Abstract
This study was performed to investigate the disinfection efficiency and the generation characteristics of disinfection by-products (DBPs) in the sewage effluent. In the case of total coliforms, disinfection efficiency higher than 99%, the required contact time was 30 min at chlorine dose of 0.5 mg/L, 20 min at 1.0 mg/L, and 10 min at 1.5 mg/L, respectively. When the sewage effluent was disinfected with chlorine dose of 0.5 mg/L for 10 min, the maximum generation concentration of trihalomethanes (THMs), haloacetonitriles (HANs) and haloacetic acid (HAAs) were $32.2{\mu}g/L$, $2.97{\mu}g/L$, and $16.29{\mu}g/L$, respectively. The concentration of chloroform was $28.4{\mu}g/L$ corresponding to 88.1% of the THMs. The concentration of HANs and HAAs were found to be inconsiderable. The average residual chlorine concentration of sewage effluent was 0.4 mg/L, the generation concentration of THMs was maximum $1.72{\mu}g/L$ and average $2.79{\mu}g/L$. HANs and HAAs were under the detection limit by GC/MSD.
하수처리장 방류수의 염소 소독효율과 소독부산물 발생 특성에 대해 고찰하였다. 총대장균군의 소독효율을 조사한 결과 99% 이상의 소독 효율을 얻기 위해서는 0.5 mg/L에서는 30분, 1.0 mg/L에서는 20분, 1.5 mg/L이상의 농도에서는 10분의 접촉시간이 필요한 것으로 나타났다. 염소주입농도 0.5 mg/L에서 10분간 접촉시킬 때 THMs의 최대 농도는 $32.2{\mu}g/L$이었으며, 이중 chloroform은 최대 $28.4{\mu}g/L$가 생성되어 THMs의 88.1%를 차지하였다. HANs의 최대 농도는 $2.97{\mu}g/L$이었으며, HAAs의 최대 농도는 $16.29{\mu}g/L$로 상당히 낮게 나타났다. 연구대상 하수처리장 최종 방류수의 연평균 잔류염소 농도는 0.4 mg/L이었으며, 염소소독부산물 실험 결과 THMs은 최대 $9.21{\mu}g/L$, 평균 $2.79{\mu}g/L$로 나타났으며 HANs과 HAAs는 검출한계 이하로 나타났다.
