温度对好氧颗粒污泥系统污泥膨胀的影响

Effect of temperature on sludge bulking in aerobic granular sludge system

为探究温度对好氧颗粒污泥系统污泥膨胀的影响以及微生物群落结构特征,采用序批式反应器,进水为人工合成废水,利用Illumina测序技术分析10℃、18℃和25℃3种温度下好氧颗粒污泥系统微生物群落结构及细菌的动态变化.结果表明,18℃条件下好氧颗粒污泥沉降性能良好SVI值维持在40mL/g左右.而10和25℃条件下好氧颗粒污泥均发生膨胀现象,SVI值分别为194.67和100mL/g.通过qPCR分析可知,10℃条件下,特定的丝状菌里Sphaerotilus natans丰度值最高,该菌大量繁殖导致SVI值极高.Illumina测序结果表明,温度导致好氧颗粒污泥系统的优势菌属具有显著差异性,18℃条件下,好氧颗粒污泥优势菌属为Tsukamurella和unclassified_f_Comamonadaceae,系统具有良好的污染物去除能力;10℃条件下,其优势菌属为Sphaerotilus,该菌属不能利用复杂的有机物;25℃条件下,优势菌属为Tsukamurella和unclassified_f_Microbacteriacea.从微观角度分析好氧颗粒污泥系统脱氮性能,利用FAPROTAX数据库预测不同温度下细菌的代谢功能差异性,在18℃条件下nitrate reduction和nitrate respiration型氮循环功能菌相对丰度分别为7.81%和7.78%,均高于其它2个好氧颗粒污泥系统,这与18℃下好氧颗粒污泥系统有较好的氮去除效果相符合.

To explore the effects of temperature on sludge bulking and the characteristics of microbial community structure in aerobic granular sludge system,three sequencing batch reactors were used with artificial wastewater as the influent.Illumina sequencing technology was used to analyze the microbial community structure and dynamic changes of bacteria in aerobic granular sludge system at 10℃,18℃and 25℃,respectively.The results showed that the particle sludge settling performance of the 18℃was good,and the SVI maintained at about 40mL/g.But under the conditions of 10℃and 25℃,aerobic granular sludge were bulked,of which the SVI were 194.67mL/g and 100mL/g,respectively.According to the qPCR analysis,at 10℃,the abundance value of Sphaerotilus Natans was the highest among the specific filamentous bacteria,it mass propagation of this bacterium would leaded to extremely high SVI.Illumina sequencing results showed that temperature caused the significant differences of dominant species among these three systems.The predominant strains at 18℃were Tsukamurella and unclassified_f_Comamonadaceae,this system had a good pollutant removal ability.And at 10℃,the predominant species was Sphaerotilus,which was unable to utilize complex organic matter.As for the system at 25℃,the dominant bacteria were Tsukamurella and unclassified_f_Microbacteriacea.To analyze the nitrogen removal performance of aerobic granular sludge system from the micro point of view,the FAPROTAX database was used to predict the differences in bacterial metabolic functions at different temperatures.At 18℃,the relative abundance of nitrate reduction and nitrate respiration bacteria,which were kinds of nitrogen cycling functional bacteria,were 7.81%and 7.78%,higher than those in other systems.This results matched the better nitrogen removal effect at the same temperatre.