Transcript Slide 1
Future of Desalination 2011 Annual Salinity Summit Multi-State Salinity Coalition 02.18.11 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 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 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 Recovering Water from 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 (EPWU/BOR/TWDB) Nano followed by RO Lime followed by RO > 2006 - present > 2002-2006 VSEP 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. 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. VSEP Pilot Test Unit - Single Membrane (from New Logic website) SWRO Unit Feed Tank Heat Exchanger 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. 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 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.