Investigation of the Active Biofilm Communities on Polypropylene Filter Media in a Fixed Biofilm Reactor for Wastewater Treatment

BACKGROUND This research is focused on the effect of temperature on the growth of active biofilms on polypropylene (PP) filter media in aerobic fixed biofilm reactors (FBR) for wastewater treatment. RESULTS High‐throughput sequencing was used to explore the composition and diversity of the microbial community of 14‐days old (starting phase) biofilms grown at 10, 20 and 30°C. Members of the classes Proteobacteria, Bacteroidetes, and Firmicutes were predominant in all the biofilm samples retrieved from PP‐FBRs. A total of 108 genera of bacteria were identified, with some of them present in all three reactors, including Trichococcus, Zoogloea, Aeromonas, Acidovorax, and Malikias, among others. Besides these shared populations, certain genera were abundantlyfound in individual biofilm samples, like Brevundimonas (17.1%), Chitinimonas (10.3%) and Roseateles (39.3%), at 10, 20, and 30°C, respectively. The metabolic capabilities of active microbial communities in PP‐FBRs were estimated by assessing the changes in different variables (BOD, DO, and pH) in the influent and effluent during operation. A note worthy BOD removal (66.6%) was shown by PP‐FBRs operating at 30°C, as compared to 20°C (28.3%) and 10°C (28.8%),consistent with the DO levels recorded in the effluents, highest at 30°C (70.5%), and decreasing with the declining temperatures. Substantial wastewater treatment efficiencies were observed in the reactors at 30°C, attributable to the higher relative and diversity of microbial biofilms. CONCLUSIONS The development of physiologically active biofilms in PP at all prevailing temperatures strongly suggests that the material is suitable to be employed in FBRs for wastewater treatment at different operational temperatures.