Publication Summary

The reason for using any form of disinfection for wastewater effluent is to render the effluent microbiologically safe for any recipient of the effluent. Chlorine and its related compounds were once considered the most effective disinfectant for this purpose. As more emphasis was put on protecting and cleaning up our environment, however, it was shown that halogen-based disinfectants reacted with dissolved organic compounds to form possible carcinogens. These halogenated organics have been called trihalomethanes (THMs). It has also been shown that the residuals of halogen disinfectants have a deleterious effect on the aquatic biota in the receiving body of water. These two problems prompted the use of UV. This publication provides answers to frequently asked questions about ultraviolet disinfection. (See Chapter T5, Section 2 of Criteria for Sewage Works Design -- link below.)