하수처리수 재이용을 위한 직접모래여과와 UF 막 공정의 적용

Abstract

The object of this study was application of direct filtration and UF membrane process to secondary effluent treatment for reuse. The turbidity of secondary effluent is less than 10 NTU and constant, so direct filtration was used without sedimentation. Filter media was used sand(Effective Size : 0.44, Uniform Coefficient : 1.26) and anthracite(Effective Size : 1.02, Uniform Coefficient : 1.26). Filter bed was composed monomedia and dual media. Dual media was more effective than monomedia. Optimum coagulant dosage was 40mg/l(jar-test) and 60mg/l(direct sand filtration). At the optimum coagulant dosage in order to know the effect of slow mixing intensity to filtration slow mixing is performed at various mixing intensity. 30RPM slow mixing intensity has good filtered effluent. Low filtration rate(7m/h) was more effective than high filtration rate(10m/h). Regenerated cellulose membrane was used for UF membrane. The coagulant dosage and slow mixing intensity was considered to affect membrane flux. 45RPM slow mixing was more effctive than 30RPM. At the UF filtration, pretreatment using coagulation improved to flux. The optimum process was selected by considering direct filtration and UF membrane filtration. When these process was used for pretreatment of reverse osmosys, the SDI(silt density index) was estimated. For Reverse osmosis, pretreatment using UF membrane was necessary.