brackish desalination – water supply planning for … - brackish desal... · 2017-02-07 ·...
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1 | emwd.org
Brackish Desalination – Water Supply Planning for Resiliency and Growth Paul D. Jones II February 2, 2017
2 | emwd.org
EMWD Agency Overview
• Established in 1950
• Unique agency, serving:
– Water/wastewater/recycled
– Wholesale and retail
• Five district-elected board members
• More than 600 employees
• Annual operating budget of $171 million for FY 2016/2017
• Five year capital program of $461 million FY 2017 – 2021
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EMWD’s Service Area
• 555 square miles
• Population: 795,000
• Moreno Valley to Temecula
• Seven cities and the unincorporated areas
• One of 26 member agencies of The Metropolitan Water District of Southern California (MWD)
• High-growth area that is 38% built-out
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EMWD Services
• Potable Water: Approx. 144,000 accounts – Imported water from the State Water Project
and Colorado River • Directed treated deliveries from MWD • Two Ultra-filtration plants
– Groundwater wells (adjudicated - managed basin)
– Brackish desalination
• Wastewater: Approx. 239,000 accounts – Four regional water reclamation facilities
• Recycled Water: Approx. 300 accounts – 35,617 acre feet sold in FY 2014/2015 – Approximately 10,800 acres of agriculture
irrigated by recycled water
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EMWD’s Retail Water Supply Portfolio
• Balanced Imported/local portfolio: – 54% of total supplies coming
from diversified local sources; – 46% of total supplies are
imported • Recycled water: 100% beneficial
reuse within service area • Brackish groundwater: Two
desalters in operation, – 6,500 AF of potable water from
an otherwise unusable source • Groundwater management:
– Adjudicated Hemet/San Jacinto sub-basin
– GSA for Perris/Menifee Sub-basin
Imported Water 46%
Groundwater 12%
Desalters 5%
Recycled Water 37%
Calendar Year 2016 (119,046 AF)
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Four Key Desalination Program Objectives
• Supply: Develop substantial brackish groundwater (>1,000 mg/l) resources from Perris and Menifee sub-basins ‒ Rising groundwater basin with substantial
natural replenishment ‒ Minimal pumping by other entities ‒ Adjudicated but under GSA
• Groundwater Management: protect groundwater sub-basins from salinity intrusion
• Salt Balance: Achieve net salt balance relative to imported water supplies
• Technology Optimization: Develop advanced brine recovery technologies
Strategic Supply Goal: Expand Brackish Groundwater Desalination to
Provide over 17,500 AF/year to Serve 35,000 Households
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Desalination Supply Objectives and Program Components
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EMWD’s Desalination Program Components
• Initial desalter built in 2002
• Groundwater Wells • Desalter feed pipelines • Treatment facilities
– Menifee and Perris I Desalters
– Perris II Desalter (future)
• Brine disposal – Inland Empire Brine Line – On-site brine recovery
(future)
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Existing Program – Menifee Desalter
• Perris South Basin
• Inland Empire Brine Line
• Feedwater pipelines • 3 production wells
Menifee Desalter – Phase I • 3.1 MGD Reverse Osmosis Desalter • 3,000 AF/year capacity • Operational in 2002
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Existing Program – Perris I Desalter
• Perris South Basin
• Inland Empire Brine Line
• Feedwater pipelines • 9 production wells
Perris I Desalter • 5.6 MGD Reverse Osmosis Desalter • 5,600 AF/year capacity • Operational in 2005
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Proposed Perris II Desalter – Phase I
• New Treatment Facility – 3.6 MGD • Production Facilities – four wells
with combined capacity of 3,000 gpm
• Brine disposal connection • Extended desalter feed pipelines • Shared site/infrastructure
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Brine Disposal
• Constructed by a five agency Joint Powers Authority
• Pipeline is 70 miles – capacity is 30 MGD
• Supports six desalters and industrial dischargers, including:
– Menifee Desalter
– Perris Desalter
• EMWD currently using about 3.5 MGD
– O&M is $1.05 M/yr.
EMWD Desalters
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Brackish Desalination Supply Costs
EMWD Supplies Alternative Supplies
$942 - $1,076
$250
$1,015 - $1,235*
$401
$2,014 - $2,257
$1,079 - $1,295
$0
$500
$1,000
$1,500
$2,000
$2,500
Imported water from MWD
Groundwater Wells
Desalinated Groundwater
Recycled Water (Purple pipe)
Ocean Desalination
Indirect Potable Reuse
Desalinated Groundwater
* Desalination operating costs are $505 per acre-foot
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Desalination Groundwater and Salinity Management Objectives
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Groundwater Basin Management Objectives
Basin Plan Objectives • Hemet /S.J. 320 mg/l (Max Ben Obj.) (500 mg/l) • S.J. Low. Press. • Lakeview Less than • Hemet North 570 mg/l • Perris North • Hemet South 730 mg/l • Menifee Approx. • Perris South 1260 mg/l
EMWD Service Area and Groundwater Basins
N
Hemet – San Jacinto Basin principal groundwater source for four
agencies and Soboba Tribe
Desalters
Rising groundwater
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Salinity Management Objectives
• Current: 2.3 MGD of desalter brine disposal through the Inland Empire Brine Line
• Proposed: 4.5 MGD disposal at full expansion
• Current salt removal ‒ 25,000 Tons Annually ‒ Slight Net Import into Region
with Imported Water
• Ultimate salt removal goal ‒ 55,000 Tons Annually ‒ Net Export
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Achieving Salt Balance
Imported Water (Average Year) SWP = 46,900 af/yr (66%) 250 mg/l or 680 lbs/af = 15,900 t/y CRA = 24,000 af/yr (33%) 520 mg/l or 1,360 lbs/af = 16,400 t/y 32,300 t/y Current Desalting and Brine Discharges EMWD Menifee and Perris I Desalters - 2.3 MGD brine 25,000 t/y Other industrial dischargers
Intl Rectifier - 0.05 MGD (30,000 mg/l) 2,300 t/y Inland Empire Energy - 0.2 MGD (6,000 mg/l) 1,800 t/y
29,100 t/y
Imported Supply Salt (TDS – mg/l) Lbs. of salt/acre foot Colorado River Water ~500 to 700 mg/l 1,360 to 1,900 lbs/af
State Water project (current) ~250 mg/l 680 lbs/af
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Technology Optimization Objective - AquaSel™ Brine Concentration Pilot Project
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Background
• Pilot Study of the AquaSel Brine Concentration Technology was completed in August 2015
• AquaSel is a proprietary process by GE which uses Electrodialysis Reversal (EDR) and a precipitator
• Tested 10 gallons per minute (gpm) pilot plant
• Pilot testing was conducted over a nine-month period
• Peer review by U.S. Bureau of Reclamation
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Summary of Findings
• Typical membrane fouling and hydraulic issues were mitigated
• Achieved significant operation time – 1,890 hours of operation – 320 hours of continuous run time
• Sustained operation with occasional downtime
• Average TDS of pilot plant product water was approximately 1,500 mg/l – Compatible with raw well water for
blending
Achieved 95 percent overall recovery of brackish groundwater through improved brine concentration
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Next Steps
• Conduct a Larger AquaSel Demonstration Project: – Validate the process at a larger scale utilizing
one full-size AquaSel module – Sized for 100 gpm (typical size of Aquasel
module) – 1/16 of a full-scale 2.3 mgd plant
• Demonstration Project will: – Include full scale components – Refine the design and sizing of the
precipitator – Utilize the same EDR stack as a full-scale plant – Confirm the AquaSel process has been
optimized for a full-scale plant – Validate preliminary estimates for operating
costs
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Summary and Conclusions
Importance of EMWD’s Multi-benefit Brackish Water Desalination Program
• Supply - creates a drought-proof sustainable potable water source to meet growth: – Will provide over 17,500 AF/year to serve 35,000 households – Is cost effective and competitive with alternative supplies
• Groundwater basin management and regional salt balance: – Protects potable basins from brackish intrusion – Net salt export – Sustains recycled water program through source water salinity
reduction • Technology optimization for brine recovery:
– Brine discharge minimization and recovery
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Contact Information
Paul D. Jones II General Manager (951) 928-3777 Ext. 6130 Email: [email protected]