基于硫自养反硝化填料对城市污水厂二沉水的脱氮性能研究

Study on the Denitrification Performance of the Secondary Sink Water of the Urban Sewage Treatment Plant Based on the Sulfur Autotrophic Denitrification Filler

为了探究硫自养反硝化工艺对二沉水中硝酸盐的去除性能,以北京某再生水厂二沉水为进水,对比不同空床停留时间(EBCT)、温度对硝酸盐去除效果的影响,探讨反洗恢复时间、产生气体情况、硫化物转化过程和微生物群落结构。结果表明,硝酸盐负荷随进水流量增大而增加,EBCT为20 min对应的平均氮去除量为9.47 mg/L;低温下系统也表现出明显的脱氮效果,当进水水温为14℃时,EBCT为60 min反应器的氮去除量仍然可以维持在9 mg/L以上;在属水平上优势菌属为独岛杆菌属(Dokdonella)、硫杆菌属(Thiobacillus)和丛毛单胞菌属(Comamonadaceae),独岛杆菌的主要作用是为硫杆菌创造缺氧环境,其相对丰度随停留时间降低而增加,硫杆菌属的相对丰度随停留时间降低而降低;反洗11 h后可恢复正常处理性能;收集气体进行分析,装置中发生反硝化过程使N_(2)含量升高,EBCT>60 min时,系统内会发生硫歧化反应出现部分含硫副产物。

The second submersible water of a reclaimed water plant in Beijing was used as the inlet water to explore the nitrate removal performance of the sulfur autotrophic denitrification process.The effects of different empty bed contact times(EBCT),the temperature on nitrate removal effect,and the recovery time of backwashing,gas generation,sulfide conversion process and microbial community structure were discussed.The results showed that the nitrate load increases with the increase of inlet water flow,and the average nitrogen removal amount at EBCT of 20 min is 9.47 mg/L.The system also exhibits a significant denitrification effect at low temperatures,and when the inlet water temperature is 14℃,the nitrogen removal amount of the reactor can still be maintained at more than 9 mg/L when the EBCT is 60 min.At the genus level,the dominant genera are Dokdonella,Thiobacillus and Comamonadaceae.The main role of Dokdonella is to create an oxygen-deficient environment for Thiobacillus,whose relative abundance increases with decreasing dwell time.The relative abundance of Thiobacillus decreases with decreasing residence time.The system reactor could be recovered within 11 h after backwash.The gas collected was analyzed,and the denitrification process increased the N_(2)content.When the EBCT>60 min,some sulfur-containing by-products will appear in the system due to the sulfur disproportionation reaction.