Hybrid type 반응조에서의 혐기성 슬러지의 탈질 (1) : 초산을 기질로 사용한 경우

Abstract

In this study, it was attempted to remove nitrate and carbon in a single-stage reac-tor using acetate as substrate. Hybrid type upflow sludge baffled filter reactor was adopted using anaerobic sludge. Sludge bed in the bottom of reactor was intended to remove carbon and nitrate by denitrafication and methanogenesis. Asd floating media in the upper part of reactor were intended to remove remaining carbon which was not removed due to the inhibition of nitrogen oxide on methane producing bacte-ria. The reactor removed over 96% of COD and most of nitrate with volumetric loading rate of 4.0 kgCOD/㎥ ㆍday, hydraulic retention time of 24hr, 4.000mgCOD/L,and 266 mgNO3-N/L. Nitrate in anaerobic sludge was converted to nitrogen gas(denitrifi-cation) or ammonia (ammonification) according to pH of influent. COD removal effi-ciency was easily affected by the change of volumetric loading rates and nitrate con-centration. And when influent pH was about 4.7, most nitrate changed to ammonia while when influent pH was about 6.8~7.0, most nitrate denitrified independent of COD/NO3-N ratio. Most granules were gray and a few were black. In gray-colored granule, black inner side was cowered with gray substance and SEM illustrated Methanoccoci type microorganisms which were compact spherical shape. Anaerobic filter removed residual COD effectively which was left in sludge bed due to the inhi-bition of nitrogen oxide