High recovery / high pressure membranes for brine conversion SWRO process development and its performance data

Abstract

Toray Industries and Toray Engineering have developed a new type reverse osmosis (RO) membranes and its process for seawater desalination, which brings advantages of high water recovery, low energy cost and lower plant installation cost. The new type RO membranes, “Brine Conversion Reverse Osmosis Membrane (SU-820BCM)”, shows a superb performance at a high pressure of more than 9.0 MPa and a high salt concentration more than 5.8% concentrated seawater. The newly developed “Brine Conversion Seawater Reverse Osmosis Desalination System (BCS system)” takes the fresh water from the concentrated brine water (salt concentration 5.8%, produced under 6.5 MPa) of first stage RO modules. The newly developed “Brine Conversion Seawater Reverse Osmosis Desalination System” (BCS system) can obtain 60% recovery of fresh water, taking from the concentrated brine water (salt concentration 5.8%, produced under 6.5 MPa) of first stage RO modules in addition to a conventional system desalination (40% recovery). The cost of producing fresh water can be saved approximately 15–20%. The space of plant is also reduced approximately 30% due to reducing the space of the pretreatment process. The continuous operating performance with SU-820BCM has proved to be in good conditions in the BCS pilot plant in Japan for more than 2 years. The total capacity of this plant is 210 m3/d with 60% recovery, and the quality of the produced fresh water has been maintained at the level of less than 200 ppm TDS, which satisfies their designed specifications for drinking water.