Since a substantial portion of pollutants in municipal sewage is associated with particulates, enhancing the particulate removal for the primary treatment of municipal sewage provides a possible solution to the high cost and space problems for the existing secondary sewage treatment systems. This study proposed a novel and economical sewage filtration process with non-woven filtering material to enhance the primary treatment, thereby reducing the cost and space for the secondary treatment significantly....[ Read more ]

Since a substantial portion of pollutants in municipal sewage is associated with particulates, enhancing the particulate removal for the primary treatment of municipal sewage provides a possible solution to the high cost and space problems for the existing secondary sewage treatment systems. This study proposed a novel and economical sewage filtration process with non-woven filtering material to enhance the primary treatment, thereby reducing the cost and space for the secondary treatment significantly.

The objectives of this study were to develop a low-cost non-woven membrane module for direct filtration of raw sewage and to investigate its feasibility to replace the conventional primary sedimentation tank in primary treatment. Different non-woven membrane modules were investigated for their capabilities in enhancing the primary treatment. The selected module was then examined with various permeate flux rates under different batch filtration conditions. It was found that the developed membrane module could achieve better effluent quality than those of conventional primary treatment. The average removal efficiencies for suspended solids (SS) and 5-day biochemical oxygen demand (BOD₅) were 70 and 47 %, respectively. When a coagulant (Ferric Chloride, FeCl₃) was dosed at 10 mg/L, the hydraulic condition was found to be important for a stable performance of the membrane. The optimum G value inside the flocculation tank was found to be 27 s^-1 while the removal efficiencies for SS, total and particulate BOD₅ were more than 90, 60 and 81 %, respectively, which were comparable to the performance of chemically enhanced primary treatment (CEPT).