Effect of shunt ratio on nitrogen removal of a constructed wetland system applied external carbon source
PING La-mei1, WANG Ning1, ZHAO Zi-jian1, SUI Jia-tong1, PAN Ling-yang2, CHU Gang1, WANG Zhen1
1. School of Resources and Environment, Anhui Agricultural University, Hefei 230036, China; 2. School of Urban Construction, Anhui Xinhua University, Hefei 230088, China
Abstract：This study was conducted to explore the effect of shunt ratio on advanced treatment of anaerobically-digested swine wastewater by a subsurface vertical flow constructed wetland (VFCW) with step-feeding when taking domestic sewage as external carbon source. The results showed that, shunt ratio significantly affected operational performances and the associated microbiological characteristics of the VFCW once domestic sewage was pumped into the system via the shunt pipe. As the shunt ratio increased from 0:1 to 1:3, the abundances of denitrifying bacteria and anaerobic ammonium oxidation bacteria (AnAOB) in the filler layer of the VFCW increased significantly, and the nitrification/denitrification process and the partial denitrification/anaerobic ammonium oxidation (DMOA) process became the two main pathways for nitrogen removal in the system, resulting that the TN removal performance of the VFCW was thereby optimized. As the shunt ratio was increased to 1:2, the denitrification performance and the anaerobic ammonia oxidation performance of the VFCW could be further improved, while its operational performance was decreased due to the excessive short hydraulic retention time of the shunt inlet pumped into the system. Notably, high pollutant removal rates could be achieved when the VFCW was operated with shunt ratio of 1:3, effluent quality of the system could reach Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002) class A standard. Regarding to the VFCW with shunt ratio of 1:3, Nitrosomonas, Nitrospira, Thauera and Candidatus_Brocadia were the four dominant bacterial genera in its filler layer. Correspondingly, nitrogen removal in the system relied on the nitrification/denitrification process and the DMOA process, resulting that the TN and NH4+-N removal rates of the VFCW were (5.90±1.86) and (4.63±1.43) g/(m2·d), respectively.
平腊梅, 王宁, 赵子健, 眭家桐, 潘玲阳, 储刚, 王振. 外加碳源时分流比对人工湿地脱氮性能的影响[J]. 中国环境科学, 2023, 43(2): 620-630.
PING La-mei, WANG Ning, ZHAO Zi-jian, SUI Jia-tong, PAN Ling-yang, CHU Gang, WANG Zhen. Effect of shunt ratio on nitrogen removal of a constructed wetland system applied external carbon source. CHINA ENVIRONMENTAL SCIENCECE, 2023, 43(2): 620-630.
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