A study on treatment performance and operation conditions of advanced drinking water treatment process to cope with fluctuations of raw water qualities

Abstract

Pilot-scale experiments of ozone/biological activated carbon (BAC) process were conducted to reduce disinfection by-products and their precursors, especially trihalomethane formation potential (THM-FP). There were no organic indicators (ultraviolet absorbance (E260), fluorescence intensity, and total organic carbon (TOC)) that were related to the behavior of THM-FP in all treatment processes. Two indicators, E260 and fluorescence intensity, of water after coagulation and sedimentation were used to predict THM-FP after ozonation. It was shown that precursors of dichloroacetic acid and trichloroacetic acid could be controlled using chloroform as an indicator. The ozone consumption per TOC to reduce THM-FP sufficiently was about 0.6 to 1.0 mg/mg C. Bromate formation after ozonation was controlled by feedback control of 0.1 mg/L of dissolved ozone at the inlet of biological activated carbon treatment.