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Groundwater Replenishment System

Mehul Patel, P.E.

GWRS Program Manager

Orange County Water District

AZ Water Association – Next Horizons in Water Treatment

February 11, 2015

Background on GWRS Project

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Orange County Water District

•OCWD, formed in 1933, is responsible for managing and protecting the Orange County groundwater basin

•OCWD encompasses 229,000 acres (925 km2 or 92,700 hectares) in the lower watershed of the Santa Ana River (SAR)

•Orange County groundwater basin provides water for over 2.4 million people

Typical OCWD Water Supply Sources to Recharge the Groundwater Basin (afy)

SAR Stormflows 50,000

MWD Untreated Full Service

Water - 20,000Other - 4,000

Natural Incidental Recharge

60,000

SAR Baseflows 102,000

GWRS - 72,000

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Primary Treatment

Secondary Treatment

Advanced WaterPurification ReuseSewage

SourceControl OCSD OCWD

Orange County Water District provides local water retailers with a reliable, adequate, high-quality groundwater supply at the lowest reasonable cost in an environmentally responsible manner

Orange County Sanitation District protects public health and the environment by providing effective wastewater collection, treatment, and recycling

Agency Responsibities

What Is The Groundwater Replenishment System (GWRS)?

► 70-MGD (265,000 m3/day or 265 MLD) advanced water purification facility

► Takes treated sewer water that otherwise would be wasted to the ocean, purifies it to near distilled quality and then recharges it into the groundwater basin

► Provides a new 72,000 acre-feet (89 million m3/year) per year source of water, which is enough water for over 500,000 people

► Operational since January 2008

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Groundwater recharge by surface spreading

RechargeRechargeBasinBasin

WellWell

Indirect Potable Reuse Practiced by OCWD

InjectionInjectionWellsWells ProductionProduction

WellWell

OceanOcean

SalineSalineWaterWater

Groundwater recharge by direct injectionGroundwater recharge by direct injectionfor a salt water intrusion barrierfor a salt water intrusion barrier

Indirect Potable Reuse Practiced by OCWD

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GWRS Advanced Water Purification Process

Ultraviolet Light (UV) with Hydrogen Peroxide

Brine Treatedin OCSD OutfallBackwash

Sent to OCSD

Microfiltration (MF) Reverse Osmosis

(RO)

Seawater Barrier

OCSD Secondary

Effluent

Normally Goes to Ocean

Recharge Basins in Anaheim

SodiumHypochlorite

MF CleaningSystem

CompressedAir

MFBackwash

MFFiltrate

RO FlushSystem

HydrogenPeroxide

RO CleaningSystem

SodiumBisulfiteRO Flush

Air

Lime

SodiumBisulfite

OCSDPlant No. 1Secondary

Effluent

OCSDPlant No. 1

OCSDEllis Ave.

Interplant Sewer

ToBarrier

Injection Wells

ToKraemer/Miller

SpreadingBasins

ToSanta Ana River

orOCSD Ocean Outfall

To OCSD Ellis Ave.Interplant Sewer

To OCSD Ocean Outfall

FilterScreens Microfiltration

MFBreakTank

ROTransfer

PumpStation

Reverse Osmosis

RO

Con

cent

rate

RO Bypass (SAR only)

ROFeedPump

CartridgeFilters

UltravioletIrradiation System

Peak Flow and Emergency Bypass

RO Flush Tank

Decarbonator

70 mgd (35 mgd for seawater intrusion 35 mgd for surface spreading)

80 mg/L TDS

Sulfuric acid andAnti-scalant addition

FPWB

AWPF Process Schematic

MF backwash waste

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Microfiltration System

► 86 MGD (325,500 m3/day or 326 MLD) Evoqua/Memcor CS Microfiltration System

► Tiny, straw like hollow fiber polypropylene membrane

► Removes bacteria, protozoa, and suspended solids

► 0.2 micron pore size

► In basin submersible system

Reverse Osmosis System

► 70 MGD (265,000 m3/day or 265 MLD) Reverse Osmosis System

► 3 stage: 78-48-24 array

► Hydranautics ESPA-2 Membranes

► Recovery Rate: 85%

► Removes dissolved minerals, viruses, and organic compounds (incl. pharmaceuticals)

► Pressure range: 150 – 220 psi (10-15 bar)

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Direct Photolysis/Advanced Oxidation

► 70 MGD (265,000 m3/day or 265 MLD) Trojan UVPhox System

► Low Pressure – High Output lamp system

► Destroys trace organics (designed for NDMA removal)

► Uses 3 mg/L Hydrogen Peroxide to create an Advanced Oxidation Process

► Provides primary disinfection credit

Process Control and Use of Critical Control

Points

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Multiple Barriers Protect Public Health

► Microbial contaminants –� MF removes bacteria and protozoa � RO removes viruses, bacteria � UV inactivates microbes, prevents replication � Retention time in groundwater

► Chemical contaminants –� Source control prevents introduction of contaminants� MF removes particles, suspended solids � RO removes dissolved salts, metals, organics, including

pharmaceuticals, endocrine disruptors� UV with hydrogen peroxide destroys small organics � Groundwater provides buffering, biodegradation, ion exchange

Process Control Points

► Key points in treatment process monitored for failure by on line instrumentation

► Allows for immediate response to off-spec product water quality

► Online sensors can detect treatment lapses Examples include:� Turbidity through MF� Pressure decay test with MF� Conductivity through RO� TOC through RO� UVT into UV AOP� UV power delivered� pH through decarbonation � pH through lime addition

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OMMP Includes Use of Critical Control Points

► Operating conditions from CDPH for GWRS requires a Operations, Maintenance, Monitoring Plan

► RWQCB permit mandates specific minimum requirements

► Serves as a guidance document for operating, maintaining and operating plant

► The concept of critical control points as a risk management approach described in the OMMP

Critical Control Points Concept for GWRS

► CCPs chosen for each major unit process

► Continuous on line analyzers monitored for changes in process performance

► Operational limits and alarms tied to each CCP and monitored by Process Control System (SCADA)

► Corrective actions required when CCP limits exceeded

► Decision trees or response plans required for each CCP

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Summary of Critical Control Points

YesNo

Check turbidity

MFE MFF

Normal

Observe Response Level II:≥ 3.0 mg/L for more than 1 hour≥ 1.5 mg/L average for dailyaverage≥ 0.5 mg/L average for 4 days≥ 0.45 mg/L average for 20 days

Notify OCSD

pEC Profile &

Sample

startup?

Plant outage/startup?

ROP TOC

or more?

ROP TOC > 0.1 mg/L for 15 consecutive points

or more?

mg/L?

ROF > 11

mg/L?

Check ROP

calibration

Check ROP TOC meter

logs and calibration

Yes

No

Yes

RO process start

TOC back

minutes?

TOC back to normal after 30

minutes?

Check

EC

Check ROP EC

EC >60 µmhos/cm (Bulk)EC >80 µmhos/cm (Unit)

Sample Q1

ROF ROPUVP

Isolate and repair RO

Keep plant online

monitoring ROF & ROP

SampleTOC > 0.1 mg/L

Continue regular plant

operation

No

Yes

TOC < 0.1 mg/L

Continue regular plant

operation

No

TOC Response Level I Decision Matrix

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Regulatory Oversight and Staffing

Regulatory Oversight

► California Dept. of Public Health (CDPH) establishes recycling criteria� Treatment and quality� TOC limit� Travel time� Blending

► Regional Water Quality Control Board issues reclamation permit

► Regional Board incorporates CDPH recommendations into permit

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Independent Advisory Panel

► Appointed by National Water Research Institute

► Leading experts in hydrogeology, chemistry, toxicology, microbiology, engineering, public health, public communications and environmental protection

► Review operations, monitoring and water quality► Panel makes recommendations to OCWD and

regulatory agencies to assure quality and reliability

Water Production Group Organization Chart

•Four Operators on shift at any one time (four 4 man shifts cover a work week)•Operators on site 24 hours a day•Maintenance, I&E, management staff work five days a week and on call on weekends

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Lessons Learned

MF/UF Lessons Learned

► On site pilot testing through multiple seasons is ideal

► Design pumps and piping to allow for expansion

► Strong procurement language required to mitigate risk

► Limiting warranty replacement period and/or operating flux mitigates uncertainty caused by lack of pilot test data

► There are not significant water quality improvements with use of UF over MF for wastewater applications

► Specify proper instrumentation and valves to increase asset life

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Issues with the Use of RO

► High initial capital costs for process equipment► O&M costs for membrane replacement► Lack of large operator level knowledge base ► Post treatment or blending issues due to corrosive

nature of product water► More economical technologies exist depending upon

desired level of treatment► Energy intensive nature makes process expensive in

areas where energy costs are high (i.e. California)

Issues to be Considered with Use of RO

► Poor performance of upstream pre-treatment has a dramatic effect on RO operation

► Cartridge filters provide inexpensive insurance

► Use of improper anti-scalant can cause significant damage to RO membranes

► High quality nature of RO permeate requires enhancement of typical water quality lab methods developed for conventional treatment

► An auto flushing system with ability to dose in preservative chemicals required if system not in full time use

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Project Costs and Public Outreach

Federal Grant, $20,000,000

State Grants, $69,000,000

,

OCWD, $196,000,000

OCSD Contribution, $196,000,000*

* OCSD contributed half of the project costs to defer construction of a second oceanoutfall estimated at $200 million

GWRS Project Funding$481 Million Capital Cost

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FY 2013-14 Operating Cost

Item Annual Cost Cost/AF

Electricity $8,737,384 $132

Chemicals $3,508,049 $53

Labor $8,526,945 $129

R&R Fund Contribution $5,898,996 $89

Plant Maintenance $3,346,337 $51

Debt Service $11,499,996 $174

Sub Total $41,517,707 $628

Operating Subsidies(Includes Demand Response and MWD LRP)

($7,573,552) ($115)

Total Net Cost $33,944,155 $513/af

Public Outreach

• Many projects stopped by public and political opposition

• Outreach began early, over 10 years prior to start-up

• Researched public concerns• Face-to-face presentations• Community leaders• Measured effects of outreach• Community support• Outreach continues today, assisted by

media interest

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Strong Community Support

►No active opposition and support from:• 100% support from cities in OCWD service area

• 100% support from OC state and federal elected officials

• 100% support from Chambers of Commerce & OCBC

• Many business including Edison and Semper Energy

• All major environmental groups

• Several health experts, medical doctors, hospitals, pharmacists and scientists

• Several key minority leaders

• Educational, religious, police and fire leaders

• More than 200 community groups like Kiwanis, Rotary, etc.

• OC Tax, AARP, OC Farm Bureau and others

Proactive face-to-face outreach with more than 1,200 presentations, 700 tours and many news stories that resulted in:

What Have We Learned From GWRS?

► Public can accept indirect potable reuse projects if:� need is clear

� outreach is effective and ongoing

� politicians and community leaders make commitment

� quality is higher than alternatives

� regulators have ongoing oversight

� independent scientific review

► The more people know about GWRS the more they accept it

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► Project meets Orange County’s water needs► Board of Director’s insistence on highest quality

water► Effective medical and minority outreach programs► History of successful water reuse in Orange County

from the Water Factory 21 recycling facility► Groundwater basin as final destination (not tap)► Excellent outreach speakers bureau program

obtained written support of project► Successful outreach from conception of facility, to

construction and finally commissioning

Keys to Success

GWRS Initial Expansion

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GWRS Expansion Project

► $143 million budget ($115M construction cost)

► Create additional 31,000 afy (38.2 million m3/year) or 30 mgd of new local water

► Construction began October 20, 2011

► Complete work by 2015

Features of GWRS Initial Expansion

► Existing facility production will be increased from 70 mgd to 100 mgd (72,000 afy to 103,000 afy)

► GWRS original design allows for two 30 mgd expansions up to 130 mgd, eventually

► Expansion includes 10 new MF cells and UV will have 5 new trains using identical equipment to existing facility

► Six new RO units will include some enhancements over existing RO units: energy recovery devices, interstage EC and flow meters

► New RO units will have Dow/Filmtec XFRLE membranes (current facility has Hydranautics ESPA2)

► New post treatment system design based around Tekkem lime system

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Features of GWRS Initial Expansion

► Six new RO units will include some enhancements over existing RO units: energy recovery devices, interstage EC and flow meters

► New RO units will have Dow/Filmtec XFRLE membranes (current facility has Hydranautics ESPA2)

► New post treatment system design based around Tekkem lime system

► Additional water produced will go to Forebay, including existing Miller/Kraemer, new Miraloma and future La Palma Basin

Questions?