Document GqoZgZ8BpJzEejMLbbb56dZx

Naval Research Laboratory Washington, DC 20375-5320 NRL/M R/6180--98-8141 Evaluation of the Effects of AFFF Inputs to the VIP Biological Nutrient Removal Process and Pass-through Toxicity--Phase IA M ujde E rten-U nal S. Paranjape G ary C. Schafran _____ ___ : Old Dominion University Department o f Civil and Envoronmental Engineering Norfolk, Virginia F.W . W illiams Navy Teclmology Centerfo r Safety and Survivability Chemistry Division February 27, 1998 Approved for public release; distribution unlimited. US00004471 REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of Information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for information Operations and Reports, 1 2 1 5 Jefferson Davis Highway, Suite 1 2 0 4 , Arlington, V A 2 2 2 0 2 -4 3 0 2 , and to the Office of Management and Budget. Paperwork Reduction Project (0 7 0 4 -0 1 8 8 ), Washington, DC 2 0 5 0 3 . 1. AGENCY USE ONLY (Leave BlankI 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED 4. TITLE AND SUBTITLE February 27, 1998 Phase IA Study, Sept. 1996-Sept. 1997 I 5. FUNDING NUMBERS Evaluation o f the Effects o f AFFF Inputs to the VIP Biological Nutrient Removal Process and Pass-through Toxicity--Phase IA 6. AUTHOR(S) Mujde Erten-Unal, S. Paranjape, Gary C. Schafran, and F.W . Williams 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Old Dominion University, Department o f Civil & Environmental Eng. KH 135, Norfolk, VA 23529-0241 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) Naval Research Laboratory Washington, DC 20375-5320 11. SUPPLEMENTARY NOTES Prob. No. 61-M393-X7 Grant No.: N00014-96-1-G021 PR-Number: 61-2330-96 Disbursing Code: N68342 AGO Code: N66020 CAGE Code: 50075 8. PERFORMING ORGANIZATION REPORT NUMBER N R L /M R /6180-98-8141 10. SPONSORING/MONITORING AGENCY REPORT NUMBER 12a. DISTRI BUTION/AVAILABIL1TY STATEMENT Approved for public release; distribution unlimited. 12b. DISTRIBUTION CODE A 13. ABSTRACT (Maximum 2 0 0 words) This report discusses the results o f a bench scale study conducted to evaluate the potential inhibitory effects o f untreated A FFF wastewater to the Virginia Initiative Plant (VIP) biological nutrient removal process. A bench-scale study was conducted to evaluate the potential inhibitory effects o f untreated AFFF wastewater to the nitrification process o f the Virginia Initiative Plant biological nutrient removal system. Under this testing, bench-safe reactors simulating the nitrification process were loaded at various AFFF concentrations and the influence on the process performance was evaluated. The purpose o f this effort was to determine the level o f AFFF that could be incorporated into the influent o f a biological nutrient removal process without causing inhibitory effects. The results o f the nitrification inhibition study showed that the AFFF concentrations tested in the range between 10 ppm to 60 ppm did not show any significant inhibition to biological nitrification. The effluent from each reactor did not exhibit any pass-through toxicity as well. 14. SUBJECT TERMS Environment AFFF 17. SECURITY CLASSIFICATION OF REPORT UNCLASSIFIED NSN 7540-01-280-5500 Wastewater Nitrification 15. NUMBER OF PAGES 53 16. PRICE CODE 18. SECURITY CLASSIFICATION OF THIS PAGE UNCLASSIFIED 19. SECURITY CLASSIFICATION OF ABSTRACT UNCLASSIFIED 20. LIMITATION OF ABSTRACT UL Standard Form 2 9 8 (Rev. 2-89) Prescribed by ANSI Std 2 3 9 -1 8 298-102 US00004472 CONTENTS 1.0 INTRODUCTION .................................. 1 1.1 O v e rv ie w .............................................................................................................................. . 1 1.2 Study Objectives ................................................................................ 4 2.0 METHODSAND MATERIALS ....................................................................................................5 2.1 Reference Reactor O p e ra tio n ................................................................................................5 2.2 Analytical MelEods ................................................................................................................7 2.3 BNR Inhibition Batch A ss a y s ................................................................................................8 2.4 Toxicity Pass-Through T e stin g ............................................................................................10 3.0 RESULTS ....................................................................... 11 3.1 AFFF Waste Characterization..............................................................................................11 3.2 Reference Reactor P erfo rm an ce......................................................................................... 11 3.3 Range Finding Test Results ................................................................................................ 17 3.4 BN R Inhibition Batch A ss a y s ..............................................................................................17 3.4.1 Inhibition Test at 60 ppm AFFF C oncentration................................................................20 3.4.2 Inhibition Test at 50 ppm AFFF C oncentration................................................................20 3.4.3 Inhibition Test at 30 ppm AFFF C oncentration................................................................ 25 3.4.4 Inhibition Test at 10 ppm AFFF C oncentration................................................................25 3.5 Toxicity Pass-Through T e stin g ........................................................................................... 25 4.0 D IS C U S S IO N ...................................................................................... 35 5.0 C O N C L U S IO N ......................................................................................................................... 41 R E FE R E N C E S........................................................................... 44 US00004473 TABLES Table 2-1, Organic and inorganic synthetic wastewater constituents ............................................... 6 Table 3-1. Chemical/Parameter Specific M easurem ents.................................................................... 12 Table 3-2. Weekly Performance o f the reference reactor during the course o f the study ........... 14 Table 3-3a. Nitrite nitrogen concentration variation during different s ta g e s ..................................16 Table 3-3b. Nitrate nitrogen concentration variation during different stages ................................16 Table 3-3c. Orthophosphate concentration variation during different stages ................................16 Table 3-4. Range finding test reactor com ponents............................................................................. 18 Table 3-5. Range finding inhibition test results ................................................................................. 19 Table 3-6. BNR Inhibition reactor components: 60 ppm A F F F ......................................................21 Table 3-7. Nitrification inhibition at 60 p p m ......................................................................................22 Table 3-8. BNR Inhibition reactor components: 50 ppm A F F F ...................................................... 24 Table 3-9. Nitrification inhibition at 50 p p m ......................................................................................26 Table 3-10. BNR Inhibition reactor components: 30 ppm A F F F...................................................... 28 Table 3-11. Nitrification inhibition at 30 p p m ......................................................................................28 Table 3-12. BNR Inhibition reactor components: 10 ppm A F F F...................................................... 31 Table 3-13. Nitrification inhibition at 10 p p m ......................................................................................32 Table 3-14. Summary o f acute toxicity test re s u lts .............................................................................34 IV US00004474 Figures Figure 2-1. BNR Inhibition Batch A s s a y s ............................................................................................9 Figure 3-1. Specific oxygen uptake rates (SOUR's) during the feed stage for 60 ppm AFFF (A-control, B-inhibition).................................................................................................... 23 Figure 3-2. Specific oxygen uptake rates (SOUR's) during the aerobic stage for 60 ppm AFFF (A-control, B -inhibition)............................................................................................................. 23 Figure 3-3. Specific oxygen uptake rates (SOUR's) during the aerobic stage for 50 ppm AFFF (A-control, B -inhibition)............................................................................................................. 27 Figure 3-4. Specific oxygen uptake rates (SOUR's) during the feed stage for 30 ppm AFFF (A-control, B -inhibition)............................................................................................................. 30 Figure 3-5. Specific oxygen uptake rates (SOUR's) during the aerobic stage for 30 ppm AFFF (A-control, B-inhibition).................................................................................................... 30 Figure 3-6. Specific oxygen uptake rates (SOUR's) during the feed stage for 10 ppm AFFF (A-control, B-inhibition).................................................................................................... 33 Figure 3-7. Specific oxygen uptake rates (SOUR's) during the aerobic stage for 10 ppm AFFF' (A-control, B-inhibition).................................................................................................... 33 Figure 4-1. AFFF inhibition study range finding test re su lts............................................................. 36 Figure 4-2a. Average ammonia concentrations for control reactors ................................................38 Figure 4-2b. Average ammonia concentrations for inhibition re a cto rs........................................... .3 8 Figure 4-3. Average ammonia nitrogen removal rates for the inhibition reactors .........................39 Figure 4-4a. Average COD removal rates for the control reactors ..................................................40 Figure 4-4b. Average COD removal rates for the inhibition reactors ............................................. 40 Figure 4-5a. Average inorganic fluoride concentration for controls ................................................42 Figure 4-5b. Average inorganic fluoride measurements as a function o f reaction tim e ..................42 Figure 4-6. Fluoride released as a function o f AFFF dose for inhibition reactors .........................43 v Abstract The U.S. Navy utilizes a surfactant in fire fighting water that improves the ability to control petroleum-based fires. This surfactant is currently manufactured by up to five companies and is commonly referred to as AFFF (aqueous film-forming foam) conforming to military specifications Mil-F-24385F. Present concerns over inhibitory effects o f AFFF wastewater have resulted in the prohibition o f its disposal to the Hampton Roads Sanitation District (HRSD), Hampton Roads VA collection system where it would eventually enter one o f the biological wastewater treatment plants operated by the District. HRSD is particularly concerned with how AFFF wastewater might interfere with biological nutrient removal (BNR) processes at its Virginia Initiative Plant (VTP). The Navy does not discharge to that plant but HRSD wants to check the impact on the VTP process because it is more sensitive than a conventional activated sludge processes used by other HRSD Plants in which the Navy discharges to and HRSD plans to upgrade all o f their plants to the VIP process eventually. HRSD has indicated that compatibility o f AFFF wastewater with the BNR process must be demonstrated prior to granting the necessary permit to discharge AFFF wastewater to the wastewater collection system leading to their plants. Previous studies were performed using surrogate AFFF compounds (AFFF-S), however, they did not address actual AFFF discharges. The overall objective o f this program was to study the impact o f AFFF wastewater to a biological nutrient removal process and determine whether pass-through toxicity occurs in the effluent o f a biological process receiving wastewater containing AFFF. A bench-scale study was conducted to evaluate the potential inhibitory effects o f untreated AFFF wastewater to the nitrification process o f the VTP BNR. In order to maintain a continuous supply o f uniform nitrifying microorganisms to the bench-scale reactors, a fill-and-draw type batch reference reactor was operated continuously at the Civil and Environmental Engineering Laboratory at Old Dominion University. The reactor was operated sequentially in aerobic feed, anaerobic, aerobic, settle and decant phases. Feed aeration, mixing, and decant were all controlled by a programmable controller. After a specified settling period, supernatant (effluent) from the reactor was withdrawn by a solenoid valve and collected in a sample bottle for analysis. Nitrification inhibition was assessed in series for untreated AFFF wastewater using a batch assay procedure. Inhibition tests were performed with different concentrations o f AFFF and controls using six, 6-liter batch reactors. The inhibition reactors were operated following the same sequential cycle o f the reference reactor. The degree o f ammonia oxidation in reactors receiving a loading of AFFF wastewater was compared to the degree o f oxidation in control reactors receiving similar volumes o f tap water. Toxicity pass-through testing was also performed to determine maximum loadings o f the untreated AFFF wastewater that would not cause toxicity in the effluent from a BNR process. Acute toxicity o f the effluent to M ysidopsis bahia (mysid shrimp) and Cyprinodon variegatus (sheepshead minnow) have been examined in toxicity testing o f both control and AFFF-loaded inhibition reactors. vn US00004476 The results o f the nitrification inhibition study showed that the AFFF concentrations tested in the range between 10 ppm to 60 ppm did not show any significant inhibition to biological nitrification. The intensity o f foaming in the reactors increased with the increasing AFFF concentrations and the loss o f solids from the reactors was associated with the foaming density. At AFFF concentrations between 10 ppm to 50 ppm, the loss o f solids increased. However, at 60 ppm, the foaming was so much denser that it did not allow solids carryover from the reactors. Uninhibited nitrification was also observed among the reactors that had excessive foaming. There was significant chemical oxygen demand (COD) removal observed for each AFFF concentration tested as well. However, the percent COD removal in the inhibition reactors was less than that o f the control reactors. While the percent COD removal decreased with increasing AFFF concentration, the amount o f COD removed actually increased (on a mg/L basis). This observation is a direct result o f the addition o f COD associated with the AFFF. The acute toxicity test results showed that the effluent from each inhibition reactor did not exhibit any pass-through toxicity. Fluoride measurements were also conducted on control samples and the AFFF wastewater samples during the inhibition testing to examine fluoride release. A linear relationship was observed up to 50 ppm AFFF which signified that organo-fluoride compounds were being decomposed in proportion to the AFFF concentration. The low release o f fluoride for the 60 ppm AFFF wastewater suggested some interference in fluoride release due to the inhibition o f the microorganisms that were capable o f decomposing these compounds or evidence o f selective substrate utilization where microorganism were consuming other preferable compounds before selecting organo-fluoride compounds. Overall, the results o f this study indicated that AFFF solutions discharged into the wastewater at concentrations 60 ppm or below did not exhibit any inhibitory effect to biological nitrification and pass through toxicity. VIII US00004477 Evaluation of the Effects of AFFF Inputs on the VIP Biological Nutrient Removal Process and Pass-Through Toxicity - Phase IA 1.0 INTRODUCTION 1.1 Overview The US Navy utilizes a surfactant in fire fighting water that improves the ability to control petroleum-based fires. The surfactant, which is widely used by the Navy including facilities in the Hampton Roads region, EEampton Roads VA, is currently manufactured by up to five companies and is commonly referred to as AFFF (aqueous film-forming foam) conforming to military specifications MS1-F-24385F. The AFFF chemical makeup is not well known and likely varies among manufacturers and between batches. The US Navy is exploring a number o f options that include disposal o f the fire fighting water to wastewater collections systems where the components o f AFFF wastewater would be removed biologically. Current disposal o f fire fighting water that includes AFFF wastewater has been limited by concerns for the environmental/toxic effects associated with AFFF. Disposal o f the fire fighting foam to sanitary sewers has been considered as an option, however, concern for the potential toxic or inhibitory effects associated with AFFF wastewater have generally led to a ban on introduction o f AFFF to wastewater collection systems. Several studies have been performed on the disposal and treatment o f AFFF surrogate (AFFF-S) wastewater using surfactants such as CalsoftL-40 (Pilot Chemical Co.), DRFS (Dominion Restoration Inc.), Micro Blazeout (Verde Environmental), and Silv-Ex (Ansul Fire Protection). Bench-scale anaerobic and aerobic reactors were used to investigate the potential inhibition o f the AFFF surrogates to nitrification, denitrification, and phosphorus release and uptake in a biological nutrient removal (BNR) process [1,2]. These effects were investigated for both untreated and pretreated AFFF-S wastewater. The results showed that pretreating a wastewater containing AFFFS allowed for complete nitrification and denitrification and untreated or pretreated wastewater did Manuscript approved December 30, 1997 US00004478 not have any adverse effect on denitrification and phosphorus release. The use o f coagulants such as alum, ferric chloride, calcium chloride, and cationic polymers also have been observed to be capable o f reducing the organic content o f AFFF [1,2,3,4], Treatability studies have also been conducted with a high-purity oxygen activated sludge system. The results showed that acceptable levels o f biological treatment could be obtained with untreated firefighting wastewater containing 3% AFFF diluted by a factor o f 100. The use of dissolved air flotation treatment on the firefighting wastewater further reduced the dilution ratio needed for acceptable effluent quality from the biological process [5,6], The use o f chemical pretreatment with dissolved air flotation (DAF) provided consistent removal o f chemical oxygen demand (COD), biochemical oxygen demand (BOD), total suspended solids (TSS), and firefighting surfactants [7]. Overall, the use o f coagulation, flocculation, and clarification aided in the reduction o f organics prior to discharge to a BNR process. Upon chemical pretreatment and using aerobic and anaerobic sequencing batch reactors, it was found that an acceptable effluent that is amenable to an aquatic stream could be processed [8, 9, 10]. Additional studies were performed to determine the biodegradability o f AFFF wastewater. Some o f the additional work included the use o f wastewater containing actual fire fighting water and AFFF. However, detailed testing on the effects o f actual AFFF wastewater on biological nutrient removal was not performed in these studies [11, 12]. The biodegradability o f commonly used AFFF surrogates which have been used in training activities were evaluated on bench-scale, continuous-feed activated sludge processes [13, 14, 15], The AFFF dose that was fed to the reactor increased gradually from 100 ppm to 250 ppm. The results exhibited very good BOD and COD removal rates, however, nitrification was inhibited with increasing AFFF concentrations. Present concerns over inhibitory effects o f AFFF wastewater have resulted in the prohibition o f its disposal to the Hampton Roads Sanitation District (HRSD) collection system where it would eventually enter one o f the biological wastewater treatment plants operated by the District. HRSD is particularly concerned with how AFFF wastewater might interfere with biological nutrient removal processes at its Virginia Initiative Plant (VIP). The Navy does not discharge to that plant but HRSD wants to check the impact on the VIP process because it is more sensitive than a conventional activated sludge processes used by the Army Base, Atlantic, and Chez-Eliz Plants in which the Navy 2 US00004479 discharges. HRSD plans to upgrade all o f their plants to the VIP process eventually. The VIP plant incorporates biological nitrogen, phosphorous, and organic matter (BOD/COD) removal through a sequential series o f anaerobic, anoxic, and oxic reactors. Nitrogen removal occurs through microbially-mediated nitrification and denitrification and phosphorous removal occurs through enhanced uptake by poly P bacteria. It is well known that the nitrification and denitrification processes can be inhibited in the presence o f various chemicals and Poly P bacteria have been observed to be inhibited by H2S and 2,4-dinitrophenol. Because o f the sensitivity o f these microbial processes to inhibition, iit is important to characterize the relationship between concentrations o f various chemicals and the rates o f conversion o f nitrogen, phosphorous, and organic substrate. HRSD has indicated that compatibility o f AFFF wastewater with the BNR process must be demonstrated prior to granting the necessary permit to discharge AFFF wastewater to the wastewater collection system leading to their plants. Toxicity pass-through potential o f AFFF is also another concern to HRSD. The US Navy at Naval base Norfolk, VA previously supported two studies [1,2] to investigate the impact o f AFFF on the BNR. process in support o f their request to dispose o f AFFF to the wastewater collection system. The study methodologies in these two studies, including the use o f a reference reactor and inhibition testing with sequencing batch reactors operating on cycles o f aerobic feed, anaerobic react, and settling were approved by HRSD. However, instead o f using AFFF that is utilized by the Navy, surrogate AFFF compounds (AFFF-S) were used. The two studies by CH2m Hill Co. were performed using AFFF-S for the sole purpose o f identifying the need for pretreatment and/or obtaining authority to construct and discharge AFFF-S wastewater to HRSD from the new fire training school at Fleet Training Center (FTC), Norfolk VA. Neither study was intended to address AFFF discharges. The current study is required to determine the level at which AFFF causes process inliibition or pass through toxicity so that discharge permits can be modified to allow the non-routine discharge o f AFFF from sources other than the fire training school at FTC Norfolk VA (i.e., hangar fire protection systems and fire truck testing). The results were not accepted by HRSD since the AFFF solution used by the Navy was not tested. This situation lead to the current study which involved directly evaluating the impact o f AFFF (as used by the Navy) on a BNR process. 3 US00004480 A bench-scale study was conducted to evaluate the potential inhibitoiy effects o f untreated AFFF wastewater to the nitrification process o f the VIP BNR. Under this testing, bench-scale reactors simulating the nitrification process were loaded at various AFFF concentrations and the influence on the process performance was evaluated. The purpose o f this effort was to determine the level o f AFFF that could be incorporated into the influent o f a biological nutrient removal process without causing inhibitoiy effects. Toxicity pass-through testing was also performed to determine maximum loadings o f the untreated AFFF wastewater that would not cause toxicity in the effluent from a BNR process. 1.2 Study Objectives The overall objective o f this work was to study the impact of AFFF wastewater to a biological nutrient removal process and determine whether pass-through toxicity occurs in the effluent o f a biological process receiving wastewater containing AFFF. Specific objectives o f this study include: - Determine the relationship between AFFF concentrations (i.e. % full strength, flouro-organic compounds, butyl carbitol concentration) in influent wastewater and the degree o f inhibition o f nitrogen, phosphorous, and COD removal under a variety o f operating conditions similar to those o f the VIP plant; - Identify conversion/removal through biological treatment o f specific components o f the AFFF surfactant (see analytical methods below); - Measure the acute toxicity o f the treatment reactors' effluent to M ysidopsis bahia (mysid shrimp) and Cyprinodon variegatus (sheepshead minnow) to assess the possibility o f toxicity pass through in a process similar to the VIP process; - Determine the chemical/parameter specific concentrations o f the AFFF wastewater effluent quality with respect to parameters specified in HRSD industrial pretreatment guidelines. Also document appropriate findings from a treatment and aesthetic standpoint. 4 US00004481 2.0 METHODS AND MATERIALS 2.1 Reference R eactor O peration In order to maintain a continuous supply o f uniform nitrifying microorganisms, a fill-and-draw type batch reference reactor was used at the Civil and Environmental Engineering laboratory at Old Dominion University. The reference reactor consisted o f a 30-gallon polyethylene tank containing a hexagonal-shaped poly vinyl chloride (PVC) air diffuser and a rapid mixer. It was initially seeded with mixed liquor suspended solids (MLSS) collected from the secondary clarifiers at the VIP plant. The solids were allowed to settle and the supernatant was decanted. The reactor was then fed over the duration o f the study with a synthetic feed solution comprised o f organic and inorganic compounds necessary to support a healthy population o f nitrifying, denitrifying and phosphorus removing bacteria. This feed was the same composition used in a previous study o f AFFF-S[2]. Table 2-1 shows the organic and inorganic constituents used for preparing the feed solution. Some changes to the feed composition were made during the study and these changes are mentioned in subsequent sections. The reactor was fed this solution throughout the feed stage with a peristaltic pump. The reactor was operated sequentially in aerobic feed, anaerobic, aerobic, and settle and decant phases. Feed aeration, mixing and decant were all controlled by a programmable controller. Air supply was adjusted to maintain 4 mg/1 o f dissolved oxygen (DO) in the reactor during the feed and aeration stages. A submersible DO probe with a DO meter was continuously used to monitor the DO concentration in the reactor. The feed tank consisted o f a 30 gallon polyethylene tank which was placed in a refrigerator at 4C. The feed tank was refrigerated to limit bacterial growth in the feed tank. The reactor was operated in a cyclical mode for a period o f sixteen hours for each cycle. Operation o f each cycle comprised o f 4-hour feed with aeration, 4-hour anaerobic, 4-hour aerobic, 4-hour settle and a two-minute decant period. During each cycle, 7.5 gallons o f feed was supplied and the same amount was decanted as supernatant. The total volume in the reactor was 24 gallons. The feed and supernatant were collected and analyzed for COD and ammonia nitrogen (NH3-N) twice per week. The reactor was also monitored for MLSS and sludge volume index (SVT) twice per week. The COD analyses was favored over BOD as it gave very fast and repeatable results. 5 T a b le ^ -I^ O rg a n ic ja n d J n o t^ a n ic j^ n th e tic w a s te w a te r co n stitu en ts __________ O rg a n ic Feed S to c k __________ __________ Constituent Ref.Conc. Cooc/CH2M Grams for Grams 94-* mg/L* 30 gai soin per Gal. Beef Extract Bactopeptone Urea KH2PO4 K2HP04 (NHOzCO, NaHC03 NazCOj CH3COOH 9.0730 13.1960 2.4740 4.7420 1.8560 9.3610 13.7330 38.4760 9.5710 56.9784 82.8709 15.5367 29.7798 11.6557 58.7871 86.2432 241.6293 60.1059 16.1748 23.5250 4.4105 8.4537 3.3088 16.6882 24.4823 68.5925 17.0626 0.5392 0.7842 0.1470 0.2818 0.1103 0.5563 0.8161 2.2864 0.5688 in o rg an ic F eed S to ck Constituent Ref.Con COOC/CH2M Grams for Grams g /L * m g/L* 30 gai soin per Gal. MgS04 CaCl2.2 HzO NaCI FeS04 MnSO^HjO CuS0 4 Na2Mo04.2H20 ZnSO^HjO 18.804 4.9500 82.50 2.0630 0.0186 0 .0 0 12 0.0007 0.0193 23.693 6.2370 103.95 2.5994 0.0234 0.0015 0.0008 0.0243 6.7259 1.7705 29.5088 0.7379 0.0066 0.0004 0 .0 0 0 2 0.0069 0.2242 0.0590 0.9836 0.0246 0 .0 0 0 2 0.0000 0.0000 0 .0 0 0 2 * - Concentrations obtained from a previous study, done by CH2M HILL. 6 US00004483 However the BODiCOD ratio was periodically checked for both the feed and the supernatant in order to evaluate the stability o f the ratio. 2.2 Analytical M ethods The analytical methods employed in this study for evaluating the effects o f AFFF wastewater inputs on biological treatment performance consisted o f procedures as prescribed by the United States Environmental Protection Agency (USEPA) [16] or in Standard M ethods [17]. All chemicals used were reagent grade or better and all quality assurance/quality control procedures were followed as closely as possible. Measurements o f organic strength were determined through carbonaceous five day BOD (CBO D 5), COD, and total organic carbon (TOC) measurements. CBOD5 (determined with a nitrification inhibitor added to BOD bottles) were measured to eliminate potential interferences that nitrification could have on the evaluation o f organics removal with the BOD test. CBOD, COD, and TOC analyses were determined using filtered samples on reactor effluent and filtered and unfiltered samples in the influent. Samples were filtered through a glass fiber filter to eliminate microorganisms and other particulate materials that are not related to the organic components o f the AFFF or the dissolved organic compounds that are in the wastewater before AFFF introduction. Since the AFFF components are water soluble and will be dissolved in solution, filtration should not directly interfere with their accurate detection. Measurements o f total suspended and volatile suspended solids (TSS and VSS, respectively) were used to determine organic solids loading, reactor MLSS concentrations, and non-settleable TSS concentrations in reactor effluent. In order to reduce variability o f TSS and VSS data, the tests were performed on the same days that solids concentrations feeding into the reactor. The nitrogen series were determined by three different analytical techniques. Persulfate digestion followed by ammonia analysis by ion selective electrode was utilized to determine total Kjeldahl nitrogen (TKN) concentrations, ammonia concentrations were measured by ion selective electrode without sample digestion, and nitrate and nitrite concentrations were determined on filtered samples using ion chromatography. Orthophosphate was similarly determined using ion chromatography. 7 US00004484 As part o f this study, butyl carbitol, a major component o f AFFF, is also being analyzed by ion chromatography utilizing electrochemical detection. Decomposition o f fluoro-organic compounds are being evaluated by ion chromatography through determination o f inorganic fluoride directly and inorganic fluoride following persulfate digestion. The change in fluoride concentration between preand post- digestion will give an indication o f the amount o f fluoride that is tied up in organic compounds. 2.3 BNR Inhibition Batch Assays Nitrification inhibition was assessed in a series o f batch experiments with AFFF-laden wastewater. Inhibition tests were performed using six, 6-liter batch reactors o f which three were controls (no AFFF added) and three were a single desired concentration o f AFFF as shown in Figure 2-1. Uniform seed biomass o f approximately 4,000 mg/L was obtained from the reference reactor for each batch reactor. Approximately 2,000 mL o f the appropriate organic and inorganic nutrients were added from the stock nutrient tank and stock (undiluted) AFFF was added in sufficient volume to the nutrient broth to obtain the test AFFF concentration needed. Each batch reactor was equipped with an air supply source, an air stone, and a mixer. After the uniform seed biomass was added to each reactor, the air was turned on and the feed stock solution was introduced manually at 0, 30, 60, and 90 minutes during the two hour fill cycle. The reactors were mixed and aerated during the feed cycle and dissolved oxygen was monitored to insure adequate aeration. At the end o f this cycle, samples were withdrawn and the reactors were covered with lids to achieve anaerobic conditions. Mixing was continued throughout this cycle to maintain the biomass in suspension. At the end o f the two hour anaerobic cycle another sample was withdrawn from each reactor, air was turned on and the lids were removed. Aeration and mixing were continued for another two hours, and additional samples were taken at the end o f the aerobic cycle. Finally, the reactor contents were allowed to settle for two hours and samples taken from the supernatant were removed during the decant cycle. Each sample from the reactors was analyzed for pH, TKN, ammonia, N 0 3', N 0 2', orthophosphate, COD, BOD, TSS, VSS, TDS, and alkalinity. Comparisons were made between the controls which did not contain any AFFF and the reactors dosed with AFFF. 8 US00004485 Figure 2-1: BNR Inhibiton Batch Assays Stock Nutrient AFFF W astewater TT 1 Control (No AFFF WW) Tt t (3,000 mL BNR Inhibition Batch Reactors 9 US00004486 The degree o f ammonia oxidation in beakers receiving a loading o f AFFF wastewater was compared to the degree o f oxidation in control reactors that did not contain any AFFF. All samples were held for less than 48 hours prior to analytical testing. While performing the inhibition batch assay experiments, dissolved oxygen concentrations were determined during the feed and aeration cycles. This was done by measuring the dissolved oxygen depletion o f a mixed liquor sample taken from each reactor into a BOD bottle for a period o f five minutes. Oxygen uptake rates (OUR) were measured and the respiration rates were determined by specific oxygen uptake rate (SOUR) measurements; SOUR = OUR/MLVSS (mixed liquor volatile suspended solids). This procedure provided an indication o f the effects o f the untreated AFFF wastewater on the microorganisms. 2.4 Toxicity Pass-Through Testing Toxicity pass-through testing was performed on the inhibition reactors (controls and AFFF- dosed) to estimate what the maximum concentration o f AFFF to the BNR process would be without causing effluent toxicity. The acute toxicity pass-through tests were performed using the procedures outlined by the USEPA [18], At the end o f the BNR inhibition batch aeration period, the mixed liquor was allowed to settle and clarified supernatant was decanted from each reactor and filtered through a coarse glass fiber filter. This filter is o f the same type that is used for suspended solids analysis with 10 micrometer nominal size and without organic binder. Prior to use, the glass fiber filters were rinsed thoroughly by passing high-purity, deionized distilled water through the filter. The filtration apparatus was rinsed between each sample aliquot using 10 percent H N 0 3, acetone and high purity water. The filter toxicity was also checked by testing filtered dilution water. Toxicity samples were submitted to a qualified bioassay laboratory, Reed and Associates, Newport News VA, for acute toxicity testing using M . bahia and C. variegatus following the current EPA procedures. It was ensured that the laboratory would perform a standard reference toxicant test on a regular basis and develop accompanying quality control charts. All samples were held for less than 48 hours prior to use in testing. 10 US00004487 3.0 RESULTS The results o f this study include AFFF waste characterization, initial range finding tests, inhibition tests and toxicity pass-through. Each result will be described in the following sections. 3.1 A FFF W aste C haracterization The AFFF compound used in this study is manufactured by the 3M Company. The name o f the compound is FC-203CE LightwaterTM brand Aqueous Film Forming Foam. Before analyzing for the priority pollutants, the manufacturer o f the AFFF was contacted and a letter from the Company was obtained specifying the levels o f different compounds that may be present in the AFFF. M ost o f the priority pollutants were either claimed not to be intentionally added, or known to be present according to 3M Company. Among the chemical specific measurements required by HRSD, BOD5is reported as 0.091 g/g, and COD is reported as 0.740g/g in the MSDS data. The pH value was measured as 8.0 at 77F. The TSS, TKN, TOC and alkalinity measurements were not specification requirements for AFFF, therefore, they were measured in the Environmental Engineering laboratory o f ODU along with the fluoride concentration. O f the pesticides and PCBs, the compound Tolyl triazole (CAS# 29385-43-1) is stated to be present at 0.05 percent as shown in the MSDS. Butyl carbitol,(CAS# 112-34-5) is also present as diethylene glycol butyl ether at 30 percent by volume. The surfactant component o f AFFF is a trade secret and was not disclosed by the 3M Company. Table 3-1 shows a summary o f the chemical/parameter specific measurements determined in the laboratory for some parameters and specified by the 3M Company for most o f the remaining parameters. 3.2 Reference R eactor Perform ance The reference reactor was operated for 16 weeks and monitored for MLSS, MLVSS, SVI, COD, ammonia nitrogen, and TKN on a semi-weekly basis (Table 3-2). Collection o f influent and effluent (supernatant) samples and the mixed-liquor allowed calculation o f COD and ammonia removal as well as the food-to-microorganisms (F/M) ratio. 11 T able 3-1 Chemical/Parameter-Specifc M easurements Param eter Concentration BODj 0.091 g/g COD 0.740 g/g TSS, EPA 160.2 <5 mg/L Cl2 residual N ot intentionally added or known to be present by the manufacturer pH, conventional 8.0 at 77C Total Phosphorus Not intentionally added or known to be present by the manufacturer TKN, EPA 351.2-1 th ru -5 <0.5 mg/L Chlorides, Standard Methods 4500.B 1 mg/L TOC, Standard Methods 156,000 mg/L n h 3, N ot intentionally added or known to be present by the manufacturer Alkalinity, standard Methods 2320.B 520 mg/1 as C aC 03 TDS N ot intentionally added or known to be present by the manufacturer Metals N ot intentionally added or known to be present by the manufacturer Cyanide, by distillation N ot intentionally added or known to be present by the manufacturer Pesticides and PCB's Tolyl Triazole, 0.05% by volume Volatile Organics Butyl Carbitol, 30% by volume Semi-volatile Organics N ot intentionally added or known to be present by the manufacturer Acrolein N ot intentionally added or known to be present by the manufacturer Acrylonitrile N ot intentionally added or known to be present by the manufacturer 12 US00004489 1,2-Diphenylhydrazine Arochlor 1252 Arochlor 1262 2,3,7,8-Tetrachlorodihenzo-p-dioxin Methyl ethyl ketone Methyl isobutyl ketone Xylenes Acetone Surfactant Fluorohydrocarbons Fluoride Butyl Carbitol Not intentionally added or known to be present by the manufacturer Not intentionally added or known to be present by the manufacturer Not intentionally added or known to be present by the manufacturer Not intentionally added or known to be present by the manufacturer Not intentionally added or known to be present by the manufacturer Not intentionally added or known to be present by the manufacturer Not intentionally added or known to be present by the manufacturer Not intentionally added or known to be present by the manufacturer Trade secret (not disclosed) Not intentionally added or known to be present by the manufacturer May be present 30% by volume; method for direct measurement still under development 13 US00004490 Table 3-2. Week V Performance of the Re ference Reactor dur ng the course of the study Week MLSS MLVSS COD mg/l %COD SVI mg/l mg/l Feed Super. removal NH3-N mg/l TKN mg/l Feed Super. Feed Super. 1 4060 3451 376 26 93.0 6.4 0.2 33.3 1.9 3940 3349 476 5 98.9 -- 22.5 0.2 34.2 4.0 2 3824 3250 495 24 95.2 ~~ 26.2 0.1 53.2 1.0 3736 3175 ~~ 145.0 23.2 0.2 55.4 2.8 3 3636 3090 452 26 94.2 156.0 25.2 0.2 46.0 0.1 2600 2210 478 22 95.4 VA< 36.6 0.1 101.6 1.8 4 2768 2352 468 10 97.8 2908 2471 -- -- S 20.4 0.0 32.0 0.0 48.4 0.1 59.3 0.2 5 3024 2570 442 5 98.9 212.0 27.1 0.1 222.8 1.6 3240 2754 672 39 94.1 37.8 0.3 202.8 2.7 6 3323 2824 672 32 95.3 265.0 ~ ~ -- ~~ -- 3436 2920 974 18 98.1 258.0 ~ ~ -- ~~ -- 7 2412 2050 968 77 92.1 344.0 ~ ~ ~~ ~~ -- 2956 2512 1421 9 99.4 314.0 26.0 0.1 144.6 2.9 8 3200 2720 -- ~~ 3600 3060 awaw -- -- 296.0 22.1 0.1 73.3 4.1 >^A >400 29.0 0.4 312.5 2.1 9 2964 2519 807 76 90.5 >400 mm ~~ ~~ 2924 2485 971 151 84.5 >400 ~ -- ~~ ~~ 10 3280 2788 1416 -- -- >400 58.3 15.3 995.1 57.9 3024 2570 2250 156 93.1 >400 92.2 14.9 977.6 87.0 11 3000 2550 1188 82 2668 2267 1231 55 12 2740 2248 1251 58 93.1 300.0 117.6 41.0 1245.4 87.0 95.5 292.0 80.9 0.2 977.6 8.5 95.4 302.0 28.3 0.3 ~~ -- 2900 2420 1338 95 92.9 279.0 ~~ AW*# -- -- 13 3220 2676 ~ ~ -- AH<V 10.6 0.2 323.7 8.8 2456 1976 ~ ~ -- -- 325.0 -- -- -- -- 14 2704 2408 1300 90 93.1 332.0 35.7 0.4 413.9 6.2 2160 1916 1300 90 93.1 15 2372 2092 1400 100 92.9 379.0 30.3 0.3 454.5 6.4 1740 1604 1200 90 92.5 >400 ~~ -- Average 2975 2454 989 59 94.2 37.5 3.6 338.7 14.3 Average VSS-62.4% note: -- = Data not available F/M Organic Load mg/l/day 0.03 0.04 0.05 -- 169.0 214.3 222.6 0.04 203.6 0.06 214.9 0.06 210.7 -- 0.05 198.8 0.07 302.5 0.07 302.4 0.10 438.3 0.14 435.5 0.17 639.6 -- 0.10 0.12 0.15 0.26 0.14 0.16 0.17 0.17 -- ~~ 0.16 0.20 0.20 0.22 0.14 363.2 437.1 637.2 1012.4 534,7 553.8 563.0 601.9 585.0 585.0 630.0 540.0 445.1 The average COD removal was approximately 95% while removal for ammonia-nitrogen averaged 90%. Throughout most o f Phase 1A, the reference reactor exhibited good nitrification with > 98% ammonia removal . However, a sharp increase in the feed ammonia concentration occurred in the 10th and 11th week carried over to the supernatant indicating that significant nitrification inhibition occurred. Inhibition may have been caused by the elevated ammonia concentrations as high ammonia concentrations can be toxic to the nitrifying bacteria and inhibit the nitrification process. To overcome this problem the feed organic strength was reduced. The SVI values o f the reactor increased significantly after five weeks o f continuous operation. One o f the reasons for this was thought to be aeration during the feed cycle and low nutrient loading to the reactor. To correct this problem, an unsuccessful attempt was made by adding hydrogen peroxide at 60 mg/1. The initial F/M ratios in the reference reactor were very low. However, by gradually increasing the COD o f the feed solution, the F/M ratios were increased. The purpose o f increasing the F/M ratio was to simulate the VIP process that operates under an F/M ratio o f approximately 0.22. As noted earlier, the reactor did not exactly simulate the VIP process. Aeration o f the reactor during the fill stage caused the reactor to cycle from aerobic to anoxic to aerobic before settling. In contrast, the VIP process consists o f an anaerobic, anoxic, aerobic sequence o f conditions. The operation o f the reference reactor under these conditions did not allow for P removal. Phosphorus removal is best achieved by having anaerobic and/or anoxic conditions preceding the aerobic cycle allowing poly P bacteria to become established. To assess the phosphorus removal and nitrate production in the reactor, the supernatant was analyzed by ion chromatography periodically and the results are tabulated in Tables 3-3 a, b, and c. As can be seen from these results phosphorus removal did not occur. Nitrite was generally low and it was observed on one occasion (February 18) to accumulate during aerobic periods indicating not all o f the ammonia was oxidized to nitrate. Nitrate concentrations were high throughout the study due to the high concentration o f TKN in the feed wastewater. Nitrate was removed during the anaerobic (anoxic) stage but the lack o f organic matter during this stage most likely limited nitrate removal. The reactor was also monitored for pH during the different stages o f operation. The pH o f the feed solution was maintained at approximately 6.7 with a bicarbonate alkalinity o f approximately 300-400 mg/1 as calcium carbonate. The pH during the various cycles ranged from 7.5 to 7.8. The 15 Table 3-3a: Nitrite Nitrogen concentration variation during different stages Sample Nitrite (NOz'-N) mg/l 1/16/97 1/23/97 2/7/97 2/18/97 Feedstock 0.0 0.0 0.0 0.7 Start-of-Feeding 0.0 0.0 1.4 2.7 Middle-of-Feeding 0.0 0.0 0.6 0.7 End-of-Feeding 1.1 0.0 1.6 3.1 Middle-of-Anaerobic 1.1 0.0 1.5 0.7 End-of-Anaerobic 1.0 0.0 0.0 0.7 Middle-of-Aerobic 0.0 0.0 0.0 2.9 End-of-Aercbic 0.0 0.0 -- 3.5 Middte-of-Settling 0.0 0.0 -- 3.2 Supernatant 0.0 0.0 0.0 3.2 Table 3-3b: Nitrate Nitrogen concentration variation during different stages Sample Nitrate (NOj'-N) mg/I 1/16/97 1/23/97 2/7/97 2/18/97 Feedstock Start-of-Feeding Middle-of-Feeding End-of-Feeding Middle-of-Anaerobic End-of-Anaerobic ^*ddle-of-Aerobic End-of-Aerobtc Middle-of-Settiing Supernatant 0.9 46.6 44.6 48.1 46.2 43.8 45.9 47.9 48.3 47.4 0.9 49.4 43.0 43.2 41.8 40.2 48.3 49.7 49.7 49.9 0.8 54.3 33.9 57.2 53.2 53.6 56.2 -- -- 57.7 0.7 94.6 83.1 82.8 76.5 75.8 86.5 101.8 101.5 101.5 Table 3-3c: Orthophosphate concentration variation during different stages Sample PO/-P mg/l 1/16/97 1/23/97 2/7/97 2/18/97 Feedstock Start-of-Feeding Middle-of-Feeding End-of-Feeding Middle-of-Anaerobic End-of-Anaerobic Middle-of-Aerobic End-of-Aerobic Middle-of-Settiing Supernatant 20.6 20.0 19.6 19.1 19.0 18.6 20.5 19.3 19.5 19.4 21.9 22.7 22.4 20.4 20.9 20.9 21.9 22.3 22.2 23.0 24.3 25.6 22.9 23.3 22.9 22.9 23.7 -- 24.1 34.1 27.5 27.2 26.0 25.4 25.7 26.1 26.8 27.0 27.1 16 US00004493 alkalinity o f the supernatant was about 100-150 mg/1 as calcium carbonate. Alkalinity o f the feed was sufficient to provide good nitrification throughout this phase o f the study. The DO concentration was also continuously monitored during the different stages o f the reactor operation. The average DO values ranged between 4.5 to 5.5 mg/L during the feed stage; 0.15 to 0.10 mg/L during the anaerobic stage; and 5.5 to 6.0 mg/L, during the aeration stage o f the reactor operation. The DO was adjusted by changing the flow o f air which was measured with the help o f a flow meter, attached to the air supply line. 3.3 Range Finding Test Results At the beginning o f the study, it was proposed that AFFF wastewater concentrations be tested at concentrations that might be expected for a worst-case scenario. The worst-case scenario was stipulated by HRSD and was identified as the highest discharge from a Navy hangar occurring at the lowest hourly flow through HRSD's Chesapeake-Elizabeth plant. Consideration o f greater dilution factors would be a cause far the District to require containment and subsequent controlled discharge. The results o f preliminary tests that were conducted at the worst case concentration indicated that the motility o f microorganisms were affected significantly. Therefore, the range finding tests were performed at lower concentrations o f AFFF solutions than the worst-case concentration. Initially, a set o f BNR inhibition batch assays were performed with different concentrations o f AFFF wastewater in order to determine a range that may be inhibitory to the nitrification process. This range aided in narrowing the span o f concentrations to be tested in the further biological nutrient removal inhibition evaluation tests. The concentrations o f AFFF used were 1,050 ppm, 105 ppm, 60 ppm, 10.5 ppm, 1.05 ppm and a control. The reactor components for each AFFF concentration and the control are summarized in Table 3-4. The results indicated that nitrification inhibition occurred at AFFF concentrations of 60 ppm, 105 ppm, and 1,050 ppm in the feed wastewater. The results o f range finding tests with respect to ammonia nitrogen and COD removal rates are shown in Table 3-5. 3.4 BNR Inhibition Batch Assays After determining a specific range o f AFFF wastewater that exhibited inhibitory effects to the biological nutrient removal process, four concentrations o f AFFF were tested in addition to paired 17 TABLE 3-4 -- Range Finding Test Reactor Components CONTROL REACTORS PARAMETER A, a 2 a 3 Total Reaction Volume (mL) 6,000 6,000 6,000 Batch MLSS (mg/L) 2,560 2,560 2,560 Seed Biomass Volume (ml) 4,000 4,000 4,000 Effective Wastewater (feed & AFFF) Volume (ml) 2,000 2,000 2,000 AFFF Concentration (ppm) 0 1,050 1,050 AFFF Volume for the simulated wastewater (ml) 0.0 70.0 7.0 Volume of synthetic Feed Solution 3,000 for the simulated wastewater (mL) 1,930 1,993 INHIBITION REACTORS B, b 2 b 3 6,000 6,000 6,000 2,560 2,560 2,560 4,000 4,000 4,000 2,000 2,000 2,000 1,050 4.0 1,050 0.70 1,050 0.07 1,996 1,999.3 1,999.93 TABLE 3-5 -- Range Finding Inhibition Test Results Reactor Feedstock Reference Reactor Control AFFF-1 AFFF-2 AFFF-3 AFFF-4 AFFF-5 AFFF ppm 0 0 Initial** NHj-N mg/L Final NH,-N mg/L % Removal Initial* NO,-N mg/L Final NO,-N mg/L Initial COD mg/L Final COD mg/L COD Removal % 0. 8.4 0.1 98.8 29.7 36.9 171 22.0 87.1 1.05 13.7 1.2 91.2 19.7 34.8 181 44.5 75.4 10.5 7.5 0.2 97.3 30.6 39.7 267 97.0 63.7 60 5.2 3.7 28.8 31.6 36.5 718 504.5 29.7 105 8.1 7.7 4.9 28.9 32.3 1128 827.0 26.7 1050 13.7 23.8 -73.7 6.0 7.4 9738 3919.5 ** * Initial Values correspond to the measurements taken at the end o f feeding stage. ** The COD vials used measured between the ranges 0 to 900 mg/L. Dilutions were not made due to very high levels of COD at this concentration. controls. During each inhibition testing, one set o f triplicate reactors (6-liter volume) were used as control which did not include any AFFF wastewater exposure. The remaining three reactors were used for one specific AFFF concentration. The inhibition concentrations that were tested include 10 ppm, 30 ppm, 50 ppm, and 60 ppm o f AFFF in the feed wastewater and mixed liquor from the reference reactor. The results o f each concentration tested will be described separately in the following sections. 3.4.1 Inhibition Test at 60ppm AFFF Concentration Triplicate reactors for control and 60 ppm AFFF concentration were set up to observe nitrification inhibition. The conditions o f this inhibition test are summarized in Table 3-6. During the testing, significant foaming occurred with the 60 ppm AFFF concentration as compared to the controls however, solids washout were not significant. A thick layer o f foam was formed on top o f the inhibition reactors which prevented the loss o f solids. The ammonia nitrogen removal rates ranged between 97 to 98 percent as shown in Table 3-7. There was no significant nitrification inhibition as compared to the control reactors. The COD removal rates were higher for the AFFFdosed inhibition reactors ranging between 92 and 95 percent. This higher removal reflects the higher initial COD concentration associated with the AFFF. Oxygen uptake rates (OUR) and SOUR were measured during the inhibition testing. The air supply to each reactor was monitored during the aerated feed and aerobic stage with a submergible dissolved oxygen probe to ensure that appropriate amount o f dissolved oxygen was provided. The results indicated a lower oxygen uptake with the inhibition reactors at 60 ppm AFFF concentration and are shown in Figures 3-1 and 3-2. 3.4.2 Inhibition Test at 50 ppm AFFF Concentration At 50 ppm AFFF concentration, significant foaming and solids removal from solution were observed. The foam was "lighter" and there was no layered foam as observed in the reactors as seen with the higher 60 ppm AFFF concentration. The solids loss was the most intense o f all the inhibition tests as shown in Table 3-8 along with the reactor components. The nitrification inhibition results indicated ammonia nitrogen removal rates ranging from 94 to 96 percent for the control reactors. Nitrification was not inhibited in the inhibition reactors as compared to the controls. The COD 20 US00004497 TABLE 3-6-- BNR Inhibition R eactor 60 ppm A FFF Com ponents PARAMETER Total Reaction Volume (mL) Batch MLSS (mg/L) Batch MLVSS (mg/L) Seed Biomass Volume (ml) Effective wastewater (feed & AFFF) Volume, ml AFFF Concentration (ppm) AFFF Volume for the simulated wastewater (mL) Volume o f Synthetic Feed Solution for the simulated wastewater (mL) r A \T r T T n A T Tk*n A A r T A n O c u n 1IVUL/ IVCiAClUM Ai 6,000 a2 6,000 a3 6,000 2,540 2,513 2,567 2,387 2,347 2,413 4,000 4,000 4,000 2,000 2,000 2,000 000 0.0 0.0 0.0 2,000 2,000 2,000 j u ^ j u L o m u n i v ^ / \ c i u iv orV T T T T O T rrT A T A T T%T A A T l A T O B, 6,000 b2 6,000 b3 6,000 2,353 2,280 2,253 2,207 2,120 2,120 4,000 4,000 4,000 2,000 2,000 2,000 60 60 60 4.0 4.0 4.0 1,996 1,996 1,996 TABLE 3-7 -- Nitrification Inhibition at 60 ppm Reactor Feedstock Reference Reactor Decant Control (Al) Control (A2) Control (A3) AFFF (Bl) AFFF (B2) AFFF (B3) AFFF ppm 0 0 ` Initial nh3- n mg/L 30.3 0.3 Final nh3- n mg/L -- -- ` Initial % NOj-N Removal mg/L -- 0.9 -- 103.5 Final NOj-N mg/L -- -- Initial COD mg/L 1931 127 Final COD mg/L COD Removal % 0 8.2 0 7.8 0 6.9 60 10.0 60 10.4 60 8.5 0.21 97.44 70.9 0.14 98.21 67.8 0.17 97.54 68.6 0.27 97.30 60.8 0.23 97.79 58.0 0.19 97.76 61.0 87.8 343 37 87.7 343 37 89.7 343 48 84.5 1206.** 97 82.5 1206.** 67 86.3 1206.** 67 89 89 86 92 95 95 * Initial values correspond to the measurements taken at the end of feeding stage. ** Corresponds to the total COD which includes: Reference Reactor decant COD = 127 mg/L, Feedstock COD=l,931 mg/L and AFFF COD = 5,180 mg/L. o -0.005 $ -001 + cm: -0.015 - l -002 3 8 -0.025 - -0.03 -0.035 A1 A2 A3 Reactors B1 B2 Figure 3-1: Specific Oxygen uptake rates (SOUR's) during the feed stage for 60 ppm AFFF (A-Control, B-Inhibition) B3 23 US00004500 TABLE 3-8-- BNR Inhibition R eactor Components: 50 ppm AFFF PARAMETER Total Reaction Volume (mL) Batch MLSS (mg/L) Batch MLVSS (mg/L) Seed Biomass Volume (ml) Effective wastewater (feed & AFFF) Volume, ml AFFF Concentration (ppm) AFFF Volume for the simulated wastewater (mL) Volume of Synthetic Feed Solution for the simulated wastewater (mL) CONTROL REACTORS At 6,000 a2 6,000 a3 6,000 2,713 2,653 2,680 4,000 2,000 4,000 2,000 4,000 2,000 000 0.0 0.0 0.0 2,000 2,000 2,000 INHIBITION REACTORS B, b 2 b 3 6,000 6,000 6,000 1,693 1,106 1,213 4,000 2,000 4,000 2,000 4,000 2,000 50 50 50 3.3 3.3 3.3 1,997 1,997 1,997 removal rates were significantly lower in inhibition reactors than the control reactors which are shown in Table 3-9. The dissolved oxygen measurements during the aerobic stage are also presented in Figures 3-3. 3.4.3 Inhibition Test at 30ppm AFFF Concentration The reactor components for this inhibition test are shown in Table 3-10. Loss o f solids was also observed in this test in the inhibition reactors as compared to the control reactors potentially due to the nature o f the foam formed with this AFFF concentration. The results showed no significant nitrification inhibition . The COD removal rates ranged between 75 to 77 percent in the inhibition reactors and 87 to 90 percent in the control reactors as shown in Table 3-11. The oxygen uptake rates in terms o f SOURs are also shown in Figures 3-4 and 3-5. 3.4.4 Inhibition Test at 10 ppm AFFF Concentration Significantly less foaming and loss o f solids were observed with the 10 ppm AFFF concentration. The reactor components and volumes are shown in Table 3-12. M ost o f the nitrification has already occurred during the aerated feed stage with the ammonia nitrogen concentrations being less than 0.2 mg/L for the control reactors. Even though the ammonia nitrogen removal rates were lower (between 10 and 45 %) for the control reactors, the effluent ammonia nitrogen values were also less than 0.1 mg/L as shown in Table 3-13. The COD removal for the inhibition reactors were riot significantly different than the control reactors possibly due to the low COD o f AFFF at the lower concentrations tested. The SOUR measurements during the feed and aerobic stages are shown in Figures 3-6 and 3-7. 3.5 Toxicity Pass-Through Testing The results o f the plant toxicity pass-through tests conducted with the mysid shrimp and sheepshead minnows did not exhibit any pass-through toxicity. The response measured during the acute toxicity tests was survival over the exposure period. The toxicity test results for the samples collected at the end o f each inhibition testing from the reactors with and without AFFF had LC50 values greater than 100 percent for both test organisms as shown in Table 3-14. The only sample that 25 TABLE 3-9 -- Nitrification Inhibition at 50 ppm Reactor Feedstock Reference Reactor Decant Control (Al) Control (A2) Control (A3) AFFF (Bl) AFFF (B2) AFFF (B3) ` Initial AFFF NHj-N ppm mg/L 0 29.73 0 0.94 Final nh3- n mg/L -- ... ` Initial % NOj-N Removal mg/L -- 0.7 . . . 105.7 Final no3- n mg/L Initial COD mg/L 997 79 Final COD mg/L COD Removal % 0 3.23 0 2.74 0 3.81 50 9.68 50 11.88 50 11.40 0.19 94.12 82.8 0.19 93.10 84.0 0.15 96.06 84.6 0.20 97.93 82.9 0.64 94.61 75.6 0.09 99.21 77.7 93.1 367 85.6 367 86.1 367 96.3 976 90.7 976 95.5 976 24.1 43.2 38.4 315.3 332.0 327.2 93.4 88.2 89.5 67.7 66.0 66.5 * Initial values correspond to the measurements taken at the end o f feeding stage. ** Corresponds to the total COD which includes RR decant COD = 79 mg/L, Feedstock COD = 997 mg/L and AFFF COD = 4320 mg/L 0 -0,005 -- 0.01 - -0.015 - - A1 A2 A3 B1 - 0.02 - -0.025 - -0.03 Reactors B2 oB3 Figure 3-3: Specific Oxygen uptake rates(SOUR's) during the aerolbic stage for 50 ppm AFFF (A--Control, B--Inhibition) Note: The SOUR's are calculated by using VSS, which were calculated by taking the average TSS:VSS ratio for the reference reactor, since they were not actually measured. 27 US00004504 TABLE 3-10-- BNR Inhibition Reactor Components: 30 ppm AFFF PARAMETER Total Reaction Volume (mL) Batch MLSS* (mg/L) Batch MLVSS* (mg/L) Seed Biomass Volume (ml) Effective wastewater (feed &AFFF) Volume, ml AFFF Concentration (ppm) AFFF Volume for the simulated wastewater (mL) Volume of Synthetic Feed Solution for the simulated wastewater (mL) CONTROL REACTORS A, A2 a3 6,000 6,000 6,000 2,787 2,760 3,300 2,573 2,293 2,753 4,000 4,000 4,000 2,000 2,000 2,000 000 0.0 0.0 0.0 2,000 2,000 2,000 * Reference reactor MLSS - 3,760 mg/L and MLVSS = 3,296 mg/L INHIBITION REACTORS B, 6,000 B2 6,000 b3 6,000 2,140 2,560 2,400 1,927 2,300 2,193 4,000 4,000 4,000 2,000 2,000 2,000 30 30 30 2.0 2.0 2.0 1,998 1,998 1,998 TABLE 3-11 -- Nitrification Inhibition at 30 ppm Reactor Feedstock Reference Reactor Decant Control (Al) Control (A2) Control (A3) AFFF (Bl) AFFF (B2) AFFF (B3) AFFF ppm 0 0 ` Initial NH3-N mg/L 35.71 0.39 Final NH3-N mg/L % Removal ` Initial NO- -N mg/L 0.0 88.2 Final NO- -N mg/L Initial COD mg/L 2675 380 Final COD mg/L COD Removal % 0 6.6 0 7.1 0 7.4 30 10.7 30 11.6 30 10.7 0.30 95.4 69.2 84.5 509 66.8 86.9 0.32 95.5 67.7 84.4 509 61.8 87.9 0.31 95.8 65.9 83.8 509 51.8 89.8 0.42 96.1 63.5 84.9 948** 232 75.5 0.69 94.0 61.5 79.8 948** 249 73.7 0.66 93.8 63.4 83.7 948** 217 77.1 * Initial values correspond to the measurements taken at the end o f the feeding stage. ** Corresponds to the total COD which includes Reference Reactor decant COD = 380 mg/L, Feedstock COD = 2675 mg/L, and AFFF COD = 2,630 mg/L US00004506 30 US00004507 TABLE 3-12--BNR Inhibition Reactor Components: 10 ppm A FFF PARAMETER Total Reaction Volume (mL) Batch MLSS * (mg/L) Batch MLVSS * (mg/L) Seed Biomass Volume (ml) Effective wastewater (feed & AFFF) Volume, ml AFFF Concentration (ppm) AFFF Volume for the simulated wastewater (mL) Volume of Synthetic Feed Solution for the simulated wastewater (mL) CONTROL REACTORS A, A2 A3 6 ,0 0 0 6 ,0 0 0 6,000 2,847 2,807 2,747 2,567 2,553 2,827 4,000 4,000 4,000 2 ,0 0 0 2 ,0 0 0 2,000 000 0.0 0.0 0.0 2 ,0 0 0 2 ,0 0 0 2 ,0 0 0 INHIBITION REACTORS B, b 2 b 3 6 ,0 0 0 6 ,0 0 0 6 ,0 0 0 2,613 2,527 2,600 2,393 2,333 2,367 4,000 4,000 4,000 2 ,0 0 0 2,000 2 ,0 0 0 10 10 10 0.7 0.7 0.7 1,999 1,999 1,999 * Reference Reactor MLS S = 4,020 mg/L, MLVSS = 3,464 mg/L TABLE 3-13 -- Nitrification Inhibition at 10 ppm Reactor Feedstock Reference Reactor Decant Control (Al) Control (A2) Control (A3) AFFF (Bl) AFFF (B2) AFFF (B3) ` Initial AFFF NHj-N ppm mg/L 0 10.61 0 0.22 Final NHj-N mg/L % Removal ` Initial NOj-N mg/L 0.0 85.4 Final NOj-N mg/L Initial COD mg/L 2396 247 Final COD mg/L COD Removal % 0 0.10 0 0.14 0 0.20 10 1.05 10 0.62 10 0.92 0.09 10.0 78.6 76.9 441 63.2 85.7 0.09 35.7 79.8 76.0 441 55.3 87.4 0.11 45.0 78.6 76.7 441 57.9 86.9 0.08 92.4 69.4 76.2 596** 118 80.2 0.11 82.3 73.4 79.4 596** 116 80.6 0.12 87.0 72.2 76.4 596** 123 79.3 * Initial values correspond to the measurements taken at the end o f feeding stage, (end o f 2 hours) ** Corresponds to the total COD which includes Reference Reactor Decant = 2,396 mg/L, Feedstock COD = 247 mg/L and AFFF COD = 1,608 mg/L 33 US00004510 Table 3.14: Summary of the Toxicity Testing for the Inhibition tests AFFF Date of test Sample Cone,(ppm) Fathead Minnow Feedstock < 6 .2 5 R.R.Mix Liquor >100 Control A1 >100 Control A2 10 3/11/97 Control A3 >100 >100 Inhibition B1 >100 Inhibition B2 >100 Inhibition B3 >100 Feedstock 17.7 R.R.Mix Liquoi >100 Control A1 >100 Control A2 >100 30 3/19/97 Control A3 >100 Inhibition B1 >100 Inhibition B2 >100 Inhibition B3 >100 Feedstock 19.5 R.R.Mix Liquoi >100 Control A1 >100 Control A2 50 2/11/97 Control A3 >100 >100 Inhibition B1 >100 Inhibition B2 >100 Inhibition B3 >100 Feedstock 33 R.R.Mix Liquor >100 Control A1 >100 Control A2 60 3/25/97 Control A3 >100 >100 Inhibition B1 >100 Inhibition B2 >100 Inhibition B3 >100 LC50 Mysid Shrimp 31 >100 >100 >100 >100 >100 >100 >100 52 >100 >100 >100 >100 >100 >100 >100 >100 >100 35 >100 >100 >100 >100 >100 34 >100 >100 >100 >100 >100 >100 >100 34 US00004511 exhibited consistent toxicity was the influent feed to the reactors which was attributed to the high ammonia concentrations present in the feed mix which ranged from 30 to 35 mg/L o f NH3-N. 4.0 DISCUSSION The results o f the: range-finding tests indicated that concentrations o f AFFF higher than 60 ppm clearly exhibited significant potential to impact nitrification. For the lower AFFF concentrations in the range finding tests, the ammonia nitrogen concentrations in the supernatant were 0.1 mg/1 for the control, 1.2 mg/L for 1.05 ppm AFFF solution, and 0.2 mg/L for 10.5 ppm AFFF solution indicating little or no inliibition as seen in Figure 4-1. For AFFF solutions o f 60 ppm and above, significant nitrification inhibition occurred in the wastewater as compared to the control reactors. N ote that the increasing ammonia concentrations at 1,050 ppm indicate conversion o f organic nitrogen to ammonia occurred. Nitrate production rates were also in accordance with the ammonia removal rates, and an excellent mass balance on the nitrogen species was observed overall. During the range finding tests, the motility o f microorganisms were also observed under the microscope for each AFFF concentration. There were no apparent changes observed between 1 and 60 ppm AFFF concentrations. However, at concentrations greater than 60 ppm AFFF, motility o f microorganisms was impacted significantly. This observation is consistent with the nitrification inhibition results. Therefore, AFFF concentrations equal to and lower than 60 ppm were tested in the inhibition study to better delineate the effects o f AFFF at concentrations approaching nitrification inhibition levels. The COD removal rates decreased with increasing AFFF concentrations from as high as 87% in the control reactor to 27 % at the greatest AFFF concentration. While the percent COD removal decreased with increasing AFFF concentration, the amount o f COD removed actually increased (on a mg/L basis). This observation is a direct result o f the addition o f COD associated with the AFFF. For example, the COD o f 300 ppm AFFF solution (1% AFFF concentrate) was measured to be 8,200 mg/L. This additional COD contributed by the AFFF had the effect o f increasing the initial COD o f the wastewater as the AFFF concentrations increased. The results o f the nitrification inhibition study showed that the AFFF concentrations tested in the range between 10 ppm to 60 ppm did not show any significant inhibition to biological nitrification. The effluent from each reactor did not exhibit any pass-through toxicity. The intensity 35 A FFF Inhibitor! R a n g e F inding R e su lts 25 20 Oa.. 15 <o 10 X z 1.05 10.5 60 105 AFFF C oncentration, ppm 1,050 Feed Aerobic Anaerobic Effluent Figure 4-1. AFFF Inhibition Study Range Finding Results 36 US00004513 o f foaming increased with the increasing AFFF concentrations. The loss o f solids from the reactors was associated with the foaming density which was in turn related to the amount o f air supplied and bubble size formed in each reactor. At AFFF concentrations between 10 ppm to 50 ppm, the loss o f solids increased. However, at 60 ppm, the foaming was so much denser that it did not allow solids carryover from the reactors. Uninhibited nitrification was also observed among the reactors that had excessive foaming. Some reductions in percent COD removal were seen as the AFFF concentrations increased. However, as indicated above these reactors actually removed more COD. The results showed no significant nitrification inhibition for any o f the AFFF concentrations tested as compared to the control reactors as shown in Figures 4-2a and 4-2b. It was observed that nitrification started to occur at the beginning o f the aerated feed stage for all o f the reactors and that significant ammonia removal occurred during this stage for both control and inhibition reactors at all AFFF concentrations tested. At the end o f the anaerobic cycle, some o f the ammonia nitrogen was released in all tests, possibly due to bacterial reduction o f nitrates and nitrites or organic nitrogen conversion to ammonia. The ammonia nitrogen concentrations decreased significantly at the end o f the aerobic cycle and in the effluent for each reactor, exhibiting no nitrification inhibition. The nitrate data for each inhibition test also supported the occurrence o f nitrification in the reactors. The nitrification occurring in each reactor can also be seen in Figure 4-3 which shows the ammonia nitrogen removal during different stages for each AFFF concentration tested. The effluent from each reactor exhibited greater than 98 percent ammonia removal. There was significant COD removal observed for each AFFF concentration tested as well. However, the percent COD removal in the inhibition reactors was less than that o f the control reactors and the percent COD reduction decreased with increasing AFFF concentrations in the inhibition reactors. These results are shown in Figures 4-4a and 4-4b. During this study, there was an increase in the foaming in the inhibition reactors with increased AFFF concentrations. This foaming was specifically heavy during the aerated feed stage o f the inhibition testing. The major influence on the reactor performance was the loss o f solids (MLSS) at higher AFFF concentrations. This loss o f solids removed microbical cells from solution and likely contributed to the lower percent COD removals. However, even at lower MLSS concentrations, the total amount o f COD removed exceeded that o f the controls. 37 Average Ammonia for Control Reactors (No AFFF Added) Time, hours ------------ 6 0 ppm C o n t r o l ------------ 5 0 ppm Control ............... 3 0 ppm Control -- -- 1 0 ppm Control Figure 4-2a. Average Ammonia Concentrations for Control Reactors Average Ammonia for Inhibition Reactors Time, hours 6 0 ppm A F F F ------------ 5 0 ppm A FFF 3 0 ppm A FFF -- -- 1 0 ppm A FFF Figure 4-2b. Average Ammonia Concentrations for Inhibition Reactors 38 US00004515 Ammonia Nitrogen Removal Rates 100 80 - 2 60 o tt 40 nI 20 60 ppm I 50 ppm 30ppm AFFF Concentration 10 ppm Figure 4-3. Feed A erobic A naerobic Effluent Average Ammonia Nitrogen Removal Rates for the Inhibition Reactors 39. US00004516 Average COD Removal for Control Reactors (No AFFF Added) ----------- 60 ppm C o n t r o l -----------50 ppm Control ............. 30 ppm Control -- -- 10 ppm Control Figure 4-4a. Average COD Removal Rates for the Control Reactors Average COD Removal for Inhibition Reactors ' Time, hours ----------- 60 ppm C o n t r o l ---------- 50 ppm Control ............. 30 ppm Control -- - -- 10 ppm Control Figure 4-4b. Average COD Removal Rates for the Inhibition Reactors 40 US00004517 Organo-fluoride compounds are known to be a constituent o f AFFF and it was suspected a priori that decomposition o f the organo-fluoride compounds would likely occur resulting in accumulations o f inorganic fluoride in solution. If this reaction occurs, then an increase in inorganic fluoride should be observed upon treatment o f a water containing AFFF. Fluoride measurements were conducted for controls and the AFFF wastewater at two-hour intervals and then examined for fluoride release. In the control samples, the fluoride concentrations remained essentially unchanged during the testing (Figure 4-5 a) as expected with no organo fluoride compounds present. This fluoride measured for these samples reflects the "background" inorganic fluoride concentration and when subtracted from the fluoride concentrations measured for the AFFFdosed wastewater (Figure 4-5b) will reflect the fluoride released from organic compounds (Figure 4-6). The linear relationship up to 50 ppm AFFF signifies that organo-fluoride compounds are being decomposed in proportion to the AFFF concentration. The low release o f F for the 60 ppm AFFF wastewater suggests some interference in fluoride release. This interference may be an inhibition o f the microorganisms that were capable o f decomposing these compounds or evidence o f selective substrate utilization (i.e. diauxic growth) where microorganism were consuming other preferable compounds before selecting organo-fluoride compounds. 5.0 CONCLUSIONS The results o f the nitrification inhibition study showed that the AFFF concentrations tested in the range between 10 ppm to 60 ppm did not show any inhibition to biological nitrification. The range finding tests indicated nitrification inhibition did occur above 60 ppm AFFF. Microscopic observations also showed significant impacts on the motility o f microorganisms at concentrations greater than 60 ppm AFFF. The reference reactor did not develop biological P removal due to the rapid consumption o f COD during the aerobic feed stage. This occurrence most likely prevented significant production o f acetate during anaerobic stage which is essential for developing poly P bacteria. It is likely that with an anaerobic feed cycle, the reactors would have exhibited P removal. Loss o f biological solids from the reactors increased with increasing AFFF concentrations up to 50 ppm, however, at 60 ppm very little solids were lost from the reactors. The intensity o f foaming increased with the increasing AFFF 41 l US00004518 - For 60 ppm - For SO ppm - For 30 ppm -For 10 ppm Figure 4-5a. Average inorganic Fluoride concentration for controls For 60 ppm For 50 ppm For 30 ppm For 10 ppm 01 2345678 Time (hours) Figure 4-5b. Inorganic Fluoride measurements as a function of reaction time concentrations however, uninhibited nitrification was also observed among the reactors that had excessive foaming. Some reductions in the percent COD removal were observed as the AFFF concentrations increased. Fluoride release suggested that organo fluoride compounds decomposed up to 50 ppm and some inhibition was observed at 60 ppm Acute toxicity test results showed that the effluent from each inhibition reactor did not exhibit any pass-through toxicity as well. Overall, the results o f Phase 1A study indicated that AFFF solutions discharged into the w astew ater at concentrations 60 ppm or below did not exhibit any inhibitory effect to biological nitrification and pass through toxicity. REFERENCES 1. CH2M Hill Co; Wastewater Effluent Pilot Study for the Advanced Fire Fighting Training Facility, Naval contract N62470-91-R-6650, Atlantic Division, Naval Facilities Engineering Command, October 1992. 2. CHjM Hill Co; Wastewater Treatability Final Report for the Advanced Fire Fighting Training Facility, Navy Contract N62470-91-C-6650, Atlantic Division, Naval Facilities Engineering Command, January 1995. 3. Chan, D. B., Disposal o f Wastewater Containing Aqueous Film Forming Foam, Technical Memorandum No. M-54-78-06, Civil Engineering Laboratory, April 1978. 4. Chan, D.B., Pam Bingham; AFFF-laden Wastewater Treatment Technology Initiation Decision Report (IDR), Technical Memorandum No. TM -71-88-11, Naval Civil Engineering Laboratory, December 1988. 5. "Toxicity o f Selected Effluents from the U.S. Navy Firefighting School, Norfolk, VA to Embryos o f Eastern Oysters". Technical Report by EG&G, Atlantic Division, Naval Facilities Engineering Command, May 1978. 6 . Union Carbide, Unox System Treatability Study Report, U.S. Navy Firefighting School, Naval Facilities Engineering Command, February 1978. 44 US00004521 7. Engineering-Science Incorporated, Physical-Chemical Treatment from Navy Firefighting Schools, Contract No. N00025-74-C-0004, Naval Facilities Engineering Command, November 1986. 8 . Saam, R., and Rakowski, P., Firefighting School Wastewater Study, Technical Memorandum No. 54-79-14, Civil Engineering Laboratory, June 1979. 9. Saam, R., Rakowski, P, and Aydlett, G., "Treatability o f Firefighting School Wastewaters: U.S. Navy Compliance with POTW Pretreatment Requirements", Proceedings o f the 34th Purdue Industrial Waste Conference, West Lafayette, Indiana, May 1979. 10. Thomas, J.F., and LeFebvre, E.E., "Biodegradability and Toxicity o f FC-200 Aqueous Film Forming Foam", Report No. EHL(K) 74-3, USAF Environmental Health Laboratory, KellyAFB, Texas;, 1973. 11. Grace and Associates Inc., "Engineering Investigation o f Impact o f AFFF on W astewater Treatment Performance at Naval Air Station, Memphis, Millington, Tennessee", U.S. Navy Contract N62467-86-C-0351, Naval Facilities Engineering Command, November 1986. 12. Lefebvre, E.E., "Biodegradability and Toxicity o f Light Water". Report No. EHL (K) 71-36, USAF Environmental Health Laboratory, November 1971. 13. Lefebvre, E.E., and Inmand, R.C., "Biodegradability and Toxicity o f ANSUL K74-100, Aqueous Film Forming Foam", Report No. EHL(K) 75-3, USAF Environmental Health Laboratory, Kelly AFB, Texas, January 1975. 14. Lefebvre, E.E., and Inmand, R.C., "Biodegradability and Toxicity o f Light water FC-206,, Aqueous Film Forming Foam", Report No. EHL(K) 74-26, USAF Environmental Health Laboratoiy, KellyAFB, Texas, November 1974. 15. Lefebvre, E.E., and Thomas, J.F., "Biodegradability and Toxicity o f AER-O-W ater 3 and 6 Aqueous Film Forming Foam", Report No. EHL(K) 73-22, USAF Environmental Health Laboratory, Kelly AFB, Texas, December 1973. 16. Environmental P rotection Agency, "Methods o f Chemical Analyses o f W ater and Wastes", Environmental Monitoring and Support Laboratory, Cincinnati, Ohio, EPA 600/4-79-020, March 1979. ................. 45 US00004522 17. American Public Health Association, American W ater Works Association, and Water Environment Federation, "Standard Methods for the Examination o f Water and Wastewater", 19thEdition, Washington, DC, 1995. 18. Environmental Protection Agency, "Toxicity Reduction Evaluation Protocol for Municipal W astewater Treatment Plants", April 1989. 46 US00004523