Trihalomethane in drinking water supplies and reused water

Most of the potable water for the Muscat area, Oman, is obtained by desalination of sea water, with about 10 per cent obtained from wells. Chlorine is the usual disinfectant for both water and sewage, and this could result in the formation of trihalomethanes (THM). Tabulated data are presented on the concentrations of THM in desalinated water and chlorinated groundwater, on the average composition of secondary sewage effluent, and on the THM concentration in chlorinated secondary effluent. THM residues in groundwater were much higher than those in desalinated water, but in general the concentrations found were lower than the WHO limits for drinking water.