微丝菌致膨的种群动态及关键影响因素

Population Dynamics and Key Influencing Factors of Microthrix parvicella Caused Sludge Bulking

针对在实际城市污水生物处理工艺低温期频发由微丝菌(M.parvicella)过量生长诱发的污泥膨胀现象,通过多维度耦合丝状菌监测方法结合分子生物学定量方法,系统分析了实际处理工艺年度完整膨胀过程中丝状菌种群的动态变化、优势丝状菌演替趋势及主要影响参数;构建实验室模拟反应器并成功模拟M.parvicella低温致膨完整过程,验证主要控制参数对优势丝状菌演替规律和污泥膨胀现象消长影响.结果表明M.parvicella致膨过程存在着显著的丝状菌种群多样性变化,优势丝状菌演替体现为骨架丝状菌Type 0092、Type 0041与M.parvicella的竞争生长过程.在较低温度条件下,污泥负荷是M.parvicella形成竞争生长优势的重要控制因子:当水温在15℃以下时,低负荷[0.05 kg·(kg·d)^(-1)]可以导致M.parvicella数量的升高与持续稳定;而随着负荷升高至0.1 kg·(kg·d)^(-1)以上时,尽管存在着低温因素,但M.parvicella数量呈现针对性地下降.

Given the frequent occurrence of the sludge bulking phenomena caused by Microthrix parvicella(M.parvicella)overgrowth during the low-temperature period in the fullscale municipal wastewater treatment plant,the filamentous bacteria dynamics of the M.parvicella population were systematically investigated during the completed bulking period using the multi-dimensional integrated filamentous monitoring method combined with the molecular quantitative method.A lab-scale reactor was constructed and successfully simulated bulking phenomena under the low-temperature condition.The trend of dominant filamentous bacterial shift and the main influencing parameters were estimated during the bulking period,to verify the key factors for filament growth and extinction of the sludge bulking phenomenon in the full-scale plant.The results showed that the bulking-caused M.parvicella was characterized by significant changes in the diversity of filamentous bacteria,and the dominant filamentous bacterial succession was reflected in the competition between the skeleton filamentous bacteria Type 0092 and Type 0041 and M.parvicella.At lower temperatures,sludge loading was an important controlling factor for the competitive growth advantage of M.parvicella:when the temperature was lower(approximately 15℃),low sludge loading[0.05 kg·(kg·d)^(-1)]could lead to the stabilized elevation of M.parvicella,and with the loading increased to 0.1 kg·(kg·d)^(-1) or more,M.parvicella populations showed a targeted decline despite the presence of the low temperature factor.