EPA-600/2-78-027 March 1978 Environmental Protection Technology Series WASTEWATER TREATMENT FOR REUSE AND ITS CONTRIBUTION TO WATER SUPPLIES Municipal Environmental Research Laboratory Office of Research and Development U.S. Environmental Protection Agency Cincinnati, Ohio 45268 ------- EPA-600/2-78-027 March 1978 WASTEWATER TREATMENT FOR REUSE AND ITS CONTRIBUTION TO WATER SUPPLIES by Howard P. Warner John N. English EPA-DC Pilot Plant Washington, D.C. 20032 Contract No. 68-03-0344 Project Officer Irwin J. Kugelman 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 ------- DISCLAIMER This report has been reviewed by the Municipal Environmental Research Laboratory, U. S. Environmental Protection Agency, and approved for publication. Approval does not signify that the contents necessarily reflect the views and policies of the U. S. Environmental Protection Agency, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. 11 ------- FOREWORD The Environmental Protection Agency was created because of increasing public and governmentconcern 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 solution and it involves defining the problem, measuring its impact, and searching for solutions. The Municipal Environmental Research Laboratory develops new and improved technology and systems for the prevention, treat- ment, 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 publi- cation is one of the projects of that research; a most vital communications link between the researcher and the user community. The study summarized in this report evaluates a combined biological/ physical-chemical pilot treatment system designed to produce a high quality reusable water. Process reliability is established and effluent constituents are related to similar materials identified in finished drinking waters. Francis T. Mayo Director Municipal Environmental Research Laboratory iii ------- ABSTRACT An 18 month study using cost effective municipal wastewater treatment technology coupled with a computerized data handling system, was conducted at the EPA/Washington, D.C. Blue Plains Pilot Plant to obtain data on the safety of the effluent for discharge upstream of drinking water intakes, and for potential domestic reuse purposes. Treatment reliability was demonstrated and performance results showed the absence of virus in the effluent. Effluent concentrations of radioactivity, trihalomethanes and other volatile organics, heavy metals, pesticides, TOC, turbidity, general inorganic compounds, and pathogenic indicator organisms were shown to be similar to those found in finished drinking waters during the EPA National Organics Reconnaissance Survey in 1975. The specific organic compounds identified in the effluent are also present in finished drinking waters. Effluent organic concentrates did not exhibit mutagenic properties, and results of an 80 element survey did not detect the presence of significant quantities of any hazardous inorganic material. Effluent endotoxin levels were comparable to levels in public drinking water supplies. This report was submitted in partial fulfillment of contract No. 68-03-0344 by the District of Columbia Pilot Plant under the sponsorship of the U.S. Environmental Protection Agency. This report covers the period from April 1975 to September 1976. iv ------- CONTENTS Foreword iii Abstract iv Figures vi Tables vii Acknowledgements viii 1. Introduction 1 2. Conclusions 3 3. Description of Treatment System 4 4. Performance 8 Virus 8 Radioactivity 8 Volatile Organics 9 Toxicity Screening 9 Metals 9 Pesticides 21 General Organics 21 General Inorganics • 27 Nutrients 27 Suspended Matter 27 Microbiological and Disinfection Parameters 27 Esthetic Parameters 38 5. References 40 ------- FIGURES Number Page 1 Schematic flow Diagram 5 2 Removal of Volatile Organics 13 3 Frequency Distribution of effluent mercury 20 4 Frequency distribution of effluent TOG 26 5 Removal of TOC 28 6 Frequency distribution of effluent COD 30 7 Frequency distribution of effluent turbidity 36 vi ------- TABLES Number 1 Design Data and Operating Conditions 5 2 Virus 9 3 Radioactivity 10 4 Volatile Organics 12 5 Volatile Organics in Process Effluents 14 6 Mutagenicity of Organic Concentrates 16 7 Results of Bacterial Endotoxin Testing 17 8 Heavy Metals 18 9 Heavy Metal Removal by Lime Clarification 22 10 Pesticides 23 11 General Organics 24 12 Variability of Effluent TOC 25 13 Variability of Effluent COD 29 14 General Inorganics 31 15 Results of 80 Element Survey 32 16 Nutrients 33 17 Suspended Matter 34 18 Variability of Effluent Turbidity 35 19 Microbiological and Disinfection Parameters 37 20 Esthetics 39 vii ------- ACKNOWLEDGMENTS A project of this magnitude, which covers 18 months of pilot plant operations, could not have been accomplished without the assistance of the entire EPA-DC Pilot Plant staff. Mr. Paul Ragsdale supervised the mechanics and instrumentation personnel. Mr. Calvin Taylor served as chief operator. Laboratory analyses were performed under the direction of Mr. David Rubis. The efforts of all the D.C. mechanics, technicians, crew chiefs, operators and laboratory personnel are gratefully acknowledged. Mr. Thomas A. Pressley and Ms. Stephanie G. Roan, On-site EPA staff, performed the detailed organic identification work and virus analyses were conducted by the Cincinnati EPA Virology Laboratory under the direction of Mr. Daniel R. Dahling. Special thanks are due Mr. Thomas P. O'Farrell, past Pilot Plant Chief, for his efforts in the early stages of the project which enabled a timely completion of fabrication of the treatment system. viii ------- SECTION 1 INTRODUCTION We are living in a Nation where millions of people are presently reusing wastewater indirectly for domestic purposes. Severe contamination of many surface supplies has occurred, as evidenced by the identification of carcinogenic organic materials in finished drinking waters, and increasing instances of groundwater contamination are being found. There is a concern on the part of health agencies in areas that use surface supplies for domestic purposes as to the potential hazards of the present covert reuse of waste- water discharged upstream of drinking water intakes. Since the typical wastewater treatment plant does not remove all of the contaminants from the wastewater there is a basis for this concern, and thus a need to know the appropriate levels of municipal treatment to ensure the safety of water supply intakes in the vicinity of the discharges. The concerns of health agencies where covert reuse is prevalent are also receiving attention by health agencies in the more arid areas of the U.S. where water utilities are proposing the overt domestic reuse of wastewater to supplement depleted groundwater supplies and unreliable surface sources. Concerns about both covert and overt reuse are the same since the problems and the research data required to solve the problems are the same. The questions that need answers are: 0 • What are the health effects of the covert/overt reuse of wastewater? • What technology is needed to remove potential hazardous materials? The Environmental Protection Agency (EPA) through its Municipal Environmental Research Laboratory (MERL) in Cincinnati, Ohio is addressing the technology question by characterizing the ability of municipal waste- water treatment systems to remove pollutants of health concern and providing knowledge of treatment system performance variability and reliability. A combined biological/physical-chemical treatment system designed to produce a high quality reusable water has been in operation at MERL's Washington, D.C. Pilot Plant for 18 months as*part of a project that had the following objectives: ------- Identification of specific pollutants in the final effluent and evaluation of the performance of the individual pro- cesses in removing these pollutants. Provide data on process and system performance variability and reliability with respect to pollutant removals. ------- SECTION 2 CONCLUSIONS Performance results showed the absence of virus in the effluent, and concentrations of radioactivity, trihalomethanes and other violatile organics, heavy metals, pesticides, TOC, turbidity, and microbiological parameters similar to those found in finished drinking waters during the EPA National Organics Reconnaissance Survey in 1975. The specific organic compounds identified in the effluent are also present in finished drinking waters. Effluent organic concentrates did not exhibit mutagenic properties and results of an 80 element survey did not detect the presence of significant quantities of any hazardous inorganic material. Effluent endotoxin levels were compara- ble to levels in public drinking water supplies. Treatment reliability was demonstrated as evidenced by the frequency distribution of the day to day concentrations of chemical, physical, and biological materials remaining in the effluent. In full scale facilities employing similar treatment processes and located upstream of drinking water intakes, or designed for domestic reuse purposes, reliability can be further enhanced by in-plant storage facilities to provide flexibility, process control instrumentation, and dedicated operating personnel. In planned reuse situations where a monetary value is set on the water, or where enforced legal restraints are placed on effluent quality reliability will become very good. ------- SECTION 3 DESCRIPTION OF TREATMENT SYSTEM The treatment system was located on the grounds of the Washington, D.C. Blue Plains wastewater treatment facility and was supervised by MERL staff and operated in cooperation with the Washington, D.C. Department of Environ- mental Services. The system treated degritted D.C. municipal wastewater using a screening device to remove coarse materials, lime clarification, dispersed growth nitrification, fixed film denitrification, carbon adsorption, dual media filtration, and chlorination for disinfection. This sequence of processes was chosen because of past experience with the performance of the individual processes and compatibility of the unit processes when combined into a treatment system that could produce a reusable high quality water from municipal wastewater. Also, a similar treatment system was identified at a workshop on "Research Needs for the Potable Reuse of Municipal Wastewater" ' ' as one of four treatment systems that had potential as a cost-effective treatment for potable reuse. A schematic flow diagram of the treatment system is presented in Figure 1 and the design and operating conditions are summarized in Table 1. The system operates continuously at 35 gpm (2.2 1/s). The backwash water from the denitrification, carbon adsorption, and filtration processes are returned to the influent of the lime clarification processes. A portion of the sludges from the lime clarification and nitrification processes are wasted to maintain process equilibrium. The treatment system was operated on a continuous basis with operators assigned to three, 8 hour shifts each day. Samples were taken manually by the operators and composited in refrigerated containers as required. Twenty-four hour composites were taken 5 days per week and no sampling was done between Friday 8 a.m. and Sunday 8 a.m. Other types of sampling were also done manually by the operators as required. Establishing the reliability of any treatment system requires a long- term program of routine monitoring of the system performance. A mass of valuable data was obtained as a result of this program and an efficient computerized data storage and retrieval system was developed to sort large quantities of data per month from 37 performance or process monitoring stations. The data storage and retrieval system was designed for use on the EPA UNIVAC 1110 Computer located at EPA Research Triangle Park in North Carolina. All the programs run in batch or demand mode. The system is modular in design to allow the addition and modification of programs without affecting the system integrity. Data is entered into and withdrawn from the computer using a terminal hookup. Statistical reports, data listing, as well as data plots can be obtained as required by project personnel to aid in establishing the system performance credibility. ------- HO tt" BACKWASH TANK S = LIME CLARIFICATION ST°RAGE METHANOL — 18 19 f H5 18 *— i i __! !H9 N Y DRAIN AO NITRIFICATION M A2 A3 A4 1 A6 BACKWASH WATER FROM: DENITRIFICATION COLUMNS, CARBON COLUMNS, AND FILTERS WASTE f WASTE POLYMER KO ii!. d 1 ^ 12 _i -}| 13 f 17 j J 1 J2 J3 DENITRIFICATION CARBON ADSORPTION } 4 1 7 _l V K1 I K3 1 K FILTRATION HOLDING TANK K7 CHLORINE CONTACT TANK CHLORINATION L7 FIGURE 1. SCHEMATIC FLOW DIAGRAM FINAL EFFLUENT ------- TABLE 1. DESIGN DATA AND OPERATING CONDITIONS PARAMETER VALUE Raw Wastewater (Constant Flow) Screening Device Type Size of Openings Lime Clarification Lime Dosage (pH 10.0)(as CaO) FeCl_ Dosage (as Fe) Hydraulic Loading Rate Detention Time Sludge Wasting Rate Percent Solids in Waste Sludge Nitrification (Suspended Growth) Detention Time MLSS SRT Air Requirement Clarifier Overflow Rate and Detention Time Denitrification (Fixed Film) Media Size Specific Surface Area Hydraulic Loading Rate Methanol/N03-N Ratio 35 gpm (2.2 x 10"3m3/s) Bauer Hydrasive Model 552 0.040 in. (1.02 mm) 200 mg/1 15 mg/1 1050 gpd/sq.ft. (42.8m3/m2d) 2.7 hr. 2% to 3% 1.5% to 2.0% 3.5 hr. 2000 mg/1 8 day 1450 cu.ft./lb BOD (90.6m3/k ) o 526 gpd/sq.ft. (21.4m3/m2d) 2-3.6 hr. 3 to 6 mm 245 sq.ft./cu.ft. (QOOm2^3^ 5.9 gpm/sq.ft. (4.1 l/m2s) 2:1 to 4:1 ------- TABLE 1 (cont'd) PARAMETER VALUE Bed Depth Detention Time (Empty Bed) Operation Granular Carbon Adsorption Detention Time (Empty Bed) Hydraulic Loading Rate Columns in Series Carbon Size (Filtrasorb 300) Operation Filtration with Alum and Polymer Hydraulic Loading Rate Dual Media Coal 1.2-1.4 mm Sand 0.6-0.7 mm Alum Disinfection with Chlorine Detention Time Residual 15 ft. (4.6 m) 9.5 min. Downflow Packed Bed 35 min. 7 gpm/sq.ft. (4.8 l/m2s) 4 8 x 30 Mesh Downflow Packed Bed 3 gpm/sq.ft. (2.04 l/m2s) 2.0 ft. (0.61 m) 1.0 ft. (0.30 m) 5 mg/1 20 min. 1 mg/1 Free Available ------- SECTION 4 PERFORMANCE VIRUS Virus in wastewater effluents are of concern to health agencies dealing with the use of contaminated surface drinking water supplies and proposed domestic reuse situations. For this reason it is important that virus analyses be included in any reuse technology monitoring program. Virus and other patho- gens were monitored at various points in the treatment system on three occasions over a three month period using methods described by Rao, V.C., et al C2)and Wallace, C., et al<3>. Samples of the raw sewage, finished effluent, and dual media filtration effluent were taken during the first sampling period. As shown in Table 2 animal viruses in raw sewage samples ranged from about 7000 to more than 17,000 PFU/100 gal (1,850-4,500 PFU/100 1). No animal viruses were observed in the dual media filtration effluent before chlorination, or the finished effluent following concentration of 100-150 gal (379-568 1) of each effluent. During the second and third months samples of the raw sewage, finished effluent and effluent from the nitrifying activated sludge were taken. Animal viruses in the raw sewage from 17,000 to 68,000 PFU/100 gal (4,500-18,000 PFU/100 1) and from 28,000 to 68,000 PFU/100 gal (7,400-18,000 PFU/100 1). Animal viruses were not detected in the final effluent in either sampling period. A total of 7 samples were concentrated during these periods ranging in volume from 50 to 238 gal (190-900 1). During the last two sampling periods, effluent from the nitrifying sludge system was tested on five occasions following concentration of 40 to 160 gal (151-605 1) of each system. In this phase of treatment, animal viruses still could not be detected. Assays were carried out on solids remaining on prefilters used for clarifying both the nitrification and final effluents. Viable animal viruses could not be detected after processing these solids. RADIOACTIVITY Samples of effluent were periodically taken for gross beta and gross alpha analyses and the results are summarized in Table 3. These levels are well below the maximum contaminant level set forth in the EPA Interim Primary Drinking Water Regulations ^' for radioactivity and they are comparable to those reported in finished drinking water supplies 8 ------- TABLE 2. VIRUS Sampling Period 1 2 *t o Animal Virus pfu/100 liters Influent 1,850 - 4,500 4,500 - 18,000 7,400 - 18,000 PROCESS Nitrification - N.D. N.D. Filtration N.D. - - Chlorination N.D. N.D. N.D. Sample Volumes - 189 liters to 900 liters N.D. - None Detected ------- TABLE 3. RADIOACTIVITY Sampling Period 1 2 3 4 Average in Drinking Water* Effluent Values pci/1 Gross Alpha < 0.3 < 0.5 < 0.5 < 0.5 5.5 Gross 7.9 + 8.1 t 7.4 + 5.0 + 2.9 Beta 0.9 0.9 0.9 0.9 ''Summary of Interstate Carrier Water Supply Radionuclide Data "Preliminary Assessment of' Suspected Carcinogens in Drinking Water" EPA, December 1975. .10 ------- VOLATILE ORGANICS Four trihalomethanes, carbon tetrachloride, and 1, 2 - dichloroethane were determined in the influent and effluent from individual processes on a twice per month basis to determine the effectiveness of the treatment system in removing these materials. A summary of the influent and effluent concen- trations of the compounds compared to the range of concentrations found in finished drinking water supplies is included in Table 4. Figure 2 shows the variation of the volatile organics through each process. Although the concentrations are quite low there is definite indication that chlorination increases the quantities of each of the six compounds. Table 5 shows the results of analyses of other volatile organics in the pilot plant influent and in the effluent from various unit processes. The types of compounds and their corresponding concentrations are similar to those present in finished drinking water supplies (•*' > Blanks in the tables indicate the compounds were below the detection limit of the GC/MS technique used (6)__ TOXICITY SCREENING Organic materials were concentrated from 500 gal (1,900 1) samples of effluent using a reverse osmosis technique that employed cellulose acetate and nylon membranes in series (''. The concentrate from each type membrane was extracted with pentane or methylene chloride at acidic (pH 2) and neutral (pH 7) conditions. The separate extracts and a composite of the extracts were tested for mutagenicity using the Ames procedure (Q) that utilizes iri vitro microbiological assays with strains of Salmonella Typhimurium TA 98 and TA 100. No mutagenicity was detected as shown by the data in Table 6. Table 7 shows the results of bacterial endotoxin tests on effluent samples as compared to similar data from ten public drinking water systems. These results were reported by Jorgensen, J.H., et al ^ from studies in which they used a Limulus assay technique for the detection of bacterial endotoxins. The concentration of endotoxins in the Blue Plains effluent is comparable to the concentrations in public drinking waters. METALS Data on the metals present in the influent and effluent are presented in Table 8 along with a list of the concentrations present in the Washington, D.C. drinking water, and the levels allowed in finished drinking water supplies as contained in the "EPA National Interim Primary Drinking Water Regulations", December 1975 ^ . None of the effluent samples taken exceeded metal concentrations cited in the EPA regulations. The reliability of the treatment system to meet these regulations is further demonstrated by the frequency distribution of effluent mercury for the second four month period of operation as shown in Figure 3. All twenty two of the data values were less than the 2 yg/1 standard. The median value was 0.70 yg/1. 11 ------- TABLE 4. VOLATILE ORGANICS COMPOUNDS (All Units Vg/1) Chloroform Bromodi- chloro- methane Dibromo- chloro- methane Bromoform Carbon Tet: chloride 1,2-Dichlo ethane INFLUENT NUMBER OF SAMPLES 14 14 14 14 ra- 13 ro- 14 ARITH. MEAN 13 0.9 5.9 <0.1 5.6 9.7 RANGE 4.44 <0.1-4.5 <0.1-23 <0.1-0.2 <0.1-32 <0. 1-134 EFFLUENT NUMBER OF SAMPLES 12 12 12 12 11 12 ARITH. MEAN 8.0 5.4 5.2 2.6 1.0 0.5 RANGE *FINISHED DRINKING WATERS RANGE OF CONCENTRATIONS <0.1-22 <0.1-2] <0.1-28 <0.1-23 <0.1-S. <0.!-2. 2 6 <0. 1-311 0.3-116 <0. 4-110 <0.8-92 <2-3 <0.2-6 DRINKING WATER WASHINGTON, D.C. (DELACARLIA PLANT) 41 8 2 **N.D. N.D. <0.3 *Based on 80 samples from National Organics Reconnaissance Survey - "Preliminary Assessment of Suspected Carcinogens in Drinking Water, Report to Congress", EPA, December 1975 **N.D. - None Detected ------- 0) Q Z D o Q. u Z < o CK O O > O CHLOROFORM O BROMODICKLOROAAETHANE X DIBROMOCHLOJIOMETHANE A BROMOFORM 0 CARBON TETRACHLORIDE 1,2 DICHLOROETHANE TREATMENT PROCESS FIGURE 2. REMOVAL OF VOLATILE ORGANICS 13 ------- TABLE 5. VOLATILE ORGANICS IN PROCESS EFFLUENTS Compound (Unit yg/l) Acetaldehyde Methanol Acetone Dichloro- methane Acrolein Carbon Disulfide Chloroform Bromodichloro- methane 1,1,1-Tri- chloroethane Chlorodir bromoethane Benzene Influent TR.* TR. TR. 4 TR. TR. 10 1 TR. 4 2 Nitri- fication TR. 3 TR. TR. 1 Denitri- fication TR. TR. TR. TR. 2 1 Carbon TR. TR. 1 TR. 5 TR. 1 Chlorin- ation TR. TR. TR. TR. 7 4 2 2 Drinking Water** „, j j J / j / / / j ------- TABLE 5 (cont'd) Compound (Unit yg/1) Dimethyl disulfide Toluene N-Hexanol Tetrachloro- ethylene Xylene Alkyl benzene Benzaldehyde Carbon tetrachloride Influent 3 2 3 TR. TR. 2 Nitri- fication TR. TR. TR. Denitri- fi cat ion TR. TR. TR. TR. Carbon TR. TR. TR. TR. Chlorin- ation TR. TR. 2 TR. Drinking Water** ' ' / ' ' / Ul * TR. - Trace (<1 yg/1) ** "Preliminary Assessment of Suspected Carcinogens in Drinking Water," Report to Congress, EPA, Dec. 1975. ------- TABLE 6. MUTAGENICITY OF ORGANIC CONCENTRATES R.O. Membrane and Solvent Fraction *Mutagenic Potential Cellulose Acetate • Pentane **N.D. • Methylene Chloride Neutral N.D. • Methylene Chloride Acidic N.D. Nylon • Pentane N.D. • Methylene Chloride Neutral N.D. • Methylene Chloride Acidic N.D. Composite N.D. .. .._ .. _^ ...._.._ .. _.,...._ ^. _.. . ...---..-..... ....,_._—...._.- , ., . _»,— . _.—.^ -„-•,-„_ * — VJ-tro with strains of salmonella typhimurium TA98 and TA100 ** N.D. - None Detected 16 ------- TABLE 7. RESULTS OF BACTERIAL ENDOTOXIN TESTING* SOURCE Blue Plains Reuse System Public Drinking Water Systems 1 2 3 4 5 6 s 7 8 9 10 ENDOTOXIN EQUIVALENTS ng/ml 2.5 - 12.5 1.25 12.5 2.5 12.5 0.625 500.0 125.0 10.0 2.5 2.5 *Limulus Assay Procedure - Jorgensen et al., Applied and Environmental Microbiology, September 1976. 17 ------- TABLE 8. HEAVY METALS Metal (Unit-yg/1) Mercury Cadmium Selenium Chromium Lead Manganese Arsenic Iron (mg/1) Barium Copper Zinc Boron (mg/1) Final Effluent n 47 44 38 57 53 60 56 227 49 56 57 8 Arit. Mean 0.666 0.143 4.76 2.24 0.308 7.96 2.25 0.0599 82.3 4.86 10.6 0.313 Range 0.100-1.25 0.020-0.530 2.00-5.00 0.600-4.30 0.030-1.07 1.40-20.0 0.300-6.00 N.D. -0.810 3.10-200 1.40-21.0 5.10-19.1 0.300-0.400 Washington, DC Drinking Water* <0.5 <2 <5 <5 <5 <5 <50 EPA Regulations** 2 10 10 50 50 50 1000 ------- TABLE 8. (cont'd) Metal (Unit-yg/1) Flour ide (mg/1) Silver Cyanide Aluminum (mg/1) Final Effluent n 62 49 32 210 Arit. Mean 0.722 0.134 4.23 0.251 Range 0.380-1.10 0.009-0.400 1.00-9.80 N.D. -0.900 Washington, DC Drinking Water* 1.0 <10 <20 EPA Regulations** 1.8 @ 65°F 50 *"Preliminary Assessment of Suspected Carcinogens in Drinking Water" Report to Congress, EPA, December 1975. **National Interim Primary Drinking Water Regulations, EPA, Federal Register, Vol. 40, No. 248, December 1975. ------- PERIOD 2 N=22 ARITHMETIC MEAN - 0.720 GEOMETRIC MEAN - O.685 MEDIAN - 0.695 STANDARD DEVIATION - 0.245 I I ' i t t i i i I i i i 0.0001 0.0020 0.0500 0.3000 0.70OO 0.9500 O.9950 FRACTION EQUAL TO OR LESS THAN GIVEN CONCENTRATION 0.9999 FIGURE 3. FREQUENCY DISTRIBUTION OF EFFLUENT MERCURY ------- In addition to determining metals in samples of the AWT system influent and effluent, the effluent from the lime clarification process was monitored for a four month period since previous data has shown that heavy metals can be removed by this process. Table 9 shows that concentration of metals in the influent, after the lime process, and in the final effluent. It is evident that the lime process is primarily responsible for the reduction in the metal concentrations. PESTICIDES Pesticide analyses were made on a less frequent basis than were analyses for metals. The data presented in Table 10 are based on samples taken twice per month. The levels in the effluent are significantly less than the EPA standards for drinking water that are listed in the table. GENERAL ORGANICS A summary of various gross measurements or organics in the influent and effluent is presented in Table 11 and includes the average of the parameters for a 14 month operation period. The treatment system is capable of reliably producing a high quality effluent on a continuous basis as evidenced by the TOG data presented in Table 12 and Figure 4. The 311 pieces of TOG data were grouped into 5 periods covering 18 months of operation and the arithmetic averages and standard deviations were determined. The average TOG in the finished drinking waters from 80 U.S. cities '*' is included in Table 12 for comparison purposes. Figure 4 is a frequency distribution of 77 pieces of TOG data taken during the fifth and last period of operation. Included in the figure for comparison purposes is a frequency distribution of the TOG data from 80 drinking waters taken during the National Organics Reconnaissance Survey in 1975 (5^. The median TOG concentrations were 1.5 mg/1 for the drinking waters and 2.5 mg/1 for the wastewater effluent. The lower levels of TOG in the drinking water data may be attributed to the cities in the survey using groundwater supplies. In an attempt to determine if additional TOG reduction was possible grab samples of effluent were ozonated on three separate occasions. An ozone dosage of 60 mg/1 in the gas stream was introduced.into a 1 liter sample using the reactor system described by Roan, S. * . The sample was reacted with the ozone stream for 60 minutes. The initial average TOG concentration was 1.21 mg/1 and the final TOG was 0.84 mg/1 which is a reduction of 30 percent. In addition, a short term side stream study was conducted using a strong acid cation resin in series with an intermediate base anion resin to determine the removal of the remaining TOG by ion exchange. These resins reduced the effluent TOG about 40 percent. 21 ------- TABLE 9. HEAVY METAL REMOVAL BY LIME CLARIFICATION Metal (Unit-yg/1) Mercury Cadmium Selenium Chromium Lead Manganese Arsenic Iron (mg/1) Barium Copper Zinc Boron (mg/1) Fluoride (mg/1) Silver Cyanide Aluminum (mg/1) Influent 0.813 1.92 4.76 16.9 23.4 149 1.49 1.30 54.3 48.9 110 0.250 0.701 3.98 5.80 - Lime Clarification 0.931 - - 5-59 0.682 19.5 1.05 - 34.3 7.72 10.7 - 0.679 0.333 - - Final Effluent 0.802 0.143 4.76 3.18 0.399 5.04 0.967 0.0467 27.2 5.66 12.6 0.313 0.724 0.0987 4.23 0.251 22 ------- TABLE 10. PESTICIDES Pesticide Unit - ng/1 (ppt) Effluent** *EPA Regulations Aldrin DDT Dieldrin Endrin Heptaclor Heptaclor Epoxide Lindane Methoxychlor Diazin Guthion Malathian Parathian 4 10 1 5 0.7 1 2 40 5 200 10 10 200 4000 105 *EPA National Interim Primary Drinking Water Regulations, Federal Register, Vol. 40, No. 248, December 24, 1975 **Average of 4 data values for each pesticide 23 ------- Table 11. GENERAL ORGANICS PARAMETER (units - mg/1) TOC COD BOD MBAS CCE CAE Phenol (yg/i) UV @ 290 mu (%T) INFLUENT N* 231 229 245 13 - - 9 - Arithmetic Mean 74.1 240 106 8.92 - - 12.9 i. - - - Standard Deviation 11.0 30.5 15.7 1.71 - - 4.02 - EFFLUENT N 234 226 221 35 2 2 54 19 Arithmetic Mean 2.79 6.53 3.12 0.14 0.75 2.25 3.66 96.9 Standard Deviation 1.35 3.12 2.15 0.08 0.64 0.64 1.52 i 0.87 NJ *N-number of samples ------- TABLE 12. VARIABILITY OF EFFLUENT TOG 4 Month Periods 1 2 3 4 5 Total *Finished Drinking Water Number of Samples 58 64 69 43 77 311 80 Arithmetic Mean (mg/ 1 ) 2.26 2.35 3.72 2.67 2.68 2.76 2.21 Standard Deviation 1.31 1.00 1.59 1.50 1.02 - Range 0.05-12.2 'Preliminary Assessment of Suspected Carcinogens in Drinking Water," Report to Congress, EPA, December 1975. 25 ------- u O ARITHMETIC MEAN - 2.68 GEOMETRIC MEAN - 2.50 MEDIAN - 2.50 STANDARD DEVIATION - 1.02 PRELIMINARY ASSESSMENT OF CARCINOGENS IN DRINKING WATER*, EPA, DEC. 1975 FINISHED DRINKING WATER-80 CITIES . I I I I I I I 0.0001 0.0020 0.0500 0.3000 0.7000 0.9500 FRACTION EQUAL TO OR LESS THAN GIVEN CONCENTRATION FIGURE 4. FREQUENCY DISTRIBUTION OF EFFLUENT TOC 0.9950 0.9999 ------- Figure 5 shows a graph of the removal of TOC by each of the processes in the treatment system. Ninety-two percent of the TOC is removed in the lime clarification and nitrification processes. The increase in TOC in the denitrification process effluent is due to some leakage of methanol. Table 13 shows the variability of the effluent COD for each of the five operating periods and Figure 6 shows a frequency distribution of 74 pieces COD data taken during the fifth operating period. The median COD value is 5.61. GENERAL INORGANICS A summary of the inorganic constituents in the influent and effluent is presented in Table 14. The arithmetic means and standard deviations of each constituent are shown. Samples of the effluent were checked for 80 elements by the Proton Induced X-ray Emission Procedure ^ ' to determine the presence of any unusual inorganic component. The results are shown in Table 15. No significant concentrations of hazardous inorganics were observed. NUTRIENTS The concentration of the phosphorus and nitrogen compounds are shown in Table 16. Over 200 pieces of data were used for each parameter in determining the means and standard deviations. No attempt was made to completely denitrify the effluent. The amount of methanol added to the denitrification process was based on allowing 2 to 4 mg/1 of N03~N in the effluent. SUSPENDED MATTER Turbidity, and suspended and total solids data for the treatment system influent and effluent are shown in Table 17. The effluent turbidity level is within the requirements of the EPA National Interim Primary Drinking Water Regulations (4) which establishes the standard at 1 turbidity unit on a monthly average basis. The variability of the effluent turbidity is shown in Table 18. At the beginning of the last four months of operation (period 5) it was noted that the turbidimeter had not been properly standardized when making readings. Implementation of the correct standardization procedure accounts for the lower turbidity values during the fifth period. Figure 7 is a frequency distribution of the 332 turbidity values for samples taken in period five. Between 98 and 99 percent of the values were less than the standard of one. The median turbidity was 0.39 FTU. MICROBIOLOGICAL AND DISINFECTION PARAMETERS Data on the chlorine dosage, demand, and free residual in the effluent are included in Table 19 along with data on the concentration of various pathogenic indicator organisms. The free residual chlorine concentration of 2.23 mg/1 and low turbidity of 1 FTU have combined to produce an effluent that consistently meets the EPA Drinking Water Regulations. 27 ------- 60 O) E 20 10 * & < 4? J$ TREATMENT PROCESS FIGURE 5. REMOVAL OF TOC 28 ------- TABLE 13. VARIABILITY OF EFFLUENT COD 4 Month Periods 1 2 3 4 5 Total Number of Samples 58 64 67 37 74 300 Arithmetic Mean (mg/1) 5.28 5.96 7.64 7.45 6.25 6.45 Standard Deviation 2.55 3.09 2.54 3.29 2.20 - 29 ------- Ul o PERIOD 5 N=74 ARITHMETIC MEAN - 6.25 GEOMETRIC MEAN - 5.92 MEDIAN - 5.61 STANDARD DEVIATION - 2.20 1 1 1 I I I I I I I I I I I I I O.OO01 0.0020 0.0500 0.3000 0.7000 0.9500 0.9950 FRACTION EQUAL TO OR LESS THAN GIVEN CONCENTRATION FIGURE 6. FREQUENCY DISTRIBUTION OF EFFLUENT COD 0.9999 ------- TABLE 14. GENERAL INORGANICS PARAMETER (unit - mg/1) PH Total Alkalinity Conductivity (umhos/cm) TDS Hardness CaCo3 Stability Chloride Sulphate Calcium Magnesium Sodium Potassium INFLUENT N* 2274 2435 - 137 35 - - - 176 178 - - Arithmetic Mean 7.20 125 - 283 115 - - - 31.2 6.47 - - Standard Deviation 0.118 15.1 _ 28.6 7.65 _ - - 2.73 0.579 - - EFFLUENT N 1081 980 830 210 40 40 158 122 218 224 228 21 Arithmetic Mean 7.34 102 514 357 162 0.198 68.6 50.1 56.6 5.49 34.1 8.23 Standard Deviation 0.146 12.1 36.0 31.6 7.18 0.394 4.56 3.83 4.40 0.481 2.94 0.318 * N-number of samples U» ------- TABLE 15. RESULTS OF 80 ELEMENT SURVEY* Elements Detected in Effluent Cng/1) Na - 37.8 Zn - 0.017 Ba - 0.034 K - 7.08 Cd - 0.002 As - 0.006 Ca - 54.0 I - 0.013 NI - 0.004 V - 0.003 Pb - 0.003 Cu - 0.013 Cr - 0.001 Ga - 0.001 Sr - 0.151 Fe - 0.031 Br - 0.100 Sn - 0.002 Co - TR. Rb - 0.007 S - 2.85 Elements Not Detected Ong/1) Mn, Mo, Ag, Sc, Ti, Ge, Y, Pd, In, Sb, Te, Cs, La, W, Pt, Tl, Bi, Si, P, Ar, Se, Kr, Zr, Nb, Ru, Rh, Xe, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, Re, Os, Ir, Au, Hg, Po, At, Rn, Fr, Ra, Ac, Th, Pa, U, Np, Pu *Proton - Induced X-Ray Emission Procedure 32 ------- TABU- 16. NUTRIENTS PARAMETER (unit - mg/1) TP04 TKN NH3-N N03+N02-N N* 244 128 24.3 232 INFLUENT Arithmetic Mean 15.1 19.0 17.5 0.095 Standard Deviation 2.19 2.50 2.32 0.08 N 232 98 223 229 EFFLUENT Arithmetic Mean 0.153 0.222 0.069 3.84 Standard )eviation 0.09 0.17 0.15 1.84 * N-number of samples 33 ------- TABLE 17. SUSPENDED MATTER PARAMETER (unit - mg/1) Turbidity (FTUD Suspended Solids Volatile Suspended Solids Total Solids INFLUENT N* _ 241 294 - Arithmetic Mean _ 109 84.0 - Standard Deviation - 21.3 16.0 - N 1395 225 . 209 EFFLUENT Arithmetic Mean 0.884 1.02 mm 362 Standard Deviation 0.448 0.954 . 30.4 * N-number of samples 34 ------- TABLE 18. VARIABILITY OF EFFLUENT TURBIDITY 4 Month Periods 1 2 3 4 5 Total Number of Samples 161 262 313 327 332 1395 Arithmetic Mean (FTU) 0.730 0.885 1.06 1.26 0.418 0.884 Standard Deviation 0.256 0.800 0.464 0.520 0.182 - 35 ------- o o u> o GO o o PERIOD 5 N= 332 ARITHMETIC MEAN - 0.420 GEOMETRIC MEAN - 0.386 MEDIAN - 0.385 STANDARD DEVIATION - 0.182 CO oe. I I I I I I I I I I I I I I I I I I I I 1 I I I I I II I I i I es 0.0001 0.0020 0.0500 0.3000 0.7000 0.9500 0.9950 FRACTION EQUAL TO OR LESS THAN GIVEN CONCENTRATION 0.9999 FIGURE 7. FREQUENCY DISTRIBUTION OF EFFLUENT TURBIDITY ------- TABLE 19. MICROBIOLOGICAL AND DISINFECTION PARAMETERS PARAMETER Chlorine Dosage mg/1 Chlorine Demand mg/1 Chlorine Residual (free) mg/1 Total Coliforms cells/100 ml Fecal Coliforms cells/100 ml Pseudomonas Aeruginosa cells/100 ml Salmonella cells/100 ml Total Count cells/100 ml EFFLUENT N* 2030 43 57 114 119 36 40 44 Arithmetic Mean 4.35 1.83 2.23 0.11 0.17 0.81 0 66.8 Standard Deviation - 1.62 1.45 0.39 O.SO 1.53 0 42.3 *N-Number of samples 37 ------- ESTHETIC PARAMETERS The effluent had no odor when compared to samples of odor free water prepared for the threshold odor test, and exhibited a level of color equal to 3.5 color units based on the platinum - cobalt standard. This data along with the average influent and effluent temperature are shown in Table 20. 38 ------- TABLE 2Q. ESTHETICS PARAMETER Temperature (°C) Odor (TON) Color (P-C units) N* 382 - - INFLUENT Arithmetic Mean 20.9 - - Standard Deviation 2.50 - - N* 320 35 84 EFFLUENT Arithmetic Mean 22.0 **N.D. 3.52 Standard Deviation 2.32 N.D. 0.37 *N-number of samples **N.D. - none detected 39 ------- SECTION 5 REFERENCES 1. "Research Needs for the Potable Reuse of Municipal Wastewater", EPA-600/9-75-007, Dec. 1975. 2. Roa, V. C., et al., "A Simple Method for Concentrating and Detecting Viruses in Wastewater". Water Research 6_: 1565-1576, 1972. 3. Wallace, C., et al., "A Portable Virus Concentrator for Testing Water in the Field". Water Research 6_: 1249-1256, 1972. 4. "National Interim Primary Drinking Water Regulations", EPA, Federal Register, Vol. 40, No. 248, Dec, 1975. 5. "Preliminary Assessment of Suspected Carcinogens in Drinking Water", Report to Congress, EPA, Dec. 1975. 6. Bellar, T. A., S Lichtenberg, J. J., "The Determination of Volatile Organic Compounds at the yg/l Level in Water by Gas Chromatography", EPA-670/4-75-009, Nov. 1974. 7. Smith, J. K., et al., "Characterization of Reusable Municipal Wastewater Effluents and Concentration of Organic Constituents", EPA Contract Project No. 68-03-2090 (Final Report in review stage). 8. Ames, B. N., et al., Proceedings of the National Academy of Sciences, Vol. 70, p. 2281, 1973. 9. Jorgensen, J. H., et al., "Rapid Detection of Bacterial Endotoxins in Drinking Water and Renovated Wastewater", Applied and Environ. Microb., Vol. 32, No. 3, p. 347, Sept. 1976. 10. Roan, S. G., et al., "Laboratory Ozonation of Municipal Wastewaters", EPA-670/2-73-075, Sept. 1973. 11. Sims, P., "Proton Induced X-ray Emission Procedure", Dept. of Physics, Purdue University. 40 ------- TECHNICAL REPORT DATA (Please read Instructions on the reverse before completing) i REPORT NO. EPA-600/2-78-027 2. 4. TITLE AND SUBTITLE WASTEWATER TREATMENT FOR REUSE AND ITS CONTRIBUTION TO WATER SUPPLIES 6. PERFORMING ORGANIZATION CODE 3. RECIPIENT'S ACCESSION-NO. 5. REPORT DATE March 1978 (Issuing Date) 7. AUTHOR(S) Howard P. Warner John N. English 8. PERFORMING ORGANIZATION REPORT NO. 9. PERFORMING ORGANIZATION NAME AND ADDRESS Government of the District of Columbia Department of Environmental Services EPA-DC Pilot Plant, 5000 Overlook Ave., S.W. Washington, D.C. 20032 10. PROGRAM ELEMENT NO. 11. CONTR~A"CT7Cnilli|IIT MO. 68-03-0344 12. SPONSORING AGENCY NAME AND ADDRESS Municipal Environmental Research Laboratory—Cin.,OH Office of Research and Development U.S. Environmental Protection Agency Cincinnati, Ohio 45268 13. TYPE OF REPORT AND PERIOD COVERED FINAL. 4/75 to 9/76 14. SPONSORING AGENCY CODE EPA/600/14 15. SUPPLEMENTARY NOTES Project Officer: Irwin J. Kugelman 513/684-7633 16. ABSTRACT An 18 month study using cost effective municipal wastewater treatment technology coupled with a computerized data handling system, was conducted at the EPA/Washington, D.C. Blue Plains Pilot Plant to obtain data on the safety of the effluent for discharge upstream of drinking water intakes, and for potential domestic reuse purposes. Treatment reliability was demonstrated and performance results showed the absence of virus in the effluent. Effluent concentrations of radioactivity, trihalomethanes and other volatile organics, heavy metals, pesticides, TOC, turbidity, general inorganic compounds, and pathogenic indicator organisms were shown to be similar to those found in finished drinking waters during the EPA National Organics Reconnaissance Survey in 1975. The specific organic compounds identified in the effluent are also present in finished drinking waters. Effluent organic concentrates did not exhibit mutagenic properties, and results of an 80 element survey did not detect the presence of significant quantities of any hazardous inorganic material. Effluent endotoxin levels were comparable to levels in public drinking water supplies. 17. KEY WORDS AND DOCUMENT ANALYSIS DESCRIPTORS Waste Treatment *Water Reclamation Nutrients Viruses Organic Compounds Potable Water Microorgani sms b.lDENTIFIERS/OPEN ENDED TERMS Reuse Heavy Metals Advanced Wastewater Treatment COSATI Field/Group 13B 18. DISTRIBUTION STATEMENT RELEASE TO PUBLIC 19. SECURITY CLASS (ThisReport) UNCLASSIFIED 21. NO. OF PAGES 49 20. SECURITY CLASS (Thispage) UNCLASSIFIED 22. PRICE EPA Form 2220-1 (9-73) 41 «U.S. GOVERNMENT PRINTING OFFICE: 1978 260-880/16 1-} ------- |