소독제 농도, pH, 온도, 암모니아 농도, 부유물질이 강우 월류수 염소 소독에 미치는 영향

Abstract

The treatment of combined sewer overflow (CSO) is one of potential concerns in domestic wastewater treatment in Korea due to the pre-announce of CSO regulations. This work investigated the effects of disinfectant (NaOCl) concentration (0.11 to 4.0 mg Cl2/L), pH (6.5 to 8.0), temperature (15 to 25°C), ammonia (10 to 41 mg N/L), and suspended solids (91 to 271 mg SS/L) on the chlorine disinfection of CSO. The effect of NaOCl concentration on the pseudo-1 order reaction rate for total coliform inactivation was described well with a saturation-type model with the half-velocity constant of 1.212 mg/L. The total coliform inactivation reaction rate decreased with SS and pH, and increased with temperature. Ammonia in the examined range did not affect the disinfection kinetics. A chlorine contact tank with the injection chlorine level of 1 mg Cl2/L and the hydraulic retention time of 1.25 min is estimated to reduce total coliform from 1 × 10 MPN/mL to 1,000 MPN/mL at 271 mg SS/L, 15°C, and pH 8.0. Chlorine would be a proper option for the disinfection of CSO.