一体式部分亚硝化-厌氧氨氧化工艺在线恢复过程中脱氮功能菌与丝状菌的羟胺调控机制研究

The combined partial nitritation-anammox process (CPNA) is a new nitrogen removal technology with high efficiency and low consumption, but the excessive reproduction of nitrite-oxidizing bacteria (NOB) will result in the accumulation of nitrate, and then impede the long-term stable operation of CPNA process. Previous study conducted by the applier of this project had found that hydroxylamine (NH2OH) could effectively regulate the NOB and restore the nitrogen removal performance of CPNA process, besides, the filamentous bacteria were developed during the restoration process. However, little is known about the regulation mechanism of hydroxylamine on the nitrogen transformation bacteria (e.g. NOB and anammox bacteria) and filaments. Therefore, through the combination of real-time PCR, high throughput sequencing and isotopic trancing approaches during the batch and continuous experiments of this project, the factors of reversible inhibition of NOB in different morphologies (biological membrane vs suspended activated sludge) by NH2OH will be investigated. The influence of hydroxylalmine on the nitrogen transformation bacteria and filaments during the in-situ restoration of CPNA will be explored，as well as their interrelationship. The function of filaments and the regulation mechanism of hydroxylamine in the in-situ restoration process of CPNA will be illuminated. Results of this project will supply the theoretical support for the long-term stable operation of CPNA process.

一体式部分亚硝化-厌氧氨氧化脱氮工艺（Combined partial nitritation-anammox, CPNA）是新型高效低耗生物脱氮技术，但亚硝酸盐氧化菌（NOB）过量繁殖导致NO3-积累，造成该工艺难以长期稳定运行。申请人前期研究发现，羟胺能够有效调控NOB，在线恢复CPNA工艺的脱氮能力，并且在该过程中出现了大量丝状菌。然而，CPNA工艺在线恢复过程中羟胺对脱氮功能菌群（如NOB、厌氧氨氧化菌）和丝状菌的调控机制不甚清楚。因此，本项目综合采用定量PCR、高通量测序和同位素示踪等手段，考察羟胺对NOB（生物膜和悬浮活性污泥形态）的抑制可逆性影响，探究CPNA工艺在线恢复过程中羟胺调控对脱氮功能菌群与丝状菌的影响，明确两者间的相互作用关系，揭示丝状菌在CPNA工艺在线恢复过程中的作用，最终阐明CPNA工艺在线恢复过程中的羟胺调控机制，为保证CPNA工艺的稳定运行提供理论支持。

一体式部分亚硝化-厌氧氨氧化脱氮工艺（Combined partial nitritation-anammox, CPNA）是新型高效低耗生物脱氮技术，但亚硝酸盐氧化菌（NOB）过量繁殖导致NO3-积累，造成该工艺难以长期稳定运行。针对NOB过量繁殖问题，传统的应对措施如降低溶解氧、缩减污泥龄甚至排空污泥重新接种启动等存在恢复周期长，或者因菌种获取困难而没有普遍性等问题。因此，本研究以一体式部分亚硝化-厌氧氨氧化SBR工艺（Combined partial nitritation-anammox, CPNA）为对象，通过投加NH2OH和N2H4，对比考察两者在NOB过量繁殖下的原位恢复效果，并从微生物层面解析其作用机理。.（1）构建三组SBR硝化系统，对比考察NH2OH和N2H4投加对实现NO2--N累积的作用效果。结果表明投加NH2OH的1#SBR最快实现NO2--N累积，且累积率最高可达85.95%。NH2OH对氨氧化菌（AOB）活性的促进作用要强于N2H4，N2H4对NOB活性的抑制存在一定程度的可逆性。.（2）针对CPNA工艺中出现的NOB过量繁殖问题，投加NH2OH对NOB的抑制效果要好于N2H4。投加NH2OH的1#SBR出水中的NO3--N可以从最初的327.08 mg/L降低至93.31 mg/L，相应的脱氮速率则能够恢复至0.2 kgN/m3.d以上。对于SBR单周期内的NO3--N产生与NH4+-N去除之间摩尔比（mole ratio of NO3--N production to NH4+-N reduced, MRNN），三组SBR分别从最初的69.78%、72.43%和64.67%恢复至19.91%、41.02%和32.96%。污泥SVI值逐渐增大，丝状菌滋生。.（3）在投加NH2OH成功实现对CPNA工艺的原位在线恢复过程中，编码氨氧化过程的amoA、hao基因以及厌氧氨氧化过程主要基因hzo的丰度能够分别提高至26.58%、43.56%和26.17%。微生物群落多样性指数呈下降趋势，且丝状菌丰度得到大幅提高。丝状菌能够发挥一定反硝化功能，将NO3--N还原为NO2--N，作为厌氧氨氧化反应底物，也就与NH2OH直接抑制NOB活性相协同，缓解系统的NO3--N累积现象，原位恢复系统的脱氮功能。