Evaluation of the Anaerobic Treatment of Sewage Below 20℃ by Novel Processes

概要

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Estimations of running costs revealed that anaerobic treatment of sewage at less than 20℃ was more economical than aerobic treatment. An anaerobic fludized-bed reactor (AFBR) and an upflow anaerobic sludge blanket(UASB) were applied to the anaerobic treatment of sewage at 20℃. Even at a hydraulic retention time (HRT) of 6 h, in both cases the quality of the effluent was 5 mg/l of BOD with a TOC removal efficiency of 80%, which would be appropriate for discharge into rivers. However, at an HRT of 3 h, TOC removal efficiency decreased to 70%, while in anactivated sludge process (21℃, HRT 3 h) the TOC removal efficiency was maintained at 83.8%. In order to investigate the effect of temperature on treatment, the temperature was decreased to 13℃ in stepwise fashion at an HRT of 6 h. In both the AFBR and UASB, temperatures above 15℃ did not effect the TOC removal efficiency, but the TOC concentration in the effluent at 13℃ increased to 12.5 mg/l in the AFBR and to 15 mg/l in the UASB. However, at an HRT of 6 h and temperatures above 15℃ as the standard conditions, the quality of the effluent treated anaerobically by the AFBR or UASB was almost the same as that by the activated sludge process (21℃, HRT 6h).
社団法人日本生物工学会の論文
1993-12-25