造粒处理对城镇污泥蚯蚓堆肥微生物群落碳源利用的影响

采用Biolog Eco微平板法探讨了城镇污泥造粒的预处理方法对蚯蚓堆肥系统中微生物碳源利用的影响.结果显示,造粒处理会显著提高城镇污泥中微生物群落对碳源利用的优势度和均匀度,但会降低碳源利用的多样性.与初始污泥相比,造粒处理对氧环境的改善在蚯蚓堆肥的前15 d明显提高了H1(a-D-乳糖)、A3(D-半乳糖酸γ内酯)、D4(L-丝氨酸)、C1(吐温40)、E1(a-环状糊精)、C3(2-羟苯甲酸)、B3(D-半乳糖醛酸)和F3(衣康酸)这8种碳源的代谢强度,增高幅度达到10.81%~24.83%.从碳源利用模式来看,蚯蚓堆肥系统中微生物的碳源利用表现出多元化向单一化发展的特点.胺类和酚类是微生物利用的主要碳源,约占总利用率的40%.污泥造粒和蚯蚓堆肥对胺类的利用无明显影响.与S组相比,15 d前造粒处理会提高氨基酸类和羧酸类的利用率8%以上,对酚类、聚合物类和碳水化合物类无明显影响.但这3类碳源对蚯蚓的作用更加敏感,蚯蚓可以使这3类碳源的利用率提高11%以上.15 d后随着基质中可利用物质的减少和蚓粪的积累,微生物对酚类、羧酸类和氨基酸类的代谢产生了明显的偏好,总体的碳源代谢能力却有所降低.

Effects of pelletized treatment on microbial carbon source utilization during vermicomposting of municipal sludge

In this study, effects of pelletized treatment on microbial carbon source utilization during vermicomposting of municipal sludge were explored by Biolog EcoPlate method. Results showed that vermicomposting of pelletized dewatered sludge increased the dominance and evenness of microbial carbon metabolism, but declined the functional diversity. Compared with the initial sludge, improving oxygen conditions of the sludge through pelletized treatment significantly enhanced the catabolic activity of B2, A4, D1, D3, E3 and H3 by 10.81%~24.83% before 15 days. The study on the utilization pattern of microbial carbon sources suggested that vermicomposting system displayed the characteristics of diversification to simplification. Amines and phenolic compounds were the main carbon sources for microbial utilization, accounting for about 40% of the total utilization rate. Utilization of amines would not be noticeably affected by pelletized treatment as well as the inoculation of earthworms during the entire experimental process. However, in the first 15 days, pelletized method could promote the utilization rate of amino acids and carboxylic acids more than 8%, and the inoculation of earthworms could improve the utilization rate of phenolic compounds, polymers and carbohydrates over 11%. Moreover, according to the data, the obvious metabolic preference for carbon sources of carboxylic acids, phenolic compounds and amino acids were generated along with the reduction of available substances and accumulation of earthworm casts after 15 days, which led to the reduction of overall catabolic activity.