The Path to Potable Reuse

2017 PNWS-AWWA Kennewick, WA May 5, 2017

Kim Ervin. P.E. West Drinking Water and Reuse Service Leader

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Trends in Water Reuse

Water reuse is increasing across North America and not just in arid geographies

– Cooling water

– Replenish groundwater levels

– Lake recharge

– Wetland Restoration

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Critical success factors for implementation of potable reuse

1. Identify the need

2. Define the requirements

3. Prove out the treatment technology

4. Provide confidence – monitoring, safety, and reliability

5. Gain public acceptance

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Identify the need

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Drivers for Water Reuse

• Supplemental or sustainable water source

• Supply independence

• Replace existing large, non-potable water users with reclaimed water

• Replenish groundwater – Potable aquifer (via surface application)

– Land application; Non-potable aquifer

• Managing WWTP discharge limits

• Surface water augmentation

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Early Adopters of Direct Potable Reuse: Windhoek, Namibia 1968

• Relentless droughts; ranks as sub-Saharan Africa’s most arid country

• Two Distant perennial rivers over 700 km away

• Reuse facilities first built in 1968 and upgraded in 1997 and 2002

• Reuse municipal waste (not industrial)

• Produces up to 50% of the water in the distribution system can be reuse water, and normally it is around 35%.

PAC Ozone Coag/floc DAF Filtration Ozone BAC GAC UF Chlorine

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California Reuse, 2009

= 600 mgd

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West Basin Municipal Water District (WBMWD) & City of LA • City of LA produces 300 mgd of

secondary effluent at Hyperion Treatment Plant

• WBMWD purchases 40 mgd: – Began operations in 1995

– Treated 165 billion gallons 1995-2015

– Provides various levels of “designer water” treatment to meet range of customer needs (tertiary, nitrified, single-pass RO, double-pass RO)

– Major end uses: seawater intrusion barrier, oil refinery cooling water and boiler feed water

– 120 miles of purple pipe and 300 sites

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Groundwater Replenishment System Orange County Water District & Sanitation District

• IPR - Advanced treated wastewater delivered to spreading grounds for infiltration and injected into the groundwater basin

• Treatment process: microfiltration + reverse osmosis + UVAOP

• Initial capacity 70 mgd (2008) and expanded to 100 mgd (2015)

• Enough water for 850,000 residents

• Extensive public outreach and education campaign

Images from OCWD

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Reuse goes down under Potable reuse in response to drought in Australia

Luggage Point Western Corridor Recycled Water Project in Southeast Queensland

• Augments drinking water reservoir

• 70 ML/d (18.5 mgd) WTP delivered in less than 2 years

• Technology advancements included chemical precipitation to improve MF and RO performance and controlling NDMA and organic fouling.

Beenyup Groundwater Replenishment Plant in Perth.

• Full-scale groundwater replenishment to replenish drinking water aquifers.

• Treatment: MF/RO with UV AOP and disinfection.

UV Advanced Oxidation, Luggage AWTP

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Necessity is the mother of invention implementation Big Springs, Texas • First Direct Potable

Reuse in the US

• May 2013, Colorado River Municipal Water District

• 2 mgd

• Blended with raw water from surface water reservoirs

Photo from WateReuse website

WWTP

AWTF

Blend with Raw Water

Member WTPs

MF RO UV

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Project Location Type of Potable Reuse Year in

Operation Capacity Montebello Forebay, CA Coastal GW recharge via spreading basins 1962 44 mgd

Windhoek, Namibia Inland Direct potable 1968 5.5 mgd

UOSA Inland Surface water augmentation 1978 54 mgd

Hueco Bolson, El Paso, TX Inland GW recharge via direct injection and spreading basins 1985 10 mgd

Clayton County, GA Inland Surface water augmentation 1985 18 mgd

West Basin, El Segundo, CA Coastal GW recharge via direct injection 1993 12.5 mgd

Scottsdale, AZ Inland GW recharge via direct injection 1999 20 mgd

Gwinnett County, GA Inland Surface water augmentation 2000 60 mgd

NEWater, Singapore Coastal Surface water augmentation 2000 146 mgd (5 plants)

Los Alamitos, CA Coastal GW recharge via direct injection 2006 3.0 mgd

Chino GW Recharge, CA Inland GW recharge via spreading basins 2007 18 mgd

GWRS, Orange County, CA Coastal GW recharge via direct injection and spreading basins 2008 70 mgd

Queensland, Australia Coastal Surface water augmentation 2009 66 mgd via three plants

Arapahoe County, CO Inland GW recharge via spreading 2009 9 mgd Loudoun County, VA Inland Surface water augmentation 2009 11 mgd

Aurora, CO Inland Surface water augmentation 2010 50 mgd

Big Spring ,TX Inland Direct potable 2013 1.8 mgd

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Define the requirements Water Reuse Regulations – How safe is safe enough?

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Defining Reuse

• Non-potable reuse – wastewater used for non-potable purposes

• Indirect potable reuse – reuse of wastewater that has been discharged to an environmental buffer such as lake, stream or groundwater aquifer

• De facto or unplanned reuse – unintentional indirect potable reuse

• Direct potable reuse – treated municipal wastewater introduced into the potable water supply with out the use of an environmental buffer.

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Washington Reuse

Groundwater Recharge Irrigation

Wetland Manufacturing/Industrial

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More Stringent Regulations

Less Stringent Regulations (although customer WQ requirements may be more restrictive)

• Agricultural Reuse on Non-food Crops • Industrial Reuse • Commercial Reuse • Landscape irrigation • Recreational Reuse • Agricultural Reuse on Food Crops • Indirect Potable Reuse

– Groundwater recharge via surface spreading

– Reservoir Augmentation – Groundwater recharge via direct

injection

• Direct Potable Reuse

Reuse regulations and guidelines typically vary depending on the use of the reclaimed water

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Is it safe? Health effects testing. Denver Potable Reuse Demonstration Plant

• Full, 2 year whole animal toxicological testing to confirm the safety of potable reuse technology.

• 1985 – 1992

• 1 mgd demonstration plant

• Evaluated alternative treatment approaches including high pH lime clarification, recarbonation, filtration, activated carbon adsorption, RO, air stripping, ozonation, and chlorination.

• No adverse health effects were detected in either the 2-year chronic toxicity testing or the generation reproductive study for any of the waters evaluated.

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Is it safe? Health effects testing. Singapore NEWater

• NEWater was the first study of its type to include chronic testing of fish in parallel with chronic testing of mice.

• 1999 - 2003

• 2.6 mgd demonstration plant

• Evaluated MF, RO, and UV disinfection treatment train.

• No adverse health effects were detected in either the 2-year mouse study or the 1-year fish study.

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Prove out the treatment

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Early indirect potable reuse Upper Occoquan Regional Water Authority

• Work began in the 1970’s

• 41.8 billion cubic meter Occoquan Reservoir was seriously degraded, major source of drinking water for Fairfax County/Washington DC

• Degradation resulted from inadequately treated sewage discharged from 11 small WWTPs upstream

• Small plants replaced by regional plant with advanced treatment

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The California Model MF/RO/UVAOP

Orange County Water District’s Groundwater Replenishment System (GWRS) – RO Based Treatment (70 mgd)

Courtesy of Jim Kutzie, OCWD

SODIUM HYPOCHLORITE

SULFURIC ACIDH2O2

MICROFILTRATION REVERSE OSMOSIS

UVAOP

RO CONC.

OCSD PLANT #1 SEC. EFF

LIME

BW Waste to WWTP Influent OCSD OCEAN

OUTFALL

ANTISCALANT

DECARBONATOR

TO BARRIER INJECTION WELLS AND

SPREADING BASINS

** Disposal of RO concentrate required

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Alternative Treatment Trains

P

AURORA RESERVOIR

RECLAIMED WATER

FOREBAY

RAPID MIX FLOC/SED

SOLIDS CONTACT CLARIFIER

UVAOP FILTRATION GAC ADSORBERS

PAC PolymerPolymer

FeCl3NaOH

PolymerCO2 H2O2

Fluorosilicic AcidCl2

Cl2Ammonia

Cl2NaOH

DISTRIBUTION SYSTEM

Polymer

FeCl3Cationic Polymer

AURORA RESERVOIR TRAIN (MOUNTAIN WATER TRAIN)

SOUTH PLATTE TRAIN (POTABLE REUSE TRAIN)

BLENDING & CHLORINE

CONTACT BASIN

KMnO4

KMnO4

RAPID MIX

MOUNTAIN SUPPLY

RIVERBANK FILTRATION

FILTRATION

SEC EFFLUENT

FROM WWTP

Prairie Waters Project, Aurora, CO – GAC Based (50 mgd)

33 mgd

17 mgd

50 mgd

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RO-Based versus GAC-Based Treatment

Issue RO-Based (MF+RO+UVAOP)

GAC-Based Treatment (Floc/Sed + Ozone+

BAC+ GAC+ UV)

Pathogens Multiple barriers Multiple barriers

Organics Excellent removal (TOC < 0.2 mg/L)

Good removal (TOC below 2 mg/L typically

not feasible)

Salts Excellent removal No removal; but can be addressed with

blending

Brine Disposal

Required; makes implementation very difficult, especially at

inland locations

Not needed

Annual Costs

Very high (power, chemicals, equipment

replacement)

Significantly lower

Capital Costs

Very high for large plants

High

$0

$50,000,000

$100,000,000

$150,000,000

$200,000,000

$250,000,000

$300,000,000

$350,000,000

$400,000,000

- 10 20 30 40 50 60 70 80 Plant Capacity (MGD)

Capital Costs

Floc/Sed/O3/BAC/GAC/UV

MF/RO/UVAOP (Ocean Disposal)

MF/RO/UVAOP(mech evap)

MF/RO/UVAOP(evap ponds)

Figure taken from WRRF-10-01. Figures are WateReuse Research Foundation’s Intellectual Property

• Significant research being conducted on non-RO based treatment for potable reuse

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Provide confidence – safety, monitoring, and reliability

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Reuse treatment facilities must provide a high level of reliability and confidence

• Multiple barriers

• Environmental and/or engineered buffers

• Continuous real-time water quality monitoring

• Treatment process testing and performance verification

• Operator training

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Critical control points in a MF/RO/UVAOP train

• Locate CCPs and QCPs at main treatment components: – WWTP: solids, pathogens, organics

– Microfiltration (MF): pathogens

– Reverse Osmosis (RO): pathogens, organics, TDS, chemicals of emerging concern (CECs)

– UV Advanced Oxidation (UVAOP): pathogens, CECs

– Finished Water Storage: pathogens (chlorine disinfection)

MONO - CHLORAMINE

ANTIS CALA NT H2O2

MICROFILTRATION REVERSE OSMOSIS UVAOP

RO CONC.

Secondary EffluentWWTP

LIME AND CO2

BW Waste to WWTP Influent Ocean Outfall

To Groundwater

Injection Wells

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Critical control points in a MF/RO/UVAOP train

• Locate CCPs and QCPs at main treatment components: – WWTP: solids, pathogens, organics

– Microfiltration (MF): pathogens

– Reverse Osmosis (RO): pathogens, organics, TDS, chemicals of emerging concern (CECs)

– UV Advanced Oxidation (UVAOP): pathogens, CECs

– Finished Water Storage: pathogens (chlorine disinfection)

MONO - CHLORAMINE

ANTIS CALA NT H2O2

MICROFILTRATION REVERSE OSMOSIS UVAOP

RO CONC.

Secondary EffluentWWTP

LIME AND CO2

BW Waste to WWTP Influent Ocean Outfall

To Groundwater

Injection Wells

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Critical control points in a MF/RO/UVAOP train

• Locate CCPs and QCPs at main treatment components: – WWTP: solids, pathogens, organics

– Microfiltration (MF): pathogens

– Reverse Osmosis (RO): pathogens, organics, TDS, chemicals of emerging concern (CECs)

– UV Advanced Oxidation (UVAOP): pathogens, CECs

– Finished Water Storage: pathogens (chlorine disinfection)

MONO - CHLORAMINE

ANTIS CALA NT H2O2

MICROFILTRATION REVERSE OSMOSIS UVAOP

RO CONC.

Secondary EffluentWWTP

LIME AND CO2

BW Waste to WWTP Influent Ocean Outfall

To Groundwater

Injection Wells

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Critical control points in a MF/RO/UVAOP train

• Locate CCPs and QCPs at main treatment components: – WWTP: solids, pathogens, organics

– Microfiltration (MF): pathogens

– Reverse Osmosis (RO): pathogens, organics, TDS, chemicals of emerging concern (CECs)

– UV Advanced Oxidation (UVAOP): pathogens, CECs

– Finished Water Storage: pathogens (chlorine disinfection)

MONO - CHLORAMINE

ANTIS CALA NT H2O2

MICROFILTRATION REVERSE OSMOSIS UVAOP

RO CONC.

Secondary EffluentWWTP

LIME AND CO2

BW Waste to WWTP Influent Ocean Outfall

To Groundwater

Injection Wells

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Properly operating instruments are critical to safe operation of potable reuse plants

• Ensure water quality stations are designed for ease of maintenance and have adequate water flow and drains

• Include manual sample points in close proximity for cross-checks

• Select reputable instruments

• Maintenance cleanings targeted at frequency appropriate to conditions

• Build maintenance and calibration functions into SCADA Control to provide electronic event logs of calibration and maintenance events

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Gain public acceptance

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Treatment is easy! Public acceptance is the final hurdle.

Positively shaping public perception and gaining acceptance for potable reuse projects is critical for moving projects from the drawing board to implementation.

As technology has evolved, so too has the public’s perspectives on water reuse and the language used to describe it. What used to be “treated sewage” was soon called “wastewater reclamation” and today, “water purification.”

All water is reused.

(WRF–07-03)

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Transparent public outreach raises acceptance of reuse Singapore NEWater

• Hands-on transparent approach to public outreach.

• Included 2.6 mgd demonstration plant from 1999 to 2003.

• Visitor center “pulled back the curtain” on treatment technologies, allowing visitors to observe the process in action via an elevated glass-encased walkway

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Research confirms observation

The Talking About Water project explored the ways in which words and images make a difference in people’s acceptance of water reuse. To gain acceptance, the industry would need to use different language and imagery, for example, “wastewater reclamation” instead of “treated sewage.”

The Effect of Prior Knowledge… explored the effectiveness of explaining reuse within the context of the entire urban water cycle, the notion that we are all downstream of someone else.

Frames from “Downstream” video. https://www.youtube.com/watch?v=GVm-d-zOxJs

The Path to Potable Reuse

2017 PNWS-AWWA Kennewick, WA May 5, 2017

Kim Ervin West Drinking Water and Reuse Service Leader