This study aimed to investigate the feasibility of improving dewaterability and settleability of sewage sludge using coagulation sludge. When mixed with sewage sludge and coagulation sludge at 1:1 ratio, capillary suction time(CST) and specific resistance to filtration(SRF) decreased by about 56% and 68%, respectively. It is found that total solids(TS) and volatile solids(VS) of mixing sludge are increased by about 59% and 53%, respectively. Also, the turbidity of the mixing sludge supernatant was reduced from 99 to 16 NTU. It is observed that the mixing of sewage sludge and coagulation sludge at 1:1 showed better effect than using poly-aluminum chloride(PAC) coagulant at 25 mg/L.

This study investigated phosphorus removal from secondary treated effluent using coagulation-membrane separation hybrid treatment to satisfy strict regulation in wastewater treatment. The membrane separation process was used to remove suspended phosphorus particles after coagulation/settlement. Membrane separation with 0.2 μm pore size of micro filtration membrane could reduce phosphorus concentration to 0.02 mg P/L after coagulation with 1 mg Al/L dose of polyaluminum chloride (PACl). Regardless of coagulant, the residual concentration of phosphorus decreased as the dose increased from 1.5 to 3.5 mg Al/L, while the target concentration of 0.05 mg P/L or less was achieved at 2.5 mg Al/L for the aluminum sulfate (Alum) and 3.5 mg Al/L for PACl. Moreover, alum showed better membrane flux as make bigger particles than PACl. Alum showed a 40% of flux decrease at 2.5 mg Al/L dose, while PACl indicated a 50% decrease of membrane flux even with a higher dose of 3.5 mg Al/L. Thus, alum was more effective coagulant than PACl considering phosphorus removal and membrane flux as well as its dose. Consequently, the coagulation-membrane separation hybrid treatment could be mitigate regulation on phosphorus removal as unsettleable phosphorus particles were effectively removed by membrane after coagulation.

혐기성 MBR은 에너지 소비가 높은 기존 호기성 처리를 대체할 수 있는 에너지 중립형 기술로서 최근 하폐수 처리의 차세대 기술로 주목받고 있다. 혐기성 MBR은 다양한 장점을 가지고 있지만, 분리막 파울링은 해결해야하는 과제이다. 따라서 본 연구에서는 막 파울링 억제를 위하여 섬유볼 미디어와 회전판을 이 용하여 혐기성 MBR의 막 파울링을 제어하였다. 혐기성 MBR을 이용하여 저농 도의 유기물 부하 조건에서 안정적인 처리수질을 보였으며, 유기물 부하가 높을 수록 높은 메탄가스 생산량을 보였다. 이를 토대로 혐기성 MBR의 적용에 효율적일 것으로 보이는 고농도 폐수의 처리 가능성 확인하기 위하여 음폐수를 대상으로 혐기성 MBR의 처리 특성을 살펴보고 고효율 혐기성 MBR 기술의 에너지 자립의 가능성을 평가하였다.