抄録
Quality of water from RO sea water desalination plants can satisfy almost all regulation items of drinking water quality regulations, except a concentration of boron, which should be lower than 0.2 mg/l. Although this is not a compulsory item now, but it may become so in near future. Thus it is necessary to know rejection ability of various RO membranes against boron and to establish necessary measures to cope with this requirement. In this research, transport parameters of boron permeation were determined using boron rejection data of some commercial membranes. Membranes used were both high and low pressure types, which may be necessary for a two stage process. A process design computer program was set up and was run to estimate boron rejections of a RO unit using transport parameters. Results show that by increasing NRe and the recycle ratio boron concentration can be reduced, but, generally it is difficult to reduce below 0.2 mg/l unless pH at the second stage is increased over 9.9.
