Boron reduction performance of reverse osmosis seawater desalination process

In recent years, seawater desalination systems using reverse osmosis (RO) m embranes have been constructed to settle the lack of drinking water. RO des alination membranes have high rejection for most of solutes in seawater. Ja panese drinking water standards for the water quality of the permeate can b e achieved except for boron. Therefore, the boron rejection needs to be con sidered in the design of the RO process and during the operation of the pla nt. Luckily, there is a simple and easy method to estimate boron concentrat ion. In this paper, we report measured boron permeabilities and their relation t o salt permeabilities using cross-linked polyamide membranes. Chemical degr adation of the membranes affected these permeabilities to different degrees . Boron concentrations in the permeate were then calculated using a compute r program that was based on the boron permeabilities calculated from the me asured salt permeabilities. Results obtained were compared with actual data taken at a RO plant of Toray Industries, Inc., Ehime, The model data fitte d the experimental result, well. It was also found that a relationship exis ted in the permeate between salt and boron concentrations and that the boro n concentration can be obtained from measurement of the salt concentration. (C) 2001 Elsevier Science B.V. All rights reserved.