零价铁介导下的猪场废水厌氧消化液自养脱氮机制研究

Biogas fermentation is an effective treatment for swine wastewater, but its digested effluent is a big challenge at present. Treatment for anaerobically digested effluent of swine wastewater to meet the discharge standard remains to be a general method in land-limited area. Digested effluent is characterized by low organic carbon and high nitrogen concentration, and efficient nitrogen removal is difficult to achieve using conventional nitrification-denitrification process. As for the low efficiency existing in heterotrophic nitrogen removal, a new autotrophic nitrogen removal phenomenon has been found, namely, SBR process system added with zero valent iron showed an extremely high nitrogen removal efficiency, while the mechanism of this efficient autotrophic nitrogen removal is still unclear by now. Based on this, a single-stage SBR processing system with adding zero valent iron would be constructed in this study to reveal the main mechanism of autotrophic nitrogen removal mediated by zero valent iron, with the studies on stoichiometry conversions of iron and nitrogen as well as mass balance, key enzymatic activities for nitrogen removal (amo, nxr, nar, nir, nor, nos, hzs), microbial community structure and transcriptional variations of functional genes. The results would help to lay a solid theoretical foundation for the development of economical and efficient technology for high concentrated ammonia nitrogen wastewater.

沼气发酵是猪场废水处理利用的有效手段，产生的厌氧消化液（沼液）是目前面临的一大难题。达标处理仍然是土地紧张地区解决沼液问题的主要方法，但沼液是典型的低碳高氮废水，采用传统异养硝化反硝化难以达到有效的脱氮处理效果。针对传统异养反硝化脱氮工艺效率低的问题，申请人在前期研究中发现了一种新型沼液自养脱氮现象，即投加零价铁的序批式反应器（SBR）处理系统表现出极高的总氮脱除率，但其高效自养脱氮机制目前尚不清楚。基于此，本项目拟构建零价铁介导下的单级SBR同步自养脱氮处理系统，通过SBR处理系统的铁氮转化化学计量学与物料平衡研究、脱氮关键酶（amo、nxr、nar、nir、nor、nos、hzs）活性分析、微生物群落结构及关键功能基因转录水平解析，揭示零价铁介导下SBR处理猪场废水厌氧消化液的自养脱氮机制，为开发经济高效的高氨氮废水脱氮工艺奠定理论基础。

沼气发酵是猪场废水处理利用的有效手段，产生的厌氧消化液（沼液）是目前面临的一大难题。达标处理仍然是土地紧张地区解决沼液问题的主要方法，但沼液是典型的低碳高氮废水，采用传统异养硝化反硝化难以达到有效的脱氮处理效果。针对传统异养反硝化脱氮工艺效率低的问题，本项目构建了零价铁介导下的单级SBR同步自养脱氮处理系统，通过分析零价铁添加量、外加碳源等工艺条件对铁氮转化、微生物活性、活性污泥形态、微生物群落结构及脱氮关键功能基因转录表达水平的影响，揭示零价铁介导下的自养脱氮机制是硝化、反硝化、厌氧氨氧化的联合作用，关键脱氮微生物为Nitrosomonas、Candidatus_Brocadia和Verrucomicrobia。该结果为同类型低碳高氮废水的脱氮处理提供了创新的研究思路和重要的技术支撑，同时为开发经济高效的高氨氮废水脱氮工艺奠定理论基础。本项目投加的零价铁为铁刨花，类似的零价铁投加剂如铁粉、废铁渣、铁刨花、废钢铁等，均可用于废水处理系统中，达到以废治废的目的，可同时实现废水中氨氮的持续脱除和废铁的充分利用，具有较好的应用前景。