A basic study has been conducted on the treatment of refractory organics in river water in order to produce safe drinking water. Through ozonation of refractory organics, assimilable carboxylic acids are produced with a slight decrease in total organic carbon(TOC) concentration. The amount of newly formed assimilable organic carbon corresponds to nearly 35% of the initial TOC in sample water.
Re-ozonation after biological treatment of the formed assimilable organics makes it possible to reduce TOC to a much lower level by transforming the residual refractory organic carbon to an assimilable one. The repeated treatment of ozonation-biodegradation processes can minimize TOC and trihalomethane formation potential to below the detectable level with a minimum of ozone consumption.