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Innovative Strategies for Removing Emerging Contaminants for Indirect Potable Water Reuse - Oak Bluffs, MA Case Study Marc Drainville, PE BCEE LEED AP.

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Presentation on theme: "Innovative Strategies for Removing Emerging Contaminants for Indirect Potable Water Reuse - Oak Bluffs, MA Case Study Marc Drainville, PE BCEE LEED AP."— Presentation transcript:

1 Innovative Strategies for Removing Emerging Contaminants for Indirect Potable Water Reuse - Oak Bluffs, MA Case Study Marc Drainville, PE BCEE LEED 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
SBRs with 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, flame retardants, pesticides) Potential Health Effects EDCs Carcinogens Developmental toxicants

10 Health effects of CEC Concentrations are very small – but what are the potential effects? Chemical Group Common Uses Reproductive Health Concerns Alkyl phenols and related chemicals Industrial and institutional cleaning sector (including domestic cleaning) Textile and leather processing Personal care products (PCPs) Pesticide Production Hormone mimicking activities Reduced male fertility, testicular size, sperm quality Phtalates Plasticizers in PVC and special polymer applications Gelling agents Solvents and fixatives in cosmetics and other PCPs Testicular toxicity Reduced anogenital distance, cleft phallus, hypospadias and undescended testes in immature males Reduced male and female fertility Fetal toxicity (possibly leading to death or malformations) Bromated flame retardants As flame retardants in industrial and electrical appliances, vehicles, lighting, wiring as well as textiles, furnishing and insulating materials such as polystyrene Estrogen mimicking Birth defects in rodents documented Impacts on nervous system and behavioral development Organotin Compounds PVC UV stabilizers Argochemicals and biocides Antifoulants Catalysts Inhibition of steroid hormone production Adverse impact on in-utero development of fetus including abnormalities in genital development in male fetuses Bisphenol-A and its derivatives Production of polycarbonate plastic used in products like baby bottles, CDs, motorcycle windshields, etc. Production of epoxy resin used in things like food packaging Estrogenic activity Altered male reproductive organs Early puberty induction Reduced breast feeding Artificial Musks Fragrance mixtures for detergents, fabric conditioners, cleaning agents, air fresheners, and other household products Cosmetic products such as soaps, shampoos, and perfumes Anti-estrogenic activity 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 Parameter
Water quality data Water Quality Parameter Unit Influent Effluent pH SU 6.6 7.16 Alkalinity mg/L 190 90 Ammonia (unionized) 26 2.7 Total Nitrogen 45 5.3 Total Phosphorous 6.7 4.8 CBOD5 200 3 COD 550 55 TSS 94 UV Absorbance (1/cm) 0.41 0.22 TOC 81 12 DOC 11

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 Treated Wastewater Effluent
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 Treated Wastewater Effluent
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 Treated Wastewater Effluent Rapid Mix Flocculation Filters 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 ACTICARB by 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% WWTP MIEX Resin with Ferric Sulfate Coagulation MIEX Treatment Rate (BV) 600 Bed Volumes Ferric sulphate (mg/L) - 30 40 50 DOC (mg/L) 12.3 5.30 5.20 5.11 DOC Removal (%) 57 58 UVA254(cm-1) 0.218 0.084 0.081 0.098 UVA254Remocal (%) 61 63 55 True Color (CU) 56 8 5 6 pH 8.40 6.37 5.79 3.82 Total Alkalinity (mg/L CaCO3) 100 Calcium Hardness (mg/L CaCO3) 80 Total Hardness (mg/L CaCO3) Settled Turbidity (NTU) 10.8 1.34 2.25 0.84

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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