排水速率对潮汐流人工湿地中CANON作用的强化

为强化潮汐流人工湿地（TFCW）中基于亚硝化的全程自养脱氮（CANON）作用，探究了不同排水速率（v_d）下系统中氮素的迁移转化机制与微生物特征.结果表明，v_d可显著影响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.当v_d由1.00降至0.50L/min时，填料层中逐渐形成较为严格的限氧环境，有利于短程硝化的稳定和厌氧氨氧化菌的富集，进而有助于CANON反应体系在TFCW中形成.而当v_d小于0.50L/min时，填料层中溶解氧相对不足，好氧氨氧化菌活性受到抑制，数量随之减少，CANON作用的强化效果有限，系统脱氮性能受到影响.当v_d为0.50L/min时，TFCW中的CANON作用可得到最大限度的强化，系统脱氮性能达到最佳，其TN和NH₄⁺-N的去除负荷分别为（116.79±13.16）和（102.75±4.35） mg/（L·d）.对v_d的合理设置可实现TFCW中CANON作用的强化，有利于CANON型人工湿地的构建.

Effect of drainage rate on the enhancement of the complete autotrophic nitrogen removal over nitrite process in a tidal flow constructed wetland

This study attempted to achieve a high-rate nitrogen removal via the complete autotrophic nitrogen removal over nitrite (CANON) process in a tidal flow constructed wetland (TFCW), thus nitrogen transformation mechanisms and the related microbiological characteristics in the TFCWs treating domestic wastewater were explored under drainage rate (v_d) constraints. The results showed that, v_d significantly affected quantities and activities of the functional microbes in the TFCWs. Correspondingly, nitrogen transformation rates in the systems fluctuated at the different five levels of v_d. As the v_d decreased from 1.00 to 0.50L/min, the oxygen-limiting microenvironment gradually formed in the TFCW, which was conductive to the stabilization of nitritation and the enrichment of anammox. Subsequently, enhancement of the CANON process was achieved in the TFCW as a result of appropriate v_d. However, as the v_d was lower than 0.50L/min, the activity of aerobic ammonia-oxidizing bacteria (AOB) was inhibited and its quantity was also insufficient because of the insufficient of dissolved oxygen (DO) in the bed, leading to an unsatisfactory effect for nitrogen removal of the TFCW. When the v_d was 0.50L/min, the CANON process could be enhanced most effectively in the system, and the mean TN and NH₄⁺-N removal rates reached up to (116.79±13.16) and (102.75±4.35)mg/(L·d), respectively. Overall, autotrophic nitrogen removal via CANON process developed in the TFCW as a result of appropriate v_d, facilitating establishment of the TFCW with CANON process.