solution for high boron ...

solution for high boron content

Seawater has naturally a high level of boron and becasue boron has a very small molecule of almost neutral charge, only a portion of it is rejected by the RO membrnaes at natural ocean water pH of 8.1 to 8.3. The WHO drinking water limit for boron is 2.4 mg/l. Seawater RO membranes would typically be able to reject boron to levels lower tha this limit. In order to achieve boron rejection to less than 1 mg/L at all times the pH of the feed water to the RO memrbanes will need to be increased to 8.9 by the addition of 30 to 40 mg/L of sodium hydroxide (casutic soda). If your target for boron is less than this level the water produced by the first pass of the RO system will need to be re-treated throuh a second pass of high-boron rejection brackish water RO membrnaes avalable by comerical supplies such as Hydranautics, Toray and Dow Filmtec.