内循环流态混合液中微生物的种群优化与强化适冷机制

In the winter, low efficiency in sewage treatment and instable secondary effluent quality often appear in many wastewater treatment plants of northern China, causing the discharge of amount of nitrogen, phosphorus and organic matter into receiving water and then posing a serious threat to urban public health and environment. Thus, the development of bioaugmentation mechanism and technology has emerged as a key priority for improving the wastewater treatment efficiency at low temperature. On our previous study, we established a pilot-scale wastewater treatment device with a total volume of 500 m3/d and found that mixed liquor at internal-loop fluidization in the bioreactor promotes the nitrification efficiency and organic matter removal at low temperature. The content of our research proposal is listed as follows: (1) to establish a Real -time quantitative PCR method that uses specific primer PCR technique to detect cold-adapted gene of microbial community in mixed liquor, and then the method was utilized to investigate the abundance and the biological stability of cold-adapted bacteria in mixed liquor or active sludge quantitatively; (2) to validate the relationship between the temporal and spatial variation of community structure and the expression of cold-adapted gene and protein, especially on the analysis of the inducible expression regulation of cold-adapted gene and protein combined with determination of cytoplasmic matrixes; (3) to develop a bioaugmentation method for the regulation of cold-adapted bacteria to improve the removal of organic matter and nitrification efficiency and to low the operation cost of wastewater treatment plant in winter.

我国北方污水处理厂冬季运行效率低，出水水质不稳定，大量超标有机物和氨氮排入受纳水体，严重威胁着城市水系生态环境。因此，开发低温生物强化技术来提高冬季生物处理系统的运行效率已成为当务之急。在微压内循环生物反应器的前期研究中，已发现混合液处于内循环流态可以强化低温下硝化效率和有机物的去除率。本项目在500m3/d微压内循环污水处理中试装置的基础上，利用检测冷适应基因表达的实时荧光定量PCR方法，准确获取混合液或活性污泥中嗜冷或耐冷菌的相对丰度，并用来分析生物处理系统中低温菌群的生物稳定性；通过研究中试装置内菌群的时空演化规律，及其与适冷蛋白、基因表达的对应关系，结合特异胞内基质分析来获得诱导适冷蛋白与基因的表达规律，解析低温菌群的冷适应机制；由此研发低温菌群调控的生物强化关键方法，提高低温环境条件下废水中的有机物去除效率和硝化效率，从而降低冬季污水生物处理的运行成本。

针对我国北方地区冬季污水生物处理效率低的现状，本项目依托中试规模的微压内循环生物反应器，开展内循环混合液中微生物的冷适应机制研究，提出了低温污水生物处理稳定运行控制方法，逐渐由实验室研究、中试验证发展到工程应用，主要成果如下：.（1）依托 500m3/d 城镇污水处理中试，结合实验室模型，利用数值模拟解析了微压内循环生物反应器内流场分布和溶解氧分布特征，获得了调节曝气量控制反应器内循环稳定流态的关键方法；.（2）利用 PCR 技术研究了反应器内溶解氧与菌群分布的时空变化与响应关系，并根据污水厂水温季节性变化特征，解析了温度胁迫下反应器内细菌的演化过程，阐明了低温脱氮与有机物去除的生物稳定性机制；.（3）开展超低水温（<5℃）条件下，微压内循环反应器处理城镇污水的实验研究，获得了城镇污水低温稳定脱氮与达标排放的调控方法；.（4）依托上述技术，在吉林省长春市长德新区建立了 20000m3/d 的城镇污水处理示范工程（已验收），综合节省能耗20%，出水稳定达标排放。