| Abstract |
| It is not easy to find reasonable area for construction of wastewater treatment facility, and biological treatment such as a conventional activated sludge process can`t remove non-point source pollutant in initial rainfall, sufficiently. So if we use bio-physical treatment as pre-treatment and disinfection process, combined sewer overflows don`t cause significant pollution. First of all, we thought the site can be reduced by the reduction of HRT(hydraulic retention time). In this study, to reduce HRT of wastewater treatment facility, the rapid biofilter clarifier was cofigurated and its characteristics were analyzed according to the velocity of filtration and cycles of backwash. Specific characteristics of the rapid biofilter clarifier with 50 ㎥/d of volume were represented that Turbidity and SS removal rate was 30.2%, 30.9% respectively, and that of BOD and COD was 22.0%, 21.0% without regard to change of quality of raw water. By comparing the rapid biofilter clarifier and sedimentation of conventional activated sludge process with haveing 50㎥/㎡· of surface-loading rate and 2.0m of depth, we could know the rapid biofilter clarifier could reduce area of clarifier 11 times as much than that of conventional activated sludge process. Cycle of backwash was represented as 24, 18 and 24 hours when velocity of filtration was 222㎥/㎡·d, 333㎥/㎡·d and 555㎥/㎡·d, and BOD, SS biologically removed in the rapid biofilter clarifier was 342.80, 346.82 g/d, 258.08, 222.72 g/d, and 142.36, 136.52g/d respectively. |
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| Key Words |
| Pretreatment, Biofilter, Sedimentation, HRT, CSOs |
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