Scott Reinert , P.E. Water Resources Manager El Paso Water Utilities Future of Desalination 2011 Annual Salinity Summit Multi-State Salinity Coalition 02.18.11 The topic of my presentation is “Future of Desalination” My name is Scott Reinert. I am the Water Resources manager for El Paso Water Utilities I am giving this presentation on behalf of Ed Archuleta who cannot be here at the Conference because of a family emergency. Scott Reinert , P.E. Water Resources Manager El Paso Water Utilities

Topics Current and future growth of desalination in the U.S. Research topics Desalination research organizations Conclusion

Growth of Desalination 1960’s: desalination had its commercial beginnings 1980: 30 U.S. municipal desalination facilities with capacity of at least 25,000 gallons per day 1970-2000: management of concentrate through disposal (ocean outfall, sewer, deep well injection, evaporation ponds, irrigation) 2000 to present: ZLD, beneficial use, volume reduction This slide outlines some of the highlights in the growth of the Desalination industry.

U.S. Municipal Desalination Plants Cumulative Number of U.S. Municipal Desalination Plants Estimated 340 Plants Estimated 300 Plants Municipal Desalination Plants operating in U.S. that are at least 25,000 gallons per day This chart shows the number of U.S. municipal desalination plants with capacity of at least 25,000 gpd. This is equivalent to 17 gpm.

Research Topics Irrigation return flows Recovering water from concentrate Cartridge filters Center for Inland Desalination Systems (CIDs) Zero Discharge Desalination (ZDD) Capacitive Deionization Concentrate Management

Irrigation Return Flows

Irrigation Return Flows (case study) Irrigation return flow is of lower quality than irrigation season (elevated TDS, sulfate, chloride) Winter flow during this time is approximately 10 MGD Treat 5 MGD of water with RO, blend with 5 MGD to produce 10 MGD 1 MGD of concentrate into the river Concept is included as a Water Management Strategy in the State Water Plan to be implemented in 2020. Additional 2,700 acre-feet annually The water quality improves with higher flows At 10 mgd TDS-2292 mg/l SO4- 726 mg/l Cl-512 mg/l 20 mgd TDS 1780 Mgd TDS -1407 mg/l High quality water could be produced from irrigation return flows.

Recovering Water from Concentrate This photo shows the 5 RO skids at the Kay Bailey Hutchison Desalination plant. The next few slides will provide information on the different research we have been doing to evaluate recovering water from the concentrate.

Recovering Water from Concentrate At full design capacity, Kay Bailey Hutchison Desalination Plant will generate 3 MGD of concentrate. Cost–benefit analysis of recovering potable water from the concentrate versus the cost of deep well injection.

> > Concentrate Research Nano followed by RO Lime followed by RO (EPWU/BOR/TWDB) > Nano followed by RO Lime followed by RO VSEP SWRO 2002-2006 > 2006 - present initial studies were conducted to evaluate silica removal from the RO concentrate using lime treatment. Untreated silica will foul the RO membranes. Lime was shown to be very effective at removing silica from the concentrate. More recent concentrate research has focussed on VSEP and SWRO.

Recovering Water from Concentrate Lime Treatment Laboratory Studies Lime is effective for removing silica from RO and nanofiltration concentrates. Vibratory Shear Enhanced Processing (VSEP) Membrane treatment system using vibrating membranes to produce shear waves that reduce the potential for membrane fouling. Sea Water Reverse Osmosis (SWRO) RO membranes used for sea water used to remove salts from concentrate. Initial pilot testing done in batch mode. VSEP - vibratory shear enhanced processing Is a membrane treatment system utilizing vibrating membranes to produce shear waves that reduce the potential for fouling at the membrane surface. ADVANTAGES Resistance to fouling Ability to handle water with high solids concentration DISADVANTAGES Extra maintenance required for the system. SWRO Very effective for recovering most of the water from the concentrate of the KBH desalination plant. A batch treatment system of concentrate would be difficult to operate.

Recovering Water from Concentrate Automated Seawater Reverse Osmosis (ASWRO) Fully automated system that uses RO to remove salts from concentrate in batch mode. Automated Continuous Flow Seawater Reverse Osmosis Future research topic. Automated continuous flow seawater reverse osmosis would be preferred. Research would be needed to evaluate feasibility of continuous flow.

VSEP Pilot Test Unit - Single Membrane (from New Logic website)

Picture of Small Seawater RO Unit Used for Conducting Initial Tests SWRO Unit Feed Tank Heat Exchanger A heat exchanger was used to keep the feed solution from overheating. Concentrate from the KBH plant was put into 30 gallon feed tank, acid and anti-scalent were added. Concentrate recycled back to the feed tank until the desired recovery was achieved. Picture of Small Seawater RO Unit Used for Conducting Initial Tests

Picture of Fully-Automated Batch Treatment Seawater RO System

Cartridge Filters Cartridge filters used to filter the influent water prior to RO treatment. Membranes manufacturers will typically recommend using 5 micron (or smaller) cartridge filters to protect membranes. Frequent replacement of cartridge filters represents a significant operation and maintenance expense. Tight cartridge filters may be too conservative.

Different Types of Cartridge Filters

Cartridge Filters (case study) EPWU evaluated cartridge filters ranging in size from 5 to 30 microns in a controlled laboratory environment. 5 micron cartridge filter clogged more frequently than the larger sizes while not offering greater protection of the RO membrane. As a result of this case study, EPWU uses a 15 micron filter that requires fewer changeouts than the 5 micron filter. EPWU is saving $100,000 annually by using the 15 micron filter. No problems have been reported with using the larger cartridge filter.

This is a picture of the laboratory set up at the KBH Desalination plant for the Cartridge Filter study. Cartridge Filters

Center for Inland Desalination Systems (CIDS) Center for Inland Desalination Systems (CIDS) is a center that is studying desalination-related issues. CIDS has several regional partners, including UTEP, El Paso Water Utilities Public Service Board, Consortium for Hi-Technology Investigations in Water and Wastewater (CHIWAWA), and Veolia Water Solutions and Technologies.

Center for Inland Desalination Systems (CIDS) Desalination-related issues studied by CIDS Recovery of concentrate produced during the desalination process Developing small-scale portable desalt equipment to be used in remote locations Developing energy efficient water treatment technologies

Zero Discharge Desalination (ZDD) ZDD offers the potential to maximize the volume of product water from a brackish source. This effort will be a partnership between UTEP, Veolia Water Solutions & Technologies, and the City of Alamogordo. ZDD technology is capable of desalination with yields as high as 97% using a proprietary silica removal system. High recovery processes are needed because of high waste disposal costs, limited water supply, and environmental concerns associated with brine.

Capacitive Deionization CDI has been reported to potentially be a cost effective alternative to membrane technologies Lower energy requirement, no membrane fouling, no chemicals needed During the flow, the ions in the saline water move towards anion/cation exchange membranes depending upon the polarity of the ions. CDI has shown a lot of promise, but is not widely used because of the low water recovery ratio.

Capacitive Deionization The schematic shows the capacitive deionization process It is a process of using electric current, an exchange membrane to remove salts from water. Perhaps we will see more interest in this technique in the years ahead.

Desalination Concentrate Management Policy Analysis - CHIWAWA Review and analysis of regulatory and policy barriers to concentrate management. Clean Water Act and Safe Drinking Water Act were established before desalination was widely utilized to produce usable water supplies. Recommendations will be made to facilitate development of brackish water desalination and concentrate management in the U.S.

Desalination Research Organizations Multi-State Salinity Coalition CHIWAWA (Consortium for High Technology Investment on Water and Wastewater) Water Reuse Foundation Water Research Foundation Bureau of Reclamation Texas Water Development Board

Conclusion Identify desalination research needs. Current state and federal funding for research is limited. Stakeholders have limited funding to participate in research projects. Effective partnerships Pool resources of matching funds and in-kind services to create opportunities for continued research.