ABSTRACT
There were four experimental groups: M0, M1, M2, and M3. For each group, experiments were conducted in triplicate, and the average value for each group was taken for analysis. A total of 12 transparent glass bottles (capacity 1000 ml) were used for making the microcosms. M0 represents an aseptic control group, which was used to confirm the effects of biological action on denitrification. The materials used in this group were treated at high temperatures and high pressures (sterilizing pot, daily sterilization 60 min, for 3 days). Then, 5 ml HgCl2 (concentration 500 mg/L) was added for enhanced sterilization. M1 represents the anaerobic group: nitrogen was filled into the bottle containing the solution until the DO concentration was less than 1 mg/L, and then the microcosms were cultivated in the anaerobic glove box. M2 represents the micro-aerobic group: nitrogen was filled into the bottle containing the solution until the DO concentration was less than 4 mg/L, and the bottle was sealed and placed in a laboratory. M3 represents the aerobic group: not treatment was applied.
