拔风管对CANON型人工湿地脱氮性能的影响

以猪场沼液为处理对象,探究了拔风管对基于亚硝化的全程自养脱氮(CANON)型潮汐流人工湿地(TFCW)氮素转化性能及微生物种群结构的影响.结果表明,拔风管数量可显著影响CANON型TFCW中脱氮功能微生物的数量与活性,进而影响其氮素转化速率.在水力负荷(HLR)≤0.18m3/(m2·d)的前提下,随着拔风管数量由0增...

Effect of air duct on nitrogen removal performance of a constructed wetland system with CANON process

This study was conducted to explore the effects of air duct on nitrogen transformation mechanisms and the associated microbiological characteristics in a tidal flow constructed wetland (TFCW) with CANON process when treating digested swine wastewater. The results showed that, the air duct number significantly affected quantities and activities of the functional microbes in the TFCWs. Correspondingly, nitrogen transformation rates in the systems fluctuated at the different five numbers of air duct. On the premise that the hydraulic loading rate (HLR) was no more than 0.18m³/(m²·d), the redox microenvironment gradually optimized in the bed of the TFCW as the air duct number increased from 0 to 6, which was conductive to the enhancement of nitritation and the enrichment of ANAMMOX bacteria (AnAOB). Subsequently, the simultaneous nitrification, ANAMMOX, and denitrification (SNAD) processes occurred in the TFCW, resulting in the improvement of nitrogen removal in the system. However, as the air duct number was more than 6, the stabilization of nitritation in the TFCW was impaired partly owing to the proliferation and increased activities of nitrite oxidizing bacteria (NOB), and then the ANAMMOX process and the denitrification process were both inhibited with the nitrogen removal performance of the system declined. Regarding to the TFCW operating with HLR of 0.18m³/(m²·d), as the air duct number was 6, the relative abundances of Nitrosomomas (the major bacteria of AOB) and Candidutus Brocadia (the major bacteria of AnAOB) could respectively reach up to 20.05% and 18.38% in the system, while the relative abundances of Nitrospira (the major bacteria of NOB) was at a low level of 1.92%. Correspondingly, the CANON process was enhanced effectively in the system, and this process could be coupled with the denitrification process dominated by Denitratisoma (the major bacteria of denitrifiers) with the relative abundance of 15.18%, resulting that the TN and NH₄⁺-N removal rates of the TFCW were (90.29±3.70)% and (93.30±2.97)%, respectively.