AWWA ACE92154

In anticipation of the Disinfectants/Disinfection Byproducts Rule, the Metropolitan Water District of South California (Metropolitan) initiated a THM action plan to pro-actively identify treatment strategies that would allow compliance for THMs and other DBPs, while maintaining control of taste-and-odor compounds and microorganisms. Metropolitan's $26 million action plan includes coagulation studies, granular activated carbon studies, a 2-year oxidant pilot-scale study evaluating ozone and PEROXONE, and a 5-year oxidation (ozone/PEROXONE) demonstration project. The focus of this paper is on the initial demonstration project ozone contactor results. Critical issues involve: testing the stability of plant operations and the reliability of liquid ozone residual sampling and analysis; calculating the CT-disinfectant concentration, C (mg/L), x contact time, T (min)-for various conditions of ozone dosage and gas flow; and collecting bromate occurrence data for State project water.