Treatment of domestic wastewater using microfiltration for reuse of wastewater

This study was conducted to evaluate the applicability of microfiltration i n treating domestic wastewater for reuse. A hollow fiber microfiltration me mbrane was used in the pilot test. The pore size of the membrane was 0.1 mu m and effective surface area was 20 m(2). The maximum capacity of the pilo t plant was 10m(3)/d. The microfiltration system could be operated for 120 days without any cleaning procedure. It was found that agitation in the mem brane tank had an effect on fouling prevention. In particular, the bi-direc tional agitation significantly reduced fouling. Chemical cleaning was effec tive in recovering of permeate flux and resistance, but in spite of chemica l cleaning, fouling slowly progressed. According to the particle size distr ibution, in the membrane tank particles were transformed into smaller size by agitator-induced shear force. Based on mass balance analysis, about 60% of dissolved TOC mass removal in the system was attributed to biodegradatio n, indicating its important role. But suspended solids and colloidal matter were removed by the sieve mechanism of the membrane. Effluent quality was found to be lower than 30 mg/L of GOD, 10 mg/L of BOD, 10 mg/L of TOC, 1 NT U of turbidity and 2 mg/L of SS, respectively. It satisfies the standard fo r wastewater reuse.