Marc Drainville , PE BCEE LEED AP | GHD Chandra Mysore, Ph.D., PE, BCEE | GHD

1. Innovative Strategies for Removing Emerging Contaminants for Indirect Potable Water Reuse - Oak Bluffs, MA Case Study Marc Drainville, PE BCEELEED AP | GHD Chandra Mysore, Ph.D., PE, BCEE | GHD Anastasia Rudenko, EIT | GHD Rhodes Copithorn, PE, BCEE | GHD

2. Outline • Background • Emerging contaminants • Plant data and current performance • Technologies considered • Characterization & bench-scale testing • Current status

3. Background

4. Plant location • Oak Bluffs, Massachusetts (Martha’s Vineyard) • Population 3,713 (US census data)

5. Wastewater treatment facility • SBRswith primary clarifier, effluent filters, and UV • Seasonal flows • Wastewater: municipal and hospital flow • Discharge to Ocean Park

6. Project need • New disposal area • Purchased new property adjacent to existing WWTF • Requirements released March, 2009 include limitations for total organic carbon (TOC) • 3.0 mg/L for discharge within a Zone II drinking water protection area and >2-year travel time to source • 1.0 mg/L for discharge within a Zone II area and <2-year travel time to source • 1.0 mg/L for discharge within a Zone II area without soil aquifer treatment • TOC limit is a daily limit (24 hour composite sample)

8. Emerging contaminants

9. Emerging contaminants • 31 million organic and inorganic substances documented • 14 million commercially available • < 250,000 inventoried or regulated • Domestic, industrial & agricultural compounds: • Pharmaceuticals: prescription & non-prescription • Personal care products • Industrial & commercial products (detergents& metabolites, plasticizers, flameretardants, pesticides) • Potential Health Effects • EDCs • Carcinogens • Developmental toxicants

10. Health effects of CEC • Concentrations are very small – but what are the potential effects? Source: Virginia Department of Environmental Quality

11. Why TOC? • TOC as a surrogate for many contaminants of emerging concern (CEC) • Studies have shown that Pharmaceuticals & Personal Care Products (PPCPs) adsorb on to particulates of organic carbon, hence removal of TOC provides for removal of PPCPs.

12. Plant data and current performance

13. Plant data • Design Flow = 370,000 gpd • Design Peak Flow = 1.3 mgd • Current status: ~ 40% design flow

14. Historical TOC data

15. Water quality data

16. Technologies considered

17. Technologies to achieve less than 3.0 mg/L(post-tertiary) • Membrane filtration • Nanofiltration, reverse osmosis, ultrafiltration • Ion exchange • Adsorption (GAC) • Advanced Oxidation Processes (AOPs) • Coagulation and filtration

18. Process alternatives

19. Process alternatives

20. Membranes • Requires pretreatment to minimize fouling • May require post-treatment for water chemistry stabilization • Concentrate disposal required (high salinity RO concentrate) • Excellent TOC and CEC removal

21. Ion exchange • Continuous process with magnetized anionic exchange resin designed for dissolved organic carbon (DOC) removal • DOC exchanged with chloride ions on the MIEX resin surface, resin has to be regenerated • Brine disposal required • Potential for good DOC and CEC removal

22. Adsorption Granular Activated Carbon (GAC) • TOC adsorbed in a downflow or upflow contactor • Requires pre-treatment and disposal / regeneration of spent GAC once breakthrough occurs • Good TOC and CEC removal Treated Wastewater Effluent GAC Contactor

23. Advanced oxidation • Oxidation by hydroxyl radicals • Typically used as polishing step following membrane filtration • Good CEC destruction, but mineralization to CO2 cost-prohibitive Hydrogen Peroxide Treated Wastewater Effluent UV Reactor

24. Pre-treatment • Alter physical / chemical properties of suspended particles to increase agglomeration (create larger flocs) • Chemical coagulants include aluminum sulfate (alum), ferric chloride, and ferric or ferrous sulfate Coagulant Sedimentation Basin TreatedWastewater Effluent Flocculation Filters Rapid Mix BASIN

25. Challenges at Oak Bluff • Requirement for a high level of treatment • Need to achieve levels below 3 mg/L (desire to be as low as 1 mg/L) • A hospital contributes in the order of 10% of the flow to the plant • Small user base with median income (year round population) at or below state median • Piloting likely needed to determine optimum process • Limited options for waste stream disposal

26. Initial approach Phase I • Focus on technologies (pre-treatment) that could reduce TOC in economic ways • Focus on low cost means to determine an ultimate treatment solution (wastewater characterization, bench testing etc.)

27. Characterization & bench-scale testing

28. Phase I • Wastewater characterization • Organic matter characterized at the University of Massachusetts • XAD-8/XAD-4 Resins and HPSEC • Bench-Scale testing

29. Influent organic matter characterization

30. Influent organic matter characterization

31. Phase I Bench-scale testing • ACTICARBby Kruger • MIEX by Orica • Ferrate by Ferrate treatment technologies • Testing by GHD

32. Bench-scale testing of ACTICARB • Alter physical / chemical properties of suspended particles to increase agglomeration (create larger flocs) • Best coagulant was ferric sulfate • 50 mg/L dose, no PAC:- 47% removal of TOC • 50 mg/L dose, 30 mg/L PAC:- 59% removal of TOC

33. Bench-testing with MIEX • Jar testing with MIEX alone • Jar testing with coagulation alone • MIEX+ coagulation • Best coagulant was ferric sulfate • Coagulation alone provided 53% • Removal by MIEX alone was marginal. • Improved removal by 5%

34. Bench-testing with ferrate • Ferrate (iron six) acts as an oxidant, coagulant, and as a disinfectant. • Research is being conducted to understand ferrate effects on emerging contaminants

35. Bench-testing by GHD • Conducted jar testing with ferric sulfate and cationic polymer • Best dose was 50 mg/L coagulant with 0.5 mg/L polymer • Resulted in TOC reduction of 45-50%

36. Phase I findings • A Ferrate dose of 2-4 ppm resulted in 56-65% removal of TOC • For the other three jar tests, ferric sulfate performed the best in terms of TOC removal • For a ferric sulfate dose (45-50 mg/L), a TOC reduction of 45%-53% is possible

37. Phase I findings (cont’d) • Pilot would be needed to confirm results • Investigate cause of wide range of TOC • Focus on Pilot-Studies to confirm findings • Pilot-studies will be conducted with: • GAC • Ferrate - test Ferrate at various application points • Based on the outcome of the pilot-study, recommend a full-scale tertiary treatment technology to Town

38. Process flow diagram of pilot

39. Current status

40. Next steps • Costs of highly complex treatment process were determined to be in excess of $5 million and these were found to be unaffordable for the town at the time • Town requested research into “regulatory” alternatives • Worked with the state DEP for one year and met unofficial alternative requirements for safe distance from drinking water well (for TOC limit only) • Met with Town Water Department to make case about safe distance • Have received unofficial approval from both DEP and Town Water Department to pursue a modified permit • Currently in permit application process and hope to have a modified permit by spring of 2014 • If the modified permit fails, the Town will pursue the TOC treatment

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