Effect of alternate aeration on the startup and nitrogen removal characteristics of short-cut nitrification
WANG Tao1,2,, SHAO Zhaowei1,2, LIU Andi1,2, LIU Hong1,2, CHEN Yongzhi1,2,, 1.School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China 2.Wastewater Treatment Industry Technology Center of Gansu, Lanzhou 730070, China
Abstract:The sequential batch activated sludge reactor(SBR) was used to treat low C/N domestic sewage. Under the conditions of 25 ℃ and two alternate aeration modes, the short-cut nitrification and nitrogen removal characteristics, nitrite oxidation rate, the variation of free ammonia(FA) concentrate, the effect of ammonia oxidizing bacteria (AOB) activity and the fitting of the Boltzmann model to AOB activity during start-up and stable operation period were analyzed. The results showed that at the aerobic/anoxic ratio of 30 min/30 min and 4 times of single cycle alternating operation, the nitrite content in effluent increased from 4.19 mg·L?1 to 16.29 mg·L?1 after 46 cycles. The nitrite accumulation rate reached a stable value of 97.03%, and the ammonia oxidation rate and AOB activity were stabilized at 0.30 g·(g·d)?1 and 110%, respectively, and the median value of the AOB activity growth period was the 10 cycle. At the anoxic/aerobic ratio of 30 min/30 min and 4 times of single cycle alternating operation, the nitrite concentration in effluent and nitrous acid accumulation rate were stabilized at 17.94 mg·L?1 and 95.04% after 50 cycles of operation, respectively. The ammonia oxidation rate and AOB activity were stabilized to 0.30 g·(g·d)?1 and 110%, respectively, and the median value of the AOB activity growth period was the 24 cycle. Therefore, the anoxic/aerobic alternating operation mode could increase the nitrogen removal rate and the nitrite accumulation rate, which led to better AOB activity, this result provides a reference for achieving and maintaining stable short-range nitrification. Key words:alternating aeration mode/ short-cut nitrification/ SBR/ low C/N domestic sewage/ Boltzmann model.
图1SBR实验装置示意图 Figure1.Schematic diagram of SBR reactor
LIU Y W, NGO H H, GUO W S, et al. The roles of free ammonia (FA) in biological wastewater treatment processes: A review[J]. Environment International, 2019, 123: 10-19. doi: 10.1016/j.envint.2018.11.039
HERMANSSON A, LINDGREN P E. Quantification of ammonia oxidizing bacteria in arable soil by real-time PCR[J]. Applied and Environmental Microbiology, 2001, 67(2): 972-976. doi: 10.1128/AEM.67.2.972-976.2001
1.School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China 2.Wastewater Treatment Industry Technology Center of Gansu, Lanzhou 730070, China Received Date: 2019-12-01 Accepted Date: 2020-06-18 Available Online: 2020-12-08 Keywords:alternating aeration mode/ short-cut nitrification/ SBR/ low C/N domestic sewage/ Boltzmann model Abstract:The sequential batch activated sludge reactor(SBR) was used to treat low C/N domestic sewage. Under the conditions of 25 ℃ and two alternate aeration modes, the short-cut nitrification and nitrogen removal characteristics, nitrite oxidation rate, the variation of free ammonia(FA) concentrate, the effect of ammonia oxidizing bacteria (AOB) activity and the fitting of the Boltzmann model to AOB activity during start-up and stable operation period were analyzed. The results showed that at the aerobic/anoxic ratio of 30 min/30 min and 4 times of single cycle alternating operation, the nitrite content in effluent increased from 4.19 mg·L?1 to 16.29 mg·L?1 after 46 cycles. The nitrite accumulation rate reached a stable value of 97.03%, and the ammonia oxidation rate and AOB activity were stabilized at 0.30 g·(g·d)?1 and 110%, respectively, and the median value of the AOB activity growth period was the 10 cycle. At the anoxic/aerobic ratio of 30 min/30 min and 4 times of single cycle alternating operation, the nitrite concentration in effluent and nitrous acid accumulation rate were stabilized at 17.94 mg·L?1 and 95.04% after 50 cycles of operation, respectively. The ammonia oxidation rate and AOB activity were stabilized to 0.30 g·(g·d)?1 and 110%, respectively, and the median value of the AOB activity growth period was the 24 cycle. Therefore, the anoxic/aerobic alternating operation mode could increase the nitrogen removal rate and the nitrite accumulation rate, which led to better AOB activity, this result provides a reference for achieving and maintaining stable short-range nitrification.