For the cost-effective biological nitrogen removal (BNR) process whose characteristics of influent have low COD/N ratios, the automatic control system for the addition of external carbon based on oxidation-reduction potential (ORP) data in an anoxic reactor has been developed. In this study, it was carried out with a pilot-scale Bardenpho process which was consisted of anoxic 1, aerobic 1, aerobic 2, anoxic 2, aerobic 3 tank and clarifier. Firstly, the correlation coefficient (R2) of the dosage of external carbon source and ORP value was about 0.97. Consequently, the automatic control system using ORP showed that the dosage of external carbon source was decreased by about 20% compared with a stable dosage of 75 mg/L based on the COD/N ratio of the anoxic influent.

Abstract
 1. 서 론
 2. 재료 및 방법
  2.1. 실험장치
  2.2. 농도분석 방법
 3. 결과 및 고찰
  3.1. 외부탄소원 주입에 따른 ORP 변화 특성
  3.2. Set-point 제어하에서의 ORP 응답특성
  3.3. set-point 변화에 따른 ORP 응답특성 및 탈질 경향
  3.4. ORP 제어시스템의 응답특성과 NO3--N의 거동
 4. 결 론
 참 고 문 헌

• 신춘환(동서대학교 에너지․환경공학과) | Choon-Hwan Shin (Department of Energy & Environmental Engineering, Dongseo University) Corresponding author