섬유상 여재 압축여과기술을 이용한 강우유출수의 부유물질 제거

Different pore sizes (15, 30, 45, and 60 PPI [pore per inch]) of polyurethane (PU) filter media were selected, and the corresponding filtration characteristics were investigated using the filter media layer pressing technology. The effects of pore size and filter layer height on the removal efficiency of suspended solids were evaluated. At a filtering linear velocity of 20 m/h, the head loss during no-load flow decreased with increasing pores per linear inch (15, 30, 45, and 60 PPI) and increasing compression ratios (0%, 17%, 33%, 50%, and 67%) of the PU foam filter. For each combination of 45 PPI and 60 PPI at 1:1, the average headloss during no-load flow was 79.6 mm, and the best removal efficiency of suspended solids was 86.2% on average at a compression ratio of 67%. As the PU media was compressed, the porosity decreased, thereby aiding the capture of more suspended solids within the filter. To determine the optimal backwashing conditions for the PU filtration system, experiments were conducted with different air injection times. The mean recovery rate of PU media filtration exceeded 99.9% when water washing was performed at 3.0 m3/m2·h for 25 min and air flow was injected at 180 m3/m2·h for 15 min. The results of the pressing filter system using PU media for non-point pollution removal met the regulations of the Ministry of Environment.