Formation and Fate of Bromoform During Desalination

Abstract

The objectives of this study were to evaluate the formation and fate of bromoform (one of the regulated trihalomethanes) in pretreatment systems at a pilot-scale desalination facility operated to evaluate various reverse osmosis (RO) systems for desalting seawater. The various RO units being tested at the facility were also assessed with regard to their capabilities for rejecting bromoform. The results show that bromoform is produced in significant quantities when raw seawater is chlorinated, and that the bromoform concentration increases through the various pretreatment processes in use at the facility with the exception of the activated carbon columns. The cellulose triacetate hollow fine fiber RO membranes do not reject bromoform, and bromoform concentrations in the RO permeate are higher than those in the feed water to the RO units. The polyether/urea and polysulfone thin film spiral wound membranes did reject bromoform effectively.