Brackish Desalination Water Supply Planning for Resiliency and Growth

Transcription

1 Brackish Desalination Water Supply Planning for Resiliency and Growth Paul D. Jones II February 2, emwd.org

2 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 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) High-growth area that is 38% built-out 3 emwd.org

4 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 4 emwd.org

5 EMWD s Retail Water Supply Portfolio Desalters 5% Calendar Year 2016 (119,046 AF) Recycled Water 37% Groundwater 12% Imported Water 46% 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 5 emwd.org

6 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 6 emwd.org

7 Desalination Supply Objectives and Program Components 7 emwd.org

8 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) 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 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 11 emwd.org

12 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. 12 emwd.org EMWD Desalters

13 Brackish Desalination Supply Costs $2,500 $2,014 - $2,257 $2,000 $1,500 $942 - $1,076 $1,015 - $1,235* $1,079 - $1,295 $1,000 $500 $0 Imported water from MWD $250 Groundwater Wells Desalinated Groundwater $401 Recycled Water (Purple pipe) Ocean Desalination Indirect Potable Reuse 13 emwd.org EMWD Supplies Alternative Supplies * Desalination operating costs are $505 per acre-foot

14 Desalination Groundwater and Salinity Management Objectives 14 emwd.org

15 Groundwater Basin Management Objectives N Desalters Rising groundwater Hemet San Jacinto Basin principal groundwater source for four agencies and Soboba Tribe Basin Plan Objectives Hemet /S.J. 320 mg/l (Max Ben Obj.) S.J. Low. Press. (500 mg/l) 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 15 emwd.org

16 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 16 emwd.org

17 Achieving Salt Balance Imported Water (Average Year) SWP = 46,900 af/yr (66%) 250 mg/l or 680 lbs/af = CRA = 24,000 af/yr (33%) 520 mg/l or 1,360 lbs/af = Current Desalting and Brine Discharges EMWD Menifee and Perris I Desalters MGD brine Other industrial dischargers Intl Rectifier MGD (30,000 mg/l) Inland Empire Energy MGD (6,000 mg/l) 15,900 t/y 16,400 t/y 32,300 t/y 25,000 t/y 2,300 t/y 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 17 emwd.org

18 Technology Optimization Objective - AquaSel Brine Concentration Pilot Project 18 emwd.org

19 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 19 emwd.org

20 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 20 emwd.org

21 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 21 emwd.org

22 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 22 emwd.org

23 Contact Information Paul D. Jones II General Manager (951) Ext emwd.org