Membrane Fouling Study In Submerged Membrane Bioreactors By Addition Of Powdered Activated Carbon And Aerobic Granular Sludge

The membrane bioreactor (MBR) is commonly regarded as a promising technology for wastewater treatment with the advantage of simultaneous pollutants biodegradation and solid-liquid separation in a compact reactor.However, membrane fouling is a major obstacle for the application of MBRs since it cause a decline in permeate flux and/or an increase in trans-membrane pressure (TMP), loss of permeate quality and deterioration of the membrane. This study hence aims at investigation of comparative methods for controlling membrane fouling with addition of powdered activated carbon (PAC) and aerobic granular sluge into submerged membrane bioreactors (SMBR). TMP and extra polymericl substance (EPS) were monitored as indicators of fouling throughout study.PAC addition into SMBRs has shown significant improvement of fouling at 2g/L PAC with 120-200 mesh size which are considered as optimal PAC dosage. The fouling was controlled as low as 40% dP/dt (dTMP/dt) compared with conventional MBR system without PAC. The EPS concentrations also found lower under PAC adding condition since their concentration from the sludge mixture and membrane surface has shown less 48.58% and 49.02% values, respectively compared to conventional MBR. The effluent quality could be slightly improved by the addition of PAC in terms of effluent COD and NH4+-N, which were improved by 2% and 5.39% respectively.TMP and EPS were also monitored under different MLSS concentration at 5000 mg/L and 10000 mg/L with the optimal PAC concentration and size. The results showed that with the increase of MLSS from 5000mg/L to 10000mg/L, the EPS concentration was increased and this results in dP/dt increase from 0.667kPa/day to 1.188kPa/day. It proved that the EPS concentration has negative effect on membrane operation which directly propotion to TMP and fouling phenomena.The aerobic granular sludge membrane bioreactor (AGMBR) system was studied to understand its fouling condition with EPS concentration. The introduction of aerobic granular sludge can effectively reduce the membrane fouling rate as the dP/dt value was 39% less than in conventional MBR. The effluent quality was also improved compared with the conventional MBR system.