| Abstract | Water pollution has become a serious issue worldwide, especially in developing countries. Continuous discharge of domestic and industrial wastewater into surface water has led to an increase in organic pollution. This brought immense pressure to the conventional drinking wat er treatment plants, as surface water is one of the main water sources for human beings. Organic matters can be considered as substrates for microbes, thus biological process has the potential to be an effective technology. Membrane bioreactor (MBR) which integrated biodegradation and membrane rejection into one system could be an attractive method. Based on which, this study developed an attached growth membrane bioreactor (aMBR) system to treat polluted surface water. In phase I of this study, aMBR syst em was built up, operated, optimized and analyzed. In preliminary test I, suitable bio carrier between APG and PVA gel was selected. In preliminary test II, suitable filling ratio was selected. After that, aMBR system were operated and compared in vari ou s HRT and filling ratio. aMBR system with PVA gel as bio carrier in 5 % filling ratio, with a HRT 2.5 h was selected as a best operation condition. It was able to provide over 50 % COD Mn removal, 20 % UV 254 removal, 97 % NH 3 N and Turbidity removal. It has l owest membrane fouling as compared to other operation conditions. Organic accumulation rate and nitrogen balance analysis between aMBR and MBR indicated that: (1) aMBR carrier side attributed to majority part of biodegradation in the system, (2) nitrification and denitrification has taken place in PVA gel (3) Membrane fouling was largely mitigated in aMBR system (4) Modified Stover Kincanoon model was a ble to describe and predict COD Mn removal in aMBR system. aMBR system can remove 50 % of COD Mn from polluted surface water with COD Mn 10 mg/L, around 3 5 mg/L of COD Mn was remaining, most of which were recalcitrant . To improve the organic matter removal, UV/O 3 reactor was integrated into aMBR system as a polishing step in recirculation stream. In phase II of this study, UV/O 3 aMBR system was operated, optimized and analyzed. O 3 concentration 1.5 mg/L and contact time 7 minutes was selected based on BDOC t est. Removal performance under recirculation ratio varies from 20, 40, 60 and 80 % were compared . Results indicated that 60 % recirculation ratio was able to provide permeate water with COD Mn less than 2 mg/L, UV 254 around 0.04 cm 1 , color 0.002 cm 1 , and NH 3 N 0.2 mg/L. UV/O 3 integration has largely improved the organic matter removal in the system. FEEM analysis shown that higher amount of FDOM was removed in UV/O 3 aMBR as compared to aMBR system; UV/O 3 process c an reduce recalcitrant and improve the trea ted water biodegradability. Biokinetic study results indicated that microbes on PVA gel enter endogenous respiration after 0 h aeration in UV/O 3 aMBR and 6 h aeration in aMBR system. Orbitrap MS was used for molecular characterization of low molecular weight dissolved organic matter changes in parallel UV/O 3 aMBR and aMBR system. 2340 molecular formulae including CHO, CHON, CHOS and CHONS class out of total peaks 5743 were identified. UV/O 3 aMBR system has much higher formulae changes including formula e decreased, increased and newly formed, as compared to aMBR system. H i ghest CHO, CHON, CHONS and CHOS decrease were all occurred in the carrier side of both systems. The integration of UV/O 3 process has improved the reaction activity in the UV/O 3 aMBR sys tem. |