[Characteristics of Nitrogen Metabolism by Denitrifying Bacterial Agents in Low Dissolved Oxygen Black Odor Water]

In order to deal with low dissolved oxygen black odor water body of Guangdong-Hong Kong-Macao Greater Bay Area, the nitrogen metabolic capacity of ammoniated bacteria, nitrifying bacteria and denitrifying bacteria under low dissolved oxygen concentration was studied, and the relationship between denitrification efficiency and nitrogen conversion of different bacteria was clarified, which provided theoretical basis for the treatment of black odor water of Guangdong-Hong Kong-Macao Greater Bay Area. Nitrogen conversion characteristics of ammoniated bacteria (Staphylococcus sp. Ay), nitrifying bacteria (Microbacterium sp. Xw), and denitrifying bacteria (Arthrobacter sp. Fy) in simulated wastewater were detected by different concentration of bacteria and different concentration of substrates. The nitrogen metabolism of Ay, Xw and Fy in black odor water at the same concentration under low dissolved oxygen condition and the characteristics of nitrogen metabolism in different concentrations of black odor water were studied. The results showed that the bacterial concentration of Ay bacterium agent increased three times, but the ammoniation efficiency did not multiply. It indicated that increasing the concentration of ammoniated bacterium was not the best way to increase the ammoniation rate. Xw bacteria have a significant effect on the change of nitrate concentration. At 60 h, the nitrate concentration was increased 180% at low bacterial concentration, was 231% at a high bacterial concentration. Fy denitrification efficiency was high, that nitrate nitrogen can be removed quickly at lower concentration. Appropriate increase of total nitrogen concentration can increase the ammoniation efficiency of Ay microbial agent, but too high would inhibit the nitrogen metabolism efficiency of Ay microbial agent. The concentration of nitrate nitrogen of Xw bacterium reagent was increased (3736%) when the total nitrogen was 25 mg·L^-1. The Fy microbial agent has no obvious effect on ammonia nitrogen removal. When the total nitrogen concentration was 25 mg·L^-1, the removal rate of nitrate by Fy bacterium was the best. Overall, the results showed that the concentration of ammoniated bacteria and denitrifying bacteria could meet the need of nitrogen metabolism, and the nitrifying bacteria could increase the nitrate nitrogen synthesis rate with the increase of the concentration of nitrifying bacteria. In a certain range, increasing the concentration of substrate could increase the efficiency of nitrogen metabolism of bacterial agents, and excessive concentration would inhibit the effect of nitrogen metabolism. The study provides data support for the problem of black odor water in Guangdong-Hong Kong-Macao Greater Bay Area.