Structure and function of the microbial consortia of activated sludge in typical municipal wastewater treatment plants in winter

To better understand the relationship between the environmental variables and microbial communities of activated sludge, we took winter samples from different biological treatment units (anaerobic, oxic, etc) from the WWTP's of a number of Chinese cities. Differences in influent organic components and activated sludge microbial communities were identified by gas chromatography-mass spectrometry and high-throughput sequencing technology, respectively. Liquid nitrogen grinding pretreatment of samples was found to aid in the obtaining of a more bio-diversified sample. Influent type and dissolved oxygen concentration influenced the activated sludge microbial community structure. Nitrospira, Caldilineaceae and Anaerolineaceae were highly related to domestic wastewater treatment systems, whereas Thauera was the most abundant putative refractory aromatic hydrocarbon decomposer found in industrial wastewater treatment systems. Within the influent composition, we speculate that Thauera, Macellibacteroides and Desulfomicrobium are the key functional genera of the anaerobic environment of the textile dyeing industry wastewater treatment systems, whilst Thauera and Thiobacillus are key functional microbes in fine chemical wastewater treatment systems.