Microbiological Characterization of Biofilm From Different Immobilization Structures Used in Submersed Aerobic Biofilters in Domestic Effluent Treatment at the City of Joinville, Brazil

Abstract

Abstract The objective of this work was to develop a structure for microbiological immobilization, in polymeric material of low environmental impact associated with its production, being used as support material in a biofiltration unit of domestic effluents, capable of promoting the efficient removal of pollutants, to meet with Brazilian legislation and/or regulations for the disposal and/or reuse of effluents. Four different structures were tested, namely: polypropylene casings without filling material (TF1); polypropylene casings, filled with expanded polystyrene grains (TF2); polypropylene casings, filled with polyurethane foam (TF3); polypropylene casings, filled with polyvinyl chloride pellets (TF4). A flow of 0.216 m3.d-1 was applied to the system, and the biofilters operated in sequential batches with a hydraulic retention time of 6 hours. The efficiency potential of the four immobilization structures was verified regarding the parameters biochemical oxygen demand, chemical oxygen demand, total ammoniacal nitrogen and total phosphorus. The microbiological analysis of the formed biofilm, performed with the 16S library sequencing method, with amplification of the 16S rRNA V3 and V3-V4 genomic regions, showed a high diversity of microbiological colonization in the four immobilization structures, linking better results and consequently greater Community stability in TF2. It is recommended to use the filter bed made up of unfilled casings, followed by the filter bed made up of casings filled with expanded polystyrene grains.