고도정수처리공정에 의한 THMs 제거 특성 분석 : 실제 정수장 장기간 운영 데이터 대상

초록

Nxumerous studies have investigated the formation mechanisms, influencing factors, and removal strategies of DBPs. However, most previous studies were based on laboratory-scale experiments or short-term data, which limited their ability to reflect actual water treatment plant (WTP) operating conditions and water quality variations, and thus failed to assess long-term effects. To address these limitations, this study analyzed 20 years of operational data from a full-scale WTP to evaluate the long-term impact of an advanced water treatment process (AWTP) on DBPs formation and removal Characteristics. Multiple linear regression (MLR) and interrupted time series (ITS) analyses were conducted to examine changes before and after AWTP implementation. Evaluation of individual unit processes revealed that the average removal efficiency of trihalomethanes (THMs) by granular activated carbon (GAC) was 17.2%, but it decreased sharply after 5-6 months due to breakthrough, while ozonation showed less than 5% removal efficiency under real operating conditions. The average THMs concentration decreased by approximately 28% (from 0.029mg/L to 0.021mg/L, p<0.001), indicating a statistically significant reduction. Furthermore, Hedges' g, MLR, and ITS analyses identified residual chlorine concentration and iodine number (an indicator of adsorption performance) as the most influential variables directly affected by AWTP implementation. These findings indicate that although the introduction of ozonation and GAC adsorption units significantly reduced THMs concentrations, the effect is largely attributable to the removal of THMs precursors (TOC) by GAC and the reduction of residual chlorine concentration—rather than direct THMs removal by ozonation or sustained adsorption performance of GAC.

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