Effects of Temperature on Shortcut Nitrification and Nitrification Activity of Nitrification in an Intermittent Aeration Sequencing Batch Reactor

Abstract

Real domestic sewage was treated with sequencing batch reactors (SBR). The aerobic/anoxic modes were alternated 4 times at 30℃ and 7 times at 18℃ in a single-cycle, respectively, and the ratio of aerobic/anoxic cycles was 30 min/30 min. The influent concentration of ammonia and nitrite was 61.44 mg·L-1 and 0.77 mg·L-1, respectively. After the experiments were run for 61 and 90 cycles, the effluent of the ammonia was 0.68 mg·L-1 and 1.28 mg·L-1 and the removal rate for ammonia was 98.94% and 99.57%, respectively. The nitrite concentrations were 20.57 mg·L-1 and 20.18 mg·L-1, and the nitrite accumulation rate reached 95.92% and 99.58%, respectively. During shortcut nitrification, the activity of the ammonia oxidizing bacteria (AOB) increased gradually before finally stabilizing at 100.00%, however the activity of nitrite oxidizing bacteria (NOB) increased first and then decreased gradually, the activity of AOB exceeded NOB at 32 and 74 cycles respectively, where the AOB became the dominant bacteria and the activity of NOB was completely inhibited at 61 and 90 cycles.