engleski

Municipal wastewater treatment in membrane bioreactor

Municipal wastewaters are often treated biologically, such as by the activated sludge process, using microorganisms for degradation of organic pollutants. Membrane bioreactors (MBRs), in which membranes are applied to biological wastewater treatment for biomass separation, provide many advantages over conventional treatment. These include minimum sludge wastage and reduced plant size by maintaining a high biomass concentration in the reactor as well as elimination a secondary sedimentation tank. Development of new vacuum driven immersed membranes with reduced energy consumption lead to increased usage of MBR technology in municipal wastewater plants. Performance of MBR equipped with an immersed hollow fibre membrane for municipal wastewater treatment was investigated as well as growth and decline of microbial population depending on amount of available substrate. MBR removed more than 92% COD present in the wastewater and more than 98% present BOD along with very stable denitrification. A very low excess sludge production was also achieved with sludge concentration stabilised for certain feed to microorganism ratio. In cultivation without any feed, decrease of floc size was observed, with rate of suspended solids decrease of 0.38-0.58 g L-1 day-1 while keeping nitrifying activity and satisfactory level of specific respiration of the activated sludge. Microscopic examinations of activated sludge and total number of living microorganisms helped to assess the condition of the biomass in an aeration basin.

municipal; wastewater; membrane; bioreactor

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