초록
이 연구의 목적은 SBR 처리장치를 사용하여 pentachlorophenol (PCP)를 함유한 폐수를 처리할 때 활성슬럿지의 대사작용에 미치는 PCP의 독성효과를 시험 분석하는 것이다. 이 연구에서 SBR 처리장치는 두가지 운전주기 1, 2 (8시간과 12시간)와 각각의 운전주기에 대한 두가지 운전조건 (I.II)으로 운전되었다. 운전조권 I은 유입폐수를 일시에 (5분 안에) 반응조에 부가하고 2시간 동안 폭기없이 교반만 하는 것이고, 운전조건 II는 운전조건 I과 똑같은 조건에서 유입폐수를 2시간 동안 서서히 반응조에 부가하는 것이다. 각 반응조의 슬럿지 일령은 15일이었다. 합설폐수가 유입폐수로서 사용되었고, 그것의 COD는 대략 380mg/l의 유입폐수 PCP 농도와 운전구기 2의 처리장치에서, MLVSS 농도는 감소하였고 미생물의 선택성 증가하므로 생태반응의 영역이 줄어 들었다. 또한 SOUR이 증가하므로 활성으럿지가 PCP에 의하여 저해를 받았음을 보여주었고, 활성슬럿지의 침전이 좋지않았다. 운전주기 2의 처리장치에서는 질산화가 거의 이러나지 않았다. 그래서 질산화가 일어나는 시기는 PCP의 저해작용으로 인하여 COD의 제거가 늦어지는 만큼 지체될 것이다. 생물학적인 인 제거는 운전주기 1 운전조건 1 그리고 저농도의 PCP에서 운전되는 처리장치에서 일어났으나 그 과정은 불안정하였고 쉽게 정지되었다. 그러나 준전주기 2, 운전조건 I과 II에서 운전되는 처리장치에서 생물학적인 인 제거는 유입폐수 PCP 농도가 1.0mg/l로 증가할 때까지 안정하게 일어났다. 유입폐수 PCP 농도가 5.0mg/l로 증가했을 때 생물학적 인 제거능력은 정지되었고 쉽게 회복되지 않았다.
The primary objective of this study was to examine the toxic effects of PCP on activated sludge and to analyze its metabolic responses while treating wastewater containing pentachlorophenol (PCP) in a sequencing batch reactor (SBR) system operating under different control strategies. This study was conducted in two phases 1 and 2 (8-hr and 12-hr cycles). Each phase was operated with two control strategies I and II. Strategy I (reactor 1) involved rapid addition (5 minutes to complete) of substrate to the reactor with continuous mixing but no aeration for 2 hours. Strategy ll (reactor 2) involved adding the feed continuously during the first 2 hours of the cycle when the system was mixed but not aerated. During both phases each reactor was operated at a sludge age of 15 days. The synthetic wastewater was used as a feed. The COD of the feed solution was about 380 mg/l. After the reference response for both reactors was established, the steady state response of each system was established for PCP feed concentrations of 0.1 mg/l, 1.0 mg/l, and 5.0 mg/l in SBR systems operating on both 8-hr and 12-hr cycles. Soluble COD removal was not inhibited at any feed PCP concentrations used. At 5.0 mg/l fined PCP concentration and in SBR systems operating on phase 2, the concentrations of MLVSS were decreased; selective pressure on the mixed biomass might be increased, narrowing the range of possible ecological responses; the settleability of activated sludge was poor; the SOURS were increased, showing that the systems were shocked. Nitrification was made to some extent at all concentrations of feed PCP in SBR systems operating on phase 2 whereas in SBR systems operating on phase 1 little nitrification was observed. Then, nitrification will be delayed as much as soluble COD removal is retarded due to PCP inhibition effects. Enhanced biological phosphorus removal occurring in the system operating with control strategy I during phase 1 of this work and in the presence of low concentrations of PCP was unreliable and might cease at anytime, whereas enhanced biological phosphorus removal occurring in the system operating with either control strategy I or II during phase 2 of this work and in the Presence of feed PCP concentrations up to 1.0 mg/l was reliable. When, however, such processes were exposed to 5.0 mg/l PCP dose, enhanced phosphorus removal ceased and never returned.