AquaSel Brine Concentration Pilot Project Update Khos Ghaderi, P.E. Director of Water Operations December 23, 2015

Importance of Brine Concentration Generated Brine Volume: Menifee Desalter 0.9 MGD Perris 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

Background December 2013 – EMWD Board Authorized AquaSel Pilot Project December 2014 – Commissioned the AquaSel Brine Concentration Pilot Unit by GE at EMWD’s Menifee Desalter Project Partners Metropolitan Water District ($192,000 grant) Foundational Action Funding Program research for new technologies to develop regional water resources U.S. Bureau of Reclamation ($131,000 grant) Desalination and Water Purification Research and Development Program Carollo Engineers Retained for Technical Support ($92,815) July 2015 – Completed AquaSel pilot plant testing

AquaSel Pilot Project Objectives Demonstrate ability to reliably treat EMWD’s brine Recover additional water through brine concentration Verify and validate preliminary cost estimates Identify any operational and maintenance issues Develop appropriate treatment train design for a demonstration and full scale plant based on findings

AquaSel Brine Concentration Technology AquaSel is a proprietary process by GE which uses electrodialysis reversal (EDR) and a precipitator Has been successfully applied in the beverage industry Conducted pilot testing at 10 GPM over a nine-month period (1,890 hours of run time)

Pilot Plant Process Schematic

Pilot Plant Performance Overview Trouble Shooting - December 2014 to February 2015 Experienced several operations and water quality related issues Silica fouling Calcium carbonate fouling (scaling) Added pre-treatment (ferric chloride, multimedia filters, and cartridge filters) Start Up – March 2015 to April 2015 Achieved steady state operation Continued experiencing occasional starts and stops due to scale formation on the membranes

Pilot Plant Performance Overview (cont’d) Phase Hours of Operation Desalter Recovery AquaSel Recovery Water Quality TDS Mg/L Performance Issues 1 500 75% 90% 3,000 Occasional EDR Fouling 2 430 70% 2,260 Unreliable / High Maintenance 3 960 80% 1,900 Steady Performance Plant performance and the project report were reviewed by USBR technical staff as well as by Carollo and District staff

Pilot Plant Performance Overview (cont’d) Phase 2 Phase 3 Start of final test period Loss of solids from the precipitator

Summary of Findings 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 Achieved 95 percent overall recovery of brackish groundwater through improved brine concentration

Ongoing Analysis Right-sizing the precipitator for improved performance Evaluating best filtration method for recirculating feed to EDR Balancing hydraulic flow Blending options Sizing a “demonstration plant” and estimating the cost Determining the best layout and return on investment (ROI) for a full scale plant

Next Steps Finalize the pilot study Complete pilot study analyses and develop plans for a potential demonstration project Cost estimates Site layout Agreement with GE Pursue external funding Present final pilot study analyses and recommendations regarding next phase demonstration project January 2016 February 2016 On-going March 2016

Khos Ghaderi, P.E. Director of Water Operations (951) 928-3777 Extension 6240 ghaderik@emwd.org