호기성 생물막을 이용한 HRT 변화에 따른 오염물질 제거

Abstract

In this study, an experiment was conducted on influent water with low concentrations of organic matter, such as river water or secondary treatment water of a sewage treatment plant, according to HRT changes by using aerobic biofilm. In the biofilm process, as the biofilm increases in thickness, the inner membrane can be low in oxygen transfer rate and become anaerobic conditions, while the detachment of biomass from biofilm occurs. To overcome these limitations in the detachment of microorganisms in biofilm, the yarn, which was made from poly propylene(PP), was weaved and manufactured into a tube. Then, a test was carried out by injecting air so that the interior of the biofilm could create aerobic conditions. The results of the experiment showed that the removal efficiency of <TEX>$TCOD_{cr}$</TEX> reached 66.1~81.2% by HRT 2hr, and 50.9 ~61.8% after HRT 1 hr. The removal efficiency of <TEX>$SCOD_{cr}$</TEX> was 45.9 to 55.1% by HRT 1hr, and 26.1% in HRT 0.5hr, showing the highest removal efficiency in HRT 1hr. The SS removal efficiency was at 81.8 to 94.6%, and the effluent SS concentration was very low, indicating less than 2.2 mg/L in all HRT's. As a result, the <TEX>$SCOD_{cr}$</TEX> and <TEX>$NH_4{^+}$</TEX>-N that were removed per specific surface area and attached to microbial biofilm showed the highest efficiency in HRT 1hr with 8.37 <TEX>$gSCOD_{cr}/m^2{\cdot}d$</TEX>, 2.93 <TEX>$gNH_4{^+}-N/m^2{\cdot}d$</TEX>. From the result of reviewing the characteristics of biofilm growth, microorganisms were found to be attached, and increased by 36 days. Later, they decreased in number through detachment, but showed a tendency to increase again 41 days later due to microbial reproduction.