The effect of the variation of aeration time on the removal of organics, nitrogen and phosphorus using synthetic wastewater was investigated in sequencing batch reactors (SBRs) which included DNPAOs and DNGAOs. The cycling times in four SBRs were adjusted to 12 hours and then included different aerobic times as 1 hr, 2.5 hr, 4 hr and 5.5 hr, respectively. Four SBR systems have been operated and investigated for over 40 days. Average TOC removal efficiencies were about 71 % in all SBRs. The NH_4^+-N removal efficiency was increased as the increase of aeration time. After changing aeration time, the total nitrogen removal efficiencies of SBRs were shown as 35 %, 85 %, 75 % and 65 %, respectively. Higher phosphorus release and uptake were occurred as the decrease of the aeration time. After all, the overall phosphorus removal efficiency decreased and the deterioration of phosphorus removal was occurred when aeration time was over 4 hr. Denitrification in aerobic conditions was observed, which showed the presence of DNPAOs and DNGAOs. In batch experiments, PAOs were shown as the most important microorganisms for the phosphorus removal in this experiment, and the role of DNGAOs was higher than that of DNAPOs for the nitrogen removal.

Abstract
 1. 서 론
 2. 재료 및 방법
  2.1. 실험재료
  2.2. 실험 및 분석방법
 3. 결과 및 고찰
  3.1. 초기 BNR 슬러지의 특성
  3.2. 포기시간 변동에 따른 유기물 제거 변화
  3.3. 포기 시간 변동에 따른 질소제거 변화
  3.3. 포기 시간 변동에 따른 인 제거 변화
 4. 결 론
 참 고 문 헌

• 정노성(대구가톨릭대학교 환경과학과) | Nosung Jeong (Department of Environmental Science, Catholic University of Daegu)
• 김동석(대구가톨릭대학교 환경과학과) | Dongseog Kim (Department of Environmental Science, Catholic University of Daegu) Corresponding Author
• 박영식(대구대학교 보건과학부) | Youngseek Park (University of Daegu, Gyeongbuk 712-702, Korea)