Haloacetic acids (HAAs) formation in desalination processes from disinfectants

A potential problem associated with the usage of chlorine as a biocide for drinking water is the formation of disinfection by-products (DBPs). Trihalomethanes (THMs), haloacetic acids (HAAs) and keto acids, for example, are some of the halogenated by-products which are health concerns due to their carcinogenic and mutagenic effects. Health organizations and other environmental agencies, e.g., WHO, USEPA, SASO, have regulated the maximum level for THMs and HAAs at 80 mu g/L and 60 mu g/L, respectively. This paper deals with the evaluation of formation potential for five haloacetic acids, viz., monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid and dibromoacetic acid in desalinated drinking water. The effect of chlorine concentrations, total organic carbon and bromide concentration on the formation potential of HAAs in seawater (feed to desalination plants), product water (from MSF), well water used for blending and blended water were studied. The concentration of haloacetic acids determined in drinking water and other streams was found to be very much below the maximum permissible level of 60 mu g/L. The study shows that the use of chlorine as a disinfectant for the products from desalination plants does not present any problems with respect to the formation of haloacetic acids and can be considered as a safe biocide for application in desalination processes.