Start up of the EGSB reactor under the condition of poor nutrition and Microbial community analysis by next generation sequencing

Abstract

The objective of this study was to investigate the successful start-up of poor nutrition simulated wastewater with sodium acetate carbon source in an EGSB reactor, and EGSB reactor inoculated the flocculent sludge from the anoxic zone in the municipal sewage treatment plant. The results demonstrated the COD removal efficiency can also achieve more than 80%, even reaching above 95%, when the COD concentration of influent was improved from 200, 500 to 1000 mg/L in the continuous operation of 73 days. Furthermore, the microbial communities of seeding source, sludge samples collected on the 43th day (A1) and at the end of operation (A2) were investigated with the next generation sequences (NGS) tool in the EGSB reactor. Analysis results showed that the microbial diversity decreased. At the bacterial phylum level, there was an apparent increase in relative sequences of Chloroflexi and Euryarchaeota (33.01% and 0.63% in A1, and 44.03% and 7.14% in A2), which was 19.40% and 0.54% in the inoculum. At the genus level, except unclassified genus, Methanosarcina, Clostridium and WCHB1-05 were found to be the main members, whose sum occupied 16.13% and 18.41% of the total sequences in A1 and A2, respectively.