Full-Scale Evaluation of THMs Formation and Minimization of THMs via Chloramination

Chlorine has been and is still widely used chemical to disinfect wastewater. Trihalomethanes (THMs) and other disinfection byproducts (DBPs) are formed when chlorine reacts with organic acids (commonly refers to humic acids). Recent years, DBPs and THMs have been regulated by the agencies that enforced POTWs to find solutions to minimize THMs and DBPs. One common solution is to use alternative disinfection technologies such as UV disinfection, ozonation, etc. However, often time, such implementations are not feasible due to budgetary and time constraints. This paper summarizes a series of bench and full-scale testing findings to minimize THMs formation (specifically dibromo-chloromethane) while adequately disinfecting wastewater to meet the antispated coliform limits. Full-scale demonstrations have showed that chloramination is simple, effective and economic solution to meet the coliform requirements and minimize disinfection by products and THM formation. The findings of this study are directly applicable to other wastewater facilities dealing with the similar problems.