폐수방류수 오존처리시 오존 및 OH 라디칼 노출량 기반 미량유기오염물질 제거 예측

Abstract

Municipal wastewater is a major source of contaminants of emerging concern in aquatic environments. Many studies have proven the effectiveness of ozonation for the removal of micropollutants, though the composition of the wastewater matrix influences the oxidation potential during this process. The ozone decomposition rate consists of two stages: instantaneous ozone consumption and slower ozone decay. In particular, with instantaneous ozone consumption, 62.8-79.7% of the initial ozone injection concentration is consumed. Determining the appropriate ozone dosage for wastewater ozonation is complicated by the complexity of the wastewater matrix composition. The purpose of this study was to propose a chemical kinetic model for the prediction of micropollutant removal during the ozonation of wastewater effluent. A kinetics approach based on the measurement of ozone and hydroxyl radical(·OH) exposure was proposed to predict the micropollutant removal efficiency. In this study, a batch-type ozone reactor was set up to measure the ozone and OH radical exposure during wastewater ozonation. Ozone and OH radical exposure was proportional to the initial dose of ozone, while OH radical exposure was found to be proportional to ozone exposure, though the deviation was relatively high at 1.0 to 1.5 gO3/gDOC. The calculated OH radical exposure was 3.0×10-10 to 5.3×10-10M·s. Of the target micropollutants, acetaminophen, sulphamethoxazole, andnaproxen, which are highly reactive with ozone and OH radicals, exhibited a removal rate of more than 80% at an ozone injection rate of 0.75 gO3/gDOC.