低温下排水速率对CANON型人工快速渗滤系统稳定性的影响

在中温(35±2)℃]、高氨氮(459.98±36.98)mg/L]浓度下启动基于亚硝化的全程自养脱氮(CANON)型人工快速渗滤(CRI)系统, 而后使其在低温(10±2)℃]下处理生活污水, 探究了排水速率(v_d)对系统氮素转化性能及微生物特性的影响.结果表明, 对v_d的合理设置可修复并优化CRI系统中的限氧微环境, 进而可在一定程度上实现CANON反应体系的复壮并提高系统的脱氮性能.当v_d为0.50L/min时, 亚硝酸盐氧化菌(NOB)丰度及活性的提高使硝化/反硝化作用取代CANON作用成为系统脱氮的主要途径, 导致其脱氮性能恶化; 当v_d由0.50降至0.20L/min后, CRI系统中的CANON作用得以较大程度的恢复, 厌氧氨氧化菌(AnAOB)复又成为系统中的优势菌群, 且其TN和NH₄⁺-N去除率分别达(72.07±5.62)%和(81.51±2.74)%; 而当v_d小于0.20L/min时, 填料层中溶解氧含量相对不足, 好氧氨氧化菌(AOB)的活性与丰度受到抑制, CANON作用的强化效果有限, 系统脱氮性能复又有所下降.

Effect of drainage rate on the stability of a constructed rapid infiltration system with CANON process at the low temperature

The constructed rapid infiltration (CRI) system with the complete autotrophic nitrogen removal over nitrite (CANON) process, which had been launched at (35±2)℃ and high NH₄⁺-N concentration of (459.98±36.98)mg/L, was used to treat domestic sewage at (10±2)℃. It was conducted to explore the nitrogen transformation mechanisms and the related microbiological characteristics in the CRI system under drainage rate (v_d) constraints. The results showed that the oxygen-limiting microenvironment could be restored and optimized in the CRI system as a result of appropriate v_d. Subsequently, recovery of the CANON process was achieved in the system, as well as its nitrogen removal performance. At the v_d of 0.50L/min, the proliferation and the increased activity of nitrite oxidizing bacteria (NOB) made the nitrification/denitrification process instead of the CANON process became the primary total nitrogen (TN) removal route in the CRI system, resulting the deterioration for nitrogen removal of the system. When the v_d decreased from 0.50 to 0.20L/min, the CANON process could be recovered largely accompanied by the dominance of anaerobic ammonium oxidation bacteria (AnAOB) in the system, and the mean TN and NH₄⁺-N removal rates could reach up to (72.07±5.62)% and (81.51±2.74)%, respectively. However, as the v_d was lower than 0.20L/min, the activity and the quantity of aerobic ammonia-oxidizing bacteria (AOB) was inhibited because of the insufficient of dissolved oxygen (DO) in the bed, thus the reduction of nitrogen removal rate in the CRI system was detected resulting from the unsatisfactory enhancement of the CANON process.