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

Innovative Strategies for Removing Emerging Contaminants for Indirect Potable Water Reuse - Oak Bluffs, MA Case StudyMarc Drainville, PE BCEE LEED AP | GHDChandra Mysore, Ph.D., PE, BCEE | GHDAnastasia Rudenko, EIT | GHD Rhodes Copithorn, PE, BCEE | GHD

2013 NYC Watershed/Tifft Science & Technical Symposium

Outline

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

Background


Plant location

• Oak Bluffs, Massachusetts (Martha’s Vineyard)

• Population 3,713 (US census data)


Wastewater treatment facility

• SBRs with primary clarifier, effluent filters, and UV

• Seasonal flows• Wastewater: municipal and hospital flow• Discharge to Ocean Park


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)

Emerging contaminants


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


Health effects of CEC

• Concentrations are very small – but what are the potential effects?

Source: Virginia Department of Environmental Quality

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

• Estrogenic activity• Anti-estrogenic activity


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.

Plant data and current performance


Plant data

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


Historical TOC data


Water quality data

Water Quality Parameter Unit Influent Effluent

pH SU 6.6 7.16

Alkalinity mg/L 190 90Ammonia

(unionized) mg/L 26 2.7

Total Nitrogen mg/L 45 5.3Total Phosphorous mg/L 6.7 4.8

CBOD5 mg/L 200 3

COD mg/L 550 55TSS mg/L 94 3

UV Absorbance (1/cm) 0.41 0.22TOC mg/L 81 12DOC mg/L 81 11

Technologies considered


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


Process alternatives


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


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


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

GACContactor


Advanced oxidation

• Oxidation by hydroxyl radicals• Typically used as polishing step following membrane filtration • Good CEC destruction, but mineralization to CO2 cost-prohibitive

Treated Wastewater

EffluentUV Reactor

Hydrogen Peroxide


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

Rapid MixBASIN

Flocculation Filters

Sedimentation Basin

Treated Wastewater

Effluent


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


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.)

Characterization & bench-scale testing


Phase I

• Wastewater characterization– Organic matter characterized at the University of Massachusetts– XAD-8/XAD-4 Resins and HPSEC

• Bench-Scale testing


Influent organic matter characterization

Oak Bluffs WWTP InfluentNOM HPSEC Fractions

Molecular Weight (Da)

10 100 1000 10000 100000

UV

Abs

orba

nce

( V)

0.000

0.002

0.004

0.006

0.008

0.010

0.012

Retention Time (min)4681012141618

unfractionatedhydrophobictransphilichydrophilic


Influent organic matter characterization

Oak Bluffs WWTP EffluentNOM HPSEC Fractions

Molecular Weight (Da)

10 100 1000 10000 100000

UV

Abs

orba

nce

(V)

0.000

0.002

0.004

0.006

0.008

0.010

0.012

Retention time (min)

4681012141618

UnfractionatedHydrophobicTransphilicHydrophilic


Phase I

Bench-scale testing– ACTICARB by Kruger– MIEX by Orica– Ferrate by Ferrate treatment technologies– Testing by GHD


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


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 58

UVA254(cm-1) 0.218 0.084 0.081 0.098

UVA254Remocal (%) - 61 63 55

Ferric sulphate (mg/L) - 30 40 50

True Color (CU) 56 8 5 6

pH 8.40 6.37 5.79 3.82

Total Alkalinity (mg/L CaCO3) 100 100 100 100

Calcium Hardness (mg/L CaCO3)

80 80 80 80

Total Hardness (mg/L CaCO3) 100 100 100 100

Settled Turbidity (NTU) 10.8 1.34 2.25 0.84

True Color (CU) 56 8 5 6


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


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%


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


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


Process flow diagram of pilot

Current status


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

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