Managing Contaminants of Emerging Concern in Water Treatment

1. PNWS AWWA 2008 Annual ConferenceVancouver, Washington Contaminants of Emerging Concern in Water and Wastewater Treatment John Bratby Brown and Caldwell

2. Contaminants of Emerging Concern in Water and Wastewater Treatment • Nature of CECs • Removal mechanisms of CECs • Removal efficiencies of CECs during treatment • Do membrane bioreactors provide enhanced removal of CECs? • Other advanced treatment for higher levels of CEC removal

3. Recent AP article • “Mary Buzby -- director of environmental technology for drug maker Merck & Co. Inc.: "There's no doubt about it, pharmaceuticals are being detected in the environment and there is genuine concern that these compounds….could be causing impacts to human health or to aquatic organisms.“ • Recent laboratory research has found that small amounts of medication have affected human embryonic kidney cells, human blood cells and human breast cancer cells. The cancer cells proliferated too quickly; the kidney cells grew too slowly; and the blood cells showed biological activity associated with inflammation. • Some scientists stress … that the documented health problems in wildlife are disconcerting.

4. Removal Pathways of Groups of CECs in Wastewater Treatment • Steroid compounds • Phytoestrogens • Surfactants • Pesticides, herbicides, fungicides • Polyaromatic compounds • Organic oxygen compounds (Bisphenol A, Phthalates, Dioxins, Organotins)

5. Potency of Steroid Compounds

6. Surfactants • Main surfactants of interest for ED are the alkylphenols (APs) and their ethoxylates (APEOs) – particularly the nonylphenol (NP) compounds • Alkyl Phenol Ethoxylates (APEO) widely used in industries as well as commercial and household functions • Detergents, lubrication, defoamers, emulsifiers, paints, pesticides • Cleaners for machinery, metal working, textiles, and personal products • Nonylphenol ethoxylate is the most common • APEOs tend to be degraded to more potent endocrine disrupting compounds during wastewater treatment • The ethoxylates can be degraded to produce NP which is more persistent and toxic than the ethoxylates • Highest freshwater concentrations of NP observed near WWTPs, pulp mills, and regions of heavy industry

7. Pesticides • Largest group of EDCs • DDT, dieldrin, 2,4-D, tributyltin, atrazine, metolachlor, cyanazine, alachlor • All herbicides, fungicides, pesticides • Atrazine one of the most difficult to remove

8. Understand Properties to Predict Physical Processes Kow values are an indicator of hydrophobicity, and have been used as a surrogate for removal during water treatment

9. CEC removal in Biological Treatment – Dependent on parameters such as: • Temperature • Sludge age, SRT • HRT • Influent concentrations • Co-metabolite transformations • Treatment type (AS, TF, MBRs) • Probably lower EDC concentrations from MBR systems due to retention of both particulate and colloidal material. Membrane systems appear to form colloid complexes to a greater extent than conventional systems

10. WWTP Removals for Select EDCs Removals of E1 and E2 reduced to 64 to 94% at 15oC (SRT 6 to 11 d)

11. Removal Rates of Steroid Estrogens at Varying Retention Times From: Johnson A.C., Belfroid A., Di Corcia A. (2000)

12. Influent and Effluent Concentrations of Alkylphenolic Compounds in WWTPs

13. Acclimation Times Required for NTA Removal With Activated Sludge Treatment NTA – Nitrilotriacetic acid – considered as a detergent builder in place of phosphates From: Rossin A.C., Lester J.N., Perry R. (1982)

14. Comparison between MBR and CAS systems (from Scruggs C. et al., WE&T, March 2005; Mansell et al., WEFTEC, 2005):

15. Hormones: Removal comparison between MBR and CAS systems(from Mansell et al., WEFTEC, 2005):

16. CEC removal: Advanced treatment processes following secondary treatment Granular activated carbon Advanced oxidation Reverse osmosis

17. Coagulation or Chemical Precipitation • Most compounds of concern are relatively polar (Kow values < 3) • Neither alum or iron coagulation or lime softening effective for atrazine or antibiotic removals • Coagulation ineffective with several pharmaceuticals and with several pesticides • Some pesticides (PAHs pyrene, fluoranthene and anthracene) removed ~50% by coagulation • Coagulation only expected to remove hydrophobic compounds associated with particulate or colloidal material • EDCs and PPCPs not associated with colloidal or particulate material very poorly removed (<10%)

18. Adsorption • Activated carbon (AC) effective for many different pesticides, PPCPs and EDCs • Hydrophobic interactions dominant mechanism (weak ion exchange interactions also contribute to adsorption) • AC can remove neutral organic compounds with hydrophobic compounds (logKow>2) • NOM in water competes for adsorption sites and decreases AC effectiveness for micropollutants • PAC can be effective; GAC probably more efficient • PAC could be good emergency measure at WTPs, particularly during low streamflow, and with upstream wastewater discharges

19. Membrane Filtration • Most organic EDCs and PPCPs are 150 to 500 daltons • Most can be removed in RO and tight NF membranes • Microfiltration and ultrafiltration will only remove those EDCs and PPCPs associated with colloidal and particulate matter • Polar and charged compounds that interact with membrane surfaces will be better removed • Hydrophobicity also affects removals. Removals by RO and NF membranes correlates with logKow

20. Effectiveness of Treatment Processes with Some CECs Off-gas Effluent to be treated Effluent

21. General removal efficiencies of treatment processes