游离亚硝酸预处理实现MBBR短程硝化的快速启动

Rapid start-up of MBBR partial nitrification by free nitrite pretreatment

短程硝化工艺具有节约硝化需氧量和反硝化碳源等优势,是目前水处理领域的研究重点。研究游离亚硝酸(FNA)预处理法实现短程硝化的快速启动和稳定运行符合节能低碳的理念。在6个相同的移动床生物膜反应器(MBBR)中分别投加质量浓度为0、3.2、6.4、9.6、12.8、16.0 mg/L的FNA,对生物膜浸泡12 h进行预处理,并以预处理前的反应器作为对照,研究FNA预处理浓度对功能微生物群落的影响,以及最佳条件下短程硝化的运行稳定性。实验结果表明,25℃、FNA质量浓度为6.4 mg/L、预处理12 h,是降低亚硝酸盐氧化菌(NOB)并维持氨氧化菌(AOB)活性的最佳条件。高通量测序和qPCR结果显示,经过FNA预处理后,NOB的相对丰度和丰度均显著减少。在FNA最佳条件下预处理生物膜,并将其接种在MBBR中,验证其运行稳定性。实验结果表明,FNA预处理生物膜可实现稳定的短程硝化,使亚氮积累率稳定维持在85%以上。

Partial nitrification process has the advantages of saving nitrification oxygen demand and denitrification carbon source,which is the focus of current research in the field of water treatment.The study of free nitrite(FNA)pretreatment method to realize start-up and stable operation of partial nitrification is in line with the concept of en⁃ergy saving and low carbon.Six identical moving bed biofilm reactors(MBBR)were pretreated with FNA at mass concentrations of 0,3.2,6.4,9.6,12.8,and 16.0 mg/L,respectively,and the biofilms were immersed for 12 h.The untreated reactor was used as a control.The effects of FNA concentration on functional microbial community and the operational stability of partial nitrification under optimal conditions were investigated.The experimental re⁃sults showed that pretreatment at 25℃and FNA mass concentration of 6.4 mg/L for 12 h could reduce nitrite oxidiz⁃ing bacteria(NOB)and maintain the activity of ammonia oxidizing bacteria(AOB).High-throughput sequencing and qPCR results showed that the relative abundance and abundance of NOB decreased significantly after FNA pre⁃treatment.The biofilm was pretreated under optimal conditions of FNA and inoculated in MBBR to verify its opera⁃tional stability.The experimental results showed that the pretreatment of biofilm by FNA could achieve stable par⁃tial nitrification and maintain the nitrite accumulation rate stably above 85%.