Hetrotrophic bacterial community assembly in two pilot and eight full-scale activated sludge wastewater treatment plants. wastewater metagenome

Abstract: Heterotrophic bacterial community assemblies at eight full-scale and two pilot scale activated sludge wastewater treatment plants (AS-WWTPs) were determined by high-throughput pyrosequencing of 16S rRNA gene amplicons. A total of 39 samples covered a range of abiotic factors spread over space and time (referred to as environmental gradients) and obtained over a period of 4 years. The impact of environmental gradients on the community assemblies in AS-WWTPs, partitioned with respect to distances in position on the ecological gradients. Following gradients were considered specifically,: • Influent wastewater characteristics, • Seasonal variations (winter vs. summer) • Treatment process differences (conventional, oxidation ditch, and sequence batch reactor [SBR]) • Reactor sizes (pilot-scale vs. full-scale reactors) • Chemical stresses defined by a higher mortality induced by return activated sludge (RAS) ozonation (RAS-ozonated vs. non-ozonated reactors) • Inter-annual variation and geographical locations.