17. projetos e regulação de reúso de Água nos estados unidos
DESCRIPTION
Apresentação no I SIRA sobre projetos e regulação de reuso de água nos EUATRANSCRIPT
Water Reuse Regulations and Case
Studies in the USA
James Crook, Ph.D., P.E.
Environmental Engineering Consultant
Boston, Massachusetts
USA
International Symposium on Water Reuse
Curitiba, Paraná, Brazil
19 October 2012
Guidelines vs. Regulations
• Guidelines (in most states) are:
• Advisory
• Voluntary
• Non-enforceable
• Regulations are:
• Legally-adopted
• Enforceable
• Mandatory
• There are no federal regulations for water
reuse in the U. S.
– U.S. EPA has guidelines for water reuse, revised in
2012
Guidelines vs. Regulations
• Guidelines – Can lead to inconsistent decisions by regulators
– Proponents may be unsure of requirements to meet
– May become de facto regulations
• Regulations – Provide definitive requirements that must be met
– Often take extensive periods to develop and adopt
– May not be as flexible as guidelines
– May hamper approval of new or innovative treatment processes not included in regulations
– May increase public acceptance
Regulations and Guidelines Vary Depending
on Type of Reuse
Potable reuse
Irrigation of food crops
Unrestricted recreational impoundments
Unrestricted urban irrigation
Restricted urban irrigation
Restricted recreational impoundments
Industrial reuse
Environmental reuse
Irrigation of non-food crops
Most Stringent Regulations
Least Stringent Regulations
Water Reuse Criteria
• Generally include:
– Water quality requirements
– Treatment process requirements
– Treatment reliability requirements
– Monitoring requirements
– Operational requirements
– Cross-connection control provisions
– Use area controls (signs, color-coded pipes,
setback distances, etc.)
Water Quality Monitoring
• Subjective and inconsistent among states
• Generally conservative
• Total or fecal coliforms usually used as
indicator organisms
• Sampling frequency varies among states
– Most require daily sampling
• Monitoring for pathogens not required (with a
few exceptions)
Typical Monitoring Frequency Requirements
Parameter Frequency
BOD Daily – weekly
Coliform Daily
Turbidity Continuous
Total suspended solids Daily
Chlorine residual Continuous
Treatment Reliability
• Standby power supply
• Alarms
• Multiple or standby unit processes
• Emergency storage/disposal provisions
• Provisions for continuous disinfection
• Non-design features
– Qualified personnel
– Monitoring
– O & M program
Use Area Controls - Examples -
• Setback distances
• Confinement to authorized use area
• Protection of drinking fountains
• Signage
• Cross-connection control
• Prohibition of hose bibbs
• Worker protection
• Surveillance activities
Cross-Connection Control (California Criteria)
• Air Gap
– Potable water used to supplement reclaimed water
• Reduced Pressure Principle Device
– Premises receiving both potable and reclaimed water
• Double Check Valve
– Residences using reclaimed water for irrigation
• Double Check Valve
– On potable water fire protection systems in buildings
where reclaimed water used
EPA Water Reuse Guidelines - Urban Reuse -
Type of Reuse Treatment Reclaimed Water Quality
• Unrestricted:
nonpotable applications
in municipal settings
where public access is
not restricted.
• Secondary
• Filtration
• Disinfection
• pH = 6 – 9
• ≤ 10 mg/L BOD
• ≤ 2 NTU
• No detectable fecal
coli/100 mL
• ≥ 1 mg/L Cl2 residual
• Restricted:
nonpotable applications
in municipal settings
where public access is
controlled or restricted
• Secondary
• Filtration
• Disinfection
• pH = 6.0-9.0
• ≤ 30 mg/l BOD
• ≤ 30 mg/l TSS
• ≤ 200 fecal coliform /100 ml
• 1 mg/l Cl2 residual (min.)
EPA Water Reuse Guidelines - Crop Irrigation -
Type of Reuse Treatment Reclaimed Water Quality
• Food crops consumed
raw: surface or spray
irrigation
.
• Secondary
• Filtration
• Disinfection
• pH = 6 – 9
• ≤ 10 mg/L BOD
• ≤ 2 NTU
• No detectable fecal
coli/100 mL
• ≥ 1 mg/L Cl2 residual
• Processed food crops:
commercially processed,
surface or spray irrigation
• Non-food crops: fodder,
fiber, and seed crops,
pastures, commercial
nurseries, and sod farms
• Secondary
• Disinfection
• pH = 6.0-9.0
• ≤ 30 mg/l BOD
• ≤ 30 mg/l TSS
• ≤ 200 fecal coliform /100 ml
• 1 mg/l Cl2 residual (min.)
EPA Water Reuse Guidelines - Impoundments -
Type of Reuse Treatment Reclaimed Water Quality
• Unrestricted: no
limitations are imposed
on body-contact
.
• Secondary
• Filtration
• Disinfection
• pH = 6 – 9
• ≤ 10 mg/L BOD
• ≤ 2 NTU
• No detectable fecal
coli/100 mL
• ≥ 1 mg/L Cl2 residual
• Restricted: body contact
is restricted
• Secondary
• Filtration
• Disinfection
• ≤ 30 mg/l BOD
• ≤ 30 mg/l TSS
• ≤ 200 fecal coliform /100 ml
• 1 mg/l Cl2 residual (min.)
EPA Water Reuse Guidelines - Environmental Reuse -
Type of Reuse Treatment Reclaimed Water Quality
• Environmental Reuse:
create wetlands, enhance
wetlands, or sustain
stream flows
• Variable
• Secondary
and
disinfection
(min.)
Variable but not to exceed:
•≤ 30 mg/l BOD
• ≤ 30 mg/l TSS
• ≤ 200 fecal coliform /100 ml
• 1 mg/l Cl2 residual (min.)
EPA Water Reuse Guidelines - Industrial Cooling Water -
Type of Reuse Treatment Reclaimed Water Quality
• Once-through cooling
.
• Secondary
• Disinfection
• pH = 6.0-9.0
• ≤ 30 mg/l BOD
• ≤ 30 mg/l TSS
• ≤ 200 fecal coliform /100 ml
• 1 mg/l Cl2 residual (min.)
• Recirculating cooling
towers
• Secondary
• Disinfection
(chemical
clarification
and filtration
may be
required)
Variable, depends on
recirculation ratio
• pH = 6.0-9.0
• ≤ 30 mg/l BOD
• ≤ 30 mg/l TSS
• ≤ 200 fecal coliform /100 ml
• 1 mg/l Cl2 residual (min.)
EPA Water Reuse Guidelines - Groundwater Recharge - Nonpotable Reuse -
Type of Reuse Treatment Reclaimed Water Quality
• Recharge aquifers which
are no used as a potable
dinking water source
• Site specific
and use
dependent
• Primary (min.)
for spreading
• Secondary
(min.) for
injection
• Site specific and use
dependent
EPA Water Reuse Guidelines - Indirect Potable Reuse -
Type of Reuse Treatment Reclaimed Water Quality
• Groundwater recharge
by surface spreading
into potable aquifers
• Secondary
• Filtration
• Disinfection
• Soil aquifer
treatment
Includes but not limited to the
following:
• No detectable fecal coli/100 mL
• 1 mg/l Cl2 residual (min.)
• pH = 6.5 – 8.5
• ≤ 2 NTU
• ≤ 2 TOC of wastewater origin
• Meet drinking water standards
after percolation through the
vadose zone
EPA Water Reuse Guidelines - Indirect Potable Reuse -
Type of Reuse Treatment Reclaimed Water Quality
• Groundwater recharge
by injection into
potable aquifers
• Augmentation of
surface water supply
reservoirs
• Secondary
• Filtration
• Disinfection
• Advanced
wastewater
treatment
Includes but not limited to the
following:
• No detectable fecal coli/100 mL
• 1 mg/l Cl2 residual (min.)
• pH = 6.5 – 8.5
• ≤ 2 NTU
• ≤ 2 TOC of wastewater origin
• Meet drinking water standards
The 2012 U.S. EPA Guidelines for Water
Reuse can be downloaded from the following
website:
http://www.waterreuseguidelines.org/images/
documents/2012epaguidelines.pdf
State Standards for Pasture Irrigation with
Reclaimed Water (Milking Animals Not Allowed)
State Quality Limits Minimum Treatment
Required
Arizona ≤ 1000 fecal coli/100 mL Stabilization ponds
California None specified Secondary
Florida
≤ 200 fecal coli/100 mL
≤ 20 mg/L BOD
≤ 20 mg/L TSS
Secondary
Disinfection
Texas
≤ 200 fecal coli or E.
coli/100 mL
≤ 35 Enterococci/100 mL
≤ 20 mg/L BOD
≤ 15 mg/L CBOD
None specified
State Standards for Landscape Irrigation with
Reclaimed Water (Restricted Access)
State Quality Limits Minimum Treatment
Required
Arizona ≤ 200 fecal coli/100 mL Secondary
Disinfection
California ≤ 23 total coli/100 mL Secondary
Disinfection
Florida
No detectable fecal coli/100 mL
≤ 20 mg/L CBOD
≤ 20 mg/L TSS
Secondary
Disinfection
Texas
≤ 200 fecal coli or E. coli/100 mL
≤ 35 Enterococci/100 mL
≤ 20 mg/L BOD
≤ 15 CBOD
Not specified
Why Specify Water Quality Limits and
Treatment Processes?
• Indicator/surrogate parameters alone don’t
adequately characterize microbial or chemical
water quality
– Coliforms, turbidity, etc. not sufficient by themselves
• Specifying both treatment processes and water
quality limits obviates need to monitor for
certain constituents
– There is a lot of data documenting pathogen
concentrations (or lack thereof) in reclaimed water
based on a combination of water quality limits and
specific treatment unit processes
State Standards for Landscape Irrigation with
Reclaimed Water (Unrestricted Access)
State Quality Limits Minimum Treatment
Required
Arizona No detectable fecal coli/100 mL
≤ 2 NTU
Secondary
Filtration
Disinfection
California ≤ 2.2 total coli/100 mL
≤ 2 NTU
Secondary
Filtration
Disinfection
Florida
No detectable fecal coli/100 mL
≤ 20 mg/L BOD
≤ 5 mg/L TSS
Secondary
Filtration
Disinfection
Texas
≤ 20 fecal coli or E. coli/100 mL
≤ 4 Enterococci/100 mL
≤ 5 mg/L BOD or CBOD
≤ 3 NTU
Not specified
Why No Virus Limits?
• Health significance of low levels questionable
• Virus analyses complex and expensive
• Complete analyses can take 4 weeks
– Water sampled is long gone
• PCR technology detects genetic material
– Doesn’t determine concentration or viability
• Treatment requirements & water quality limits
(together) effective to indicate virus reduction
State Standards for Reclaimed Water Spray
Irrigation of Food Crops Eaten Raw (direct contact with edible part of crop allowed)
State Quality Limits Minimum Treatment
Required
Arizona No detectable fecal coli/100 mL
≤ 2 NTU
Secondary
Filtration
Disinfection
California ≤ 2.2 total coli/100 mL
≤ 2 NTU
Secondary
Filtration
Disinfection
Florida Use prohibited*
Texas Use prohibited*
* Irrigation of edible crops that will be peeled, skinned, cooked, or
thermally processed before consumption is allowed. Reclaimed
water quality and treatment requirements same as for
unrestricted access landscape irrigation.
State Standards for Industrial Cooling* with
Reclaimed Water
State Quality Limits Minimum Treatment
Required
Arizona Not covered Not covered
California
≤ 2.2 total coli/100 mL
≤ 2 NTU (24-hour avg.)
≤ 10 NTU (max.)
Secondary
Filtration
Disinfection
Florida
No detectable fecal coli/100 mL
≤ 20 mg/L BOD
≤ 5 mg/L TSS
Secondary
Filtration
Disinfection
Texas
≤ 200 fecal coli or E. coli/100 mL
≤ 35 enteroccci/100 mL
≤ 20 mg/L BOD
≤ 15 mg/L CBOD
Not specified
* Cooling towers where mist is created that may reach populated areas
Indirect vs. Direct Potable Reuse
• Indirect potable reuse:
– Augmentation of a drinking water source (surface
water or groundwater) with reclaimed water followed
by an environmental buffer that precedes normal
drinking water treatment
• Direct potable reuse:
– Introduction of reclaimed water directly into a
potable water supply distribution system
downstream of a water treatment plant or into the
raw water supply immediately upstream of a water
treatment plant
Environmental buffer
• Environmental buffer:
– A natural water body (e.g., reservoir or river)
that physically separates product water from
a water reuse facility and the intake to a
drinking water plant or distribution system.
For groundwater recharge, an aquifer and/or
soil act as the environmental buffer that
separates product water from a water reuse
facility and a potable water extraction well
Wastewater
Treatment
Surface Water
or
Groundwater
City A
City B
Water
Treatment
Incidental or Unplanned Indirect Potable Reuse (“De Facto” Reuse)
Wastewater
Treatment
Water
Treatment
Surface wateror
Groundwater*
*Extracted Groundwater may
not receive further treatment
Indirect Potable Reuse
Definitions
Water
Treatment
Surface Water
or
Groundwater Wastewater
Treatment
Direct Potable Reuse (No environmental buffer)
Definitions
Water
Treatment
Surface Water
or
Groundwater Wastewater
Treatment
Direct Potable Reuse (Pipe-to-Pipe)
Potable Reuse - Major Concerns/Issues -
• Water Quality
• Treatment Reliability
• Unregulated chemical constituents
• Limited Health Effects Data
• Treatment process and water quality monitoring
– Real-time online monitoring
• Public Acceptance
• Lack of regulations
Draft California Department of Public Health (CDPH)
Regulations for Groundwater Recharge into Potable Aquifers
Quality Limits Treatment Required
• ≥12-log virus reduction
• ≥10-log Giardia cyst
reduction
• ≥10-log Cryptosporidium
oocyst reduction
• Drinking water MCLs
(except for nitrogen)
• Action levels for lead and
copper
• ≤10 mg/L total nitrogen
• TOC ≤0.5 mg/L/RWC
Spreading
• Secondary
• Filtration
• Disinfection
• Soil aquifer
treatment (SAT)
Injection
• Secondary
• Filtration
• Disinfection
• Reverse osmosis
• Advanced
oxidation process
(AOP)
Control of Chemical Contaminants - Regulated Chemicals -
• Quarterly monitoring of recycled water for: – Primary drinking water MCLs for chemicals (except
nitrogen)
– Action levels for lead and copper
• Annual monitoring of recycled water for secondary MCLs
• Quarterly sampling at each monitoring well for: – Total nitrogen, nitrate, nitrite
– Secondary MCLs
– Other chemicals specified by CDPH
– Monitoring may be reduced to annually upon CDPH approval
Control of Unregulated Chemicals
• Total organic carbon (TOC) used as a surrogate for the unknown and unregulated organic chemicals
• RWC = recycled water contribution
• Recycled water compliance calculation: – TOC ≤ (0.5 mg/L) / (RWC)
• Example: If proposed RWC is 20% (0.20) – Allowable TOC of wastewater origin must be
≤ (0.5 mg/L) / (0.20), which is ≤ 2.5 mg/L
– I.e., dilution can be used to meet TOC requirement
• Sample Weekly
Response (Retention) Time
• No less than two months required between
recharge and extraction of the water
– Need sufficient time to allow for the identification
and effective response to any treatment failures
– GRRP’s response time must be approved by CDPH
– Longer response time may be required
• Tracer study required
Other Selected Requirements
• Industrial pretreatment and source control
program
• Operations plan
• Contingency plan
• Public hearings
• Monitoring well locations and sampling
requirements
• Review by an independent advisory panel
• Reports
St. Petersburg, Florida
• Dual water system in operation since 1977
– Focus at that time was on disposal, not conservation
– Objective was to achieve zero discharge
• Reclaimed water customers 10,600
• Reclaimed water uses:
– Landscape irrigation, including: residential lawns,
shrubs, and plants; parks, playgrounds,
schoolyards, golf courses, medians
– Industrial uses
– Air conditioner chiller water
– Backup source for fire protection
Distribution System
• 100 miles (160 km) of trunk and transmission
mains
– 10 to 48 inches (25 to 120 cm) diameter
• 200 miles (320 km) of distribution piping
– 2 to 8 inches (5 to 20 cm) diameter
• Transmission mains from all 4 WRFs are
interconnected
• 9 booster pump stations (5 are City owned and
operated)
• System pressure monitored at key locations
St. Petersburg, Florida
• Wastewater flow = 33 mgd (125,000 m3/d) from 4
treatment plants
• Quantity reused = 17 mgd (64,000 m3/d)
– 40% of total water provided by City
• In-plant uses ≈ 1 mgd (3,800 m3/d)
• Deep well injection = 15 mgd (57,000 m3/d)
• Potable water pumped = 26 mgd (98,000 m3/d)
Florida Water Reuse Regulations - Nonpotable Uses -
Type of Use Water Quality Limits Treatment
Required
Restricted Public
Access Irrigation*
Industrial Uses
200 fecal coli/100 mL
20 mg/L TSS
20 mg/L CBOD
Secondary
Disinfection
Public access
irrigation
Food crop irrigation
Toilet flushing
Fire protection
Commercial laundries
Vehicle washing
No detectable fecal
coli/100 mL
5 mg/L TSS
20 mg/L CBOD
Secondary
Filtration
Disinfection
* Sod farms, forests, pasture land, areas used to grow trees, fodder, fiber,
and seed crops, and similar areas
St. Petersburg, Florida
• Reclaimed water quality (avg. from 4 WRPs):
– BOD = 2.6 mg/L
– TSS = 1.0 mg/L
– Turbidity = 2.4 NTU
– TDS = 580-1070 mg/L
– NO3 = 0.27 mg/L
– NO2 = 0.75 mg/L
– NH3 = 16.9 mg/L
– PO4 = 2.0 mg/L
– Chlorides = 441 mg/L
– Fecal coliforms < 1/100 mL
– Cl2 residual = 3.9 mg/L
Pathogens in Reclaimed Water (Tertiary Treatment) - St. Petersburg, Florida -
Enterovirus
(PFU/100 L)
Cryptosporidium
(oocysts/100 L)
Giardia
(cysts/100 L)
Helminths
(ova/L)
Untreated WW
% Positive 100 67 100 33
Average 1,033 1,456 6,890 16.5
Maximum 4,450 12,200 12,500 111
Reclaimed Water
% Positive 8 17 25* 0
Average 0.01 0.75 0.49 ---
Maximum 0.133 5.35 3.3 ---
* All Giardia cysts in reclaimed water were determined to be nonviable
Deep Well Injection
• Excess reclaimed water and inadequately-treated reclaimed water are disposed of via injection wells
• Total of 10 wells at the water reclamation plants
• Wells penetrate a saltwater aquifer about 1,000 feet (305 m) below land surface
• Groundwater chloride level = 22,000 mg/L – Precludes its use as a potable source of supply
Program Cost*
• Cost to date: $145,000,000
– EPA grant funding estimated to be $100,000,000
• Upgrade the four treatment plants
• Construct the distribution system
– City funded share $20,000,000 (contribution not
targeted for recover)
– The remaining $15,000,000 is recoverable through
the Voluntary Assessment Program
* 1 U.S. Dollar ≈ 2 Brazilian Reals
Operating Cost and Subsidy
• Operating cost = $5,300,000
• System revenue = $2,600,000
• Remaining operating cost of $2,700.000
subsidized by city’s water and wastewater
utilities
– Each utility pays half of that cost
St. Petersburg, Florida - Residential Irrigation with Reclaimed Water -
• Reclaimed water use is voluntary
• Residents pay cost of extending distribution
lines to serve them
– Ranges from $500 to $1,200 per customer
• Total connection charge = $435
– $242 tapping fee
– $168 for backflow preventer
– $15 inspection fee
Operating Cost and Subsidy
• Residential user fees
– Flat rate charge = $15.62 for first acre (0.4 ha) and
$8.95 for each additional acre (0.4 ha) or portion
thereof
• Commercial user fee
– Volume rate = $0.45/1,000 gallons ($0.12/m3)
Agricultural Irrigation
Salinas Valley Reclamation Project
(Monterey, California)
Operational since 1998
Monterey Wastewater Reclamation Study for
Agriculture (MWRSA)
• 7-year Demonstration Project
• Completed on 1987
• Cost = $7 x 106
• Goal: assess safety and feasibility of using tertiary
treated reclaimed water to irrigate crops eaten raw
– Artichokes, broccoli, cauliflower, lettuce, and celery
• Evaluated 3 types of irrigation water
– Tertiary treated reclaimed water receiving direct filtration
– Tertiary treated reclaimed water receiving chemical
coagulation-clarification prior to filtration
– Local well water (Control)
• Demonstration plots = 12 acres (5 ha)
Salinas Valley Reclamation Project - Operational in 1998 -
• Treatment plant capacity = 30 mgd (114,000 m3/d)
• Current flow = 20 mgd (76,000 m3/d)
• Treatment:
– Secondary (trickling filters)
– Rapid mix of coagulant and polymer added
– Flocculation
– Dual media gravity filtration
– Disinfection using gaseous chlorine
– Diurnal flow equalization storage
• Crops irrigated: artichokes, broccoli, cauliflower,
lettuce, celery, and strawberries
Irrigation Distribution System
• Distributes reclaimed water to 222 parcels of farmland
• Irrigate 12,000 acres (4,900 ha) of food crops
• Distribution pipelines = 46 miles (74 km) – Diameter = 8 to 15 inches (20 to 38 cm)
• 22 supplemental wells for peak demand
• 111 flow-metered turnouts
• Pressure and flow metering stations
• Centralized control system
• 3 booster pump stations
• Cathodic protection for ferrous metal piping
Costs
• Capital costs
– Treatment facilities: $30 million (US dollars)
• Only includes cost of additional treatment
– Distribution system: $37 million
• O&M costs/year
– Treatment facilities: $3.9 million
– Distribution system: $1.5 million
• Repayment of loans/year: $1.8 million
• Cost to treat & deliver water = $0.86/1000 gallons
($0.22/ m3)
– Excludes secondary treatment costs
– Includes debt service and O&M costs
Salinas Valley Reclamation Project - Microbial Water Quality -
Organism Raw
Wastewater
Secondary
Effluent
Tertiary
Reclaimed
Water
Fecal coliform (MPN/100 mL) 7 x 106 –
30 x 106
230 x 106 –
800 x 103 ND
E. Coli 0157:H7 (MPN/100 mL) ND ND ND
Salmonella (MPN/100 mL) ND – 16 2.2 – 9.2 ND
Giardia (cysts with internal
structure/100 mL)
2,000 –
22,400 0.4 – 12.2
ND – 0.3
(empty
cysts)
Cryptosporidium (cysts with
internal structure/100 mL) ND – 200 ND – 1.8 ND – 0.41
Virus (MPN/L) -- -- ND
ND = Not detected
Acceptance of Produce Grown in Reclaimed water
• Acceptable to brokers, wholesalers, and store
managers
• Special labeling not required by regulatory
agencies
• Growers believe reclaimed water is as good as –
or better than – other irrigation water they use
– Reluctant to advertise source of water
– Concerned about perception issues
Indirect Potable Reuse
Orange County Water District (California)
Groundwater Replenishment System (GWRS)
Operational since 2008
Local Supplies
Groundwater & Recycling
L.A. Aqueduct
Colorado River Aqueduct
State Water Project
Transfers & Storage
Orange County
• One hour south of Los
Angeles
• Coastal community
• Dry, arid climate with
little rain
• Sources of water include
groundwater and
imported water
Typical OCWD Water Supply Sources to
Recharge the Groundwater Basin (m3/yr)
SAR Baseflows 126 x 106
SAR Stormflows 62 x 106
Natural Incidental Recharge 74 x 106
MWD Untreated Full Service
Water - 25 x 106
Other - 5 x 106
GWRS - 89 x 106
Orange County Sanitation District (OCSD): Wastewater Collection, Source Control, Treatment
and Disposal
Orange County Water District (OCWD): Manages and protects the Groundwater Basin, AWT
Primary
Treatment
Secondary
Treatment
Advanced Water
Purification Reuse Sewage
Source
Control OCSD OCWD
Joint Partnership
Partnership since 1972 for Wastewater Reclamation
GWRS Flow System 70 mgd (265,000 m3/d)
Ultraviolet
Light
(AOP)
Brine
OCSD Outfall
Backwash
OCSD Plant 1
Microfiltration
(MF)
Reverse
Osmosis
(RO)
Product
Water
with
hydrogen
peroxide
Enhanced
Source
Control
Secondary
Treatment
Ground-
water
Recharge
(injection &
spreading)
OCSD
Secondary
Effluent
Where Does GWR System Water Go?
• Water is returned to groundwater basin
– 35 mgd (132,500 m3/d) is sent to injection wells for
seawater intrusion barrier
– 35 mgd (132,500 m3/d) is sent to recharge basins in
Anaheim to augment groundwater aquifers
Orange County Water District Groundwater
Replenishment System (GWRS)
Ocean
Outfall
OCWD
Groundwater Basin
Santa Ana River
N
Pacific Ocean
Santiago Creek
OCSD
Facilities
Pumping
Facilities
SeawaterIntrusion
Barrier
Kraemer/Miller Basins
GWRS Pipeline
Future Mid-Basin
Injection/Recharge
Water Quality Produced by GWRS
• Meets all drinking water standards
• Total dissolved solids:
– Influent = 1,000 mg/L
– Product water = <30 mg/L
• Total organic carbon:
– Influent = 11-12 mg/L
– Product water <0.15 mg/L
• Pharmaceuticals removed to nondetectable levels
• Other chemicals also effectively removed by RO
• N-Nitrosodimethylamine (NDMA) destroyed by UV
• 1,4-dioxane removed by RO, AOP
• Trihalomethanes reduced to nondetectable levels
GWRS Project Funding
$481 Million Capital Cost
Federal Grant,
$20,000,000 State Grants,
$69,000,000
,
OCWD,
$196,000,000
OCSD
Contribution,
$196,000,000
Annual operating cost = $425/af ($0.34/m3)
Benefits of GWR System
• Higher quality than other water sources in Orange County
• Provides additional groundwater supply
• Uses 40% less energy than that needed for imported water
• Reliable, drought-proof source
• Protects basin from seawater intrusion
• Reduces salinity build up
• Decreases wastewater discharge to ocean
• Defers need for a new ocean outfall
• Provides needed water for Orange County