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A taxonomy of chemicals of emerging concern based on observed fate at water resource recovery facilities
Chemosphere 170 (2017) 153e160
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A taxonomy of chemicals of emerging concern based on observed fate at water resource recovery facilities Steven M. Jones, Ph.D., P.E. a, Zaid K. Chowdhury, Ph.D., P.E., B.C.E.E. b, Michael J. Watts, Ph.D., P.E. c, * a b c
Garver, 2049 E. Joyce Blvd., Suite 400, Fayetteville, AR 72703, USA Garver, 1300 E. Morelos St., Chandler, AZ 85225, USA Garver, 3010 Gaylord Pkwy., Suite 190, Frisco, TX 75034, USA
h i g h l i g h t s Primary and secondary effluents were analyzed for three WRRFs under dry conditions in Texas and Oklahoma for a suite of 95 CECs. For the study set of 95 CECs, 82 were detected above the corresponding minimum reporting limit (MRL) in the primary effluent. 14 CECs were not detected in any WRRF samples. 18 of the studied 95 CECs were fully (100%) removed by full-scale WRRF biological treatment. 64 of the 95 studied CECs were found to exist in the secondary effluent at residual concentrations above MRL.
a r t i c l e i n f o
a b s t r a c t
Article history: Received 10 September 2016 Received in revised form 11 November 2016 Accepted 15 November 2016
As reuse of municipal water resource recovery facility (WRRF) effluent becomes vital to augment diminishing fresh drinking water resources, concern exists that conventional barriers may prove deficient, and the upcycling of chemicals of emerging concern (CECs) could prove harmful to human health and aquatic species if more effective and robust treatment barriers are not in place. A multiple month survey, of both primary and secondary effluents, from three (3) WRRFs, for 95 CECs was conducted in 2014 to classify CECs by their persistence through conventional water reclamation processes. By sampling the participating WRRF process trains at their peak performance (as determined by measured bulk organics and particulates removal), a short-list of recalcitrant CECs that warrant monitoring to assess treatment performance at advanced water reclamation and production facilities. The list of identified CECs for potable water reclamation (indirect or direct potable reuse) include a herbicide and its degradants, prescription pharmaceuticals and antibiotics, a female hormone, an artificial sweetener, and chlorinated flame retardants. © 2016 Elsevier Ltd. All rights reserved.
Handling Editor: Shane Snyder Keywords: Water resource recovery facility Chemicals of emerging concern Wastewater Activated sludge Trickling filters Direct potable reuse
1. Introduction Record drought, shrinking water supply alternatives, and growing water demand from population centers across the West, South Central and Southeast United States (US) have combined to push municipal wastewater potable reuse to the forefront as a vital solution to augment public water supplies (Tisdale, 2015). Capital expenditures for potable reuse infrastructure are anticipated to
* Corresponding author. E-mail addresses: [email protected] (S.M. Jones), ZKChowdhury@ GarverUSA.com (Z.K. Chowdhury), [email protected] (M.J. Watts). http://dx.doi.org/10.1016/j.chemosphere.2016.11.075 0045-6535/© 2016 Elsevier Ltd. All rights reserved.
exceed $11 billion over the next decade. As reuse of treated municipal wastewater becomes vital to augment diminishing fresh drinking water resources, both State and Federal agencies in the U.S. have cataloged the presence of chemicals of emerging concern (CECs) in publicly-owned treatment works (POTW) discharges and receiving streams, as well as reclaimed water for beneficial use (EPA, 2014; Ferrey, 2013). CECs are predominantly water soluble contaminants of anthropogenic origin. CECs in water resource recovery facility (WRRF) effluent include pharmaceuticals and personal care products such as hormones, antibiotics, stimulants, surfactants, as well as preservatives, artificial sweeteners, and caffeine. While the focus
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S.M. Jones et al. / Chemosphere 170 (2017) 153e160 SE Samples
PE Samples Influent
Screens
Grit Chamber Primary Clarifier
Trickling Filter
Intermediate Clarifier
Nitrification Basin
Secondary Clarifier
Fig. 1. Process flow diagram (PFD) for the sampled TF/AS plants (Lawton, OK and Garland, TX).
Fig. 2. Process flow diagram (PFD) for the Norman WRRF, OK.
of engineered treatment systems for potable reuse projects begins with minimizing the risk associated with wastewater pathogens, non-regulated trace organic contaminants have become important considerations for treatment system design (Dickenson and Drewes, 2008; Gerrity et al., 2013; Tchobanoglous et al., 2015). Municipal WRRF primary and secondary effluents have been found to contain trace levels of CECs (Purdom et al., 1994; Drewes, 2006; Behera et al., 2011; Luo et al., 2014). Often-cited studies have linked, in certain aquatic species, the presence of CECs in POTW discharges and specific bioactivity, including estrogenic activity (Purdom et al., 1994; Folmar et al., 1996; Rodgers-Gray et al., 2000). While multiple studies have attempted to catalog the presence and concentration of CECs in municipal wastewater effluents, due to the complexity and cost of trace CEC sampling and analysis, few have utilized sampling plans for a broad spectrum of wastewater CECs (by class or intended use) over multiple weeks when municipal wastewater treatment facilities (or WRRF) are considered to be operating under optimum conditions. This research program was designed to conduct CEC sampling in both primary and secondary effluents from three (3) WRRFs (all located in the South-Central U.S.) at the peak of biological treatment process efficiency (dry conditions in summer months). By doing so, the resulting CEC occurrence data can be used to identify the anthropogenic organic compounds that are recalcitrant in municipal wastewater, even during ideal WRRF operating conditions (for biological oxidation). Two (2) of the three (3) sampled WRRFs are identical in treatment regime - trickling filters followed by nitrification e while a third sampled WRRF employed conventional activated sludge. However, the sampled treatment facilities were representative of conventional, secondary wastewater treatment, and as such provided an important screening tool for identification of CECs resistant to state-of-the-art biological treatment. The resulting list of recalcitrant CECs can be used in the development of monitoring protocols for CECs in reclaimed waters receiving advanced treatment, and for additional screening of both potential public and aquatic health effects.
and suspended-growth activated sludge (TF/AS) facility, permitted to treat 24 MGD. The Texas Commission for Environmental Quality (TCEQ) administers a Texas Pollutant Discharge Elimination System (TPDES) permit which dictates the monthly average effluent limits from Rowlett Creek for carbonaceous biochemical oxygen demand (cBOD) of 10 mg/L, total suspended solids (TSS) of 15 mg/L, and seasonal ammonia nitrogen limits of 5 mg/L (December through March) and 2 mg/L (April through November). Effluent is discharged from this facility to the East Fork of the Trinity River. The City of Lawton, Oklahoma, also owns and operates a tertiary TF/AS plant to treat sanitary sewer flows from their southwest Oklahoma population of 85,872 residents. PE and SE samples were collected from the Lawton WRRF, which currently treats an average daily flow of 10 MGD with average daily effluent water quality of 3 mg/L cBOD, 9 mg/L TSS, and 0.2 mg/L ammonia nitrogen. Effluent is discharged to Nine Mile Creek in the Red River watershed; however, up to 5 MGD is dedicated for reuse by the Public Service Company of Oklahoma (PSO) for their industrial cooling towers. Fig. 2 presents a simplified process flow diagram of treatment at the Lawton and Garland WRRFs, as well as the locations of PE and SE sample collection in the process train. The City of Norman, Oklahoma, owns and operates a WRRF to treat flows from their Oklahoma City suburban and research university population of over 100,000 residents. Samples were collected for this study from the conventional, suspended-growth, activated sludge (AS) facility; permitted to treat 17 MGD. Monthly average effluent limits from the WRRF are cBOD of 13 mg/L, TSS of 30 mg/L, and ammonia nitrogen limits of 4.1 mg/L. Effluent is discharged to the Canadian River in the Arkansas River watershed. The Norman WRRF provides seasonal reuse to the University of Oklahoma for irrigation of the Jimmie Austin Golf Course. Fig. 2 presents a simplified process flow diagram of the Norman WRRF, and the locations of PE and SE sample collection in the process train. 2.2. Effluent sampling Two (2) sampling locations were identified per WRRF. The sample locations included the influent to the biological reactor(s) and the effluent of the final (or secondary) clarifiers. Samples collected on the influent side of the biological reactor were always prior to being combined with the return activated sludge (RAS) flow. The sampling location of the secondary clarifier effluent, at each WRRF, was after all clarifier effluents had been combined, but prior to any tertiary treatment or disinfection. Sampling was performed in August and September of 2014, with one sample event per week. Table 1 lists the number of discrete sample events during
2. Materials and methods 2.1. Water resource recovery facilities The City of Garland, Texas, owns and operates two tertiary WRRFs (Rowlett Creek and Duck Creek) to treat flows from their Dallas/Fort Worth suburban population of 235,000 residents. Primary effluent (PE) and secondary effluent (SE) for this research was collected from the Rowlett Creek WRRF, a fixed-film trickling filter
Table 1 Sampling events and WRRF flow treated during sampling in August/September 2014. WRRF Norman (OK) Lawton (OK) Garland (TX)
No. of sample events
Avg. flow treated (MGD)
4 4 3
9.6 11 12.7
S.M. Jones et al. / Chemosphere 170 (2017) 153e160 Table 2 Analytes examined in each WRRF sample (PE or SE) with corresponding LC/MS/MS electrospray ionization mode (ESI). Analytes
CAS
MRL (mg/L)
Ionization mode
1,7-Dimethylxanthine Acetaminophen Albuterol Amoxicillin Andorostenedione Atenolol Atrazine Azithromycin Bezafibrate Bromacil Caffeine Carbadox Carbamazepine Carisoprodol Chloridazon Chlorotoluron Cimetidine Cotinine Cyanazine DACT DEA DEET Dehydronifedipine DIA Diazepam Dilantin Diltiazem Diuron Erythromycin Flumequine Fluoxetine Isoproturon Ketoprofen Ketorolac Lidocaine Lincomycin Linuron Lopressor Meclofenamic Acid Meprobamate Metazachlor Metolachlor Nifedipine Norethisterone Oxolinic acid Pentoxifylline Phenazone Primidone Progesterone Propazine Quinoline Simazine Sulfachloropyridazine Sulfadiazine Sulfadimethoxine Sulfamerazine Sulfamethazine Sulfamethizole Sulfamethoxazole Sulfathiazole TCEP TCPP TDCPP Testosterone Theobromine Theophylline Trimethoprim 2,4-D 4-nonylphenol 4-tert-Octylphenol Acesulfame-K Bendroflumethiazide BPA
611-59-6 103-90-2 51022-70-9 26787-78-0 63-05-8 29122-68-7 1912-24-9 83905-01-5 41859-67-0 314-40-9 58-08-2 6804-07-5 298-46-4 78-44-4 1698-60-8 15545-48-9 51481-61-9 486-56-6 21725-46-2 3397-62-4 6190-65-4 134-62-3 67035-22-7 1007-28-9 439-14-5 57-41-0 42399-41-7 330-54-1 114-07-8 42835-25-6 54910-89-3 34123-59-6 22071-15-4 74103-06-3 137-58-6 154-21-2 330-55-2 51384-51-1 644-62-2 57-53-4 67129-08-2 51218-45-2 21829-25-4 68-22-4 14698-29-4 6493-05-6 60-80-0 125-33-7 57-83-0 139-40-2 91-22-5 122-34-9 80-32-0 68-35-9 122-11-2 127-79-7 57-68-1 144-82-1 723-46-6 72-14-0 115-96-8 13674-84-5 13674-87-8 58-22-0 83-67-0 58-55-9 738-70-5 94-75-7 25154-52-3 140-66-9 55589-62-3 73-48-3 80-05-7
0.01 0.5 0.005 0.2 0.005 0.05 0.005 0.02 0.005 0.005 0.5 0.005 0.005 0.005 0.005 0.005 0.05 0.1 0.005 0.005 0.005 1 0.005 0.005 0.005 0.02 0.005 0.005 0.01 0.01 0.01 0.1 0.005 0.005 0.005 0.01 0.005 0.2 0.005 0.005 0.005 0.005 0.02 0.005 0.01 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.05 0.005 0.01 1 0.1 0.005 0.01 0.02 0.005 0.005 0.1 0.05 0.02 0.005 0.01
ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI() ESI() ESI() ESI() ESI() ESI()
155
Table 2 (continued ) Analytes
CAS
MRL (mg/L)
Ionization mode
Butalbital Butylparaben Chloramphenicol Clofibric Acid Diclofenac Estradiol Estrone Ethinyl Estradiol Ethylparaben Gemfibrozil Ibuprofen Iohexal Iopromide Isobutylparaben Methylparaben Naproxen Propylparaben Sucralose Triclocarban Triclosan Warfarin
77-26-9 94-26-8 56-75-7 882-09-7 15307-86-5 50-28-2 53-16-7 57-63-6 120-47-8 25812-30-0 15687-27-1 66108-95-0 73334-07-3 4247-02-3 99-76-3 22204-53-1 94-13-3 56038-13-2 101-20-2 3380-34-5 81-81-2
0.005 0.005 0.01 0.005 0.005 0.005 0.005 0.005 0.02 0.005 0.01 0.01 0.005 0.005 0.02 0.01 0.005 0.1 0.005 0.01 0.005
ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI()
this period at each WRRF, along with the average flow (in million gallons per day, or MGD) treated at each facility. For each sample event, grab samples of effluent (PE and SE) were collected using prepared fluorocarbon polymer sample bottles containing ascorbic acid and sodium azide as preservatives. Samples were chilled to below 4 C and shipped on ice or frozen gel packs overnight to the analytical laboratory. All sample analysis was performed within 30 days of sample collection. 2.3. Sample analysis The collected effluent samples were then shipped overnight to the Eurofins Eaton Analytical Laboratory in Monrovia, CA. Applying a liquid chromatography, tandem mass spectroscopy method (LC/ MS/MS) developed with support from the Water Research Foundation (Vanderford et al., 2013), each effluent sample was then analyzed for up 94 different CECs. Samples were pre-concentrated using a previously developed direct online extraction/analysis method (Haghani et al., 2009), to achieve low-ng/L method reporting limits (MRL). Table 2 lists the analytes that were quantified in each sample. 3. Results 3.1. Trickling filter/activated sludge samples As the Garland and Lawton WRRF utilized similar biological treatment processes to meet NPDES permit limits (see Figs. 1 and 2), their respective CEC occurrence data can be compared. Table 3 lists the relevant measures of WRRF organics, and particulate removal during scheduled sample events in August and September 2014. With the exception of mean sludge age (SRT, days), each TF/ AS WRRF sampled had similar operating mixed-liquor suspended solids concentrations (MLSS) and removal performance for bulk organics (BOD and COD). As with average treatment performance at the TF/AS WRRFs, there was also general agreement within CEC detection and observed removal from primary to secondary effluent. Notable exceptions include specific prescription antibiotics, natural hormones, a plastic monomer, and a herbicide. Tables 4 and 5 present the mean observed concentrations of ESI(þ) and ESI() CECs, respectively, in samples of PE and SE from both TF/AS WRRFs. Notably, significant discrepancies in average CEC removal were observed for amoxicillin, bisphenol-a (BPA), butalbital, diclofenac,
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S.M. Jones et al. / Chemosphere 170 (2017) 153e160
Table 3 Mean treatment performance of the TF/AS WRRFs during sampling events in August/September 2014. WRRF
Mean effluent temp. ( C)
BOD removal (%)
COD removal (%)
TSS removal (%)
Mean MLSS (mg/L)
Mean SRT (days)
26.4 –a
99 98
75 90
97 99
1590 1970
10.3 3.7
Lawton (OK) Garland (TX) a
Data not collected by participating WRRF.
and trimethoprim. With the exception of butalbital, significantly improved removal rates for each CEC were observed at the Lawton WRRF. Butalbital was detected at similar mean concentrations in primary effluent at both WRRFs. However, PE and SE concentrations detected, in all TF/AS sampling, were at low ng/L-levels (14e44 ng/L on average). While both the Lawton and Garland WRRFs treated similar influent flowrates and recorded excellent removal rates for bulk wastewater organics (BOD and COD) during sampling in 2014, the mean sludge age varied significantly between the two (2) treatment facilities. Previous studies have linked the microbial population density and diversity with increasing SRT to enhanced elimination of CECs at WRRFs (Gerrity et al., 2013; Maeng et al., 2013). The mean observed attenuation rate of BPA in Lawton WRRF sampling matched closely the reported biotransformation rate of the plastic monomer in a Greek activated sludge facility (Stasinakis et al., 2010). However, Stasinakis et al. (2010) reported no appreciable increase in BPA biotransformation with an increase
in sludge age from 10 to 20 days. Other full-scale WRRF CEC removal studies have also reported limited improvement in the attenuation or biotransformation of trace CECs at SRTs greater than 10 days (Joss et al., 2005). Surprisingly, 22 compounds had observed attenuation rates at the Lawton and Garland WRRFs greater than 90% (on average). The extent of CEC degradation observed at these facilities is in stark contrast to previous CEC recalcitrance classification studies that have reported significant biotransformation with activated sludge for as few as 4 out of 35 studied CECs (Joss et al., 2006). In certain cases, concentrations of detected CECs increased between primary effluent, and secondary effluent sampling. This is not uncommon with grab sampling regimes, where CECs (and other organic solutes) may sorb/de-sorb from the solids inventory that is maintained for biological treatment efficiency. An additional consideration in the evaluation of data from grab samples is that it often does not follow the same batch of water passing through the treatment process and may
Table 4 Mean concentrations of ESI(þ) CECs in PE and SE samples from TF/AS WRRFs. Only CECs where detection was observed in more than one (N > 1) PE or SE sample are reported. “Blanks” are indicative of no observed CEC detection, or a CEC concentration less than the MRL. SD ¼ Standard deviation on the mean PE or SE concentration detected. Lawton WRRF
Mean PE (ng/L)
1,7-Dimethylxanthine Acetaminophen Albuterol Amoxicillin Andorostenedione Atenolol Atrazine Azithromycin Caffeine Carbamazepine Carisoprodol Cimetidine Cotinine DACT DEA DEET DIA Dilantin Diltiazem Erythromycin Fluoxetine Ketoprofen Ketorolac Lidocaine Lincomycin Lopressor Meprobamate Metolachlor Nifedipine Pentoxifylline Primidone Quinoline Simazine Sulfadiazine Sulfamethoxazole TCEP TCPP TDCPP Theobromine Theophylline Trimethoprim
2,490 29,595 31 5,800 119 885 72 1,867 31,750 155 147 493 2,950 97 7,675 173 51 72 66 21 313 20 855 223 5 65 15 92 177
1,798 360 1,183 623 2,745 3,773 450
Mean SE (ng/L)
% Removal
% Removal
Mean SE (ng/L)
Mean PE (ng/L)
Garland WRRF
100% 99% 27% 4%
410 33 11,600
3,633 60,000 26 11,167
190 84 2,043 48 167 282 166 54
100% 100% 7% 80% 100% 79% 17% 9% 100% 8% 92% 66% 98%
61 22 16 289 27
37% 100% 100% 67% 48%
59
520 91 2,700 48 180 98 509 113 29 373 113 67 191 85 19 115 43 18 383 174 367 254
1,290 123 2,633 35,333 180 60 1,507 2,100 21 175 16,333 36 150 171 52 117 128 42 657 406 2,033 250
88 18 6
17% 100% 65% 50% 100% 46% 54% 48% 56% 100% 4% 90% 100%
60% 26% 3% 100% 0% 63% 66% 95% 36% 113% 99% 83% 28% 51% 63% 2% 66% 57% 42% 57% 82% 2%
1,443 233 1,000 588 111 30 51
20% 35% 15% 6% 96% 99% 89%
70% 82% 6% 83% 25% 68% 32% 16% 1% 23% 99% 99% 28%
22 11 113 29 26 140 1,273 287 1,960 787 140 85 433
75 62 107 165 34 440 1,867 340 1,933 1,027 10,033 8,900 600
1,7-Dimethylxanthine Acetaminophen Albuterol Amoxicillin Andorostenedione Atenolol Atrazine Azithromycin Caffeine Carbamazepine Carisoprodol Cimetidine Cotinine DACT DEA DEET DIA Dilantin Diltiazem Erythromycin Fluoxetine Ketoprofen Ketorolac Lidocaine Lincomycin Lopressor Meprobamate Metolachlor Nifedipine Pentoxifylline Primidone Quinoline Simazine Sulfadiazine Sulfamethoxazole TCEP TCPP TDCPP Theobromine Theophylline Trimethoprim
45 29 1,153
7 158 458 343 8 29
S.M. Jones et al. / Chemosphere 170 (2017) 153e160
157
Table 5 Mean concentrations of ESI() CECs in PE and SE samples from TF/AS WRRFs. Only CECs where detection was observed in more than one (N > 1) PE or SE sample are reported. “Blanks” are indicative of no observed CEC detection, or a CEC concentration less than the MRL. SD ¼ Standard deviation on the mean PE or SE concentration detected. Lawton WRRF
Mean PE (ng/L)
Mean SE (ng/L)
% Removal
% Removal
Mean SE (ng/L)
Mean PE (ng/L)
Garland WRRF
2,4-D Acesulfame-K BPA Butalbital Clofibric Acid Diclofenac Estrone Gemfibrozil Ibuprofen Iohexal Iopromide Methylparaben Naproxen Propylparaben Sucralose Triclocarban Triclosan
543 17,773 485 42 24 236 13 1,363 2,133 16,000 3,575 761 2,111 236 23,000 653 690
176 3,228 34 39 21 72 11 48
68% 82% 93% 7% 11% 69% 18% 96% 100% 97% 97% 100% 96% 100% 12% 86% 92%
80% 90% 99% 69%
32 2,333 116 14
163 23,667 58 44
19% 22% 79% 100% 48%
93 8 160
79 11 747 5,200 14,400
2,4-D Acesulfame-K BPA Butalbital Clofibric Acid Diclofenac Estrone Gemfibrozil Ibuprofen Iohexal Iopromide Methylparaben Naproxen Propylparaben Sucralose Triclocarban Triclosan
505 97 76 20,250 91 58
reflect different concentrations (at varying times) of CECs coming in to the treatment facility.
3.2. Conventional activated sludge samples The Norman WRRF employs a form of conventional activated sludge secondary treatment. Table 6 lists the relevant measures of Norman WRRF organics, and particulate removal during scheduled sample events in August and September 2014. It should be noted that COD was not monitored by the WRRF for discharge permit compliance, and thus is not shown in Table 6. Mean effluent temperature, and BOD and TSS removal efficiencies were comparable to the TF/AS WRRFs sampled, however, mean mixed liquor suspended solids concentrations were three (3) times greater at the Norman WRRF (than for the Lawton or Garland WRRFs). Tables 7 and 8 present the mean observed concentrations of ESI(þ) and ESI() CECs, respectively, in samples of PE and SE from the Norman WRRF. A notable omission from the list of ESI(þ) CECs detected in Norman WRRF sampling was the broad-leaf herbicide Atrazine. While banned in the European Union, Atrazine use continues in the U.S. with estimated application rates as high as 64 lb/ sq. mi. (USGS, 2014) in States East of the Rocky Mountains. While not present (above the MRL) in PE and SE samples from the Norman WRRF, the metabolites of atrazine were detected, DACT, DEA and DIA. These dealkylated metabolites were first detected in atrazinecontaminated soils during bioremediation trials (Struthers et al., 1998). The detection of well-studied atrazine metabolites in SE samples (and not PE samples) is an indication that atrazine removal was occurring in the secondary treatment processes at Norman, be it via biotransformation and/or sorption mechanisms. However, atrazine removal was not observed at the TF/AS WRRFs during the same period, in agreement with previously reported atrazine biotransformation studies that have shown atrazine to be recalcitrant even in advanced wastewater treatment (AWT) processes, such as membrane bioreactors (Bernhard et al., 2006).
3.3. Undetected CECs Of the analytes listed in Table 2, 15 were not detected in any PE or SE samples collected at participating WRRFs. The list of CECs that either were not present in the sanitary sewer influent, or were removed to levels below their MRLs, included:
97% 100% 19% 90% 93%
7,500
55 33,000 49 75
1,977 540 27,667 493 1,080
Bendroflumethiazide Carbadox Chloridazon Ethinyl Estradiol Flumequine Isoproturon Meclofenamic Acid Metazachlor Oxolinic acid Phenazone Propazine Sulfachloropyridazine Sulfamerazine Sulfamethazine Sulfamethizole
A significant focus of recent research on the removal of CECs in municipal WRRF has been the fate (during engineered treatment) of natural and synthetic female hormones, and their associated estrogenic activity (Kirk et al., 2002; Servos et al., 2005; Racz and Goel, 2010). As noted in the list above, the female hormone Ethinyl Estradiol (also known as 17a-ethinylestradiol, or EE2) was not detected in any samples from this study, and the known estrogen, Estradiol (also known as 17b-estradiol) was infrequently detected in either PE or SE samples, often at concentrations near the MRL. The mean concentration of Estradiol in all PE samples collected was 39 ng/L, with no positive Estradiol detections in any SE samples. However, the female hormone Estrone (also known as E1), proved difficult to remove even during optimal biological treatment conditions at the sampled WRRFs. The variable removal observed for Estrone in the sampled WRRFs agrees with previous studies that reported inconsistent removal rates for the hormone (Servos et al., 2005). However, the observed concentrations of Estrone in final effluent samples were an order-of-magnitude below the reported no-effect-concentrations for fish reproduction (Fig. 3). While reported fish reproductive toxicity testing has indicated the greatest sensitivity from test organisms to Ethinyl Estradiol (Caldwell et al., 2012), Ethinyl Estradiol was not detected in either primary or secondary effluent samples collected from the studied WRRFs. 3.4. Labile and recalcitrant CECs A significant outcome of the reported work is that the CECs, in both occurrence and rate of removal, were consistent between
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Table 6 Mean treatment performance and operating characteristics of the AS WRRF during sampling events in August/September 2014. WRRF
Mean effluent temp. ( C)
BOD removal (%)
TSS removal (%)
Mean MLSS (mg/L)
Mean SRT (days)
26.8
99
97
4501
10.7
Norman (OK)
sampled WRRFs, and biological treatment processes. No appreciable difference was observed in CEC removal between the two secondary treatment bioreactor configurations of AS and TF/AS. Thus, the collective CEC data set can be used to determine the CECs most resistant to secondary treatment at WRRFs. Table 9 lists the studied CECs that were identified as either well-removed (>80% removal by the WRRF, on average), or recalcitrant (<20% removal by the WRRF, on average) in WRRF PE and SE sampling in August/ September 2014. By aggregating the CEC concentration data across the studied CECs, clear trends emerge for identifying analytes with the most, and the least resistance to the sampled secondary treatment systems. The State of Texas is the only U.S. State to have approved the direct potable reuse (DPR) of municipal WRRF effluent, on a caseby-case basis. In 2015, the Texas Water Development Board (TWDB) published a Resource Document to guide DPR project development in Texas (TWDB, 2015). The TWDB Resource Document for DPR listed nineteen (19) different indicator chemicals to be monitored for DPR treatment performance, with sixteen (16) of the nineteen (19) currently unregulated either federally or locally
Table 7 Mean concentrations of ESI(þ) CECs in PE and SE samples from the AS WRRF. Only CECs where detection was observed in more than one (N > 1) PE or SE sample are reported. SD ¼ Standard deviation on the mean PE or SE concentration detected. Norman WRRF
Mean PE (ng/L)
1,7-Dimethylxanthine Acetaminophen Albuterol Amoxicillin Andorostenedione Atenolol Azithromycin Caffeine Carbamazepine Carisoprodol Cimetidine Cotinine DACT DEA DEET DIA Dilantin Diltiazem Fluoxetine Ketoprofen Ketorolac Lidocaine Linuron Lopressor Meprobamate Primidone Progesterone Simazine Sulfadiazine Sulfamethoxazole TCEP TCPP TDCPP Theobromine Theophylline Trimethoprim
3,743 46,600 27 8,100 640 1,853 2,567 57,333 240 90 1,230 3,500 266 8,767 17 760 153 133 99 28 450 23 987 1,077 160 1,090 150 610 3,300 460 787 483 16,253 11,667 1,003
Mean SE (ng/L) 873 22 5,786
1,143 81 282 60 915 32 8 10 84 74 414 87 121
219 11 498 711 128 200 150 1,231 224 1,614 644 82 534
% Removal 100% 98% 18% 29% 100% 100% 55% 100% 18% 33% 26% 99% 100% 96% 99% 100% 46% 43% 9% 100% 100% 51% 52% 50% 34% 20% 100% 33% 75% 63% 51% 100% 33% 100% 99% 47%
Table 8 Mean concentrations of ESI() CECs in PE and SE samples from the AS WRRF. Only CECs where detection was observed in more than one (N > 1) PE or SE sample are reported. SD ¼ Standard deviation on the mean PE or SE concentration detected. Norman WRRF
Mean PE (ng/L)
Mean SE (ng/L)
% Removal
2,4-D Acesulfame-K BPA Butalbital Butylparaben Clofibric Acid Diclofenac Estrone Ethylparaben Gemfibrozil Ibuprofen Iohexal Iopromide Isobutylparaben Methylparaben Naproxen Propylparaben Sucralose Triclocarban Triclosan
321 16,500 97 28 27 21 92 10 1,694 1,567 4,000 16,333 54 28 977 2,497 463 20,333 175 535
45 520
86% 97% 100% 65% 100% 100% 15% 40% 100% 97% 100% 94% 100% 100% 100% 99% 100% 3% 92% 95%
10
78 14 51 1,000
13 19,784 14 29
(in TX). Comparing the labile and recalcitrant CEC classified in Table 9, there are five (5) CECs that were identified in this study as well removed or labile, which were also suggested indicator chemicals for DPR monitoring by the TWDB. These CECs included Triclosan, Iopromide, Gemfibrozil, DEET, and Caffeine. A sixth, E2 or Estradiol, was not detected in any secondary effluent samples from the studied WRRFs. However, three (3) recalcitrant CECs, as identified by WRRF sampling in 2014, do appear on the TWBD monitoring list, Meprobamate, Primidone and Sucralose. The TWDB's Monitoring Trigger Threshold (MTT) for these three chemicals in reclaimed effluents are 200 mg/L, 10 mg/L, and 150 mg/L, respectively. Despite their apparent recalcitrance, the aggregate mean concentrations of either Meprobamate, Primidone or Sucralose in the secondary effluent of the participating WRRFs were well below their respective MTTs (without additional advanced physical, chemical, or biological treatment).
4. Conclusions Given the scope of both WRRF facilities sampled, and CECs analyzed in this study, the resulting CEC occurrence data can be used to identify CECs by their respective resistance to conventional water reclamation processes. The excellent treatment performance (with respect to particulate and bulk organics removal) of all three of the studied WRRF at the time of sampling allows for determination of the truly recalcitrant, to conventional secondary wastewater treatment processes, CECs (from an initial survey list of 95 chemical constituents). Given both the observed recalcitrance and the frequency of detection in secondary effluent samples, the following short-list of CECs should be considered for advanced treatment process performance monitoring for potable reuse projects:
S.M. Jones et al. / Chemosphere 170 (2017) 153e160
159
Fig. 3. Box-and-whisker plots of aggregated (all WRRF samples) PE and SE sample concentrations of Estrone (E1), Estradiol (E2), and Ethinyl Estradiol (EE2), and no-effect concentrations (NOEC) reported from fish reproductive toxicity studies with each estrogen (NOEC Source: (Caldwell et al., 2012)).
Table 9 Aggregated mean concentrations of well-removed (>80% removal from PE to SE samples) and poorly-removed (<20% removal) CECs in all WRRF sampling from August to September 2014. DF ¼ Detection Frequency (out of 11 events). All concentrations are listed in ng/L. >80% removal
<20% removal
Analytes
Primary effluent
Secondary effluent
Mean
DF
Mean
DF
1,7-Dimethylxanthine Acesulfame-K Acetaminophen Andorostenedione Caffeine Chloramphenicol Cotinine DEET Ethylparaben Gemfibrozil Ibuprofen Iopromide Ketorolac Methylparaben Naproxen Progesterone Propylparaben Quinoline Theobromine Theophylline Triclocarban Triclosan
3,009 19,909 41,120 106 39,090 287 2,770 9,782 679 1,214 3,750 1,804 93 646 1,990 763 434 163 8,776 7,190 474 757
91% 91% 91% 73% 100% 27% 91% 100% 55% 100% 73% 73% 55% 55% 100% 27% 91% 64% 100% 100% 73% 64%
41 2,485 390
9% 91% 55% 82% 82% 73% 91% 9% 36% 18% 91%
55% 64% 36% 73% 91%
% Removal
Analytes
Primary effluent
Secondary effluent
% Removal
Mean
DF
Mean
DF
99% 88% 99% >95% 100% >96% 98% 99% >97% 93% 99% 95% 86% >96% 100% >99% >98% 87% 99% 99% 88% 84%
Albuterol Atrazine Azithromycin Carbamazepine Carisoprodol Clofibric Acid DACT DEA DIA Dilantin Estrone Meprobamate Primidone Sucralose TCPP TDCPP
27 80 2,198 172 107 22 16 167 27 314 12 448 110 22,455 1,189 655
91% 55% 91% 100% 45% 36% 27% 64% 55% 100% 64% 100% 100% 100% 100% 100%
27 87 1,890 171 169 21 16 187 53 291 10 418 96 23,100 1,219 614
82% 55% 91% 91% 55% 9% 45% 64% 64% 91% 55% 91% 91% 91% 91% 91%
2% -10% 14% 1% -58% 5% 3% -12% -96% 7% 13% 7% 13% -3% -3% 6%
160
S.M. Jones et al. / Chemosphere 170 (2017) 153e160
Albuterol Atrazine/DEA/DIA/DACT Azithromycin Carbamazepine Dilantin Estrone (or E1) Meprobamate (TWDB suggested indicator chemical) Primidone (TWDB suggested indicator chemical) Sucralose (TWDB suggested indicator chemical) TCPP TDCPP
While the toxicity thresholds that govern the maximum allowable concentrations in reclaimed water are expected to vary (and require further research to identify), this list includes chemical constituents that are anticipated to have either aquatic environment (i.e., Estrone, Azithromycin) or human health effects (i.e., TCPP, TDCPP, Atrazine). Therefore, the short-list of CECs identified by this research represents potential criteria pollutants for both indirect and direct potable reuse projects. Of note, the regulated herbicide, Atrazine, does not appear on the TWDB chemical list, but the clear resistance to removal, for either the parent or daughter compounds (DACT, DIA, and DEA), with secondary treatment should make it a recommended chemical for DPR treatment performance monitoring. Acknowledgements This research was made possible by the financial support of the City of Norman (OK), the City of Lawton (OK), and the City of Garland (TX). Additional sampling support was provided by Michael Graves (Garver), Jeffrey Sober (Garver), Afsaneh Jabbar (Lawton), John Pruitt (Garver), Wes Kucera (Garland), Malcolm Parker (Garland), Kyle Kruger (Garver), Lyna Neal (Lawton) and Steven Hardeman (Norman). In addition, Dr. Andrew Eaton (Eurofins) provided valuable technical support for sampling protocol development and sample analysis. References Behera, Shishir Kumar, Kim, Hyeong Woo, Oh, Jeong-Eun, Park, Hung-Suck, 2011. Occurrence and removal of antibiotics, hormones and several other pharmaceuticals in wastewater treatment plants of the largest industrial city of Korea. Sci. Total Environ. 409 (20), 4351e4360. Bernhard, Marco, Müller, Jutta, Knepper, Thomas P., 2006. Biodegradation of persistent polar pollutants in wastewater: comparison of an optimised lab-scale membrane bioreactor and activated sludge treatment. Water Res. 40 (18), 3419e3428. Caldwell, Daniel J., Mastrocco, Frank, Anderson, Paul D., L€ ange, Reinhard, Sumpter, John P., 2012. Predicted-no-effect concentrations for the steroid estrogens estrone, 17b-estradiol, estriol, and 17a-ethinylestradiol. Environ. Toxicol. Chem. 31 (6), 1396e1406. € rg E., 2008. Removal of Pharmaceuticals and Personal Dickenson, Eric, Drewes, Jo Care Products During Activated-sludge Wastewater Treatment. World Environmental and Water Resources Congress, Ahupua'A, 2008. €rg E., 2006. Final report. Removal of Endocrine Disrupting Compounds in Drewes, Jo Water Reclamation Systems, 1 vols. Water Environment Research Foundation, Alexandria, VA. EPA, U.S, 2014. Treating Contaminants of Emerging Concern - A Literature Review
Database. edited by U.S. Environmental Protection Agency. Ferrey, Mark, 2013. Pharmaceuticals, Personal Care Products, and Endocrine Active Chemical Monitoring in Lakes and Rivers. Minnesota Pollution Control Agency, Saint Paul, MN, 2013. Folmar, Leroy C., Denslow, Nancy D., Rao, Vijayasri, Chow, Marjorie, Andrew Crain, D., Enblom, Jack, Marcino, Joseph, Guillette Jr., Louis J., 1996. Vitellogenin induction and reduced serum testosterone concentrations in feral male carp (Cyprinus carpio) captured near a major metropolitan sewage treatment plant. Environ. Health Perspect. 104 (10), 1096. Gerrity, Daniel, Holady, Janie C., Mawhinney, Douglas B., Quinones, Oscar, Trenholm, Rebecca A., Snyder, Shane A., 2013. The effects of solids retention time in full-scale activated sludge basins on trace organic contaminant concentrations. Water. Environ. Res. 85 (8), 715e724. Haghani, A.W., Eaton, A., Wan, J., Cha, Y.Y., 2009. Multi-residue Analysis for Emerging Contaminants Using Direct Online Injection. AWWA Research Symposium: Emerging Organic Contaminants, Austin, TX. €bel, Anke, McArdell, Christa S., Joss, Adriano, Keller, Elvira, Alder, Alfredo C., Go Ternes, Thomas, Siegrist, Hansruedi, 2005. Removal of pharmaceuticals and fragrances in biological wastewater treatment. Water Res. 39 (14), 3139e3152. € bel, Anke, Hoffmann, Burkhard, Lo € ffler, Dirk, Joss, Adriano, Zabczynski, Sebastian, Go McArdell, Christa S., Ternes, Thomas A., Thomsen, Angela, Siegrist, Hansruedi, 2006. Biological degradation of pharmaceuticals in municipal wastewater treatment: proposing a classification scheme. Water Res. 40 (8), 1686e1696. Kirk, Lucy A., Tyler, Charles R., Lye, Christina M., Sumpter, John P., 2002. Changes in estrogenic and androgenic activities at different stages of treatment in wastewater treatment works. Environ. Toxicol. Chem. 21 (5), 972e979. Luo, Yunlong, Guo, Wenshan, Ngo, Huu Hao, Nghiem, Long Duc, Hai, Faisal Ibney, Zhang, Jian, Liang, Shuang, Wang, Xiaochang C., 2014. A review on the occurrence of micropollutants in the aquatic environment and their fate and removal during wastewater treatment. Sci. Total Environ. 473, 619e641. Maeng, Sung Kyu, Choi, Byeong Gyu, Lee, Kyu Tae, Song, Kyung Guen, 2013. Influences of solid retention time, nitrification and microbial activity on the attenuation of pharmaceuticals and estrogens in membrane bioreactors. Water Res. 47 (9), 3151e3162. Purdom, C.E., Hardiman, P.A., Bye, V.V.J., Eno, N.C., Tyler, C.R., Sumpter, J.P., 1994. Estrogenic effects of effluents from sewage treatment works. Chem. Ecol. 8 (4), 275e285. Racz, LeeAnn, Goel, Ramesh K., 2010. Fate and removal of estrogens in municipal wastewater. J. Environ. Monit. 12 (1), 58e70. Rodgers-Gray, Trevor P., Jobling, Susan, Morris, Steven, Kelly, Carole, Kirby, Sonia, Janbakhsh, Afsaneh, Harries, Jule E., Waldock, Michael J., Sumpter, John P., Tyler, Charles R., 2000. Long-term temporal changes in the estrogenic composition of treated sewage effluent and its biological effects on fish. Environ. Sci. Technol. 34 (8), 1521e1528. Servos, M.R., Bennie, D.T., Burnison, B.K., Jurkovic, A., McInnis, R., Neheli, T., Schnell, A., Seto, P., Smyth, S.A., Ternes, T.A., 2005. Distribution of estrogens, 17b-estradiol and estrone, in Canadian municipal wastewater treatment plants. Sci. Total Environ. 336 (1), 155e170. Stasinakis, Athanasios S., Kordoutis, Constantinos I., Tsiouma, Vasiliki C., Gatidou, Georgia, Thomaidis, Nikolaos S., 2010. Removal of selected endocrine disrupters in activated sludge systems: effect of sludge retention time on their sorption and biodegradation. Bioresour. Technol. 101 (7), 2090e2095. Struthers, J.K., Jayachandran, K., Moorman, T.B., 1998. Biodegradation of atrazine by Agrobacterium radiobacter J14a and use of this strain in bioremediation of contaminated soil. Appl. Environ. Microbiol. 64 (9), 3368e3375. Tchobanoglous, G., Cotruvo, J., Crook, J., McDonald, E., Olivieri, A., Salveson, A., Trussell, S., 2015. Framework for Direct Potable Reuse. WateReuse Research Foundation, Alexandria, VA. Tisdale, R., 2015. U.S. Municipal wastewater reuse: opportunities and forecasts, 2015-2025. Int. Desalination Assoc. 6 (15), 14e18. TWDB, 2015. Final Report: Direct Potable Reuse Resource Document. Texas Water Development Board, Austin, TX. USGS, 2014. Pesticide National Synthesis Project. http://water.usgs.gov/nawqa/ pnsp/usage/maps/show_map.php? year¼2011&map¼ATRAZINE&hilo¼L&disp¼Atrazine. €rg E., Eaton, Andrew, Guo, Yingbo C., Haghani, Ali, Vanderford, Brett J., Drewes, Jo Hoppe-Jones, Christiane, Schluesener, Michael P., Snyder, Shane A., Ternes, Thomas, Wood, Curtis J., 2013. Results of an interlaboratory comparison of analytical methods for contaminants of emerging concern in water. Anal. Chem. 86 (1), 774e782.
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A taxonomy of chemicals of emerging concern based on observed fate at water resource recovery facilities Steven M. Jones, Ph.D., P.E. a, Zaid K. Chowdhury, Ph.D., P.E., B.C.E.E. b, Michael J. Watts, Ph.D., P.E. c, * a b c
Garver, 2049 E. Joyce Blvd., Suite 400, Fayetteville, AR 72703, USA Garver, 1300 E. Morelos St., Chandler, AZ 85225, USA Garver, 3010 Gaylord Pkwy., Suite 190, Frisco, TX 75034, USA
h i g h l i g h t s Primary and secondary effluents were analyzed for three WRRFs under dry conditions in Texas and Oklahoma for a suite of 95 CECs. For the study set of 95 CECs, 82 were detected above the corresponding minimum reporting limit (MRL) in the primary effluent. 14 CECs were not detected in any WRRF samples. 18 of the studied 95 CECs were fully (100%) removed by full-scale WRRF biological treatment. 64 of the 95 studied CECs were found to exist in the secondary effluent at residual concentrations above MRL.
a r t i c l e i n f o
a b s t r a c t
Article history: Received 10 September 2016 Received in revised form 11 November 2016 Accepted 15 November 2016
As reuse of municipal water resource recovery facility (WRRF) effluent becomes vital to augment diminishing fresh drinking water resources, concern exists that conventional barriers may prove deficient, and the upcycling of chemicals of emerging concern (CECs) could prove harmful to human health and aquatic species if more effective and robust treatment barriers are not in place. A multiple month survey, of both primary and secondary effluents, from three (3) WRRFs, for 95 CECs was conducted in 2014 to classify CECs by their persistence through conventional water reclamation processes. By sampling the participating WRRF process trains at their peak performance (as determined by measured bulk organics and particulates removal), a short-list of recalcitrant CECs that warrant monitoring to assess treatment performance at advanced water reclamation and production facilities. The list of identified CECs for potable water reclamation (indirect or direct potable reuse) include a herbicide and its degradants, prescription pharmaceuticals and antibiotics, a female hormone, an artificial sweetener, and chlorinated flame retardants. © 2016 Elsevier Ltd. All rights reserved.
Handling Editor: Shane Snyder Keywords: Water resource recovery facility Chemicals of emerging concern Wastewater Activated sludge Trickling filters Direct potable reuse
1. Introduction Record drought, shrinking water supply alternatives, and growing water demand from population centers across the West, South Central and Southeast United States (US) have combined to push municipal wastewater potable reuse to the forefront as a vital solution to augment public water supplies (Tisdale, 2015). Capital expenditures for potable reuse infrastructure are anticipated to
* Corresponding author. E-mail addresses: [email protected] (S.M. Jones), ZKChowdhury@ GarverUSA.com (Z.K. Chowdhury), [email protected] (M.J. Watts). http://dx.doi.org/10.1016/j.chemosphere.2016.11.075 0045-6535/© 2016 Elsevier Ltd. All rights reserved.
exceed $11 billion over the next decade. As reuse of treated municipal wastewater becomes vital to augment diminishing fresh drinking water resources, both State and Federal agencies in the U.S. have cataloged the presence of chemicals of emerging concern (CECs) in publicly-owned treatment works (POTW) discharges and receiving streams, as well as reclaimed water for beneficial use (EPA, 2014; Ferrey, 2013). CECs are predominantly water soluble contaminants of anthropogenic origin. CECs in water resource recovery facility (WRRF) effluent include pharmaceuticals and personal care products such as hormones, antibiotics, stimulants, surfactants, as well as preservatives, artificial sweeteners, and caffeine. While the focus
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S.M. Jones et al. / Chemosphere 170 (2017) 153e160 SE Samples
PE Samples Influent
Screens
Grit Chamber Primary Clarifier
Trickling Filter
Intermediate Clarifier
Nitrification Basin
Secondary Clarifier
Fig. 1. Process flow diagram (PFD) for the sampled TF/AS plants (Lawton, OK and Garland, TX).
Fig. 2. Process flow diagram (PFD) for the Norman WRRF, OK.
of engineered treatment systems for potable reuse projects begins with minimizing the risk associated with wastewater pathogens, non-regulated trace organic contaminants have become important considerations for treatment system design (Dickenson and Drewes, 2008; Gerrity et al., 2013; Tchobanoglous et al., 2015). Municipal WRRF primary and secondary effluents have been found to contain trace levels of CECs (Purdom et al., 1994; Drewes, 2006; Behera et al., 2011; Luo et al., 2014). Often-cited studies have linked, in certain aquatic species, the presence of CECs in POTW discharges and specific bioactivity, including estrogenic activity (Purdom et al., 1994; Folmar et al., 1996; Rodgers-Gray et al., 2000). While multiple studies have attempted to catalog the presence and concentration of CECs in municipal wastewater effluents, due to the complexity and cost of trace CEC sampling and analysis, few have utilized sampling plans for a broad spectrum of wastewater CECs (by class or intended use) over multiple weeks when municipal wastewater treatment facilities (or WRRF) are considered to be operating under optimum conditions. This research program was designed to conduct CEC sampling in both primary and secondary effluents from three (3) WRRFs (all located in the South-Central U.S.) at the peak of biological treatment process efficiency (dry conditions in summer months). By doing so, the resulting CEC occurrence data can be used to identify the anthropogenic organic compounds that are recalcitrant in municipal wastewater, even during ideal WRRF operating conditions (for biological oxidation). Two (2) of the three (3) sampled WRRFs are identical in treatment regime - trickling filters followed by nitrification e while a third sampled WRRF employed conventional activated sludge. However, the sampled treatment facilities were representative of conventional, secondary wastewater treatment, and as such provided an important screening tool for identification of CECs resistant to state-of-the-art biological treatment. The resulting list of recalcitrant CECs can be used in the development of monitoring protocols for CECs in reclaimed waters receiving advanced treatment, and for additional screening of both potential public and aquatic health effects.
and suspended-growth activated sludge (TF/AS) facility, permitted to treat 24 MGD. The Texas Commission for Environmental Quality (TCEQ) administers a Texas Pollutant Discharge Elimination System (TPDES) permit which dictates the monthly average effluent limits from Rowlett Creek for carbonaceous biochemical oxygen demand (cBOD) of 10 mg/L, total suspended solids (TSS) of 15 mg/L, and seasonal ammonia nitrogen limits of 5 mg/L (December through March) and 2 mg/L (April through November). Effluent is discharged from this facility to the East Fork of the Trinity River. The City of Lawton, Oklahoma, also owns and operates a tertiary TF/AS plant to treat sanitary sewer flows from their southwest Oklahoma population of 85,872 residents. PE and SE samples were collected from the Lawton WRRF, which currently treats an average daily flow of 10 MGD with average daily effluent water quality of 3 mg/L cBOD, 9 mg/L TSS, and 0.2 mg/L ammonia nitrogen. Effluent is discharged to Nine Mile Creek in the Red River watershed; however, up to 5 MGD is dedicated for reuse by the Public Service Company of Oklahoma (PSO) for their industrial cooling towers. Fig. 2 presents a simplified process flow diagram of treatment at the Lawton and Garland WRRFs, as well as the locations of PE and SE sample collection in the process train. The City of Norman, Oklahoma, owns and operates a WRRF to treat flows from their Oklahoma City suburban and research university population of over 100,000 residents. Samples were collected for this study from the conventional, suspended-growth, activated sludge (AS) facility; permitted to treat 17 MGD. Monthly average effluent limits from the WRRF are cBOD of 13 mg/L, TSS of 30 mg/L, and ammonia nitrogen limits of 4.1 mg/L. Effluent is discharged to the Canadian River in the Arkansas River watershed. The Norman WRRF provides seasonal reuse to the University of Oklahoma for irrigation of the Jimmie Austin Golf Course. Fig. 2 presents a simplified process flow diagram of the Norman WRRF, and the locations of PE and SE sample collection in the process train. 2.2. Effluent sampling Two (2) sampling locations were identified per WRRF. The sample locations included the influent to the biological reactor(s) and the effluent of the final (or secondary) clarifiers. Samples collected on the influent side of the biological reactor were always prior to being combined with the return activated sludge (RAS) flow. The sampling location of the secondary clarifier effluent, at each WRRF, was after all clarifier effluents had been combined, but prior to any tertiary treatment or disinfection. Sampling was performed in August and September of 2014, with one sample event per week. Table 1 lists the number of discrete sample events during
2. Materials and methods 2.1. Water resource recovery facilities The City of Garland, Texas, owns and operates two tertiary WRRFs (Rowlett Creek and Duck Creek) to treat flows from their Dallas/Fort Worth suburban population of 235,000 residents. Primary effluent (PE) and secondary effluent (SE) for this research was collected from the Rowlett Creek WRRF, a fixed-film trickling filter
Table 1 Sampling events and WRRF flow treated during sampling in August/September 2014. WRRF Norman (OK) Lawton (OK) Garland (TX)
No. of sample events
Avg. flow treated (MGD)
4 4 3
9.6 11 12.7
S.M. Jones et al. / Chemosphere 170 (2017) 153e160 Table 2 Analytes examined in each WRRF sample (PE or SE) with corresponding LC/MS/MS electrospray ionization mode (ESI). Analytes
CAS
MRL (mg/L)
Ionization mode
1,7-Dimethylxanthine Acetaminophen Albuterol Amoxicillin Andorostenedione Atenolol Atrazine Azithromycin Bezafibrate Bromacil Caffeine Carbadox Carbamazepine Carisoprodol Chloridazon Chlorotoluron Cimetidine Cotinine Cyanazine DACT DEA DEET Dehydronifedipine DIA Diazepam Dilantin Diltiazem Diuron Erythromycin Flumequine Fluoxetine Isoproturon Ketoprofen Ketorolac Lidocaine Lincomycin Linuron Lopressor Meclofenamic Acid Meprobamate Metazachlor Metolachlor Nifedipine Norethisterone Oxolinic acid Pentoxifylline Phenazone Primidone Progesterone Propazine Quinoline Simazine Sulfachloropyridazine Sulfadiazine Sulfadimethoxine Sulfamerazine Sulfamethazine Sulfamethizole Sulfamethoxazole Sulfathiazole TCEP TCPP TDCPP Testosterone Theobromine Theophylline Trimethoprim 2,4-D 4-nonylphenol 4-tert-Octylphenol Acesulfame-K Bendroflumethiazide BPA
611-59-6 103-90-2 51022-70-9 26787-78-0 63-05-8 29122-68-7 1912-24-9 83905-01-5 41859-67-0 314-40-9 58-08-2 6804-07-5 298-46-4 78-44-4 1698-60-8 15545-48-9 51481-61-9 486-56-6 21725-46-2 3397-62-4 6190-65-4 134-62-3 67035-22-7 1007-28-9 439-14-5 57-41-0 42399-41-7 330-54-1 114-07-8 42835-25-6 54910-89-3 34123-59-6 22071-15-4 74103-06-3 137-58-6 154-21-2 330-55-2 51384-51-1 644-62-2 57-53-4 67129-08-2 51218-45-2 21829-25-4 68-22-4 14698-29-4 6493-05-6 60-80-0 125-33-7 57-83-0 139-40-2 91-22-5 122-34-9 80-32-0 68-35-9 122-11-2 127-79-7 57-68-1 144-82-1 723-46-6 72-14-0 115-96-8 13674-84-5 13674-87-8 58-22-0 83-67-0 58-55-9 738-70-5 94-75-7 25154-52-3 140-66-9 55589-62-3 73-48-3 80-05-7
0.01 0.5 0.005 0.2 0.005 0.05 0.005 0.02 0.005 0.005 0.5 0.005 0.005 0.005 0.005 0.005 0.05 0.1 0.005 0.005 0.005 1 0.005 0.005 0.005 0.02 0.005 0.005 0.01 0.01 0.01 0.1 0.005 0.005 0.005 0.01 0.005 0.2 0.005 0.005 0.005 0.005 0.02 0.005 0.01 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.05 0.005 0.01 1 0.1 0.005 0.01 0.02 0.005 0.005 0.1 0.05 0.02 0.005 0.01
ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI(þ) ESI() ESI() ESI() ESI() ESI() ESI()
155
Table 2 (continued ) Analytes
CAS
MRL (mg/L)
Ionization mode
Butalbital Butylparaben Chloramphenicol Clofibric Acid Diclofenac Estradiol Estrone Ethinyl Estradiol Ethylparaben Gemfibrozil Ibuprofen Iohexal Iopromide Isobutylparaben Methylparaben Naproxen Propylparaben Sucralose Triclocarban Triclosan Warfarin
77-26-9 94-26-8 56-75-7 882-09-7 15307-86-5 50-28-2 53-16-7 57-63-6 120-47-8 25812-30-0 15687-27-1 66108-95-0 73334-07-3 4247-02-3 99-76-3 22204-53-1 94-13-3 56038-13-2 101-20-2 3380-34-5 81-81-2
0.005 0.005 0.01 0.005 0.005 0.005 0.005 0.005 0.02 0.005 0.01 0.01 0.005 0.005 0.02 0.01 0.005 0.1 0.005 0.01 0.005
ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI() ESI()
this period at each WRRF, along with the average flow (in million gallons per day, or MGD) treated at each facility. For each sample event, grab samples of effluent (PE and SE) were collected using prepared fluorocarbon polymer sample bottles containing ascorbic acid and sodium azide as preservatives. Samples were chilled to below 4 C and shipped on ice or frozen gel packs overnight to the analytical laboratory. All sample analysis was performed within 30 days of sample collection. 2.3. Sample analysis The collected effluent samples were then shipped overnight to the Eurofins Eaton Analytical Laboratory in Monrovia, CA. Applying a liquid chromatography, tandem mass spectroscopy method (LC/ MS/MS) developed with support from the Water Research Foundation (Vanderford et al., 2013), each effluent sample was then analyzed for up 94 different CECs. Samples were pre-concentrated using a previously developed direct online extraction/analysis method (Haghani et al., 2009), to achieve low-ng/L method reporting limits (MRL). Table 2 lists the analytes that were quantified in each sample. 3. Results 3.1. Trickling filter/activated sludge samples As the Garland and Lawton WRRF utilized similar biological treatment processes to meet NPDES permit limits (see Figs. 1 and 2), their respective CEC occurrence data can be compared. Table 3 lists the relevant measures of WRRF organics, and particulate removal during scheduled sample events in August and September 2014. With the exception of mean sludge age (SRT, days), each TF/ AS WRRF sampled had similar operating mixed-liquor suspended solids concentrations (MLSS) and removal performance for bulk organics (BOD and COD). As with average treatment performance at the TF/AS WRRFs, there was also general agreement within CEC detection and observed removal from primary to secondary effluent. Notable exceptions include specific prescription antibiotics, natural hormones, a plastic monomer, and a herbicide. Tables 4 and 5 present the mean observed concentrations of ESI(þ) and ESI() CECs, respectively, in samples of PE and SE from both TF/AS WRRFs. Notably, significant discrepancies in average CEC removal were observed for amoxicillin, bisphenol-a (BPA), butalbital, diclofenac,
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Table 3 Mean treatment performance of the TF/AS WRRFs during sampling events in August/September 2014. WRRF
Mean effluent temp. ( C)
BOD removal (%)
COD removal (%)
TSS removal (%)
Mean MLSS (mg/L)
Mean SRT (days)
26.4 –a
99 98
75 90
97 99
1590 1970
10.3 3.7
Lawton (OK) Garland (TX) a
Data not collected by participating WRRF.
and trimethoprim. With the exception of butalbital, significantly improved removal rates for each CEC were observed at the Lawton WRRF. Butalbital was detected at similar mean concentrations in primary effluent at both WRRFs. However, PE and SE concentrations detected, in all TF/AS sampling, were at low ng/L-levels (14e44 ng/L on average). While both the Lawton and Garland WRRFs treated similar influent flowrates and recorded excellent removal rates for bulk wastewater organics (BOD and COD) during sampling in 2014, the mean sludge age varied significantly between the two (2) treatment facilities. Previous studies have linked the microbial population density and diversity with increasing SRT to enhanced elimination of CECs at WRRFs (Gerrity et al., 2013; Maeng et al., 2013). The mean observed attenuation rate of BPA in Lawton WRRF sampling matched closely the reported biotransformation rate of the plastic monomer in a Greek activated sludge facility (Stasinakis et al., 2010). However, Stasinakis et al. (2010) reported no appreciable increase in BPA biotransformation with an increase
in sludge age from 10 to 20 days. Other full-scale WRRF CEC removal studies have also reported limited improvement in the attenuation or biotransformation of trace CECs at SRTs greater than 10 days (Joss et al., 2005). Surprisingly, 22 compounds had observed attenuation rates at the Lawton and Garland WRRFs greater than 90% (on average). The extent of CEC degradation observed at these facilities is in stark contrast to previous CEC recalcitrance classification studies that have reported significant biotransformation with activated sludge for as few as 4 out of 35 studied CECs (Joss et al., 2006). In certain cases, concentrations of detected CECs increased between primary effluent, and secondary effluent sampling. This is not uncommon with grab sampling regimes, where CECs (and other organic solutes) may sorb/de-sorb from the solids inventory that is maintained for biological treatment efficiency. An additional consideration in the evaluation of data from grab samples is that it often does not follow the same batch of water passing through the treatment process and may
Table 4 Mean concentrations of ESI(þ) CECs in PE and SE samples from TF/AS WRRFs. Only CECs where detection was observed in more than one (N > 1) PE or SE sample are reported. “Blanks” are indicative of no observed CEC detection, or a CEC concentration less than the MRL. SD ¼ Standard deviation on the mean PE or SE concentration detected. Lawton WRRF
Mean PE (ng/L)
1,7-Dimethylxanthine Acetaminophen Albuterol Amoxicillin Andorostenedione Atenolol Atrazine Azithromycin Caffeine Carbamazepine Carisoprodol Cimetidine Cotinine DACT DEA DEET DIA Dilantin Diltiazem Erythromycin Fluoxetine Ketoprofen Ketorolac Lidocaine Lincomycin Lopressor Meprobamate Metolachlor Nifedipine Pentoxifylline Primidone Quinoline Simazine Sulfadiazine Sulfamethoxazole TCEP TCPP TDCPP Theobromine Theophylline Trimethoprim
2,490 29,595 31 5,800 119 885 72 1,867 31,750 155 147 493 2,950 97 7,675 173 51 72 66 21 313 20 855 223 5 65 15 92 177
1,798 360 1,183 623 2,745 3,773 450
Mean SE (ng/L)
% Removal
% Removal
Mean SE (ng/L)
Mean PE (ng/L)
Garland WRRF
100% 99% 27% 4%
410 33 11,600
3,633 60,000 26 11,167
190 84 2,043 48 167 282 166 54
100% 100% 7% 80% 100% 79% 17% 9% 100% 8% 92% 66% 98%
61 22 16 289 27
37% 100% 100% 67% 48%
59
520 91 2,700 48 180 98 509 113 29 373 113 67 191 85 19 115 43 18 383 174 367 254
1,290 123 2,633 35,333 180 60 1,507 2,100 21 175 16,333 36 150 171 52 117 128 42 657 406 2,033 250
88 18 6
17% 100% 65% 50% 100% 46% 54% 48% 56% 100% 4% 90% 100%
60% 26% 3% 100% 0% 63% 66% 95% 36% 113% 99% 83% 28% 51% 63% 2% 66% 57% 42% 57% 82% 2%
1,443 233 1,000 588 111 30 51
20% 35% 15% 6% 96% 99% 89%
70% 82% 6% 83% 25% 68% 32% 16% 1% 23% 99% 99% 28%
22 11 113 29 26 140 1,273 287 1,960 787 140 85 433
75 62 107 165 34 440 1,867 340 1,933 1,027 10,033 8,900 600
1,7-Dimethylxanthine Acetaminophen Albuterol Amoxicillin Andorostenedione Atenolol Atrazine Azithromycin Caffeine Carbamazepine Carisoprodol Cimetidine Cotinine DACT DEA DEET DIA Dilantin Diltiazem Erythromycin Fluoxetine Ketoprofen Ketorolac Lidocaine Lincomycin Lopressor Meprobamate Metolachlor Nifedipine Pentoxifylline Primidone Quinoline Simazine Sulfadiazine Sulfamethoxazole TCEP TCPP TDCPP Theobromine Theophylline Trimethoprim
45 29 1,153
7 158 458 343 8 29
S.M. Jones et al. / Chemosphere 170 (2017) 153e160
157
Table 5 Mean concentrations of ESI() CECs in PE and SE samples from TF/AS WRRFs. Only CECs where detection was observed in more than one (N > 1) PE or SE sample are reported. “Blanks” are indicative of no observed CEC detection, or a CEC concentration less than the MRL. SD ¼ Standard deviation on the mean PE or SE concentration detected. Lawton WRRF
Mean PE (ng/L)
Mean SE (ng/L)
% Removal
% Removal
Mean SE (ng/L)
Mean PE (ng/L)
Garland WRRF
2,4-D Acesulfame-K BPA Butalbital Clofibric Acid Diclofenac Estrone Gemfibrozil Ibuprofen Iohexal Iopromide Methylparaben Naproxen Propylparaben Sucralose Triclocarban Triclosan
543 17,773 485 42 24 236 13 1,363 2,133 16,000 3,575 761 2,111 236 23,000 653 690
176 3,228 34 39 21 72 11 48
68% 82% 93% 7% 11% 69% 18% 96% 100% 97% 97% 100% 96% 100% 12% 86% 92%
80% 90% 99% 69%
32 2,333 116 14
163 23,667 58 44
19% 22% 79% 100% 48%
93 8 160
79 11 747 5,200 14,400
2,4-D Acesulfame-K BPA Butalbital Clofibric Acid Diclofenac Estrone Gemfibrozil Ibuprofen Iohexal Iopromide Methylparaben Naproxen Propylparaben Sucralose Triclocarban Triclosan
505 97 76 20,250 91 58
reflect different concentrations (at varying times) of CECs coming in to the treatment facility.
3.2. Conventional activated sludge samples The Norman WRRF employs a form of conventional activated sludge secondary treatment. Table 6 lists the relevant measures of Norman WRRF organics, and particulate removal during scheduled sample events in August and September 2014. It should be noted that COD was not monitored by the WRRF for discharge permit compliance, and thus is not shown in Table 6. Mean effluent temperature, and BOD and TSS removal efficiencies were comparable to the TF/AS WRRFs sampled, however, mean mixed liquor suspended solids concentrations were three (3) times greater at the Norman WRRF (than for the Lawton or Garland WRRFs). Tables 7 and 8 present the mean observed concentrations of ESI(þ) and ESI() CECs, respectively, in samples of PE and SE from the Norman WRRF. A notable omission from the list of ESI(þ) CECs detected in Norman WRRF sampling was the broad-leaf herbicide Atrazine. While banned in the European Union, Atrazine use continues in the U.S. with estimated application rates as high as 64 lb/ sq. mi. (USGS, 2014) in States East of the Rocky Mountains. While not present (above the MRL) in PE and SE samples from the Norman WRRF, the metabolites of atrazine were detected, DACT, DEA and DIA. These dealkylated metabolites were first detected in atrazinecontaminated soils during bioremediation trials (Struthers et al., 1998). The detection of well-studied atrazine metabolites in SE samples (and not PE samples) is an indication that atrazine removal was occurring in the secondary treatment processes at Norman, be it via biotransformation and/or sorption mechanisms. However, atrazine removal was not observed at the TF/AS WRRFs during the same period, in agreement with previously reported atrazine biotransformation studies that have shown atrazine to be recalcitrant even in advanced wastewater treatment (AWT) processes, such as membrane bioreactors (Bernhard et al., 2006).
3.3. Undetected CECs Of the analytes listed in Table 2, 15 were not detected in any PE or SE samples collected at participating WRRFs. The list of CECs that either were not present in the sanitary sewer influent, or were removed to levels below their MRLs, included:
97% 100% 19% 90% 93%
7,500
55 33,000 49 75
1,977 540 27,667 493 1,080
Bendroflumethiazide Carbadox Chloridazon Ethinyl Estradiol Flumequine Isoproturon Meclofenamic Acid Metazachlor Oxolinic acid Phenazone Propazine Sulfachloropyridazine Sulfamerazine Sulfamethazine Sulfamethizole
A significant focus of recent research on the removal of CECs in municipal WRRF has been the fate (during engineered treatment) of natural and synthetic female hormones, and their associated estrogenic activity (Kirk et al., 2002; Servos et al., 2005; Racz and Goel, 2010). As noted in the list above, the female hormone Ethinyl Estradiol (also known as 17a-ethinylestradiol, or EE2) was not detected in any samples from this study, and the known estrogen, Estradiol (also known as 17b-estradiol) was infrequently detected in either PE or SE samples, often at concentrations near the MRL. The mean concentration of Estradiol in all PE samples collected was 39 ng/L, with no positive Estradiol detections in any SE samples. However, the female hormone Estrone (also known as E1), proved difficult to remove even during optimal biological treatment conditions at the sampled WRRFs. The variable removal observed for Estrone in the sampled WRRFs agrees with previous studies that reported inconsistent removal rates for the hormone (Servos et al., 2005). However, the observed concentrations of Estrone in final effluent samples were an order-of-magnitude below the reported no-effect-concentrations for fish reproduction (Fig. 3). While reported fish reproductive toxicity testing has indicated the greatest sensitivity from test organisms to Ethinyl Estradiol (Caldwell et al., 2012), Ethinyl Estradiol was not detected in either primary or secondary effluent samples collected from the studied WRRFs. 3.4. Labile and recalcitrant CECs A significant outcome of the reported work is that the CECs, in both occurrence and rate of removal, were consistent between
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Table 6 Mean treatment performance and operating characteristics of the AS WRRF during sampling events in August/September 2014. WRRF
Mean effluent temp. ( C)
BOD removal (%)
TSS removal (%)
Mean MLSS (mg/L)
Mean SRT (days)
26.8
99
97
4501
10.7
Norman (OK)
sampled WRRFs, and biological treatment processes. No appreciable difference was observed in CEC removal between the two secondary treatment bioreactor configurations of AS and TF/AS. Thus, the collective CEC data set can be used to determine the CECs most resistant to secondary treatment at WRRFs. Table 9 lists the studied CECs that were identified as either well-removed (>80% removal by the WRRF, on average), or recalcitrant (<20% removal by the WRRF, on average) in WRRF PE and SE sampling in August/ September 2014. By aggregating the CEC concentration data across the studied CECs, clear trends emerge for identifying analytes with the most, and the least resistance to the sampled secondary treatment systems. The State of Texas is the only U.S. State to have approved the direct potable reuse (DPR) of municipal WRRF effluent, on a caseby-case basis. In 2015, the Texas Water Development Board (TWDB) published a Resource Document to guide DPR project development in Texas (TWDB, 2015). The TWDB Resource Document for DPR listed nineteen (19) different indicator chemicals to be monitored for DPR treatment performance, with sixteen (16) of the nineteen (19) currently unregulated either federally or locally
Table 7 Mean concentrations of ESI(þ) CECs in PE and SE samples from the AS WRRF. Only CECs where detection was observed in more than one (N > 1) PE or SE sample are reported. SD ¼ Standard deviation on the mean PE or SE concentration detected. Norman WRRF
Mean PE (ng/L)
1,7-Dimethylxanthine Acetaminophen Albuterol Amoxicillin Andorostenedione Atenolol Azithromycin Caffeine Carbamazepine Carisoprodol Cimetidine Cotinine DACT DEA DEET DIA Dilantin Diltiazem Fluoxetine Ketoprofen Ketorolac Lidocaine Linuron Lopressor Meprobamate Primidone Progesterone Simazine Sulfadiazine Sulfamethoxazole TCEP TCPP TDCPP Theobromine Theophylline Trimethoprim
3,743 46,600 27 8,100 640 1,853 2,567 57,333 240 90 1,230 3,500 266 8,767 17 760 153 133 99 28 450 23 987 1,077 160 1,090 150 610 3,300 460 787 483 16,253 11,667 1,003
Mean SE (ng/L) 873 22 5,786
1,143 81 282 60 915 32 8 10 84 74 414 87 121
219 11 498 711 128 200 150 1,231 224 1,614 644 82 534
% Removal 100% 98% 18% 29% 100% 100% 55% 100% 18% 33% 26% 99% 100% 96% 99% 100% 46% 43% 9% 100% 100% 51% 52% 50% 34% 20% 100% 33% 75% 63% 51% 100% 33% 100% 99% 47%
Table 8 Mean concentrations of ESI() CECs in PE and SE samples from the AS WRRF. Only CECs where detection was observed in more than one (N > 1) PE or SE sample are reported. SD ¼ Standard deviation on the mean PE or SE concentration detected. Norman WRRF
Mean PE (ng/L)
Mean SE (ng/L)
% Removal
2,4-D Acesulfame-K BPA Butalbital Butylparaben Clofibric Acid Diclofenac Estrone Ethylparaben Gemfibrozil Ibuprofen Iohexal Iopromide Isobutylparaben Methylparaben Naproxen Propylparaben Sucralose Triclocarban Triclosan
321 16,500 97 28 27 21 92 10 1,694 1,567 4,000 16,333 54 28 977 2,497 463 20,333 175 535
45 520
86% 97% 100% 65% 100% 100% 15% 40% 100% 97% 100% 94% 100% 100% 100% 99% 100% 3% 92% 95%
10
78 14 51 1,000
13 19,784 14 29
(in TX). Comparing the labile and recalcitrant CEC classified in Table 9, there are five (5) CECs that were identified in this study as well removed or labile, which were also suggested indicator chemicals for DPR monitoring by the TWDB. These CECs included Triclosan, Iopromide, Gemfibrozil, DEET, and Caffeine. A sixth, E2 or Estradiol, was not detected in any secondary effluent samples from the studied WRRFs. However, three (3) recalcitrant CECs, as identified by WRRF sampling in 2014, do appear on the TWBD monitoring list, Meprobamate, Primidone and Sucralose. The TWDB's Monitoring Trigger Threshold (MTT) for these three chemicals in reclaimed effluents are 200 mg/L, 10 mg/L, and 150 mg/L, respectively. Despite their apparent recalcitrance, the aggregate mean concentrations of either Meprobamate, Primidone or Sucralose in the secondary effluent of the participating WRRFs were well below their respective MTTs (without additional advanced physical, chemical, or biological treatment).
4. Conclusions Given the scope of both WRRF facilities sampled, and CECs analyzed in this study, the resulting CEC occurrence data can be used to identify CECs by their respective resistance to conventional water reclamation processes. The excellent treatment performance (with respect to particulate and bulk organics removal) of all three of the studied WRRF at the time of sampling allows for determination of the truly recalcitrant, to conventional secondary wastewater treatment processes, CECs (from an initial survey list of 95 chemical constituents). Given both the observed recalcitrance and the frequency of detection in secondary effluent samples, the following short-list of CECs should be considered for advanced treatment process performance monitoring for potable reuse projects:
S.M. Jones et al. / Chemosphere 170 (2017) 153e160
159
Fig. 3. Box-and-whisker plots of aggregated (all WRRF samples) PE and SE sample concentrations of Estrone (E1), Estradiol (E2), and Ethinyl Estradiol (EE2), and no-effect concentrations (NOEC) reported from fish reproductive toxicity studies with each estrogen (NOEC Source: (Caldwell et al., 2012)).
Table 9 Aggregated mean concentrations of well-removed (>80% removal from PE to SE samples) and poorly-removed (<20% removal) CECs in all WRRF sampling from August to September 2014. DF ¼ Detection Frequency (out of 11 events). All concentrations are listed in ng/L. >80% removal
<20% removal
Analytes
Primary effluent
Secondary effluent
Mean
DF
Mean
DF
1,7-Dimethylxanthine Acesulfame-K Acetaminophen Andorostenedione Caffeine Chloramphenicol Cotinine DEET Ethylparaben Gemfibrozil Ibuprofen Iopromide Ketorolac Methylparaben Naproxen Progesterone Propylparaben Quinoline Theobromine Theophylline Triclocarban Triclosan
3,009 19,909 41,120 106 39,090 287 2,770 9,782 679 1,214 3,750 1,804 93 646 1,990 763 434 163 8,776 7,190 474 757
91% 91% 91% 73% 100% 27% 91% 100% 55% 100% 73% 73% 55% 55% 100% 27% 91% 64% 100% 100% 73% 64%
41 2,485 390
9% 91% 55% 82% 82% 73% 91% 9% 36% 18% 91%
55% 64% 36% 73% 91%
% Removal
Analytes
Primary effluent
Secondary effluent
% Removal
Mean
DF
Mean
DF
99% 88% 99% >95% 100% >96% 98% 99% >97% 93% 99% 95% 86% >96% 100% >99% >98% 87% 99% 99% 88% 84%
Albuterol Atrazine Azithromycin Carbamazepine Carisoprodol Clofibric Acid DACT DEA DIA Dilantin Estrone Meprobamate Primidone Sucralose TCPP TDCPP
27 80 2,198 172 107 22 16 167 27 314 12 448 110 22,455 1,189 655
91% 55% 91% 100% 45% 36% 27% 64% 55% 100% 64% 100% 100% 100% 100% 100%
27 87 1,890 171 169 21 16 187 53 291 10 418 96 23,100 1,219 614
82% 55% 91% 91% 55% 9% 45% 64% 64% 91% 55% 91% 91% 91% 91% 91%
2% -10% 14% 1% -58% 5% 3% -12% -96% 7% 13% 7% 13% -3% -3% 6%
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S.M. Jones et al. / Chemosphere 170 (2017) 153e160
Albuterol Atrazine/DEA/DIA/DACT Azithromycin Carbamazepine Dilantin Estrone (or E1) Meprobamate (TWDB suggested indicator chemical) Primidone (TWDB suggested indicator chemical) Sucralose (TWDB suggested indicator chemical) TCPP TDCPP
While the toxicity thresholds that govern the maximum allowable concentrations in reclaimed water are expected to vary (and require further research to identify), this list includes chemical constituents that are anticipated to have either aquatic environment (i.e., Estrone, Azithromycin) or human health effects (i.e., TCPP, TDCPP, Atrazine). Therefore, the short-list of CECs identified by this research represents potential criteria pollutants for both indirect and direct potable reuse projects. Of note, the regulated herbicide, Atrazine, does not appear on the TWDB chemical list, but the clear resistance to removal, for either the parent or daughter compounds (DACT, DIA, and DEA), with secondary treatment should make it a recommended chemical for DPR treatment performance monitoring. Acknowledgements This research was made possible by the financial support of the City of Norman (OK), the City of Lawton (OK), and the City of Garland (TX). Additional sampling support was provided by Michael Graves (Garver), Jeffrey Sober (Garver), Afsaneh Jabbar (Lawton), John Pruitt (Garver), Wes Kucera (Garland), Malcolm Parker (Garland), Kyle Kruger (Garver), Lyna Neal (Lawton) and Steven Hardeman (Norman). In addition, Dr. Andrew Eaton (Eurofins) provided valuable technical support for sampling protocol development and sample analysis. References Behera, Shishir Kumar, Kim, Hyeong Woo, Oh, Jeong-Eun, Park, Hung-Suck, 2011. Occurrence and removal of antibiotics, hormones and several other pharmaceuticals in wastewater treatment plants of the largest industrial city of Korea. Sci. Total Environ. 409 (20), 4351e4360. Bernhard, Marco, Müller, Jutta, Knepper, Thomas P., 2006. Biodegradation of persistent polar pollutants in wastewater: comparison of an optimised lab-scale membrane bioreactor and activated sludge treatment. Water Res. 40 (18), 3419e3428. Caldwell, Daniel J., Mastrocco, Frank, Anderson, Paul D., L€ ange, Reinhard, Sumpter, John P., 2012. Predicted-no-effect concentrations for the steroid estrogens estrone, 17b-estradiol, estriol, and 17a-ethinylestradiol. Environ. Toxicol. Chem. 31 (6), 1396e1406. € rg E., 2008. Removal of Pharmaceuticals and Personal Dickenson, Eric, Drewes, Jo Care Products During Activated-sludge Wastewater Treatment. World Environmental and Water Resources Congress, Ahupua'A, 2008. €rg E., 2006. Final report. Removal of Endocrine Disrupting Compounds in Drewes, Jo Water Reclamation Systems, 1 vols. Water Environment Research Foundation, Alexandria, VA. EPA, U.S, 2014. Treating Contaminants of Emerging Concern - A Literature Review
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