Performance and Microbial Community analysis on denitrification of electronic wastewater using various External Carbon Source

Abstract

Objectives:In the biological denitrification process of electronic wastewater, the denitrification performance of various types of external carbon sources and the changes in the bacterial community before and after denitrification were evaluated through NGS analysis.Methods:After selecting 6 types of external carbon sources, the concentration of nitrate nitrogen was analyzed for 6 hours under anoxic conditions with a C/N ratio of 4 to evaluate the denitrification rate, and the changes in the community distribution of bacteria before and after denitrification were confirmed through NGS analysis.Results and Discussion:As a result of comparing the denitrification performance of various external carbon sources, Ethylene glycol(EG) was the best at 79.9% after 6 hours, and the specific denitrification rate(SDNR) was 1.000mg NO<sub>3</sub><sup>-</sup>-N removal/g MLVSS·hr. The bacterial community change using NGS was distributed more than 90% of 10 phylums at the phylum level, and <i>Proteobacteria, Saccharibacteria</i>, and <i>Chloroflexi</i> were dominant, and among them, <i>Saccharibacteria<</i> and <i>Chloroflexi</i> were confirmed to be bacteria contributing to denitrification. At class and genus level, when a external carbon source was added, the number of <i>γ-proteobacteria</i> increased in all experimental conditions, but the distribution of denitrifying bacteria was less than 1.27%, indicating that various bacteria contributed to denitrification. Conclusion:In the case of Ethylene glycol(EG), it is judged that it can be used as an external carbon source, and there was no significant change in the community depending on the type of carbon source injected, and various bacteria such as <i><Saccharibacteria</i> and <i>Chloroflexi</i> contributed to denitrification and eliminated nitrogen pollutants.