Study on Fouling Behavior and Treatment Performance of Flat Sheet Woven Fiber Microfiltration (WFMF) Membrane

Abstract

Woven-fiber microfiltration (WFMF) membrane was investigated as onsite treatment technology for water and wastewater treatment. In this regard, flat sheet woven-fiber microfiltration (WFMF) membrane was submerged in septic tank as membrane based septic tank (MBST) for wastewater treatment. Objective was to reduce fouling frequency and prolong filtration time by operating laboratory scaled MBST at three filtration-relaxation modes (FRM) of 30min-10min, 45min-15min and 60min-20min corresponding to 36, 24 and 18 cycles/day, operated at 8 LMH flux. The average fouling rate (dTMP/dt) was found to be 17, 10 and 15 kPa/day respectively. Results revealed that 45min-15min to be optimum FRM while the variation in removal efficiencies of COD, TSS and NH4-N was 55-78, 60-85 and 30-40% respectively. Flat sheet WFMF membrane was also evaluated for water treatment having turbidity 25±5, TSS 200±50 and fecal coliform 120±20 using optimized FRM. The removal efficiencies for turbidity, TSS and fecal coliform were 78-89, 56-65 and 92-99% respectively. The treated water needed further disinfection to be within limits of WHO drinking water quality standard. Physical and chemical cleaning was applied separately on membrane and it was found that pore blockage resistance which caused irreversible fouling may only be controlled by chemical cleaning