.9 5.5 5.1 5.5 5.2 5.6 Eff., Q2 mg/i 0.12 0.03 0.10 0.10 0.08 0.05 0.05 0.06 0.05 0.07 Reduct. 98 99 98 98 99 99 99 99 99 99 turbidity m l., Qi TU 26 33 49 41 44 41 35 53 42 Eff., Q2 TU 1.3 1.1 1.3 0.9 1.1 1.3 1.2 1.0 1.1 Reduct. 95 97 97 98 98 97 97 98 97 pH ml., Qi pH 7.6 7.6 7.5 7.5 7.5 7.6 7.6 7.3 7.4 7.5 Elf., Q2 pH 11.3 11.6 11.6 11.5 11.5 11.5 11.4 11.4 11.6 11.5 Magnesium Inf., Qi mg/i 22 22 22 22 24 24 24 26 27 24 Elf., Q2 mg/i 0.3 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.2 0.2 Reduct. 98.6 99.6 99.6 99.6 99.2 99.2 99.2 98.9 99.3 99.2 ------- TABLE 13. EFFECT OF CHEMICAL TREATMENT ON HEAVY METALS October 1976 through June 1977 Heavy Metal Clarifier Influent (Ql), pg/l Clarifier Effluent (Q2),pg/l Percent Removal As 3.3 2.5 24 Ba 81 36 56 Cd 29 2.4 92 Cr 154 37 76 Cu 266 73 73 Fe 325 40 88 Pb 19 3.6 81 Mn 35 4.4 87 Hg 9 2.6 71 Se <2.5 <2.5 — Ag 5.5 0.8 85 Zn 380 239 37 TABLE 14. EFFECTIVENESS OF AMMONIA STRIPPING PROCESS October 1976 through June 1977 Month October November December January February March April May June Mean NH 3 —N conc., mg/i Influent Effluent (Q2) (Q4) 34 5.7 33 4.9 30 5.4 24 6.0 37 5.5 36 7.6 41 8.7 37 7.5 46 6.5 Percent Removal 83 85 82 75 85 79 79 80 86 Average 35 6.4 82 breakpoint chlorination, the increased concentrations of chlorinated organics which result, and the potential decrease in activated—carbon adsorption have made the OCWD question whether the benefits of the low ammonia requirements are worth the costs. Filtration—— Following single—stage recarbonation, the water receives mixed—media filtration prior to activated—carbon adsorption. Again, alum (12 mg/i) and Dow A23 anionic polymer (0.05 mg/l) were added to improve turbidity removal. Typical filter runs were 20—30 hours, with a mean filter run of 26 hours, re- sulting in an average effluent turbidity of 0.28 TU. Table 15 summarizes 27 ------- TABLE 15. FILTER PERFORMANCE FOR TURBIDITY REDUCTION October 1976 through June 1977 Month Mean Turbidity, TU Percent Removal Influent (Q5) Effluent (Q6) October November December January February March April Nay June Average 6.7 1.4 1.4 0.90 1.2 1.1 1.1 1.3 1.4 1.8 0.72 0.31 0.24 0.18 0.24 0.34 0.3 0.5 0.4 0.36 89 79 83 80 80 69 73 62 71 80 filter performance for the second period of plant operation. These data dem- onstrate the consistent performance of the mixed—media filters and their abil- ity to produce water with turbidities below 1 TU as required by State regula— tions. Activated—Carbon Adsorption—— During the second period the activated—carbon columns were operated in a packed—bed upflow configuration, with a 30—minute contact time. Overall per- formance of the granular activated—carbon system was good. Ability to remove organics is summarized later under organics. Activated—carbon treatment was also effective in reducing several heavy metals as summarized in Table 16. Chromium, copper, iron, lead and zinc were reduced in concentration, and all other metals exhibited essentially no change or a slight increase In concentration. However, effluent concentrations of all heavy metals are sufficiently low to meet U.S. EPA drinking water standards. Chlorination—— Following activated—carbon treatment, the water flows by gravity to the chlorine contact basin, primarily for post—chlorination to destroy any bac- teria or virus. Prior to April 1977 breakpoint chlorination was practiced at the recarbonation basin and post—chlorination required only a small chlorine dose of 2—5 mg/i to insure complete disinfection and removal of bacteria and virus as discussed later under VIRUS. ORGANICS COD and TOC The COD analysis gives a general measurement of the total concentration 28 ------- TABLE 16. HEAVY METALS REMOVAL BY ACTIVATED CARBON October 1976 through June 1977 Heavy Metal Mean Concentration, ilg/l Percent Removal Influent (Q6) Effluent (Q8) As Ba Cd Cr Cu Fe Pb Mn Hg Se Ag Zn 1.8 31 1.8 41 49 207 4.7 6.2 3.6 <2.5 1.3 412 2.4 31 1.7 26 32 66 5.3 4.9 6.7 <2.5 1.5 162 increase 0 6 37 35 68 increase 21 increase — increase 61 of organics present in a water in terms of the quantity of oxygen which would be required for oxidation to carbon dioxide, water and ammonia. Results of COD analysis on composite samples taken at various locations at Water Factory 21 during the first and second periods of operation, and over the entire pe- riod are summarized in Table 17. Influent COD and plant performance in the removal of COD were similar during the two periods. Influent COD averaged 131 mg/l, and this was reduced by 60 percent to 52 mg/i by chemical treatment. This only partly resulted from removal of suspended organics. The filter effluent contained 45 mg/l COD, and this was reduced 67 percent to 15 mg/i by passage through activated carbon, which was particularly effective for dis- solved organics. Water Factory 21 overall removed 90 percent of the influent organics. TOC is also a general parameter for total organics. The mean influent (Q6) and effluent (Q8) concentrations for activated carbon adsorption listed in Table 18 indicate this process removed approximately 49 percent of the or- ganic carbon passing through it, which is somewhat less than for COD reii val. Perhaps activated carbon is more selective in the removal of reduced organics having a higher COD to TOC ratio. The coefficient of variation (100 standard deviation/mean) for effluent COD was 53 percent and for TOC was 35 percent. These values are quite small and indicate that the treatment systems produce an effluent which is rela- tively consistent in general organic content. Volatile Organic Analysis This analysis was conducted on grab samples obtained periodically since February 1976. Concentrations of the two major haloforins found during the first period before breakpoint chlorination was initiated are indicated in 29 ------- TABLE 17. COD REMOVAL BY WATER FACTORY 21 Sampling Period and Characteristic Plant Influeni Ql Chem.Treat. Effluent Q2 Filter Effluent Q6 ict.Carb. ff1uent Q8 RO Influent Q21A RO Effluent Q21B Jan. through June 1976 Mean, mg/i 108 53 45 13 Std. dev.,mg/1 16 7 7 8 Range, mg/i 78—14/ 23—69 25—67 2—52 No. samples 78 80 87 238 Oct. 1976 through June 1977 Mean, mg/i 142 52 45 18 24 1.8 Std. dev.,mg/i 37 11 7 7 14 1.5 Range, mg/i 89—27: 20—109 31—78 4—51 4—69 <1—9 No. samples 160 160 160 159 118 119 Total Period, Jan. 1976 through June 1977 Mean, mg/i Std. dev.,mg/i 131 35 52 10 45 7 15 8 Range, mg/i 78—27 20—109 25—78 2—52 No. samples 238 240 247 397 TABLE 18. TOC REMOVAL BY WATER FACTORY 21 Sampling Period Activated Carbon Activated Carbon and Influent Effluent Characteristic Q6 Q8 January through June 1976 Mean, mg/i 15 7.3 Std. dev., mg/i 4 2.6 Range, mg/i 8—31 3.5—20 No. samples 82 238 October 1976 through June 1977 Mean, mg/i 14 6.7 Std. dev., mg/i 3 2.2 Range, mg/i 0.5—28 2.5-14 No. samples 111 117 Total Period, January 1976 through June 1977 Mean, mg/i 14 7.1 Std. dev., mg/i 3 2.5 Range, mg/i 0.5—31 2.5—20 No. samples 193 355 30 ------- Table 19. Influent concentrations were low and were decreased even further through ammonia stripping. Lime treatment had essentially no effect on halo— form concentration. Chlorination for disinfection only (< 10 mg/i Cl 2 ) after activated—carbon treatment appears to have increased the concentration of chloroform (CHC1 3 ) and broxnodichloromethane (CHBrC1 9 ) slightly. Following the initiation of breakpoint chlorination in October 1976, con- centrations of the various haloforins increased significantly during treatment (Table 20). Breakpoint chlorination generally followed ammonia stripping and maximum concentrations of haloforms were noted in samples taken prior to activated—carbon contacting. Activated—carbon treatment was responsible for a reduction in haloform levels. These results are better illustrated in Figure 3 showing haloform concen- trations for the influent to the carbon contactors and for the final effluent. Haloform formation was variable. For the first month, chlorine dosages var- ied widely as did haloform concentration while seeking good operational pro- cedures. After this period, however, haloform concentrations still varied considerably. For a few days in December, breakpoint chlorination was prac- ticed in the final chlorine contact chamber rather than after ammonia strip- ping, and resulted In a decrease in haloforms at point Q6. From April through June chlorination for ammonia removal was practiced at Q8 only, resulting in a significant reduction in haloforms at Q6. Figure 3 illustrates that the haloform concentration in the final ef flu- ent was less variable and lower than in samples taken before activated—carbon treatment. Of particular significance is the decrease in effluent haloform concentration during December which resulted when the flow was diverted to carbon contactors containing fresh activated carbon. Haloforms soon began passing through the contactors, but at significantly reduced concentrations. TABLE 19. HALOFOR}f CONCENTRATIONS PRIOR TO BREAKPOINT CHLORINATION January 1976 through June 1976 Characteristic Sampling Location Influen Ql Act.—Carb Influent Q6 Act.—Carb. Effluent Q8 Final Effluent Q9 CUC1 3 Mean, pg/l Standard deviation, pg/i Range, pg/l Number of samples CHBrC1 2 Mean, pg/i Standard deviation, pg/l Range, pg/i Number of samples 1.5 1.0 0.4—5.5 39 0.2 0.3 0.0—1.2 14 0.3 0.2 0.1—0.6 4 0.0 0.0 0.0 4 0.6 0.4 0.4—1.0 3 0.1 0.2 0.0—0.3 3 2.1 1.1 0.6—5.3 40 0.9 1.0 O.03.9 40 31 ------- TABLE 20. HALOFORN CONCENTRATIONS DURING SECOND PERIOD October 1976 through June 1977 Sample Location Ammonia Activ.- Contact Clarif. Tower Filter Carbon Basin RO RO Influent Effluent Effluent Effluent Effluent Effluent Influent Effluent Ql Q2 Q4 Q6 Q8 Q9 Q21A Q2 IB CHO1 3 Mean, pg/i 2.5 1.2 0.2 19 9.3 10 5.5 9.6 Std. Dev,, pg/i 6.1 0.7 0.1 22 8.5 8.4 8.1 10.5 Range, pg/i 0.2—39 0.4—2.3 0.1—0.5 0.1—97 0.3—36 0.8—40 0.1—21 0.1—35 No. of Samples 40 ii 32 36 39 40 6 16 CHBrC1 2 Mean, pg/l 0.24 0.4 0.03 8.8 2.1 3.6 4.6 5.7 Std. Dev., pg/l 0.22 0 .6 0.1 70 2.4 3.0 9.1 8.0 Range, pg/i 0—1.1 0—1.4 0—0.2 0—32 Tr—l0 0.2—14.0 0—23 Tr—22 No. of Samples 26 9 20 38 39 40 6 16 CHBr 2 C1 Mean, pg/i 2.2 0.1 0.06 4.0 0.6 2.0 1.8 22 Std. Dev. , pg/l 3.2 0.3 0.10 5.0 0.9 2.3 3.4 4.6 Range, pg/i 0—10.0 0—0.7 0—0.3 0—18.0 0—3.5 0—10 0—7.9 0—17 No. of Samples 20 9 10 33 31 38 6 15 CHBr 3 Mean, pg/i 0.5 0 0 1.8 0.2 0.4 O.i 0.5 Std. Dev. ,pg/1 1.0 0 0 5.1 0.5 0.6 0.2 1.0 Range, pg/i 0—2.9 0 0 0—23 0—2.3 O—i.8 0—0.4 0—2.8 No. of Samples 14 5 9 23 23 26 3 10 ------- Figure 3. 0’ I — z w 0 z 0 0 z 0 I — z I i i 0 z 0 C.) Haloform concentrations at filtration effluent and activated—carbon effluent during second period of operation (October 1976 through June 1977). DAY OF OPERATION ------- During periods when breakpoint chlorination was changed to point Q8, the ef- fluent haloform concentration did not increase above the previous effluent level, suggesting perhaps that the major organic precursors of the haloforins were effectively removed by carbon contacting. However, the required 9:1 ra- tio of chlorine to ammonia could not be maintained at Q8 due to pH problems and this may have reduced the potential for haloform formation also. Some haloforms were formed as can be seen by a comparison of Q6 and Q9 concentra- tions after April 1977 (Figure 3). The VOA analysis allows measurement for chlorinated compounds other than haloforms as listed in Table 21 for the period since October 1976. The chrom- atographic peaks for l,l,l—trichloroethane and carbon tetrachloride coincided so that differentiation between these compounds was not possible. However, the presence of l,1,l—trichloroethane, but not carbon tetrachioride, was veri- fied by GC/MS. Because insufficient samples were analyzed, it is difficult to draw firm conclusions. The data in Table 21 do illustrate the effectiveness of ammonia strip- ping in removal of volatile compounds (compare Q4 with Q2 values). No other process at Water Factory 21, including activated—carbon contacting, was gen- erally as effective in the removal of these materials, although each process played a part in the overall removals obtained. Closed—Loop Stripping Analysis Samples taken between 1/19/77 and 6/12/77 and from various stages of the treatment were extracted and analyzed. On 9 sampling dates complete sets of samples (Ql, Q2, Q4, Q6, Q 8 , Q9) were taken, and on 4 sampling dates only the chlorinated effluent and the reverse osmosis plant effluent were sampled. In Ql, the load of organics was often too high and results were not reliable. Eight of the most prominent substances of health significance (ethylben— zene; chlorobenzene/o—xylene; 1, 3—,l ,4—, and 1 ,2—dichlorobenzene; 1,2, 4—tn— chlorobenzene and naphthalene) were selected as indicators for the efficiency of the various treatment processes. Mean values, standard deviation, range, and numbef of samples are given in Table 22. Average concentrations in Ql vary from 210 ng/l for l,2,4—trichlorobenzene to 2000 ng/1 for 1,4— and 1,2— dichlorobenzenes. Individual measurements vary more than one hundred percent and the standard deviations in some cases are larger than the mean value. Therefore direct comparisons of the mean values are difficult. A better picture of the effect of the treatment is obtained by averaging the change of the paired values (values obtained from samples taken at the same time). For the 2 processes which are effective In removing volatile trace organics (ammonia stripping, and activated—carbon treatment) these values are included in Table 23. All selected trace contaminants showed an average removal of more than 60 percent during ammonia stripping with the ex- ception of naphthalene (40 percent) and 1,2,4—trichlorobenzene (50 percent). In a few cases, an apparent increase in the concentration was measured which probably was caused by variations in the influent concentrations. The effec- tiveness of ammonia stripping in removing this broad range of organic 34 ------- TABLE 21. CONCENTRATIONS OF HIGHLY VOLATILE CONSTITUENTS OTHER THAN HALOFORMS (ugh) October 1976 through June 1977 (J U I Sample Location Influent Qi Clarif. Effluent Q2 Ammonia Tower Effluent Q4 Filter Effluent Q6 Activ.— Carbon Effluent Q8 Contact Basin Effluent Q9 RO Influent Q21A RO Effluent Q21B CH 2 C1 2 Mean Std. Dev. Range No. of Samples C1 3 C—CH 3 ICC1 4 Mean Std. Dev. Range No. of Samples C1 2 C = CHC1 Mean Std. Dev. Range No. of Samples CC12 CC1 2 Mean Std. Dev. Range No. of Samples 24 20 1.7—74 40 6.3 4.7 0—24 37 1.5 1.5 0—39 33 1.3 3.0 0—15 24 6.2 7.1 0.9—12 11 3.9 9.1 0—28 11 0.7 0.9 0—2.4 10 0.4 0.4 0—1.0 9 2.7 3.1 Tr.—12 32 0.2 0.6 0—2.5 28 0.1 0.3 0—1.4 27 0.03 0.07 0—0.2 12 3.3 4.1 0.1—18 38 0.08 0.2 0—1.2 36 0.1 0.4 0—2.4 33 0.3 0.6 0—20 33 2.6 8.9 0.2—12 38 0.08 0.2 0—1.0 34 0.03 0.06 0—0.2 33 0.1 0.3 0—0.9 31 3.4 5.6 0.2—33 40 0.1 0.3 0—1.2 37 0.04 0.1 0—0.3 34 0.1 0.3 0—0.9 38 0.8 0.4 0.4—1.5 6 0 0 O—Tr. 6 Tr. Tr. O—Tr. 6 Tr. Tr. 0—0.1 6 1.4 1.6 0.2—6.2 16 0.03 0.08 0—0.3 16 0.03 0.06 H0.O2 15 0.04 0.07 0—0.2 14 Tr less than 0.05 ------- TABLE 22. CLOSED—LOOP STRIPPING ANALYSES FOR SELECTED ORGANICS (ng/1) October 1976 through June 1977 Sample Location Influent Ql Clarif. Effluent Q2 Ammonia Tower Effluent Q4 Filter Effluent Q6 Activ.— Carbon Effluent Q8 Contact Basin Effluent Q9 RO Effluent Q21B Ethyl benzene Mean 1300 310 70 60 30 40 35 Std. Dev. ± 910 260 60 20 20 50 20 Range 230—1900 110—880 10—170 30—100 Tr.—50 Tr.—180 Tr.—60 No. of Samples 3 7 8 8 7 16 6 Chlorobz /O—Xylene Mean 900 540 130 100 50 70 90 Std. Dev. 540 490 80 60 50 90 65 Range 200—1300 130—1700 25—240 30—210 Tr.-130 Tr.—370 Tr.—150 No. of Samples 4 8 8 8 5 16 6 1, 3—Dichlorobenzene Mean 300 130 30 30 5 140 16 Std. Dev. 310 170 30 60 10 180 20 Range 60—840 15—530 0—60 0—160 0—20 0—500 0—40 No. of Samples 5 8 8 8 8 14 5 1, 4—Dichlorobenzene Mean 2000 800 50 30 20 15 20 Std. Dev. 1790 540 40 10 20 10 30 Range 600—4900 130—1900 Tr.—120 Tr.—40 0—50 Tr.—30 0—60 No. of Samples 5 8 7 7 8 14 5 1, 2—Djchlorobenzene Mean 2000 1100 340 300 60 100 70 Std. Dev. 1560 1070 320 450 50 80 70 Range 600—4700 40—3200 Tr.—750 10—1200 0—130 Tr.—320 Tr.—200 No. of Samples 5 8 8 8 7 15 6 Table 22 continued ------- TABLE 22 (cOntinued) ( ) Sample Location Influent Ql Clarif. Effluent Q2 Ammonia Tower Effluent Q4 Filter Effluent Q6 Activ.— Carbon Effluent Q8 Contact Basin Effluent Q9 RO Effluent Q21B l,2,4—Trichlorobenzer Mean Std. Dev. Range No. of Samples Naphthalene Mean Std. Dev. Range No. of Samples 210 270 Tr.—520 4 220 130 130—410 4 190 170 0—510 8 530 380 90—940 7 70 70 0—160 8 180 160 40—500 8 20 50 0—110 8 110 100 0—230 8 10 10 0—20 8 40 40 0—100 8 120 190 0—500 16 30 30 0—80 14 60 80 0—120 6 20 10 Tr.—40 6 Tr 20 ng/1. ------- volatiles is not surprising since the enrichment procedure in the analytical test is similar to the ammonia—stripping process. The effectiveness of the activated—carbon treatment can be seen from the averaged relative removals calculated from the paired values Q6 and Q8 in Table 23. The data indicate an average removal of more than 50 percent for all of the selected compounds. Again in a few cases, the concentration of the effluent was found to be higher than the corresponding concentration of the influent, thus causing a big variation in the averaged removal. For the other processes, an interpretation of removal efficiency is more difficult. Lime clarification (Ql, Q2) reduced concentrations in all cases except for naph— thalene (Table 22). The Influent water contained particulate as well as sol- uble organic matter, and this made quantification unreliable; therefore no valid data on removal efficiency can be given for this process at this time. Recarbonation and filtration (Q4, Q6) do not affect the concentration of the volatile compounds significantly. Also, for the reverse osmosis (RO) pro- cess, rio significant removal effect could be found. The RO effluent (Q21B) samples showed approximately the same mean concentrations as the chlorination effluent (Q9). The same was found for the haloforms (Table 20). However, RO was quite effective in overall COD removal (Table 17). Thus, many organics are removed by RO, but not the more volatile and low molecular weight sub- stances measured by VOA and CLSA. Removal of volatiles by the overall plant TABLE 23. EFFICIENCY OF AMMONIA STRIPPING AND CARBON ADSORPTION FOR REMOVAL OF SELECTED TRACE ORGANICS BASED UPON PAIRED SAMPLES Process Ammonia Stripping Carbon Adsorption ‘ No. of Paired i amp±es Percent Removal No. of Paired Samples Percent Removal Mean Std. Dev. Mean Std. — Dev. Ethy lbenzene Chlorobenzene/ o—xylene 1,3—Dichlorobenzene l,4—Dichlorobenzene 1,2—Dichlorobenzene 1,2, 4—Trichloro— benzene Naphthalene 6 7 7 7 7 6 6 80 60 80 90 70 50 40 10 25 20 10 35 60 70 6 5 6 6 5 50 50 * 60 70 * 70 25 40 40 35 30 *Values too close to the detection limit to calculate reliably the efficiency of removal. 38 ------- (except lime treatment) is illustrated in Figure 4. Illustration A represents a chroinatogram of a CLS extract of a Q2 sample, illustration B one of a Q9 sample (samples taken 6/23/77). The column effluent was detected simulta- neously with a flame—ionization detector and with an electron capture detector. The major contaminants remaining at Q9 are those with a strong ECD response, which represents halogenated substances produced by chlorination, mainly tn— halogenated methanes as indicated previously under VOA analysis. Solvent Extraction Analysis Pesticides and PCBs—— During the initial period of WF21 operation, effiqent samples were ex- tracted with hexane and tested for the organochlorine pesticides indicated in the following. The detection limits for BHC, lindane, DDE, dieldrin, endrin, aidrin, and heptachior were around 10 ng/i, and for DDT and methoxychior around 100 ng/l. In the 15 samples analyzed between February 12 and June 24, 1976, no pesticides were found above these limits. In the second period from October 1976 through June 1977, samples were analyzed and again, no pesti- cides could be found in the effluent within the above detection limits (see Appendix Table B—8). Figure 5 shows the profiles of a typical chromatogram obtained from a hexane extract of an influent sample (Qi). Figures 6A and 6B represent simi— lar analyses of pesticide and PCB standards. None of the peaks matches unam- biguously with those of the pesticides except for heptachlor. However, investigations with GC/MS did not confirm this finding since no trace of heptachior could be found. There is a pattern of peaks which matches a test chromatogram of a PCB 1242 solution. Elemental sulfur was occasionally iden- tified in the influent. Other peaks not belonging to the PCB pattern have not yet been identified. The measured PCB values are given in Table 24. Their concentrations in the influent were consistently high. Values varied from 2.3 to 7.8 pg/i and the average was 4.8 pg/i. Lime clarification reduced the mean concentration to 1.3 pg/i and in all subsequent samples the mean values remained around 0.4 pg/i. This is the detection limit at this time and there may well be inter- ferences which cause this relatively high number. In addition, the pattern changes in some cases and no reliable quantification was possible. Estimated values are given in parentheses. Phthalates—— Diethylphthalate and dioctyiphthaiate (bis (2—ethylhexyi)--phthalate) were quantified by means of the same internal standard. The dibutylphthalate peak was obscured by a sulfur peak which prevented quantification. The mean val- ues of the determined quantities of diethylphthaiate and dioctylphthaiate are also given in Table 24. In the influent (Qi) and the lime—treated effluent (Q2) the concentrations found are consistently in the low microgram per liter level. Values range from approximately 1 to more than 10 pg/l. For diethyl— phthalate no clear removal effects can be seen since individual measurements seem erratic for unknown reasons. The mean value for dioctylphthalate was lower after lime treatment (by about 60 percent). However during the 39 ------- B- A. Figure 4. Chromatograins of CLS extracts with simultaneous flame ionization and electron capture detection. A: Q2 taken 6/12—13/1977; B: Q9 taken 6/12—13/1977 (numbers refer to Table 25). 40 ! 10 20 30 40 50 TIME, mm SOLVENT 58 88 118 148 178 TEMP, °C B 29 23 28 I 0 29 B 22 0 L SOLVENT 23 ATTEN 10 8 58 B. 20 88 30 118 40 148 50 TIME, mm II 178 TEMP,°C ------- 0 0 20 30 TIME, mm I L—. 90 210 70 1 230 TEMP, °C Figure 5. ECD—chromatogram (setting 337/2k) of Qi extract, internal standard 2.34 pg/i. 1: dlethyiphthaiate; 4: dioctylphthalate; 3: retention time as lindane; 2: unknown. IS. QI 5/1-2/77 POB 4 130 41 ------- I I.S. 2 j PESTICIDE STANDARD 8 I JJ 0 10 20 30 TIME., mm F- II 90 130 170 210 230 TEMP, C Figure 6A. Pesticide standard (ECD setting 337/2 ). 1: BHC isomers 260 pg; 2: lindane 260 pg; 3: heptachlor 160 pg; aidrin 160 pg; 7: diel— drin 160 pg; 8: DDE 194 pg; 9: endrin 170 pg; 10: TDE 500 pg; 11: DDT 240 pg; 1.s.: internal standard, 1170 pg; 4,6: impurities. PCB IS. AROCHLOR 1242 0 10 20 30 TIME, mm I II II I 90 30 170 210 230 TEMP, °C Figure 6B. PCB arochior 1242 standard, 2.66 ng; internal standard, 0.464 ng. Detector 337/2k. 42 ------- TABLE 24. PCBs AND PHTIIALATE CONCENTRATIONS AT VARIOUS SAMPLING POINTS* April 1977 through June 1977 . Sample Location Influent Qi Clarif. Effluent Q2 Ammonia Tower Effluent Q4 Filter Effluent Q6 Activ.— Carbon Effluent Q8 Basin Effluent Q9 RO Effluent Q21B PCB 1242 Mean, pg/i Std. Dev., pg/i Range, pg/i No. ofSainp les Diethyl phthalate Mean, pg/i Std. Dev., pg/i Range, pg/i No. ofSamp les Dioctyl phthaiate Mean, pg/i Std. Dev., pg/i Range, pg/i No. ofSampies 4.8 2.0 2.3—7.8 6 6.1 4.4 2.5—13 5 8.2 5.0 1.7—14 5 1.3 1.0 0.3—3.1 6 8.3 3.7 1.7-19 5 2.8 2.9 0.3—7.6 6 (0.3) 0.5 0.1—0.8 6 5.6 3.7 2.1—10 6 1.0 0.6 0—2.0 6 (0.3) 0.4 0—0.8 5 10.9 8.2 3.6—21 5 1.3 0.7 0.4—2.0 5 (0.2) 0.4 0—0.8 6 5.8 4.9 0—13 6 1.4 1.4 0—4.0 6 (0.3) 0.4 0—1.0 8 2.5 2.6 0—6 8 2.0 2.0 0.4—6 8 0 3 1.3 0—2.7 3 2.0 0.4—5.3 3 * Values in parentheses are estimates. ------- subsequent treatment, the average concentration did not change significantly. At this point the origin of these materials present in secondary effluent is not known. Detailed Characterization A number of extracts have been investigated with GCIMS without an attempt at quantification. The main emphasis to date has been to detect the presence or absence of substances of toxicological concern. Since only a small number of samples have been analyzed, no definite conclusions about variability in contaminant levels can be drawn. The organics found can be divided Into the following categories based upon their presumed origin. A. Aromatic hydrocarbons B. Synthetic chlorinated compounds C. Chlorination products D. Natural products E. Miscellaneous The organic substances tentatively identified by GC/MS are listed in Table 25. The numbers refer to Figure 7 which shows a total ion chromatogram of a CLS extract of the Q2 sample taken on 2/6/77. The amount of internal standards added (l—chloroalkanes; 1—Cl—C 2 , 1—Cl—C 8 , 1 —Cl—C 10 ) were 500 ng/l and compar- ison of the peak heights may be used to approximate the concentrations. In Table 25 relative heights in different sample locations are given which give an indication of the degree of removal or formation during treatment. The trend observed is the same as in the routine analysis: Ammonia stripping and activated—carbon treatment are effective in removing the volatile organics. Chlorination products are found in the influent and in the effluent. Their concentration increases upon chlorination (see volatile organic analysis). In addition to the haloforms, which are analyzed by the VOA, a number of other substances which are produced by chlorination have been found: Halogenated ketones (Peak 32, 24, 25) and chioroxylene (33). Their concentration is in the low nanogram per liter range. In Table 26 substances are listed which were found in the hexane ex tracts. Identifications are based on mass spectra only and are tentative for most substances. 44 ------- TABLE 25. COMPOUNDS IN WF—21 SAMPLES ANALYZED BY CLSA AND THEIR TOTAL ION CURRENT PEAK HEIGHTS RELATIVE TO TIlE INTERNAL STANDARD, 1. C1_C8* Peak No. Sample Location Clarif Filter Act iv. Carbon Basin in Effi. Effi. Effi. Effi. Figure 7 Co pound Q2 Q6 Q8 Q9 A. Aromatic Hydrocarbons 1 Benzene 2 Toluene 3.32 0.76 0.26 0.24 3 Ethylbenzene 1.34 0.17 0.09 0.05 4 p—xy lene 0.80 0.15 0.08 0.05 5 in—xy lene 2.98 0.44 0.13 0.12 6 o—xy lene 1.27 0.44 0.13 0.12 7 C 3 _benzenest 0.5 0.15 0.06 0.05 8 C 4 —benzenes 9 Indane 10 C 1 —indanes 11 Naphtha lene 1.06 0.24 0.25 0.11 12 Nethy lnaphthalenes 0.67 0.18 0.06 0.1 13 C 2 —naphtha lenes 14 Styrene B. Synthetic Chlorinated Compounds 15 Trichioroethylene 1.12 16 Tetrachioroethylene 17 Trichioroethane Tr 18 Hexachioroethane 0.4 0.24 0.08 0.08 19 Chlorobenzene 20 1, 2—dichlo rob enzene 21 1,3- .dich lorobenzene 1.11 0.09 0.01 22 1,4—dichlorobenzene 2.94 0.29 0.05 23 Trichlorobenzene 0.87 0.06 0.01 24 Tetrachlorobenzene 25 PCB (1— and 2—chiorines) Tr C. Chlorination Products 26 • Chloroform 27 Dichlorobromomethane 0.3 0.53 0.23 0.20 28 Chlorodibromoniethane 6.3 0.27 0.32 29 Bromoform 0.45 30 Dichloroiodomethane 0.09 0.09 0.03 31 Chiorobromo iodomethane 32 1,l,l—trichloroacetone 33 Chloroxylene 34 Chlorobromopentanone 35 Bromoketone 0.3 1.1 0.12 0.12 TABLE 25 continued 45 ------- TABLE 25 continued Peak No. in Figure 7 Compound Sample Location Clarif. Effi. Q 2 Filter Effi. Q6 Activ. Carbon Effi. Q8 Basin Effi. Q9 36 37 38 39 40 41 42 D. Natural Products 0.05 > 4 1.97 1 0.34 0.20 1.0 Terpene Terpene alcohol E. Miscellaneous Phthalates Benzaldehyde Tolualdehydes Ethyiphenol Apparent MW 196 * blank indicates peak height not measurable. tValue of one typical compound of this group measured. TABLE 26. STJBSTABCES TENTATIVELY IDENTIFIED IN HEXANE EXTRACTS Substance Sample Location* Clarif. Effl. Q2 Basin Effl. Q9 PCB (see Table 24) Biphenyl Alkylated biphenyls Phenanthrene/Anthracene Methylphenanthrene Diethylphthalate (Table 24) Dibutylphthalate Dioctylphthalate (Table 24) Sulfur S 8 x X X x X x X x X Tr Tr Tr x X X * x = present in measurable concentration. Tr= close to detection limit. —— = not detectable The complexity of the mass spectra did not allow an identifica- tion of a number of peaks yet. 46 ------- 0-2 2/6/77 2S IS Q-2 2/6/77 250 IS 100 150 00 c j Figure 7. Typical total ion chromatogram (computer reconstructed) of a CLS extract from Q2. Lower graph is independently normalized. Numbers refer to substances in Table 25. L ( -ii 1! N -. ‘1 L ‘I ‘-I -l CN TIC 2 c — i 50 200 00 250 47 ------- VIRUS James N. Montgomery Engineers (JMM) determined the number of virus in samples taken from the following locations at Water Factory 21: (1) the in— fluent, Qi, (2) the lime—clarifier effluent, Q2, and (3) the final effluent, Q9. In addition, samples were analyzed occasionally to determine the types of virus present. Most identifications were conducted by the California Depart- ment of Public Health, but some were made by JMM. Virus in Water Factory 21 Influent A snmm ry of results for native virus assays of influent samples is given in Table 27 and Figure 8. The geometric mean values listed at the bottom of Table 27 were taken from the 50—percent value from Figure 8 for the period from November 1975 through June 1976, and from a similar plot for the data from October 1976 through July 1977. Several samples analyzed had no detect- able viruses. For example, of the 77 samples analyzed between October 1976 and July 1977, 29 contained no detectable viruses (Table 27). The number of viruses which were measured in the remaining samples are listed in increasing order in the tables. A comparison of the data in Table 27 for the two different periods indi- cates that for the BGN procedure, plaque confirmation as defined in the Sampl- ing and Analytical Procedures section is essential. The values obtained for the second period when confirmation of the assay results was made were thirty- fold lower than for the first period when it was not. Figure 9 illustrates the seasonal distribution of virus, and as commonly believed, the data suggest that virus levels are lowest during the winter and highest during the summer. Also, between December 1, 1976 and March 15, 1977 only 48 percent of the samples were positive for virus, while during the warmer remainder of the year, 68 percent of the samples were positive. Table 28 presents a summary of the viruses identified in influent samples to Water Factory 21. The significance of these particular virus isolates in relation to human disease has not been investigated. Virus in Chemical Clarifier Effluent Virus were measured in the effluent from the clarifier after lime treat- ment (Q2) only during the first period from November 1975 through June 1976. The purpose was to determine the effectiveness of lime treatment at pH greater than 11.3 on virus reduction. During this period, however, the viral assays were not confirmed as this was then not known to be necessary, and so actual effluent concentrations are not known. The results do suggest, however, that reductions by lime treatment are significant. A summary of the analyses con- ducted Is given in Table 29. The geometric mean values were obtained as be- fore from the intersection of the drawn line through data on log—probability paper with the 50—percent point on the graph. A comparison of the calculated geometric mean values with those for the same period and same assay procedure in Table 27 indicates that lime treatment resulted in 99.88 percent reduction 48 ------- TABLE 27. VIRUS CONCENTRATION IN INFLUENT (Q1) November 1975 through June 1976 Oct. 1976 through July 1977 PAG (unconfirmed) BGM (unconfirmed) BGN (confirmed) No. of Samples iø pfu/m 3 No. of Samples , 1O 3 pfu/m No. of Samples 10 pfu/m 3 1 N.D.* 0 29 N.D.* 1 0.18 1 4.0 5 0.5 1 2.0 1 6.6 5 0.8 1 2.5 1 10.6 2 1.1 1 3.2 1 12.5 7 1.3 2 4.0 1 13.2 1 1.6 1 5.0 1 16 3 1.9 1 5.3 1 26 3 2.1 1 8.7 1 29 1 2.4 1 9.3 1 40 1 2.6 1 13.2 1 49 1 2.9 1 148 1 52 1 3.2 1 63 2 3.4 1 160 1 3.7 1 260 2 4.2 1 4.5 1 4.8 2 5.0 2 5.3 1 5.6 1 5.8 1 6.1 1 6.6 1 6.9 1 7.1 1 48 13 4.5 14 27 77 1.1 (Total (Geom. (Total (Geom. (Total (Geom. Samples) Mean) Samples) Mean) Samples) Mean) * None detected. as determined by the unconfirmed PAG procedure and 97.7 percent by the uncon— firmed BGM procedure. Samples obtained during this period were also analyzed by the California Department of Public Health. For influent samples the State laboratory found all 12 samples analyzed to be positive. For samples after chemical treatment, 49 ------- %J I .05 .5 5 I0 20 40 60 80 90 95 99 99.9 99.99 .01 .1 I 10 100 VIRUS ASSAY, thousand PFU/m 3 Figure 8. Probability plot of virus assay levels. LU -j z LU > V I U, U) (I) 0 F- z LU U LU 50 ------- TABLE 28. VIRUSES IDENTIFIED IN WATER FACTORY 21 INFLUENT (Q1) Virus Calif. Dept. of Health James Montgomery No. of Samples Total No. of Plagues No. of Sample Total No. of Plagues Polio2 16 27 1 4 Echol 8 17 Echo7 7 16 Reo2 5 12 Echol4 7 8 Coxsackie B5 6 8 1 1 Polio3 7 7 Echo8 6 6 Reo 6 6 Unknown 5 5 Echol2 3 5 Coxsackie B4 5 5 Coxsackie B2 3 4 Coxsackie B3 1 3 Echoll 2 3 Reol 3 3 Coxsackie B6 2 2 Coxsackie A17 2 2 Coxsackie A13 1 1 Coxsackie A18 1 1 Coxsackie A20 1 1 Echo3 1 1 Echo9 1 1 Echol9 1 1 Echo25 1 1 Poijol 1 1 1 1 Total No. Samples with Virus 46 4 the State laboratory found only 3 samples to be positive while JMM found 28 ositives. This discrepancy again indicates the importance of conducting confirmed analyses. It also leaves open the question of the true effective- ness of lime treatment on virus reduction. The three viruses identified in the three positive samples by the State laboratory for lime—treated effluent samples were Echo 8, Echo 20, and Polio 1. Of the three, only Echo 8 was also found in the plant influent during this period. Viruses in Final Effluent (Q9 ) Over the period of this study, 77 samples of chlorinated final effluent (Q9) were analyzed for virus. Only one of the samples analyzed was positive for virus. This sample was collected on March 1, 1977. There was one con— firmed plaque in the four ml assayed in this sample. Identification by the 51 ------- 48 I0 8 In E z 4 cfl4 0 I I.- 2 0 OCT NOV 1976 E 1 ii E L] DEC JAN FEB MAR APR 1977 MAY JUN JUL Figure 9. Seasonal variation in natural viruses in Water Factory 21 influent. ------- TABLE 29. VIRUS CONCENTRATION IN CHEMICAL CLARIFIER EFFLUENT (Q2) November 1975 through June 1976 FAG (unconfirmed) BGM (unconfirmed) No. of Samples pfu/rn 3 No. of Samples 1O 3 fufm 3 15 N.D. 4 N.D. 3 0.03 1 0.05 1 0.05 2 0.11 2 0.08 1 0.13 1 0.53 1 1 2 5 1 2 1 1 1 1 2 1 1 2 1 1 0.19 0.20 0.3 0.5 0.8 1.1 1.3 1.6 1.8 2.1 2.6 3 4 5 7 11 22 0.005 32 0.6 (Total (Geoni. (Total (Geom. Samples) Mean) Samples) Mean) plaque reduction technique indicated that it was Polio Type 2. The one con- firmed plaque in four ml assayed for the plant influent (Qi) on that same day was also identified as Polio Type 2. The firm of .1MM which conducted the assays for virus indicated the pos- sibility that the virus could have resulted either from cross—contamination or was actually indigenous to the effluent sample analyzed. They felt that the possibility of cross—contamination was low and thus the virus was most likely indigenous to the sample. On the day that the virus was detected, there was an operational problem. An unusually high concentration of activated—carbon fines was in the effluent; for this reason the turbidity was 2.3 and the pH was 6.6. At the time of sampling, the chlorine residual was not determined, but because of normal interactions between chlorine and activated carbon, it could have been low. 53 ------- It has been well documented that the presence of particulates interferes with disinfection. Activated carbon has been shown to be a very effective virus adsorbent, consequently any virus in the effluent would likely be on the carbon. Activated carbon also reacts very quickly to remove chlorine and as a result the attached virus are likely to have been protected from its action. The release of activated—carbon fines has been an occasional problem at Water Factory 21 and for this reason, some major modifications have been completed in an effort to reduce the problem. 54 ------- SECTION 7 DISCUSSION BACKGROUND This study has been conducted to evaluate the effectiveness of advanced wastewater treatment for removal of inorganic, organic, and biological con— taminants which remain in municipal wastewater after normal secondary treat- ment. The performance of Water Factory 21 was evaluated during the first one and one—half years of its operation. This advanced treatment plant receives up to 0.66 m 3 /sec (15 mgd) of trickling filter effluent from the Orange County Sanitation District and treats it by a combination of physical and chemical processes. The ability of this treatment plant to effectively remove many materials of toxicological significance prior to reuse or gro undwater injec- tion has been demonstrated. The information this study has generated should be useful in evaluations of the reliability of advanced treatment plant opera- tion and the determination of quality of reclaimed waters relative to that of potential alternative supplies. GENERAL INORGANICS The advanced was tewater treatment at Water Factory 21 has resulted in changes in the concentrations of ammonia, phosphate, calcium and magnesium. In addition, treatment of a portion of the wastewater by a reverse osmosis pilot plant has resulted in a significant reduction of inorganics in general. Ammonia is removed both by air stripping and by breakpoint chlorination. During the first six months of operation only ammonia stripping was practiced, and this process reduced the concentration of ammonia nitrogen from 43 to 19 mg/i for an average removal of 56 percent. The operation of the two strip- ping towers was then modified to provide for series rather than parallel op- eration. Even though the same quantity of air was used (3000 IL 3 air/rn 3 water), this change resulted in decreasing the ammonia nitrogen from 37 to 6.5 mg/i, which is a reduction of 82 percent. Thus, series operation offers a decided advantage. Breakpoint chlorination resulted in reduction of ammonia nitrogen to the 1 mg/i level required by regulations. This necessitated a chlorine to ammo- nia nitrogen weight ratio of 9 or greater. Breakpoint chlorination was dif- ficult to control when it was combined with disinfection in the final chlorine contact chamber because the high concentration of chlorine required resulted in an excessive decrease in pH. This problem was solved by moving the 55 ------- breakpoint chlorination process upstream to the effluent from the ammonia stripping tower. Here, the pH was near 11 and the water had a good buffering capacity. After chlorine addition, the pH was lowered to the desired level by recarbonation, and the recarbonation basins provided the time required for ammonia oxidation to be completed. A significant disadvantage of breakpoint chlorination, however, was the forniationof several chlorinated organics which were not efficiently removed by activated—carbon adsorption. This was previously discussed more fully under the section on Organics. There was also concern over the effect the resulting free chlorine residual might have on the capacity of the activated— carbon columns. For these reasons and because the cost of breakpoint chlori- nation is high, the OCWD has requested that the 1 mg/l limit on ammonia nitro- gen In injection water be reviewed, especially since some additional removal by ion exchange In the aquifer Is likely. Chemical treatment with lime at a pH greater than 11.3 is very effective for the removal of phosphates and magnesium. Over the entire one and one—half years of this study, phosphate phosphorus was reduced from a mean influent concentration of 5.5 mg/i to 0.08 mg/i, or 99 percent, and magnesium was re- duced from a mean influent concentration of 25 mg/l to 0.7 mg/i, or 97 percent. Calcium concentration, however, increased through lime addition during the first six months of operation from 102 mg/i to 142 mg/i, but was reduced dur- ing ammonia stripping, recarbonation and settling to a final effluent concen- tration which averaged 107 mg/i. During the last year of operation, a pilot reverse osmosis (RO) system was operated to determine efficiency for dissolved salt removal which could be expected when the 0.22 m 3 /s (5 mgd) full—scale facility was completed. The pilot RO unit reduced the specific conductance from a mean value of 1530 to 80 S/cm,or by 95 percent. It also reduced the sodium, chloride, sul- fate, and COD concentrations by 93, 94, 100, and 93 percent, respectively. Certain low molecular weight organics were not removed effectively as dis- cussed later under the section on Organics. However, the above results indi- cate that RO treatment is quite effective for removal of a broad range of general inorganics and organics. HEAVY METALS Of the several heavy metal trace contaminants monitored, only one was continuously higher in concentration In the secondary influent to Water Fac- tory 21 than the regulatory requirements for the effluent from the advanced wastewater treatment plant. This was chromium, and it was removed down to the regulatory requirement of 50 ug/l by the treatment processes. Thus, heavy metal removal is not a critical aspect of Water Factory 21 operation. How- ever, it is worthwhile to consider the effectiveness of heavy metal removal by the treatment plant both for other applications and because several trace metals in the influent on occasion rise above the limits. Two metals, mercury and selenium, were not removed to a significant de- gree by the advanced wastewater treatment system. Also, arsenic was not 56 ------- removed significantly during the last year of operation, although during the first six months there was an indication that chemical treatment removed some- what over 50 percent. All three metals were in the low g/l range, near the detection limit. Therefore, firm conclusions about removability cannot be made. All other trace heavy metals monitored were generally removed 50 percent or more by chemical treatment. These included barium, cadmium, chromium, iron, lead, manganese, silver, and zinc. Subsequent treatment (RO was not evaluated, however) did not result in additional removal except for chromium, copper, and zinc which were reduced an additional 41, 64, and 78 percent, re- spectively, by activated—carbon treatment. Chemical treatment was consistently good for iron and manganese, provid- ing over 85 percent removal. Copper removals averaged between 65 and 75 per- cent for the two different periods, and barium removal varied between 50 and 60 percent. Silver, chromium, lead, and cadmium removals averaged from 40 to 65 percent during the first six months, but increased during the last year of operation to over 75 percent, with cadmium reductions the best at 94 percent. On the other hand, zinc removal was highest during the first period (90 per- cent) and lowest during the second period (37 percent). Iron and zinc concentrations were quite variable throughout the plant, especially during the first six months of operation, due to corrosion, espe- cially in the ammonia stripping tower. Zinc in particular increased in con- centration from 29 to 670 jig/l through ammonia stripping, although the concen- tration was then reduced to 133 pg/l by activated-carbon treatment. The corrosion problem was not so severe during the last year of the study. These results indicate that the concentration of many heavy metals of health concern can be reduced by chemical treatment with lime at a pH greater than 11.3. This treatment should provide a good safeguard against occasional high concentrations of heavy metals, which may be present in municipal waste— waters. In the case at hand, however, in the influent water only chromium exceeded the regulatory requirements for the effluent and necessitated reduc- tion on a continuous basis. Some of the other metals exceeded requirements occasionally, thus treatment was required to insure continuous compliance with regulations. Lime treatment was the most effective process in general at Water Factory 21 for this purpose. ORGANICS General The COD analysis measures a broad group of organic compounds and thus changes in ttu.s parameter provide indications of the overall performauce or the treatment system for organics in general. The COD of the secondary in— fluent to Water Factory 21 averaged 131 mg/i. This was reduced by 60 percent (about 36 percent particulate and 24 percent dissolved) to a mean concentra- tion of 52 mg/l by chemical treatment due to the removal of suspended organics. 57 ------- An additional reduction in the mean COD concentration to 45 mg/i took place after ammonia stripping and filtration. Activated—carbon adsorption provided an additional 67 percent reduction to a mean value of 15 mg/i, which had a standard deviation of 8 mg/i in the 397 samples analyzed over the one and one—half years of operation. Thus, overall COD reduction by the advanced wastewater treatment plant was almost 90 percent. While the COD procedure provides information on organics in general, it does not indicate the perfor- mance for removal of many individual organics which may be of toxicological concern. Trace Organic Contaminants The trace organics identifiable by closed—loop stripping analysis have been divided arbitrarily Into five separate groups as related to their most probable origin. Presence of Group A compounds reflects contamination of water with petroleum products. This can be concluded from the fact that var- ious groups of isomers such as the xylenes are present in typical relative concentrations. Quantification of the complex mixture of substances in petro- leum products is obviously very difficult. The aliphatic portion of such products are probably removed to a large degree during secondary treatment, either due to their better microbial degradability or through aeration. This was indicated in an earlier investigation (6). The Group B synthetic chlorinated products are widely used in household and in industry. They are commonly found in natural waters and in drinking water supplies of all industrialized nations (8). Their occurrence in Water Factory 21 samples is therefore not surprising. The first quantitative esti— mates indicate that they are present all the time. The Group C compounds are formed during the chlorination process in water and wastewater treatment plants, and include the well—known haloforms (2,3,10). However, other chlorinated organics such as chloroxylene (7), and alpha— haloketones (6) are also known to be formed, leading us to assume that these compounds as well as the bromochloroketone and trichloroacetone found are products of chlorination at Water Factory 21 and of its chlorinated influent. The Group A alkylated benzenes may also be chlorinated (7). The structure of some of the organics which resulted from chlorination remain to be elucidated. Natural products identified include terpenes and terpene alcohols. Little attention has been given to these materials since they are not of health concern. They are removed effectively during treatment. The Group E substances do not fit into the other categories. Except for phthalates, which are widely used as plasticizers, little is known of their origin. The SEA analysis permits the identification of additional groups of com— pounds, including chlorinated pesticides, PCBs, and some of the polynuclear aromatics. They are of public health concern and some members are included in the EPA primary drinking water standards and those formulated by the World Health Organization (13). Additional information on their frequency distribu- tion in reclaimed waters is desirable. 58 ------- A major concern is the high concentration of polychlorlnated biphenyls in the plant influent. It was found to be about 10 times higher than in an earlier investigation (16). Although they are removed to a large extent, traces have been found in the effluent. A more sensitive procedure will al- low more precise monitoring of PCBs in the product water. On the other hand, chlorinated hydrocarbon pesticides were not detected. Schmidt, Risebrough, and Gress (16) reported a DDT concentration up to 0.64 pg/i. The current lack of detection probably reflects the fact that this pesticide is no longer in heavy use. Efficiency of Advanced Wastewater Treatment The initial results from this study indicate that advanced was tewater treatment is capable of removing about 90 percent of the total organic mate- rial remaining after primary and secondary treatment of municipal wastewaters. For many of the relatively low molecular weight organics of health concern, the efficiency of removal was greater than 90 to 95 percent. On the other hand, there was a group of organics which were formed by chlorination, and the effluent concentration of these was greater than the influent concentra- tion. A problem for future operation is how to minimize the formation of such chlorination products and at the same time satisfy other effluent re- quirements related to pathogens and nitrogen species. Chemical clarification and activated—carbon adsorption are well—known processes for removing organic materials. This study has demonstrated that air stripping for ammonia removal is also highly effective for the removal of a wide range of organic materials of toxicological significance. In particu- lar this process is effective in removing a wide range of highly volatile, low molecular weight, and relatively nonpolar organics which are not easily removed by activated—carbon adsorption or reverse osmosis. Included are several one— and two—carbon halogenated solvents and chlorination products. In addition, several aromatic compounds such as chlorinated and alkylated benzenes and naphthalenes are significantly removed by air stripping, thus reducing the need for reliance solely on activated—carbon adsorption. An ad- ditional important aspect for Water Factory 21 is that the group of organics removed by air stripping are some of the most likely compounds to cause prob- lems If Injected into a groundwater aquifer, because of their refractory nature and potential for movement with little hinderance from adsorption. The intermedla transfer of organics from the water to the air by ammonia stripping may cause some concern, and the environmental implications need to be considered. This should be viewed in a broad context since a similar in— termedia transfer would no doubt result from any discharge of wastewaters to surface waters, whether or not ammonia stripping is employed. An additional consideration is that the lifetime of many refractory organics is less in the air because of exposure to solar radiation than In the ground. A reso— lution of these complex issues was not attempted in this study. The formation of chlorinated organics by breakpoint chlorination raises additional issues which need to be resolved. Are health risks in a ground- water injection system greater from pathogens or from chlorinated organics? Is removal of ammonia to low levels, requiring breakpoint chlorination, 59 ------- necessary to the satisfactory operation of an injection system and to the quality of withdrawn water? These questions also have not been addressed in this study but remain for future research. This study has shown that the combination of processes used at Water Fac- tory 21 is effective for reducing the concentration of a broad range of organic materials present in effluents from secondary wastewater treatment. Future studies will be concerned with additional quantification of materials of health concern, seeking of analytical procedures for other organics of impor- tance, and determining their variation with time in Water Factory 21 effluent. The information provided should aid in the formulation of policy decisions about wastewater reuse in general, and in particular for municipal purposes. VIRUS Enteric viruses have been found present in a majority of the Influent samples to Water Factory 21. Over 25 different viruses have been identified in these samples. A reduction in viral numbers appears to occur during chem- ical treatment, although this analysis was conducted during the first six months of operation, when confirmed assays were not conducted. Subsequent studies have Indicated that confirmed analyses are essential to a good inter- pretation of data. Over 77 samples of final effluent were analyzed for virus concentration. Only one sample was positive for virus. This positive response appears to be related to the discharge of a relatively high concentration of activated— carbon fines In the effluent. Water Factory 21 has recently undergone modif I— cation to reduce such carbon fines in the future, which should also reduce the potential for virus passage. PLANT RELIABILITY An important aspect of this study was an evaluation of the reliability of Water Factory 21 to produce an effluent with good consistency in quality. In order for a plant to be reliable, either (1) the plant must be able to successfully treat wastewaters with great variability In quality, (2) the flexibility must be available so that the treatment plant need not accept a wastewater for treatment if It Is of questionable quality, or (3) if the treated water does not meet the intended reuse criteria, then it must be pos- sible to dispose of it by other means. In addition, the treatment plant must be able to treat the wastewater with its normal variability and consistently and reliably improve its quality to the required level. Water Factory 21 has been designed to provide considerable flexibility in line with the above. The OCWD can treat wastewater at whatever constant flow rate It desires. The Orange County Sanitation Districts, which supply the secondary effluent to OCWD, have on occasion had problems either in the operation of their biological treatment plant or with the introduction of un- usual wastes into the contributing sewers. They have then notified the OCWD, and if found desirable for water quality considerations, Water Factory 21 has 60 ------- been shut down. Water Factory 21 is also routinely shut down for a period of two to three months each year for general maintenance or plant modifications. In addition, plant operation is stopped whenever desirable for emergency maintenance or less extensive modifications. When the plant is restarted, treated water can be discharged to a sewer until the quality is consistent with regulatory requirements. This flexibility is possible since the ef flu- ent is recharged to the groundwater aquifer which is a large storage basin, unaffected by short—term stoppages in the injection of treated water. The plant operation can be properly balanced within one day after starting and effluent quality is then consistent and adequate. The ability to stop plant operation at will and to restart it rapidly gives a good meas- ure of assurance on plant reliability. The other measure of reliability is consistency in the characteristics of the reclaimed water. A measure of this can be obtained from the variabil- ity in measured effluent quality. Table 30 indicates the variability of in- organic constituents and Table 31 the variability of organic constituents in Water Factory 21 effluent. Most values represent analyses of final effluent after chlorine contact (Q9), although some as indicated are from before chlo- rine contact (Q8). The values are summarized from the detailed results listed in Appendix B. TABLE 30. VARIABILITY OF INORGANIC CONSTITUENTS IN WATER FACTORY 21 EFFLUENT Constituent January through June 1976 October 1976 through June 1977 Mean Conc. Coef. of Var., % Mean Conc. Coef. of Var., % Ca, mg/i 107 22 Na, mg/i 205 9 Cl, mg/i 246 9 SO 4 , mg/i 312 13 Alkalinity, mg/i 137 19 B, mg/i 0.63 22 F, mg/i 0.64 25 EC, pS/cm 1470 9 pH 6.7 2 Turbidity, TU 0.85 45 NH 3 —N, mg/i 3.3 88 As, pg/i 1.1 27 2.4 75 Ba, pg/i 33 70 31 71 Cd, pg/i 2.2 82 1.7 100 Cr, pg/i 48 67 26 92 Cu, pg/i 27 52 32 47 Fe, pg/i 45 150 66 120 Pb, pg/i 26 123 5.2 240 Mn, pg/i 4.1 34 4.9 90 Hg, pg/i 4.9 430 6.7 210 Se, pg/i 6.4 55 <2.5 — Ag, pg/i 14 410 1.5 190 Zn, pg/l 124 58 162 48 61 ------- TABLE 31. VARIABILITY OF ORGANIC CONSTITUENTS IN WATER FACTORY 21 EFFLUENT Constituent January through June 1976 October 1976 through June 1977 Mean Cone. Coef. of Var., Z Mean Conc. Coef. of Var., 7 COD, mg/i 13 62 18 39 TOC, mg/i 7.3 36 6.7 33 Org—N, mg/i 0.6 67 1.3 38 CHC1 3 , pg/i 2.1 52 10 84 CHBrC1 2 , pg/i 0.9 iii 3.6 83 CHBr 2 C1, pg/i 2.0 115 CHBr 3 , pg/i 0.4 150 CH 2 C1 2 , pg/i 3.4 160 C1 3 C—CH 3 /CC1 4 , pg/i 0.1 300 C1 2 C=CHC1,pg/1 0.04 250 CC 1 2 =CC 1 2 ,pg/1 0.1 300 Ethyl benzene, ugh 40 125 Ch lorobenzene/ o—xylene,ng/1 70 130 1, 3—dichioro— benzene, ng/i 140 130 1 ,4—dichioro— benzene, ng/1 20 50 1, 2—dichioro— benzene, ng/1 100 80 1,2, 4—trichioro— benzene, ng/1 120 160 Naphtha lene,ng/1 30 67 PCB 1242, ng/i 300 130 Diethyl- phthalate,ng/i 2500 104 Dioctyi— phthaiate,ng/1 2000 100 The coefficients of variation listed in Tables 30 and 31 were obtained by dividing the standard deviation for each constituent analysis by the mean value and multiplying by 100. The result indicates the magnitude of the stan- dard deviation in relationship to the mean. The mean and standard deviation indicate the magnitude and spread of the data. If the data followed a normal distribution, one could calculate from these values the frequency at which a given effluent concentration for a given constituent would be exceeded in the treated effluent. Table 30 indicates that the variability of the general inorganic con- stituents which comprise the major portion of the total dissolved solids is low, the coefficient of variation Is generally less than 25 -percent. The 62 ------- variability of turbidity, ammonia concentration, and heavy metals in general is much greater, sometimes exceeding 100 percent. Constituents falling in the latter category are cadmium, iron, lead, mercury, and silver. A portion of this variability is due to the fact that these concentrations are near the analytical limit, at which point analytical errors tend to be quite high. At such concentrations, contamination of samples can be a serious problem and may contribute to the variability found. The high coefficients of variation indicate that the mean values are affected significantly by a few high val- ues. Also, coefficients of variation greater than 100 percent, and indeed somewhat lower than this, suggest that the data do not follow a normal dis- tribution. Probably a log normal distribution would fit the data much better. This will be studied in more detail during the coming year of research. The variability of organic constituents is shown in Table 31. That of the gross parameters such as COD, TOC, and organic nitrogen are not as great as for the individual constituents. Again this is partly reflective of the variability of the analysis itself. The coefficient of variation is particu- larly high for constituents such as C1 3 C—CH 3 /CC14, C1 2 CCHC1, and CC1 2 CC1 2 which are present in concentrations just at the borderline of detection. The great variability here can be attributed largely to analytical problems. For other constituents, with coefficients of variation near 100 percent, analyti- cal problems are partly responsible, but most of the variation probably can be attributed to actual variation in effluent quality. It is no doubt desirable to be able to separate that portion of the meas- ured constituent variability which is due to analytical errors and that which is due to actual variation in treatment plant quality. However, for each constituent of concern this can be a costly undertaking. The decision to make the effort required should properly be related to the actual need for more re- fined numbers. If the constituent is at a measured concentration which is near a required limit, or if it exceeds the limit on occasion, then for that constituent, more refined measurements may be fully justified. If even at the highest concentrations measured, a given constituent is far below the re- quired limit, then additional refinement can probably not be justified. Since there are presently no regulatory requirements for organics except COD, addi- tional refinements for most of the organics listed are perhaps not justified at this time. Another aspect of reliability in performance which must be considered at *ater Factory 21 is ability of the aquifer itself to even out the variations which occur. The aquifer system represents a very large reservoir. As the reclaimed wastewater is injected into it, the organics will adsorb to and then be desorbed from the clays, and by this process they will move more slowly through the system than the water itself. This process of adsorption and desorption will result in spreading of the peak and valley concentrations of given organics so that variations of a given constituent at an observation well will be very much less than in the injected water. This effect will be greater the further the distance of the observation well from the point of injection. For this reason, the mean concentration may be a much more mean- ingful value than the extremes in reclaimed effluents used for groundwater in- jection. It must be kept in mind, however, that if variation in effluent quality is great, then many more samples must be analyzed in order to calcu- late a mean value which is sufficiently close to the true mean. 63 ------- REFERENCES 1. Standard Methods for the Examination of Water and Wastewater (14th ed.). American Public Health Association, Washington, D.C., 1976. 2. Bellar, T. A., and J. J. Lichtenberg. Determination Volatile Organics at the pg/i Level in Water by Gas Chromatography. Jour. AWWA, 67:634, 1974. 3. Symons, J. N., et al. National Organics Reconnaissance Survey for Halogenated Organics in Drinking Water. Jour. AWWA, 67:634, 1975. 4. Argo, David G. Wastewater Reclamation Plant Helps Manufacture Fresh Water. Water & Sewage Works, Reference Issue, R—160, April 30, 1976. 5. U.S. Environmental Protection Agency. Methods for Organic Pesticides in Water and Wastewater. National Environmental Research Center, Cincinnati, 1971. 6. Giger, V., N. Reinhard, C. Schaffner, and F. Zurcher. Analysis of Organic Constituents, Chapter 26 in Identification and Analysis of Organic Pollu- tants in Water (L. H. Keith, ed.), Ann Arbor Science Publishers, Ann Arbor, Michigan, 1976. pp. 433—452. 7. Reinhard, M., V. Drevenkar, and W. Giger. Chlorination cf the Aromatic Fraction of Dieselfuel. Jour. Chromatogr., 116:43, 1976. 8. Keith, L. H. (ed.). Identification and Analysis of Organic Pollutants in Water, Ann Arbor Science Publishers, Ann Arbor, Michigan, 1976. 9. Argo, D. G. Advanced Wastewater Treatment Produces a Recyclable Product. Proc. 5th Ann. md. Pollu. Control Conf., Water and Wastewater Manufac- turer Assoc., April 1977, pp. 223—254. 10. Rook, J. J. Formation of Haloforms during Chlorination of Natural Waters. Water Treatment and Examination, 23(2):234—254, 1974. 11. Stenhagen, E., S. Abrahamsson, and F. W. MacLafferty (eds.). Registry of Mass Spectral Data, John Wiley & Sons, New York, 1974. 12. Grab, K., and F. Zurcher. Stripping of Trace Organic Substances, Jour. Chromatogr., 117:285, 1976. 13. World Health Organization. European Standards for Drinking Water, 2nd ed., 1970. 64 ------- 14. Grob, K., and G. Grob. Techniques of Capillary Gas Chromatography, Jour. Chromatogr., 5:3, 1972. 15. Law, M. L. R., and D. F. Goerlitz. Microcoluinn Chromatographic Cleanup for the Analysis of Pesticides in Water, Jour. of the AOAC, 53(6):1296, 1970. 16. Schmidt, T. T., R. W. Risebrough, and F. Gress. Input of Polychiorinated Biphenyls into California Coastal Waters from Urban Sewage Outfalls, Bull. Env. Cont. & Tox., 6(3):253, 1971. 65 ------- APPENDIX A TABLE A—i. MAJOR DESIGN CRITERIA OCWD 0.66 m 3 /s ADVANCED WASTEWATER TREATNENT PLANT INFLUENT PUMP STATION Number of pumps: 32 Capacity: 0.41 in Is @ 8.8 m TDH 0.44 m 3 /s @ 8.2 in TDH Type: Vertical mixed flow CHEMICAL CLARIFICATION SYSTEM Rapid Mixing Number of basins: 2 in series Mechanical mixer in each basin Dimension: length — 3.7 in; width — 3.7 in; depth — 3.7 in Detention time: 2.4 minutes total @ 0.66 m 3 /s Chemical addition: First basin — lime, alum, recycled lime sludge Second basin — polymer Flocculation Number of basins: 2, three compartments each 3 Detention time: 10 nun/compartment (30 mm total) @ 0.66 in Is Chemical addition: Polymer, 1st and 3rd compartments Dimensions: length — 15 in; width — 12.5 in; depth — 3.4 in Flocculator mechanism: Oscillating type Settling Basins Number of basins: 2 rectangular Dimensions: 37 in long x 12 in wide, each Surface Overflow Rate: 2.7 m 3 /m 2 —hr @ 0.66 m 3 /s Each basin equipped with settling tubes Clarifier Effluent Pump Station Number of pumps: 4 Capacity: 0.21 m 3 /s @ 23 in; 0.22 m 3 /s @ 20 in Discharge: To ammonia stripping tower or to the OCSD plant or to the recarbonation basins Lime Feeders and Slakers Number: 2 gravimetric feeders and paste type slakers Capacity: 0.5 kg/s 66 ------- TABLE A—i. (continued) Polymer Feed System Number of mixing tanks: Number of feed pumps: 3 4 Capacity: 0 to 0.1 in /h 2 (4 in 3 each) dual head each head Alum Feed System Number of storage tanks: Number of feed pumps: 3 Capacity: 0.1 in 3 /h each 2 (18 m 3 each) (2 double head and 1 single head) head AMMONIA STRIPPING/COOLING TOWERS Number of towers: 2 Dimensions: length — 63 in; width Capacity: 0.33 m 3 /s each @ 0.044 Number of fans: 6 per tower, 5.5 Air Capacity: 990 m 3 /s per tower Not water streams: Tower No. 1 — Tower No. 2 — RECARBONATION — 19 in; depth of packing = 7.6 in in 3 /m 2 -min in diameter, 2 (3000 m 3 /m 3 ) 0.50 m 3 /s cool 46°C to 26°C 0.69 m 3 /s cool 50°C to 30°C Number: 2 (3 compartment basins: 1st stage recarbonation, intermediate settling, 2nd stage recarbonation) Detention Time, 1st and 2nd stage recarbonation: 15 minutes each Overflow rate, intermediate settling: 5 m 3 /m 3 —h @ 0.66 in 3 /s FILTRATION Number of filters: 4 Dimensions: 6.7 in x 7.3 in Type: open, gravity, mixed media Hydraulic loading rate: 0.2 m 3 /in 2 —min @ 0.66 m 3 /s Maximum operating head loss: 3 in Filter aids: alum and polymers Backwash system: Hydraulic with rotating surface wash arms Backwash rate — 0.6 m 3 /m 2 —Inin Surface wash rate — 0.024 m 3 /m 2 —inin Backwash water receiving tank volume: 705 in 3 ACTIVATED CARBON ADSORPTION Number of contactors: 17 Normal Service: 16 in parallel operation, 1 for carbon storage and standby service Type: Upflow, countercurrent, in steel pressure vessels Dimensions: Overall height — 12.5 in; Sidewall height — 7.3 in; Diameter — 3.7 in 3 Contact Time: 34 minutes at 0.66 in Is Carbon Size: 8 x 30 mesh Carbon Weight: 35 Mg per contactor (660 Mg total) speed electric motors 67 ------- TABLE A—i. (continued) CHLORINATION Number of contact basins: 1 In—line feeding and mixing Contact Time: 30 minutes Chlorine Feeders: 3 (900 kg/day each) On site generation of chlorine: 900 kg/day CHEMICAL SLUDGE TREATMENT AND RECOVERY SYSTEMS Sludge Pumps Number: 3 3 Capacity: 0.032 to 0.044 in /s Influent solids capability: 5% maximum Sludge Thickener Number: 1 Dimensions: 14 in diameter, 2.5 in sidewater depth Loading: 24 m 3 /rn 2 -d @ 1.5% solids from clarifier at flow of 0.66 m 3 /s dry solids loading = 15 kg/m 3 —h Thickened sludge concentration: 8 to 15% solids Thickened Sludge Pumps Number: 3 Capacity: 5 liter/rn at 18 in head each, variable speed Influent solids capability: 18% maximum Centrifuges Number: 2 Capacity: 900 kg/hour each Feed Rate: 3 to 6.6 liters/rn Recalcining Furnace Number: 1,6 hearth Dimensions: 6.8 in OD; 6.1 in ID Capacity: 0.1 to 0.5 kg/s dry CaO Scrubber: 3 stage jet impingement Fuel: natural gas with propane standby Lime Storage Bins Number: 2 Capacity: 32 Mg each Dimensions: 3.8 in diameter by 4.6 m storage depth (overall height = 8.7 in) Carbon Dioxide Compressors Number: 3 3 Capacity: 0.76 in /s (12% C0 2 ) each 68 ------- TABLE A—i. (continued) ACTIVATED CARBON REGENERATION Regeneration Furnace Number of furnaces: 1, 6 hearth Dimensions: 2.8 m OD; 2.1 m ID Capacity: 0.01 to 0.063 kg/s (dry basis) Steam Addition: No. 4 and No. 6 hearths (optional); 1 kg steam per kg carbon Air Pollution Control: Fuel: natural gas with propane standby Scrubber: Venturi followed by water separator Afterburner: Vertical, refractory lined steel, 760°C at 0.5 seconds minimum gas retention time Carbon Wash and Transfer Tanks Number: 2 Dimensions: l.5nidiameter by 3 in high Equipped with bag dump and dust collector Regenerated Carbon Wash Tanks Number: 2 Dimension: 1.5 m diameter by 3 m high Spent Carbon Dewatering Tanks Number: 2 (open top) Dimensions: 1.5 m x 1.5 m x 4.4 in high Furnace feed system: 0.3 m diameter screw conveyor, stainless steel with capacity of 0.01 to 0.063 kg/s on a dry basis Carbon Slurry Pumps (transfer carbon from regeneration furnace to carbon wash tanks) Number: Type: Diaphragm slurry, air operated, 7.6 cm suction and discharge Capacity: 0.03 m Is max. with 4:1 turndown ratio 69 ------- SCALE CHLORINATOR I NHIBITOR FEEDER PRETREATME 0 TRANSFER PUMPS ACID STORAGE TANK CLEANING TANK SOLUT ION FLUSH TANK FLUSH PUMPS CLEANING PUMPS HIGH PRESSURE FEED PUMPS BLOWER DECAR BONATOR PRODUCT PUMPS z Ill -4 0 ACID ACID ACID ACID TRANSFER DAY INJECTION DILUITON PUMPS TANK PUMPS PUMPS I Figure A—i. Reverse Osmosis Plant Flow Diagram. ------- APPENDIX B SUMMARY ANALYSES FOR GENERAL CONSTITUENTS, TRACE INORGANICS, RADIOACTIVITY AND PESTICIDES* Table Number Page B—i Summary Analyses for General Constituents, January through June 1976 72 B—2 Summary Analyses for General Constituents, October 1976 through June 1977 . 74 B—3 Summary Analyses for General Constituents, January 1976 through June 1977 (Entire Period of Study). 77 Summary Analyses for Trace Inorganics, January through June 1976 80 B—5 Summary Analyses for Trace Inorganics October 1976 through June 1977 82 B—6 Summary Analyses for Trace Inorganics, January 1976 through June 1977 (Entire Period of Study). 84 B—7 Radioactivity Analysis at Q9 . . 86 B—8 Pesticide Analyses 87 * Description of sample locations referred to in tables are as follows: Qi, Influent; Q2, Clarifier Effluent; Q4, Ammonia Tower Effluent; Q6, Filter Effluent; Q 8 , Activated—Carbon Effluent; Q9, Chlorine Contact Basin Effluent; Q21A, Reverse Osmosis Influent; and Q21B, Reverse Osmosis Effluent. 71 ------- TABLE B-i. SUMMARY ANALYSES FOR GENERAL CONSTITUENTS January through June 1976 Constituent and Parameter Location* Qi Q2 Q4 Q6 Q8 Q9 Ca, mg/i Mean 102 142 107 Std. dev. 10 29 23 Range 72—134 98—253 85—268 No. samples 90 90 87 Mg, mg/i Mean 25 1,0 Std. dev. 1.5 1.0 Range 20—29 0.1—5 No. samples 70 68 Na, mg/i Mean 209 205 Std. dev. 19 19 Range 178—284 173—261 No. samples 70 68 NU 3 —N, mg/i Mean 43 19 Std. dev. 10 5 Range 2 7—100 10—36 No. samples 84 75 Ci, mg/i Mean 231 246 Std. dev. 20 23 Range 201—311 158—306 No. samples 90 87 SO 4 , mg/i Mean 284 312 Std. dev. 45 39 Range 219—403 238—408 No. samples 90 87 Alkalinity, mg/i Mean 306 137 Std. dev. 35 26 Range 206—460 No. sampies 89 86 B, mg/i Mean 0.63 Std. dev. 0.14 Range 0.3—1.1 No. samples 85 TABLE B-i continued 72 ------- TABLE B—i (continued) Constituent and Parameter Location* — Qi Q2 Q 4 Q6 Q8 Q9 F, mg/i Mean 0.64 Std. dev. 0.16 Range 0.3—1 No. samples 86 P0 4 —P, mg/i Mean 5.2 0.09 Std. dev. 1.2 0.17 Range 0—8 0.00—1.3 No. samples 90 90 EC, pS/cm Mean 1870 1470 Std. dev. 160 130 Range 1270—254( 980—1820 No. samples 85 82 pH Mean 7.6 11.4 6.7 Std. dev. 0.1 0.1 0.15 Range 7.4—8.1 11.2—11.7 6.3—7.2 No. samples 87 87 83 Turbidity, TIJ Mean 24 1.9 0.85 Std. dev. 8 1.6 0.38 Range 0—45 0—13 0—3 No. samples 89 89 86 COD, mg/i Mean 108 53 45 13 Std. dev. 16 7 7 8 Range 78—144 23—69 25—67 2—52 No. samples 78 80 87 238 TOC, mg/i Mean 15 7.3 Std. dev. 4 2.6 Range 8—31 3.5—20 No. samples 82 238 Org—N, mg/i Mean 1.6 1.1 0.6 Std. dev. 0.8 0.8 0.4 Range 0.5—5.3 0.2—4.8 0.2—2.6 No. samples 86 86 80 * Sample Locations: Qi, Influent; Q2, Clarifier Effluent; Q 4 , Ammonia Tower Effluent; Q6, Filter Effluent; Q8, Activated—Carbon Effluent; and Q9, Chlorine Contact Basin Effluent. 73 ------- TAILE B—2. STM(ARY ANALYSES FOR GENERAL CONSTITUENTS October 1976 through June 1977 Constituent and Parameter Location* _______ Qi Q2 Q6 Q8 Q9 Q21A Q21B Ca, lug/i Mean 110 Std. dev. 22 Range 59—148 No. samples 37 Mg, mg/i Mean 24 0.2 Std. dev. 2 0.1 Range 20—28 0.1—0.2 No. samples 34 35 Na, mg/i Mean 218 210 14 Std. dev. 31 27 6 Range 165—264 81—263 8—27 No. samples 34 113 114 NH 3 —N, mg/i Mean 45 37 3.3 Std. dev. 15 12 2.9 Range 18—138 13—85 0.0—14 No. samples 153 153 152 Cl, mg/i Mean 258 277 18 Std. dev. 82 37 6 Range 191—737 179—523 10—42 No. samples 35 119 120 SO 4 , mg/i Mean 248 1 Std. dev. 63 2 Range 150—500 <1—22 Alkalinity, mg/i CaCO 3 Mean 116 Std. dev. 49 Range 27—330 No. samples 156 B, mg/i Mean 1.0 0.84 Std. dev. 0.2 0.21 Range 0.7—1.8 0.1—1.6 No. samples 34 34 TABLE B—2 continued 74 ------- TABLE B—2 (continued) Constituent and Parameter- Location * Qi Q2 Q8 Q9 Q21A Q21B F, mg/i Mean Std. dev. Range No. samples P0 4 —P, iug/l Mean 5.6 0.07 Std. dev. 0.8 0.04 Range 4—9 0.00—0.25 No. samples 156 155 TDS, mg/i Mean 1020 Std. dev. 100 Range 860—126( No. samples 51 EC, US/cm Mean 1850 2070 1530 88 Std. dev. 280 240 200 36 Range 230—270( 1500—3100 620—l95( 37—230 No. samples 177 179 108 118 pH Mean 7.5 11.5 Std. dev. 0.2 0.2 Range 6.5—7.9 11.6—11.9 No. samples 165 183 Turbidity, TU Mean 42 1.1 Std. dev. 14 0.5 Range 19—95 0.1—4 No. samples 161 115 COD, mg/i Mean 142 52 18 24 1.8 Std. dev. 37 11 7 7 14 15 Range 89—272 109—160 31—78 4—51 4—69 <1—9 No. samples 160 160 160 159 118 .119 TOC, mg/i Mean 13.8 6.7 Std. dev. 2.9 2.2 Range 0.5—28 2.5—14 No. samples 111 117 TABLE B-2 continued 75 ------- TABLE B—2 (continued) Constituent and Parameter Location * Qi Q2 Q6 Q8 Q9 Q21A Q21B Org—N, rag/i Mean 8.3 3.9 1.26 Std. dev. 2.0 1.5 0.48 . Range 5—23 1.7—10 0.0—3.8 No. samples 157 157 156 Phenol, ig/l Mean Std. dev. Range No. samples CN, Mean Std. dev. Range No. samples MBAS, rag/i Mean Std. dev. Range No. samples * Sample Locations: Qi, Influent; Q2, Clarifier Effluent; Q6, Filter Ef flu- ent; Q8, Activated—Carbon Effluent; Q9, Chlorine Contact Basin Effluent; Q21A, Reverse Osmosis Influent; and Q21B, Reverse Osmosis Effluent. 76 ------- TABLE B-3. SUMMARY ANALYSES FOR GENERAL CONSTITUENTS January 1976 through June 1977 (Entire Period of Study) Constituent and Parameter Location* Qi Q2 Q4 Q6 Q8 Ca, mg/i Mean 104 Std. dev. 15 Range 59—148 No. Samples 127 Mg, mg/i Mean 25 0.7 Std. dev. 1.7 0.9 Range 20—29 0.1—5 No. samples 104 103 Na, mg/i Mean 212 Std. dev. 24 Range 165—284 No. samples 104 NH 3 —N, mg/i Mean 39 Std. dev. 12 Range 13—100 No. samples 237 Cl, mg/i Mean 239 Std. dev. 48 Range 191—737 No. samples 125 SO 4 , mg/i Mean Std. dev. Range No. samples Aikalinity, mg/i Mean Std. dev. Range No. samples B, mg/i Mean Std. dev. Range No. samples TABLE B-3 continued 77 ------- TABLE B—3 (continued) Constituent and Parameter Location * Qi Q2 Q4 Q6 Q8 F, mg/i Mean Std. dev. Range No. samples P0 4 —P, mg/i Mean Std. dev. Range No. samples TDS, mg/i Mean Std. dev. Range No. samples EC, iS/cm Mean Std. dev. Range No. samples pH Mean Std. dev. Range No. samples Turbidity, TIJ Mean Std. dev. Range No. samples COD, mg/i Mean Std. dev. Range No. samples TOC, mg/i Mean Std. dev. Range No. samples 515 1.0 0—9 246 1860 250 1230—2700 262 7.5 0.2 6.5—8.1 252 36 15 0—95 250 131 35 78—272 238 0.08 0.11 0.0—1.3 245 11.5 0.2 11.2—11.7 270 1.4 1.2 0—13 204 52 10 20—109 240 45 7 25—78 247 14 3 0.5—31 193 15 8 2—52 397 7.1 2.5 2.5—20 355 TABLE B-3 continued 78 ------- TABLE B—3 (continued) Constituent and Parameter Location * Ql Q2 Q4 Q6 Q8 Org—N, mg/i Mean 5.9 2.9 Std. dev. 3.6 1.9 Range 0.5—23 0.2—10 No. samples 243 243 Phenol, pg/i Mean Std. dev. Range No. samples CN Mean Std. dev. Range No. samples MBAS, mg/i Mean Std. dev. Range No. samples * Sample Locations: Qi, Influent; Q2, Clarifier Effluent; Q4, Ammonia Tower Effluent; Q6, Filter Effluent; and Q8, Activated—Carbon Effluent. 79 ------- TABLE B-4. SUMMARY ANALYSES FOR TRACE INORGANICS January through June 1976 Constituent and Parameter Location* Qi Q2 Q6 Q8 As, pg/i Mean 2.5 1.1 1.1 1.1 Std. dev. 1.1 0.7 0.4 0.3 Range 1—5.5 0—2.8 0.7—2.8 0.5—2.5 No. samples 74 74 71 76 Ba, pg/i Mean 81 41 32 33 Std. dev. 21 22 22 23 Range 33—134 20—120 8—93 11—97 No. samples 74 74 71 76 Cd, pg/i Mean 9 2.9 2.5 2.2 Std. dev. 6 1.7 1.6 1.8 Range 4—30 0.7—10 0.7—8 0.6—7.8 No. samples 74 74 71 76 Cr, pg/i Mean 192 88 84 48 Std. dev. 86 51 45 32 Range 76—582 16—289 16—228 3—128 No. samples 74 74 71 76 Cu, pg/i Mean 285 93 88 27 Std. dev. 67 28 24 14 Range 152—436 29—172 32—164 5—80 No. samples 74 74 71 76 Fe, pg/i Mean 179 17 40 45 Std. dev. 68 ii 25 67 Range 58—398 6—53 15—185 18—309 No. samples 74 74 71 76 Ebb, pg/i Mean 40 23 22 26 Std. dev. 77 39 31 32 Range 10—650 6—359 6—213 6—174 No. samples 74 74 71 76 In, pg/i Mean 35 1.5 2.3 4.1 Std. dev. 10 1.5 1.1 1.4 Range 14—75 0.3—9 0.6—9 1.5—9 No. samples 74 74 71 76 TABLE B—4 continued 80 ------- TABLE B-4 (continued) Constituent and Parameter Lo cation* Q2 Q6 Q8 Hg, Pg/i Mean 1.2 0.9 1.2 4.9 Std. dev. 3.4 2.2 3.2 21 Range No. samples 0.1—20 54 0.1—15 54 0.1—16 51 0.2—168 56 Se, pg/i Mean 6.2 6.5 6.3 6.4 Std. dev. 2.9 3.5 3.3 3.5 Range No. samples 2—13 74 2—17 74 2—14 72 2—22 76 Ag, pg/i Mean 13 8 12 14 Std. dev. 52 33 64 58 Range 2—423 1—234 0.3—516 0.0—457 No. samples 57 57 54 59 Zn, pg/i Mean 300 29 670 124 Std. dev. 210 84 320 72 Range No. samples 140—1930 74 5—740 74 150—2400 71 12—536 76 * Sample Locations: Qi, Infiuent; Q2, Clarifier Effluent; Q6, Filter Ef— fluent; and Q8, Activated—Carbon Effluent. 81 ------- TABLE B—5. SUMMARY ANALYSES FOR TRACE INORGANICS October 1976 through June 1977 * Constituent Location and Parameter . Qi Q2 Q6 Q8 As, pg/i Mean 3.3 2.5 1.8 2.4 Std. dev. 1.2 1.7 1.2 1.8 Range 1.5—5.0 0.0—5.0 0.0—5.0 0.0—5.0 No. samples 27 27 27 27 Ba, pg/i Mean 81 36 31 31 Std. day. 26 21 19 22 Range 40—177 15—114 10—97 12—114 No. samples 26 26 26 26 Cd, jig/i Mean 29 2.4 1.8 1.7 Std. dev. 16 1.6 1.0 1.7 Range 12—97 0.3—8.4 0.3—5.4 0.3—9.8 No. samples 32 32 32 32 Cr, jig/i Mean 154 37 41 26 Std. dev. 76 25 39 24 Range 62—490 9—111 8—219 4—112 No. samples 33 33 33 33 Cu, pg/i Mean 266 73 49 32 Std. dev. 87 25 34 15 Range 130—470 19—112 3—114 6—69 No. samples 27 27 27 27 Fe, pg/i Mean 325 40 207 66 Std. dev. 156 45 275 77 Range 51—779 4—216 12—1520 12—449 No. samples 33 33 33 33 Pb, pg/i Mean 19 3.6 8.0 5.3 Std. dev. ii. 2.5 15.5 12.5 Range 3—62 0.6—11 0.2—71 0.1—72 No. samples 26 26 26 27 Mn, pg/i Mean 35 4.4 6.2 4.9 Std. dev. 13 9.2 7.5 4.4 Range 9—98 0.2—45 0.3—34 0.3—26 No. samples 33 33 33 33 TABLE B—S continued 82 ------- TABLE B—5 (continued) Constituent and Parameter Location * Qi Q2 Q6 Q8 Hg, pg/i Mean 9 2.6 3.6 6.7 Std. dev. 30 2.0 7.7 13.8 Range 0.1—177 0.7—11 0.6—46 0.3—57 No. samples 26 20 26 13 Se, pg/i Mean <2.5 <2.5 <2.5 <2.5 Std. dev. Range <2.5 <2.5 <2.5 <2.5 No. samples 30 33 33 33 Ag, pg/i Mean 5.5 0.8 13 1.5 Std. dev. 1.4 0.6 1.6 2.8 Range 1.8—8 0.1—2.3 0.0—7.2 0.0—15 No. samples 21 16 21 21 Zn, pg/i Mean 380 239 412 162 Std. dev. 130 105 328 78 Range 130—830 20—512 70—1980 20—304 No. samples 27 17 27 23 * Sample Locations: Ql, Influent; Q2, Clarifier Effluent; Q6, Filter Ef- fluent; and Q8, Activated—Carbon Effluent. 83 ------- TABLE B—6. SUMMARY ANALYSES FOR TRACE ENORGANICS January 1976 through June 1977 (Entire Period of Study) Constituent and Paran ter Location* Qi Q2 Q4 Q6 Q8 As, pg/i Mean 2.7 1.5 1.3 1.4 Std. dev. 1.2 1.2 0.8 1.1 Range 1—5.5 0.0—5 0.0—5 0.0—5 No. samples 101 101 98 103 Ba, pg/i Mean 81 40 32 32 Std. dev. 22 22 21 23 Range 33—177 15—120 8—97 11—114 No. samples 100 100 97 102 Cd, pg/i Mean 15 2.7 2.3 2.1 Std. dev. 14 1.7 1.5 1.8 Range 4—97 0.3—10 0.3—8 0.3—9.8 No. samples 106 106 103 108 Cr, pg/i Mean 180 72 70 41 Std. dev. 85 50 47 31 Range 62—582 9—289 8—228 3—128 No. samples 107 107 104 109 Cu, pg/i Mean 280 88 77 28 Std. dev. 73 29 32 14 Range 130—470 19—172 3—164 5—80 No. samples 101 101 98 103 Fe, pg/i Mean 224 24 93 121 Std. dev. 123 28 173 79 Range 51—779 4—216 12—1520 12—449 No. samples 107 107 104 109 Pb, pg/i Mean 35 18 18 21 Std. dev. 67 35 28 30 Range 3—650 1—359 0.2—213 0.1—174 No. samples 100 100 97 103 Mn, pg/i Mean 35 2.4 3.5 4.3 Std. dev. ii 5.4 4.7 2.7 Range 9—98 0.2—4.5 0.3—34 0.3—26 No. samples 107 107 104 109 TABLE B-6 continued 84 ------- TABLE B—6 (continu’ d) Constituent and Parameter . * Location Q2 Q4 Q6 Q 8 Hg, pg/i Mean 4 1.2 2.0 5 Std. dev. 17 2.3 5.2 20 Range 0.1—177 0.1—15 0.1—46 0.2—168 No. samples 80 74 77 69 Se, pg/i Mean 5 5 5 5 Std.dev. 3 3 3 3 Range <2—13 <2—17 <2—14 <2—22 No. samples 104 107 105 109 Ag, pg/i Mean 11 6 9 10 Std. dev. 44 29 54 50 Range 2—423 0.1—234 0—516 0—457 No. samples 78 73 75 80 Zn, pg/i Mean 321 68 600 133 Std. dev. 195 120 340 75 Range 130—193( 5—740 50—2400 12—536 No. samples 101 91 98 99 * Sample Locations: Qi, Influent; Q2, Clarifier Effluent; Q4, Ammonia Tower Effluent; Q6, Filter Effluent; and Q8, Activated—Carbon Effluent. 85 ------- TABLE B-7. RADIOACTIVITY ANALYSIS OF EFFLUENT (Q9) Sample Date Gross Alpha Activity pci/i Gross Beta Activity pCi/i Jan. 31, 1976 0.6 ± 1.5 28 ± 8 Feb. 5 0.0 ± 1.2 28 ± 8 Feb. 9 0.6 ± 1.9 25 ± 11 Feb. 26 0.3 ± 1.3 22 ± 10 Mar. 4 0.0 ± 1.8 20 ± 10 Mar. 11 0.0 ± 1.6 22 ± 10 Apr. 15 0.0 ± 0.5 29 ± 9 Apr. 22 0.1 ± 1.0 20 ± 9 Apr. 29 0.0 ± 0.4 28 ± 10 May6 0.5±0.9 41±10 May13 0.0±0.8 40±11 May20 0.1±0.9 42±11 June3 0.0±0.5 31±11 June17 0.7±2.0 38±11 June24 2.2±1.8 23±11 Julyl 0.0±0.5 44±11 July15 0.6±1.0 50±9 July 22 0.1 ± 0.8 51 ± 10 Oct. 14 0.0 ± 1.8 49 ± 19 Oct. 21 0.0 ± 2.0 63 ± 20 86 ------- TABLE B—8. PESTICIDE ANALYSES Pesticides Evaluated and Concentration Limit: Concentration above which pesticide not found in any Pesticide sample, pg/i BHC 0.01 Lindane 0.01 Heptachior 0.01 Aidrin 0.01 DDE 0.01 Dieidrin 0.01 Endrin 0.01 DDT 0.1 Methoxychior 0.1 Number and Location of Samples Analyzed for Pesticides: Sampling Period Qi Q2 Q6 Q9 January through June 1976 3 1 9 October 1976 through June 1977 10 10 8 19 87 ------- TECHNICAL REPORT DATA (Flease read Jias.tructions on the reverse before completing) 1. REPORT NO. 2. EPA—600/2—78—076 3. REcIPIENT’S ACCESSIO #NO. 4. TITLE AND SUBTITLE WATER FACTORY 21: RECLAIMED WATER, VOLATILE ORGANICS, VIRUS, AND TREATMENT PERFORMANCE 5. REPORT DATE June 1978 (Issuing Date) 6. PERFORMING ORGANIZATION CODE 7. AUTHOR(S) Perry L. McCarty, Martin Reinhard, Carla Dolce, Huong_Nguyen,_and_David_G._Argo 8. PERFORMING ORGANIZATION REPORT NO. 9. PERFORMING ORGANIZATION NAME AND ADDRESS Department of Civil Engineering Stanford University Stanford, California 94305 10. PROGRAM ELEMENT NO. 1BC611 1L O OIITnAOT/GRANTNO. EPA—S—803873 12. SPONSORING AGENCY NAME AND ADDRESS Municipal Environmental Research Laboratory-—Cin.,OH Office of Research and Development US. Environmental Protection Agency cincinnati, Ohio 45268 13. TYPE OF REPORT AND PERIOD COVERED Pre—final 1—76 to 6—77 14,SPONSORING AGENCY CODE EPA—600—14 15. SUPPLEMENTARY NOTES Project Officer: John N. English 513/684—7613 16.ABSTKACT This report describes the performance of Water Factory 21, a 0.66 m 3 /s advanced wastewater treatment plant designed to reclaim secondary effluent from a municipal wastewater treatment plant so that it can be used for injection and recharge of a groundwater system. Included in this evaluation of the first one and one—half years of performance are summary data for general inorganics, heavy metals, virus, and a broad range of organic materials. Processes included in the plant are lime treatment, ammonia stripping, breakpoint chlorination, filtration, activated—carbon adsorption, reverse osmosis, and final chlorination. The performance of individual processes as well as overall efficiency was evaluated. 17. KEY WORDS AND DOCUMENT ANALYSIS DESCRIPTORS b.IDENTIEIERS/OPEN ENDED TERMS C. COSATI Field/Group Waste Treatment Treatment Water Reclamation Nutrients Viruses Organic Compounds Potable Water Microorganisms Reuse Heavy Metals Haloforms Trihalomethanes Advanced Was tewater 13B 18. DISTRIBUTION STATEMENT RELEASE TO PUBLIC 19. SECURITY CLASS (This Report) UNCLASSIFIED 21. NO. OF PAGES 100 20. SECURITY CLASS (This page) UNCLASSIFIED 22. PRICE EPA Form 2220-1 (9.73) 88 . U. S. G0V RNEIIT P INTIN 0FFICE 1978—757—140/1345 Regon No. 5-I l ------- |