Brackish Desalination Water Supply Planning for Resiliency and Growth

Transcription

1 Brackish Desalination Water Supply Planning for Resiliency and Growth Joe Mouawad, P.E. November 17, emwd.org

2 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 emwd.org

3 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 3 emwd.org

4 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 4 emwd.org

5 EMWD s Water Supply Portfolio Desalter 6% Calendar Year ,087 AF Recycled Water 36% Groundwater 12% Imported Water 46% 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 Source: EMWD 2015 Urban Water Management Plan 5 emwd.org

6 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 6 emwd.org

7 Salinity Management GMZ Groundwater Management Zones Ambient Water Qualities (AWQ) 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 emwd.org

8 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) 8 emwd.org

9 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 emwd.org

10 Existing Program Perris I Desalter Perris South Basin Feedwater pipelines 9 production wells Inland Empire Brine Line Perris I Desalter 5.6 MGD Reverse Osmosis Desalter 5,600 AF/year capacity Operational in emwd.org

11 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 11 emwd.org

12 Brackish Desalination Supply Costs $2,500 $2,014 - $2,257 $2,000 $1,500 $1,000 $979 - $1,073 $1,015 - $1,235 $1,200 - $1,400 $500 $0 Imported water from MWD $250 Groundwater Wells Desalinated Groundwater $401 Recycled Water Ocean Desalination Indirect Potable Reuse EMWD Supplies Alternative Supplies 12 emwd.org

13 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 13 emwd.org

14 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 14 emwd.org

15 Perris/Menifee Desalters Operational Costs Category Labor and staffing Chemicals Energy Materials and services Brine disposal charges Wells Average cost Cost $85/AF $45/AF $45/AF $35/AF $200/AF $95/AF $505/AF 15 emwd.org

16 EMWD s AquaSel Brine Concentration Pilot Project 16 emwd.org

17 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 17 emwd.org

18 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 18 emwd.org

19 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 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 19 emwd.org

20 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 20 emwd.org

21 Contact Information Joe Mouawad, P.E. Senior Director of Engineering Phone Number (951) Ext emwd.org