Treatment of nitrate-nitrogen-containing wastewater via aerobic denitrifying bacteria using different carbon sources

The effect of different carbon sources was studied relative to the treatment effect of aerobic denitrifying bacteria during the treatment of nitrate-containing wastewater as well as the influence of co-metabolism flora. Three carbon sources, i.e., glucose, citric acid, and sodium acetate, were selected to study the changes in the pH, nitrate nitrogen, chemical oxygen demand removal, nitrite nitrogen concentration, physical and chemical properties of sludge and volatile fatty acids, and high-throughput sequencing to study any changes in flora. The results showed that the denitrification ability of the system using citric acid as the carbon source was stronger than the denitrification ability of the system using glucose or sodium acetate as the carbon source. The removal of nitrate nitrogen in the system was the result of the co-metabolism of acid producing bacteria and aerobic denitrifying bacteria. Due to the greater number of types and greater amount of dominant bacteria in the sludge domesticated and cultured with citric acid as a carbon source, the co-metabolism flora formed was more stable, so it could better remove nitrate nitrogen.