Full-scale AQUA-SEP® skids for RO reject and brine concentration

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Why RO reject goes to AQUA-SEP®

Reverse osmosis (RO) uses a high-pressure pump to force water across a membrane, leaving almost all of the dissolved salts in the reject stream. The saltier the feed, the more pressure RO needs, and Petro Sep's own chart marks the maximum salt content for RO at roughly 6 to 7 percent total dissolved solids (TDS). AQUA-SEP® works differently: the brine runs along one side of a hydrophobic, microporous hollow-fiber membrane, the other side is kept under vacuum, and water passes through as vapor while almost all of the dissolved salts stay behind. Petro Sep rates AQUA-SEP® for feeds of 25 percent salt and more and describes it as suitable for high-TDS brine, especially RO reject. Its RO material says that routing the RO reject to AQUA-SEP® could raise water recovery to as much as about 95 percent. These are general figures for the technology, not measurements from this plant.