AWWA ACE58278

Low-pressure membrane filtration is typically used to treat surface water after coagulation and sedimentation. However, recent advancements in membrane technology are making it possible to incorporate low-pressure membrane filtration directly after coagulation with no sedimentation required. Due primarily to stringent regulations regarding disinfection byproducts (DBPs) and upcoming regulations regarding Cryptosporidium, the City of Kerrville, Texas is planning to expand its 5 mgd conventional water treatment plant (WTP) by installing membrane filtration combined with chemical coagulation. The source water for the Kerrville WTP is surface water from the Guadalupe River, which has a range of total organic carbon (TOC) from 1 to 11 mg/L. To ensure long-term regulatory compliance, direct coagulation with low-pressure membrane filtration followed by chlorination was selected for treatment of Guadalupe River water. Enhanced coagulation provides DBP control, membranes enable pathogen removal, and chlorine provides viral inactivation and a residual disinfectant for distribution. Includes tables, figures.