Maintaining adequate residual chlorine concentration is an important criteria to provide secure drinking water. The chlorine decay can be influenced by unstable flow due to the transient event caused by operation of hydraulic devices in the pipeline system. In order to understand the relationship between the transient event and the chlorine decay, the probability density function based on the water demand curve of a hypothetical water distribution system was used. The irregular transient events and the same number of events with regular interval were assumed and the fate of chlorine decay was compared. The chlorine decay was modeled using a generic chlorine decay model with optimized parameters to minimize the root mean square error between the experimental chlorine concentration and the simulated chlorine concentration using genetic algorithm. As a result, the chlorine decay can be determined through the number of transients regardless of the occurrence intervals.

ABSTRACT
 1. 서 론
 2. 연구방법
  2.1 가상의 물 수요곡선에 근거한 확률밀도함수
  2.2 실험적 조건
  2.3 염소 감쇄 모델
 3. 결과 및 고찰
  3.1 수충격 발생 소개 및 염소농도 감쇄 결과
  3.2 염소 감쇄 매개변수의 최적화 결과
 4. 결 론
 기호 설명
 사 사
 References

• 백다원(부산대학교 환경공학과, Department of Environmental Engineering, Pusan National University) | Dawon Baek
• 김현준(부산대학교 환경공학과, Department of Environmental Engineering, Pusan National University) | Hyunjun Kim
• 김상현(부산대학교 환경공학과, Department of Environmental Engineering, Pusan National University) | Sanghyun Kim Corresponding author