Application of low-density electric current to performance improvement of membrane bioreactor treating raw municipal wastewater
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The main objective of this study was to investigate the effect of low-density electrical current application on the performance of a laboratory-scale membrane bioreactor (MBR) treating municipal wastewater. The MBR operation was divided in two experimental runs: without (run I) and with electrocoagulation process (run II). The results demonstrated that the use of electrocoagulation process was beneficial for organic matter and nutrient removal, enabling the average removal efficiencies for COD, NH4+–N and PO43−–P of 98.5, 99.8 and 99.2%, respectively. Despite the decreasing of MLVSS/MLSS ratio during the period with electrocoagulation, both autotrophic and heterotrophic biomass activities have increased. Data from the 16S RNA genetic sequencing showed that the electric current application affected the nitrifying bacteria population, specially the genre Nitrospira, which exhibited a significant increase in its relative abundance. Such behavior probably occurred due to electrostimulation phenomenon that can improve microbial metabolism and increase cell growth. These results demonstrate that the electric currents application can improve the MBRs performance on wastewater treatment.
KeywordsElectrocoagulation Electrostimulation Microbial community composition Biomass activity Phosphorus removal
The authors would like to acknowledge the Brazilian National Council for Scientific and Technological Development (CNPq) and Coordination of Superior Level Staff Improvement (CAPES) for their financial support.
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