Use of Biofiltration for Removal of Natural Organic Matter to Achieve Biologically Stable Drinking Water

The presence of organic carbon in raw drinking waters can cause problems such as trihalomethane formation during disinfection with chlorine, regrowth of bacteria in the distribution system and reduced GAC adsorber bed life. This research concerns biofiltration for the removal of organic matter from drinking water sources. A major objective of this research is to examine how differences in the source and composition of the natural organic matter relate to the biodegradability of the natural organic matter and influence biofiltration effectiveness. Most of the organic matter in Dismal Swamp water, one of the four sources of organic matter to be evaluated in this study, has an apparent molecular weight in the 3-10 K range and the < 0.5 K range as shown by an apparent molecular weight analysis using ultrafiltration. Aerobic batch biodegradation experiments were performed using Dismal Swamp water ozonated at a dose of 1 mg O₃/mg TOC. A 30 % reduction in total organic carbon over an 11-day incubation period was observed.