A Thermal Distillation Process for Expanding Water Resources

A Thermal Distillation Process for Expanding Water ResourcesDr. Andrew Lowenstein AIL Research Principal InvestigatorMost of the world's freshwater usage—as high as 70%—goes to agriculture. Unfortunately inmany of the country's major farming regions secure sources of agriculture water are threatened:freshwater aquifers are being over pumped coastal saltwater intrusion is tainting freshwatersupplies agricultural run-off is dumping nitrates into the environment and severe droughts areperiodically interrupting supplies.The US. Geological Survey estimates brackish groundwater reserves spread across the countrycould meet U.S. water needs for the next 800 years. The proposed work will convert these largebrackish water reserves into an agricultural water resource by overcoming a major obstacle: thecost and environmental impact of the disposal of brine generated by membrane baseddesalination technologies such as RO.The goal of affordable brine disposal with minimalenvironmental impact can be reached using a process with only stable mineral solid waste i.e. aZero Liquid Discharge (ZLD) process.In Phase I AIL Research successfully completed proof-of-concept tests for the two majorsubsystems of a ZLD solution.These tests proved that innovative designs for both a brineconcentrator and crystallizer could continuously separate water from solutions saturated withsalts while managing the precipitation of salt crystals so that critical heat transfer surfaces andflow passages did not foul or scale.In Phase II a commercial-scale module for the brine concentrator will be designed built andtested under conditions that simulate its operation in the field. The successful completion ofthese tests will allow the design and fabrication of one or more containerized 5-gpm brineconcentrators in a Phase III effort.These prototypes would be installed and operated by ourcommercialization partner Global Water Innovations (GWI) providing GWI the critical brinedisposal means it needs to close on pending projects to provide water to farmers in California'sCentral Valley.The Phase II tests of a commercial-scale module for the brine concentrator alsoallows our second commercialization partner Trevi Systems to evaluate the SBIR technology asa possible addition to desalination and waste brine systems it now manufactures and sells.The Phase I proof-of-concept tests for the second component of a ZLD facility—the brinecrystallizer--while successful identified areas needing further development before thetechnology can be scaled to commercial size.Phase II work will fulfill these technology needswhich center on the lifetime of critical coatings that protect the crystallizer's surfaces fromscaling.Following the successful completion of this task in Phase II commercial-scale modulesof the brine crystallizer would be designed built and tested in Phase III.Our first-generation ZLD facility is projected to reduce the cost of waste brine disposal by afactor of at least five—from a current cost on the order of $17 to $3.40 per cubic meter.At thiscost the conversion of brackish water will start to penetrate the agricultural market for thehighest value crops. As the technology matures disposal costs should approach $2 per cubicmeter making brackish water conversion cost-effective for many growers.