1 | emwd.org
Brackish Desalination – Water Supply Planning for Resiliency and GrowthJoe Mouawad, P.E.
November 17, 2016
2 | emwd.org
EMWD 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
3 | emwd.org
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)
• EMWD Representative –Randy Record, Chairman
4 | emwd.org
Products and Services
Fresh Water: 145,000 accounts
• Imported Water
• Hemet Water Filtration Plant
• Perris Water Filtration Plant
• Menifee Desalter
• Perris I Desalter
• Perris II Desalter (design)
• Groundwater Wells
Wastewater: 237,000 accounts
4 wastewater treatment plants
• Capacity: 70 MGD
• Currently treating: 45 MGD
Recycled Water:
• EMWD treats 100% of wastewater generated
• 100% of effluent is reused for RW application
5 | emwd.org
EMWD’s Water Supply Portfolio
• Balanced Portfolio of Supplies with 54% of total supplies from diversified local sources; 46% imported
• 100% beneficial reuse of recycled water within service area; fully subscribed
• Two brackish desalters in operation - ~7,400 acre feet production in CY 2015 of potable water from otherwise unusable groundwater
• Groundwater production from an adjudicated/managed basin with replenishment resumed in CY 2016
Imported Water46%
Ground-water12%
Desalter6%
Recycled Water36%
Calendar Year 2015123,087 AF
Source: EMWD 2015 Urban Water Management Plan
6 | emwd.org
Brackish Desalination Program
• Objectives:
– Develop substantial unused brackish (>1,000 mg/l) groundwater in service area that receives sub-surface recharge
– Protect adjacent groundwater resources from salinity intrusion
– Achieve net salt balance relative to imported water supplies
– Utilize available brine disposal options and advance recovery technologies
– Implement timely and cost effective expansion projects
7 | emwd.org
Salinity Management
GroundwaterManagement Zones –
Ambient Water Qualities (AWQ)
GMZ AWQ
(mg/L)
Canyon 340
San Jacinto Upper Pressure 350
San Jacinto Lower Pressure 800
Lakeview 860
Hemet North 860
Perris North 760
Hemet South 940
Menifee 2030
Perris South 2400
8 | emwd.org
EMWD’s Desalination Program Components
• Groundwater Wells
• Desalter Feed Pipelines
• Treatment Facilities
– Menifee and Perris I Desalters
– Perris II Desalter (future)
• Brine Disposal
– Inland Empire Brine Line
– On-site recovery (future)
9 | emwd.org
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
10 | emwd.org
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
11 | emwd.org
Proposed Perris II Desalter – Phase I
• Treatment Facility – 3.6 MGD with Reverse Osmosis
• Production Facilities – four wells with combined capacity of 3,000 gpm
• Brine Disposal
• Desalter feed pipelines
• Finished water pipeline
12 | emwd.org
Brackish Desalination Supply Costs
$979 - $1,073
$250
$1,015 - $1,235
$401
$2,014 - $2,257
$1,200 - $1,400
$0
$500
$1,000
$1,500
$2,000
$2,500
Imported waterfrom MWD
GroundwaterWells
DesalinatedGroundwater
Recycled Water OceanDesalination
Indirect PotableReuse
EMWD Supplies Alternative Supplies
13 | emwd.org
Importance of Brine Concentration
• Menifee and Perris I Desalters reject 25% of treated flow as brine (75% recovery rate)
– Typical of reverse brackish source water reverse osmosis systems
• Generated Brine Volume:
– Menifee Desalter 0.9 MGD
– Perris I Desalter 1.4 MGD
2.3 MGD
• Loss of Valuable Water Resources:
– Presently – 2,500 AF/year
– Future – 4,000 AF/year
• Brine Management Objectives:
– Maximize available water resources
– Reduce disposal costs
14 | emwd.org
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 has 5.9 MGD pipeline capacity and is currently using about 3.5 MGD
– Cost for O&M $1.05 M/yr
• Cost for purchased capacity:
– Pipeline capacity $3.75 Million/MG
– Treatment and disposal capacity $8.6 million/MG
EMWD Desalters
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Perris/Menifee Desalters Operational Costs
Category Cost
Labor and staffing $85/AF
Chemicals $45/AF
Energy $45/AF
Materials and services $35/AF
Brine disposal charges $200/AF
Wells $95/AF
Average cost $505/AF
17 | emwd.org
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 (1,890 hours of run time)
• Peer review by U.S. Bureau of Reclamation
18 | emwd.org
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
– May be used as potable water if desalted
Achieved 95 percent overall recovery of brackish groundwater through improved brine concentration
19 | emwd.org
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 Aquaselmodule)
– 1/16 of a full-scale 2.3 mgd plant
• This 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
20 | emwd.org
Summary and Conclusions
Advantages of EMWD Brackish Water Desalination Program
• Creates local potable water source to meet growth:
– Will provide over 14,600 AF/year to serve 30,000 households
• Reduces dependence on imported water
• Is cost effective and competitive with alternative supplies
• Supports regional salinity management and offset objectives
• Sustains recycled water program through source water salinity reduction
• Provides opportunities for expansion through technology
– Brine minimization and recovery
21 | emwd.org
Contact Information
Joe Mouawad, P.E.Senior Director of EngineeringPhone Number (951) 928-3777 Ext. 4463
Email: [email protected]
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