Concentrate Management Technologies
Self-Sealing Evaporation Ponds
Sandia National Laboratories is developing chemical treatments that cause evaporation ponds to seal themselves by growing clay minerals from the concentrate. The clay mineral is a magnesium silicate (sepiolite) that can precipitate in alkaline saline waters. We are currently evaluating the water permeability of in-situ produced sepiolite.
Zero Liquid Discharge
This technology is designed to separate and purify saleable resources from the concentrate stream, and involves both reverse osmosis and electrodialysis for brackish waters. This is a proprietary technology from University of South Carolina that uses selective ion exchange membranes and selective precipitation reactions to precipitate gypsum.
UNM Work in Concentrate Management
Wen-Yi Shih, Anditya Rahardianto, Ron-Wai Lee, and Yoram Cohen, Morphometric characterization of calcium sulfate dihydrate (gypsum) scale on reverse osmosis membranes, Journal of Membrane Science 252 (2005) 253.
The University of New Mexico is studying the applicability of using a desupersaturator reactor to remove troublesome and insoluble salts that scale RO membranes at high water recoveries. High recoveries lead to less concentrate formation. The technology takes a slipstream of a supersaturated (with respect to Ca SO4
) solution and subsequently contacts it in a seeded precipitation reactor to remove gypsum.