重金属胁迫下的好氧颗粒污泥微生物特性及其脱氮机理

Trace metals have the close relationship with the microbial metabolic processes, which can regulate the biological enzyme activity, promote the transportation of the macro amount elements, participate in hormone synthesis, etc. However, the frequent emergency of the excess heavy metals in the municipal sewage will inhibit microbes' growth and its metabolic activities, which could greatly reduce the stability of the biological wastewater treatment system..Based on the development of the microorganisms, the nitrogen removal mechanism of the aerobic granular sludge on the heavy metal stress should be illustrated by the continuous and batch experiments and molecular biological technique. The two typical heavy metals of Zn (Ⅱ) and Cr (Ⅵ) had been chosen in this study. The influence mechanism of the different concentrations of Zn(Ⅱ)、Cr(Ⅵ) on the basic characteristics of the aerobic granular sludge will been studied. The stress mechanism of Zn(Ⅱ)、Cr(Ⅵ) on the microorganisms of the aerobic granular sludge can be illustrated, which is dependent on the analysis of the microbial compositions, biological activity, microbial community diversity, and nitrogen removal flora. Through the research on the nitrogen removal process, nitrogen removal patterns and its principles of the aerobic granular sludge at different concentrations of Zn(Ⅱ)、Cr(Ⅵ), the response relationships between the nitrogen removal mechanism with its microorganisms of the aerobic granular sludge on the heavy metal stress can be established. Based on that, the nitrogen removal control and optimization strategy of the aerobic granular sludge on the heavy metal stress will be put forward. The study results can provide the scientific basis for the application of aerobic granular sludge technology..The project has the feasible academic thinking, reasonable technical solutions, well-knit research foundations, dependent researcher team and perfect study conditions. Those all provide the complete technical support and guarantee for the research with the high quality accomplishment.

针对现有污水中重金属频繁出现进而影响污泥稳定性及微生物活性等问题，以基于重金属胁迫的好氧颗粒污泥脱氮机理为目标，从微生物发展变化规律入手，采用动态和静态试验并紧密结合分子生物学方法，研究不同浓度Zn(Ⅱ)、Cr(Ⅵ)条件下，Zn(Ⅱ)、Cr(Ⅵ)对好氧颗粒污泥基本特性的影响机制；深入探讨好氧颗粒污泥微生物活性与群落组成的发展变化规律，揭示重金属对好氧颗粒污泥微生物的胁迫机理；进一步分析好氧颗粒污泥的脱氮过程、不同脱氮途径及其相关动力学参数，建立基于重金属胁迫的好氧颗粒污泥脱氮原理。整合以上研究成果，形成重金属胁迫下的好氧颗粒污泥脱氮机制与脱氮微生物的响应合关系，提出好氧颗粒污泥脱氮的调控措施与优化方法，为好氧颗粒污泥技术的广泛应用提供科学依据。

重金属可通过饮水和食物链的积累在生物体内富集，进而影响生物体正常的生理代谢活动。由于越来越多的污水处理厂倾向将工业废水和生活污水结合处理，污水处理厂进水中长期含有低浓度重金属的可能性和短期含有高浓度重金属的风险均逐渐增加。.本研究选择Zn(II)、Cr(VI)两种典型重金属，从微生物发展变化规律入手，探讨重金属对其基本性质的影响机理，研究不同重金属条件下的微生物活性与群落特征，建立重金属胁迫下的好氧颗粒污泥脱氮途径与脱氮微生物的响应机制。通过本项目研究，为好氧颗粒污泥工艺推广应用提供了科学的理论依据。本研究发表学术论文11篇，其中SCI检索4篇（含已录1篇）、核心期刊6篇；培养硕士研究生6人，已毕业4人，主要研究成果如下：.在10和15mg/L Zn(II)长期作用下污泥SVI逐渐升高，COD和NH4+-N的去除率均呈下降趋势，且后者下降更快。10 mg/L以上Zn(II)会对好氧颗粒污泥氮利用速率产生明显抑制作用，抑制程度由大到小依次为比氨氧氧化速率、亚硝酸盐化速率和比反硝化速率。20 mg/L Zn(II)冲击10天后，对硝化速率的抑制幅度达到25.3%。拟杆菌、螺杆菌属、黄杆菌属、菌胶团、原核生物、β变形菌成为优势菌种。.在1,3,5,10 mg/L Cr(VI)长期作用下好氧颗粒污泥COD去除率能保持在90%以上，而TN和NH4+-N去除率则逐渐下降。10 mg/L Cr(VI)会使颗粒污泥的结构由椭圆型变成扁平状。 此时好氧颗粒污泥脱氮途径主要为自养硝化、异养反硝化和同步硝化反硝化。食酸菌属、黄杆菌属、土壤细菌、亚硝化螺菌属、原核细胞型微生物、β变形菌、假单胞菌是优势菌种，且脱氮细菌数量约为总细菌数量的三分之一。25, 50 mg/L Cr(VI)冲击10天后，对硝化速率的抑制幅度分别为58.04%、75.62%，25 mg/L的Cr(VI)会破坏颗粒污泥的结构。螺杆菌属、菌胶团、β变形菌、能氧化亚硝酸盐的贝塔变形菌是Cr(VI)短期作用下的优势菌种。.1mg/L Cr(VI)和3,5 mg/L Zn(II)会使好氧颗粒污泥影响较小，而在其余浓度重金属作用下好氧颗粒污泥颗粒的粒径减小，沉降性能变差，Fe和Ca含量均明显下降；PS分泌量大幅增加，PN增幅较小，PS/PN增大；总细菌数量大幅降低，脱氮功能菌中，反硝化菌所占比例最高，其次分别为AOB和NOB。