The production of brominated methanes in desalination plants in Kuwait

Abstract

Abstract Dissolved organic matter in sea water reacts with chlorine used for disinfection and as a molluscicide yielding a mixture of brominated methanes. A study has been made of the formation and distribution of these compounds in the various stages in desalination units of four different plants in Kuwait. Usually, bromoform comprised 95–97% of the total, with lesser amounts of dibromochloromethane (2–4%) and traces of dichlorobromomethane ( ). However, exceptionally, in one unit the dichlorobromomethane reached a maximum of 26% when the level of residual chlorine was very low. Over 98% of the haloform formed was discharged to the atmosphere at the deaeration stage. In general, there was a significance to very significant correlation between the concentration of residual chlorine at the pump and that of total haloform present at any particular stage in the unit. Mean total haloform concentrations in the final distillate varied from one unit to another in the range 2.7–22.8 μg1−1, and rarely exceeded 30 μg1−1, well below the 100 μg 1−1 level set by the U.S. Environmental Protection Agency.