Emerging Contaminants: Fate During Wastewater Treatment and Strategies to Enhance Removal David Quanrud The University of Arizona New Directions in Wastewater Treatment AZ Water Association 21 October 2014

Outline 1.Let’s talk terminology: ECs and EDCs 2.Fate of estrogenic activity during WW treatment – Comparison of AZ WWTPs – WERF project: WWTP mass balances 3.How can we improve removal of ECs during WWT?

Terminology Salad Emerging contaminants (ECs) Compounds of emerging concern (CECs) Trace organic contaminants (TOrCs) Pharmaceutically active compounds (PhACs) Pharmaceuticals and personal care products (PPCPs) Endocrine disrupting compounds (EDCs) Hormonally active agents (HAAs) Many terms are in use but they do not all mean the same thing…

What is an emerging contaminant? It is possible to distinguish 3 categories of emerging contaminants: 1.New compounds not previously present in the environment for which toxicity is known/suspected (e.g. nanoparticles, PBDEs) 2.Compounds that have existed for a while but environmental contamination issues were not appreciated until recently (e.g. estrogens) 3.“Legacy” contaminants for which new information exists on their toxicity (e.g. arsenic) A more accurate term: “Compounds of emerging concern”

Number of articles by year containing term “emerging contaminant” (ScienceDirect literature search, )

Why are we more aware of ECs now? Our Stolen Future (1996) USGS national reconnaissance survey (2002) Associated Press investigation (2008) Increased usage over time (e.g. additives in hand soaps) Improved analytical methods! (ppb, ppt, ppq) Caffeinated soap!

Examples of ECs Pharmaceuticals – over-the-counter – prescription – caffeine – nicotine – veterinary drugs Personal care products – soaps – sunscreens – cosmetics – bug sprays Industrial compounds – flame retardants – plasticizers – bisphenol A Some of the these compounds are endocrine disruptors (EDCs), but many are not… So, what is an endocrine disruptor?

What is an endocrine disrupting compound? “An endocrine disruptor is an exogenous substance or mixture that alters function(s) of the endocrine system and consequently causes adverse health effects in an intact organism, or its progeny….” From: “Global Assessment of the State-of-the-Science of Endocrine Disruptors.” International Programme on Chemical Safety, World Health Organization (2002)

Yeast estrogen screen (YES) bioassay In vitro reporter gene bioassay Utilizes human estrogen receptor → Total estrogenic activity reported as equivalent concentration of EE2, based on comparison to standard curve

Fate of Estrogenic Activity during Conventional Wastewater Treatment (trickling filter) Where did it go? Two possibilities: –compound destruction (biodegradation) –mass transfer (adsorption to the sludge) influent effluent ~50% removal

Oxidation ditch Membrane bioreactor Activated Sludge + BNR Activated Sludge (pure O 2 ) Biotower #1 (shorter SRT) Biotower #2 (longer SRT) Estrogenic Activity: Comparison of Arizona WWTPs Influent Effluent Sludge

Comparison of six Arizona WWTPs Oxidation DitchMembrane Bioreactor Act. Sl. + BNR Biotower #1Activated SludgeBiotower #2 Estrogenic activity remaining in solid (sludge) (%) 16% 18% <0.1% 14% <0.01% 1% <0.01% Estrogenic activity remaining in effluent (%) 63% 24% <0.01% 3% Influent Effluent Sludge

Fate of Estrogenic Compounds During Municipal Sludge Stabilization & Dewatering WERF Project 04-HHE-6 Beverley Stinson, PhD Kathleen Esposito Mohammed Abu-Orf, PhD Edward Furlong, PhD James Gray, PhD Dana Kolpin Patrick Phillips David Quanrud, PhD Wendell Ela, PhD Sondra Teske Dave Newman Alan Hais, PE, BCEE

Analytical Methods Chemical analysis In vitro bioassay –yeast estrogen screen (YES) WERF Project 04-HHE-6

Wastewater Treatment Processes Lime Addition Anaerobic Digestion thermophilic Anaerobic Digestion mesophilic Primary Treatment Secondary Treatment Settling Aerobic Digestion (Plant A) (Plant B) (Plant C) (Plant D) WERF Project 04-HHE-6

Most Important Contributors to Estrogenicity WERF Project 04-HHE-6 Compound Name Abbr. Log K ow Mol. Wt. Potency, relative to EE 2 [g/mol][mol EE2 /mol] 17α-ethinylestradiolEE α-estradiolE2a β-estradiolE EstroneE EstriolE n-Octylphenol4nOP tert-Octylphenol4tOP Octylphenol monoethoxylatesOP1EO Octylphenol diethoxylatesOP2EO NonylphenolNP Nonylphenol monoethoxylatesNP1EO Nonylphenol diethoxylatesNP2EO DiethylstilbestrolDES Bisphenol ABPA Benzophenonebenzoph Diethylhexyl phthalateDEHP

Plant B (Activated sludge) Mesophilic anaerobic digestion WERF Project 04-HHE-6 (total masses of estrogenic activity per day) Liquid phase: – Estrogenic activity reduced by ~85% – Hormones are responsible for most of the estrogenic activity in effluent Solid phase: – Estrogenicity increased during anaerobic digestion of sludge – Alkylphenols are converted into more estrogenic metabolites (e.g. NP)

Plant D (Activated sludge) Thermophilic anaerobic digestion WERF Project 04-HHE-6 (total masses of estrogenic activity per day) Liquid phase: – Estrogenic activity reduced by ~95% – Hormones are responsible for most of the estrogenic activity in effluent Solid phase: – Estrogenicity increased during anaerobic digestion of sludge – Alkylphenols are converted into more estrogenic metabolites (e.g. NP)

Summary Observations Liquid phase: – Estrogen hormones account for majority of estrogenic activity in effluent of WWTPs – Most estrogenic compounds are efficiently removed during conventional activated sludge treatment Solid phase—anaerobic digestion: – Estrogenicity increases – Alkylphenols are converted into more estrogenic metabolites (e.g. nonylphenol) – Important to consider the ECs present in biosolids (e.g. what happens during land application?) WERF Project 04-HHE-6

Examples of trace organic compounds present in municipal wastewater CompoundUseLog K ow IopromideX-ray contrast agent-2.30 PFOS (Scotchgard)Surfactant-1.08 SucraloseArtificial sweetener PFOASurfactant-0.90 PrimidoneAnti-convulsant0.11 SulfamethoxazoleAntibiotic0.48 TrimethoprimAntibiotic0.91 TCEPFlame retardant1.63 Fluoxetine (Prozac)Anti-depressant1.80 DEETMosquito repellent2.18 CarbamazepineAnti-convulsant2.45 Tonalide (synthetic musk)Fragrance5.90 hydrophilic hydrophobic Log K ow : a measure of how hydrophilic ("water-loving") or how hydrophobic ("water-fearing") a chemical substance is (water- loving) (water- fearing) (None of these compounds are currently regulated in USA)

Possible removal mechanisms for ECs during WWT Significant Not Significant Sorption to solids —Dependent on hydrophobicity Biodegradation —Aerobic —Anoxic —Anaerobic Volatilization —Low Henry’s constants Chemical transformations —Hydrolysis —Acid base —Photocatalytic

Generalizing on EC Fate during Wastewater Treatment Hydrophobicity (log K OW ) Biodegradability ibuprofen & lots of others (maybe not much reason for concern) alkylphenols (e.g. NP) (may survive in sludges) PBDEs, triclosan, PFCs (concern in land applied biosolids) iopromide, PFOS, carbamazepine, sulfamethoxazole (concern in treated WW) Long half lives High toxicity Compounds of greatest concern:

Examples of compounds most susceptible to removal during conventional WWT Ibuprophen Thymol Estrone Aspirin Bezafibrate Fenoprofen Salicylic acid Estriol Acetaminophen Cortisol Prednisone Dexamethasone Carbamazepine Diclofenac Metoprolol Iopromide Sotalol Examples of compounds least susceptible to removal during conventional WWT Oulton et al Pharmaceuticals and personal care products in effluent matrices: a survey of transformation and removal during wastewater treatment and implications for wastewater management. Journal of Environmental Monitoring biodegradation + sorption No biodegradation No sorption

What are the options to increase removal of ECs during WWT? 1.Optimize biological treatment conditions – Increase SRT – Add BNR 2.Incorporate advanced treatment processes – Activated carbon adsorption – Ozonation – Advanced oxidation processes (AOPs) – Membranes (NF, RO)

Solids Retention Time Several studies have shown that increasing the SRT provides for greater removal of ECs Increases the biodegradative capacity of activated sludge – May promote better adapted microbial populations for EC removal Increases the sorptive capacity of activated sludge – May Improve hydrophobic/hydrophilic properties of flocs and their ability to act as sorbents for ECs However, other studies have found no correlation of SRT with removal of ECs, e.g. Joss et al. (2005); Gobel et al. (2007)

Laboratory simulation of wastewater treatment (activated sludge) Clarified Effluent /Clarifier Synthetic Wastewater CMAS Reactor BioStat MD Control Unit Pumps Garrett Configuration Garrett 1958

Effect of increasing sludge age on EDC removal during activated sludge treatment EC removal can be improved by increasing the sludge age

General consensus on effect of SRT A majority of studies have shown a positive correlation between increased SRT and increased percentage removal of ECs As sludge age increases, EC removal efficiency also increases Other factors may also be important… – Temperature, pH, seasonal variations – Microbial populations may vary among WWTPs BNR: removal efficiency of ECs increases with higher rates of nutrient removal However…

What is an appropriate MCL for estrogens in effluent? Environment Agency of England and Wales suggests a predicted no-effect concentration (PNEC) of 1 ng/L total estrogens to protect aquatic wildlife British Columbia has set an environmental guideline at 0.5 ng/L EE2 Australia and Norway have used a PNEC of 0.1 ng/L EE2 for risk assessment (1 ng/L = 1 part per trillion = 1 penny in 10 billion dollars) Question: Can AS be sufficiently optimized to achieve these guidelines?

Sum of E1 and E2 in effluentEE2 in effluent Even with long SRT, conventional WWT cannot achieve <1 ng/L of total estrogen hormones in effluent Future regulation may necessitate use of advanced wastewater treatment?… Credit: Linda Gaulke, EAWAG Effluent estrogen concentration vs. SRT

Advanced Wastewater Treatment EC destruction processes Ozone Advanced oxidation processes (AOPs) EC removal (separation) processes Membranes (e.g. RO, NF) Activated carbon Advanced treatment can provide complete to near complete removal of most ECs, but at a high cost

Comparison of PPCP Removal efficiencies by different WWTP technologies Oulton et al Pharmaceuticals and personal care products in effluent matrices: a survey of transformation and removal during wastewater treatment and implications for wastewater management. Journal of Environmental Monitoring

Incidence of intersex in fish (Roach) (after 6 months exposure to different effluent treatment streams) SF = sand filtration; ASP = activated sludge process Baynes et al Additional treatment of wastewater reduces endocrine disruption in wild fish—a comparative study of tertiary and advanced treatments. Environmental Science and Technology Testis (control) Ovary (control) Intersex Testis (12 mo ASP) Intersex Testis (6 mo ASP) male female intersex Testis of Roach fish exhibited intersex characteristics after 6 and 12 months exposure to ASP effluent Conclusion: based on the in vivo fish intersex assay, tertiary SF provides equivalent benefits to more expensive advanced WWT options

Cost comparison for tertiary and advanced wastewater treatments treatment option Total Cost ($/pe/yr) GAC5.53 ClO22.91 Ozone2.25 SF1.69 (from Baynes et al., 2012) CO 2 (kg/pe/yr) 13 6 <3 - Sand filtration (SF) provided an effluent equivalent in quality to GAC, at about 1/3 of the total financial cost (based on in vivo fish intersex assay)

Economic ranking of options for reducing ECs in effluent discharge 1.Advanced treatment ―Membranes, activated carbon ―Ozone, advanced oxidation processes 2.Tertiary treatment ―BNR ―Sand filtration 3.Optimize conventional WWT —Increase SRT 4.Source control —(Effectiveness is uncertain) High cost Low cost

Will there be regulations pertaining to ECs? Regulating ECs is problematic… – ECs can exert biological effects at very low doses (ng/L) – Measuring ECs accurately is challenging and expensive – ECs occur as complex mixtures in wastewater; are biological effects multiplied by mixtures? – Should a biological test (bioassay) be used to assess ECs? (in vitro? in vivo?) – in vivo: what biological endpoint should be used? (reproduction? intersex?) – In the end, a combination of chemical and bioassay-based tests may be implemented to assess ECs in effluent

Summary 1.EC fate during conventional WWT is dependent on overall biological process efficiency 2.The majority of estrogenic activity in effluent is due to estrogen hormones 3.It is important to recognize ECs are also present in the solid phase 4.EC removal can be improved by increasing SRT 5.Additional biological treatment (SF, BNR) is effective 6.Advanced WWT is most effective and most expensive 7.Some type of future regulation of ECs is possible and may include a combination of chemical and bioassay-based parameters

Questions? Lower Santa Cruz River Tucson, AZ

Sweetwater Recharge Facilities (Tucson, AZ) (Courtesy of Tucson Water) Soil aquifer treatment (SAT)

EC Removal during Soil Aquifer Treatment (Sweetwater Recharge Facilities, Tucson, AZ)

Occurrence of selected EDCs in treated biosolids in the U.S. Published in: Joel A. Citulski; Khosrow Farahbakhsh; Environ. Sci. Technol. 2010, 44,

Twenty years of biosolid application Soil analyzed for:  estrogenic activity  Nonylphenol  PBDEs Biosolids Field Marana Agricultural Center (MAC) Land Application of Biosolids: Long Term Fate of Trace Organics? Tucson, AZ Marana, AZ NW ~20mi

Land Application of Biosolids: Fate of TOrCs? Estrogenic activity Polybrominated diphenyl ethers (PBDEs) Nonylphenol Estrogenic activity and nonylphenol are removed under aerobic conditions and do not accumulate over time PBDEs accumulate in soil over time and degrade very slowly, if at all

Plant B: Activated sludge Mesophilic anaerobic digestion

(Model of Concentration Addition) Plant D: Activated sludge Thermophilic anaerobic digestion

Summary Observations (cont.) Estrogenicity increase – Lime stabilization – Anaerobic digestion Estrogenicity decrease – Aerobic digestion Magnitude of estrogenicity increase during anaerobic digestion may correlate with digestion temperature and/or amount of alkylphenol degradation occurring “in the pipe” prior to wastewater treatment

Definition (USGS) “Emerging contaminants can be broadly defined as any synthetic or naturally occurring chemical or any microorganism that is not commonly monitored in the environment but has the potential to enter the environment and cause known or suspected adverse ecological and/or human health effects.”

Fate of Ecs in the environment? ECs are not uniquely special--they have measurable physical properties just like contaminants we’ve dealt with in the past, e.g. pesticides and others ECs can be expected to follow similar behaviors as “legacy” pollutants that have similar physical properties…. Properties: – Hydrophobicity – Volatility – Biodegradation potential

PlantSolid Stabilization ProcessReduction AAerobic Digestion18% BMesophilic Anaerobic Digestion-31% CLime addition to dewatered sludge-312% DThermophilic Anaerobic Digestion-135% Reduction of Estrogenic Activity (based on YES bioassay)

Factors affecting removal efficiency of ECs during biological treatment processes SRT, HRT pH, temperature BNR--nitrification/denitrification

What are the variables we can manipulate to enhance the removal of ECs during WWT? HRT SRT Additional unit processes Nutrient removal What else?

Can we improve EC removal during conventional WW treatment? Hypothesis: increasing the solids retention time (sludge age) can improve EC removal during conventional activated sludge wastewater treatment

Sources of Emerging Contaminants epa.state.oh.us

Which treatment parameter(s) influence removal of ECs? Helbing et al Micropollutant biotransformation kinetics associate with WWTP process parameters and microbial community characteristics. Environmental Science and Technology

How to proceed w.r.t. ECs? First, optimize existing (biological) treatment processes for EC removal (SRT, HRT, etc.) Second, plan for flexibility in long-term WWTP design to take into account potential for future regulation of ECs Third, incorporate advanced WWT processes as needed

Credit: Linda Gaulke, EAWAG Sum of E1 and E2 in effluent Is there a correlation between SRT and effluent concentrations of estrogens? (compilation of data from 8 research studies)

Credit: Linda Gaulke, EAWAG EE2 in effluent Less data and lower concentrations; no apparent trend due to low values at both high and low SRT (compilation of data from 5 research studies)

Economics of advanced wastewater treatment Treatment Option Pop. Size Capital Cost (Standard) ($ million) Capital Cost (Advanced) ($ million) Operating Cost (Standard) ($ million) Operating Cost (Advanced) ($ million) Total Cost (per m 3 ) ($) Activated sludge with GAC + ozone 5, , , Activated sludge with MF + RO 5, , , Hypothetical comparison of total costs of advanced wastewater treatment options for three WWTP sizes (adapted from Jones et al., 2007). (1,000 gal = 3.79 m 3 )

Cost comparison for tertiary and advanced wastewater treatments Treatment Option Pop. Size Total Cost (per m 3 ) ($) Activated sludge with GAC + ozone 5, , , Activated sludge with MF + RO 5, , , (1,000 gal = 3.79 m 3 ) (from Jones et al., 2007) treatment option Total Cost ($pe/yr) GAC5.53 ClO22.91 Ozone2.25 SF1.69 (from Baynes et al., 2012) CO2 (kg/pe/yr) 13 6 <3 - SF provided equivalent effluent quality as GAC, based on in vivo fish intersex tests, at about 1/3 of the total cost

Improved analytical techniques – parts per billion (ppb) (µg/L) – parts per trillion (ppt) (ng/L) – parts per quadrillion (ppq) (pg/L) Why are we more aware of ECs now? Our understanding of toxicity has not caught up with our ability to measure these compounds….

Economics of advanced wastewater treatment Summary findings: Capital Costs: advanced WWT can exceed conventional WWT Operating Costs: advanced WWT (membranes) can greatly exceed (up to 6x) conventional WWT (along with increased energy consumption and CO 2 emissions) Modifying existing conventional WWT (increase SRT, add nutrient removal processes) may be almost as effective in removing ECs, but with much lower capital and operating costs Jones et al. Questioning the excessive use of advanced treatment to remove organic micropollutants from wastewater

Chemical vs. bioassays Some studies have shown