Abstract
BACKGROUNDThis 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.
RESULTSHigh-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 degrees 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 abundantly found in individual biofilm samples, like Brevundimonas (17.1%), Chitinimonas (10.3%) and Roseateles (39.3%), at 10, 20, and 30 degrees 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 noteworthy BOD removal (66.6%) was shown by PP-FBRs operating at 30 degrees C, compared with 20 degrees C (28.3%) and 10 degrees C (28.8%),consistent with the DO levels recorded in the effluents, highest at 30 degrees C (70.5%), and decreasing with declining temperatures. Substantial wastewater treatment efficiencies were observed in the reactors at 30 degrees C, attributable to the higher relative abundance and diversity of microbial biofilms.
CONCLUSIONSThe 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. (c) 2018 Society of Chemical Industry