Student Name: ATHULYA M V
Guide Name: Dr. S Mathava Kumar, Associate Professor, CE, IIT Madras
Project Area: WASTE WATER TREATMENT
Year: 2020 , Duration: 1
The deterioration of water bodies by waste water is one of the major concerns of environmental engineers. Membrane bioreactors (MBRs) are advanced method for treating sewage and also to produce water which is acceptable for reuse purposes. The membrane bioreactor is a combination of activated sludge and membrane separation processes. The need of a secondary clarifier is eliminated through MBR systems by replacing with membranes. The main advantages of MBR is higher HRT provides high quality effluent. The MBRs are especially effective at the biological removal of ammonia and total COD. A semi permeable membrane is placed into an aeration tank and wastewater pulled up by the suction pump enters inside the membranes and leaves the Mixed Liquid Suspended Solids (MLSS) inside the aeration tank. Membrane filtration removes biological pollutants, particulate materials and colloids, turbidity, microorganisms, suspension impurities and some elements. Membrane fouling is a major threat for MBR which significantly reduces membrane performance and lifespan.
The study focussed on the treatment of domestic waste water by using the membrane bioreactor. A 22.4L of MBR were setup for treating synthetic wastewater at different hydraulic retention times (HRT) of 24 hr and 12hr.The synthetic waste water having the characteristics of domestic wastewater was made at every run to eliminate the variations in composition. This study aims to investigate the effects of HRT on reactor performance. A comparative analysis was carried out for physiochemical quality parameters such as COD, NH3-N and nitrates. A batch study was also carried out to determine the nitrification rate.The protein concentration assay conducted for MLSS and outlet to determine the efficiency of membrane to retain the protein in the reactor tank. The importance of backwashing in the membrane performance to reduce the transmembrane pressure (TMP) is also discussed in this study. A satisfactory organic removal was obtained throughout the study. Around 95% COD removal obtained at 24hr HRT. The optimum HRT for nutrient removal and COD removal was 24hr HRT.higher SRT was preferred in MBR due to more active biomass formation and less protein concentration.
Keywords: Membrane bioreactor, transmembrane pressure, ammonia, nitrate, chemical oxygen demand, hydraulic retention time, aeration tank, filtration.
