AWWA JAW41434

A computer simulation methodology is described that examines, on a case-specific basis, the effect of water quality on the formation of trihalomethanes (THMs) and their associated theoretical cancer risks. The strategy of controlling organic carbon concentrations at the point of chlorination was evaluated for its ability to reduce predicted cancer incidence. In waters containing bromide, the absolute concentrations of the more brominated THMs can increase as organic carbon concentration is reduced at the point of chlorination; total theoretical cancer risks induced by THMs, however, decreased for all water qualities considered. Reduction of THM-induced cancer risks by enhanced coagulation, granular activated carbon adsorption, and membrane filtration increased as the source water bromide concentration increased. When risks induced by haloacetic acids are considered, these technologies may achieve significantly greater levels of risk reduction than are estimated by considering THM risks only. Includes 16 references, tables, figures.