선택조가 무산소-호기 MBR시스템 성능에 미치는 영향

초록

Selectors are increasingly being used in full-scale activated sludge plants for bulking control to boost sludge activity. In a pilot-scale plant experiment with existing anaerobic-anoxic-oxic activated sludge processes, an anoxic selector and aerobic membrane bioreactor (MBR) were tested to evaluate the performance of the system in treating domestic wastewater containing night-soil (pH 6.8±0.5, BOD 136.6±33.7 mg/L, COD 91.6±22.6 mg/L, SS 145.9±48.6 mg/L, T-N 35.537±11.045 mg/L). The anoxic-selector-aerobic MBR system had a hydraulic retention time (HRT) of 5.7 h and was submerged with two plate-type membrane modules with an effective pore size of 0.4 um. Consequently, the aerobic MBR process with a selector improved organic and nitrogen removal by 15-20% over systems without a selector. The nitrification and denitrification rates were also 10-15% higher with the selector at a BOD/T-N value of 3.9 and a returned sludge ratio of 1.0Q. The transmembrane pressure (TMP), an indicator of membrane fouling was 10-20% lower in the process with a selector. These results are attributed to the increased activity of the activated sludge due to reaeration in the selector. The reaeration play a important role in transformating a filamentous into a floc formation bacteria.

키워드