抄録
Alcaligenes faecalis, a typical heterotrophic nitrifying and denitrifying bacterium, was added into activated sludge and was made to be a dominant species in the activated sludge ecosystem under anoxic conditions. Influent COD to total nitrogen ratios (C:N) and quantities of the inoculated A. faecalis were changed to test the responses of the systems. The systems' behaviors of N2O emission and wastewater treatment were evaluated. On the other hand, a batch experiment was also conducted in which Helium (He) was used to bubble an activated sludge system. Characteristics of N2O emission from the system were tested. Experimental results showed that N2O production of the systems containing A. faecalis was generally about 50% less than those of the control reactors containing only activated sludge. In addition, the former systems had a higher total nitrogen removal capability, and their average total nitrogen removal efficiencies were about 7-56% higher than those of the control activated sludge systems. Moreover, TOC removal efficiencies of the systems containing A. faecalis were a little higher than those of the control systems. On the other hand, more alien A. faecalis addition and higher influent C:N ratio led to lower N2O emission and better effluent water qualities. Therefore, increasing A. faecalis' population in activated sludge should be encouraged for controlling N2O emission and upgrading wastewater treatment capability under anoxic conditions. Batch experiments showed that bubbling led to higher N2O production. A critical He flowrate existed corresponding to the highest N2O production yield.
