[Microbial Community Structure Analysis of Activated Sludge in Chinese Biological Sewage Wastewater Treatment Processes].

Abstract

As a widely investigated issue in sewage treatment, the efficient and stable removal of carbon, nitrogen, phosphorus, and other pollutants is the ultimate goal of biological wastewater treatment process control and optimization. A microbial community with reasonable composition and distribution and a dynamic response to changes in important control parameters is the key to achieving this goal. After sampling 19 typical sewage treatment processes in six large cities in China during summer and winter, the results of MiSeq high-throughput sequencing and the Microbial Database for Activated Sludge（MiDAS）comparison and classification showed that the core communities in Chinese sewage treatment processes were significantly similar： 29 genera could be observed in all 38 samples, while 1 901 genera were found in 1 or a few （n<10） processes； the abundance of high-frequency genera was high, whereas the abundance of low-frequency genera was relatively low, with 286 genera, numbering only 10% of all species, accounting for up to 80% of the total cumulative abundance. Among the dominant genera in the core community, the carbon removal populations were mainly dominated by anaerobic fermentation and aerobic/anaerobic heterotrophic bacteria, such as Bacillus and Lysinbacillus, which have strong survivability in various environments； the anaerobic fermenters Intestinibacter and Thermomonas, which are characterized by the function of substrate fermentation and parthenogenetic anaerobic fermenters Entercoccus； aerobic/anaerobic heterotrophic Ferruginibacter, IMCC26207, and Hyphomicrobium； Rhodoplanes, Ottowia, and Iamia with a denitrification function； Paracoccus with suspected denitrification function； and other functional genera. The abundance of these most dominant genera could be altered to a certain extent by process form, changes in influent quality, and seasonal temperature variations. The nitrifying genera were mainly composed of Nitrosomonas and Nitrospira； Rhodobacter and Paracoccus were the main dominant denitrifying functional genera in the processes； Tetrasphaera was widely distributed in the processes as a dominant polyphosphate-accumulating genus； the polyglucogenic-accumulating genera were dominated by Candidatus_Competibacter and Defluviicoccus； and the dominant genera of filamentous bacteria were Candidatus_Microthrix, Candidatus_Promineofilum, and Trichococcus. Although the geographic distance between the sampled processes in China was more than 1 000 km and the operational parameters were not the same, especially with Denmark being located on a different continent, it was again verified that the core community was widely present in the activated sludge of the sewage treatment process and had similar composition and ecological functions.