Enhancement of Microbial Function for a Sulfur Redox Cycle Action in a Sewage Treatment Process Combining an UASB and an Aerobic Filter Reactor

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The objective of this research is to make a novel wastewater treatment process activated by a sulfur-redox cycle action of microbe in low temperature conditions. This action is carried out by sulfate-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB). The reactor system was comprising of an UASB reactor as pre-treatment and an aerobic downflow hanging sponge (DHS) reactor as post-treatment. As the results of reactor operation, the whole process achieved that over 90% of CODcr removal efficiency, less than 35mg-CODcr/L (less than 20mg-BOD/L) of final effluent, at 12hr of HRT and at 8℃ of UASB reactor temperature. As the result of the effect of temperature methane-producing activity (MPA) and sulfate-reducing activity (SRA) of sludge retained in the UASB reactor, below the 25℃ condition, SRA was greater than MPA from acetate and H2/CO2 as test substrate. And that MPA was all but destitute at 15℃, SRA was certain despite at 5℃. The proposed sulfur-redox action process was considered as an applicable process for low strength wastewater treatment in low temperature conditions.The combined system was also applied for low temperature treatment of deicing fluid wastewater. The whole process achieved over 90% of CODcr removal efficiency with less than 30mg-CODcr/L in the final effluent, at an operating temperature of 8 -C and at an HRT of 12h. In UASB sludge, Acetobacterium sp. and Desulfobulbus sp. were found to be predominant species as the relative abundance to DAPI-stained total cells was 10% and 14%, respectively.