蚯蚓处理对污泥中微生物碳量及脱氢酶活性的影响

将含水率80.6%的脱水污泥制成5 mm的污泥颗粒,以添加蚯蚓(赤子爱胜蚓)为处理组,无蚯蚓为对照组,测定不同时期污泥的理化性质、微生物碳量(MBC)和脱氢酶活性(DHA)的变化,重点研究了蚯蚓对污泥降解过程中MBC和DHA变化的影响.结果表明,相比对照组,蚯蚓处理组p H变化幅度较小;实验结束时,蚯蚓处理组的电导率(EC)和溶解性有机碳(DOC)显著高于对照组,而有机质(OM)显著低于对照组.实验前30 d,蚯蚓处理组MBC显著高于对照组,40 d至实验结束,蚯蚓处理组MBC显著低于对照组.DHA的结果表明,蚯蚓处理组和对照组在前30 d并没有显著性差异,40 d后蚯蚓处理组的DHA显著低于对照组,DHA稳定在2.98~6.40 mg·g-1·h-1(以TPF计).相关分析表明,DHA、MBC和OM之间显著正相关.研究表明,接种蚯蚓在实验前期显著提升了系统的微生物量,加快污泥有机质的降解,从而导致后期产物的微生物量及其活性较低,最终产物更稳定.

Effects of earthwormson the microbial biomass carbon and dehydrogenase activity in decomposition treatment of sewage sludge

This study investigated the effects of earthworms on changes of microbial biomass carbon(MBC)and dehydrogenase activity(DHA)in the sewage sludge at the different stages during the 60-day decomposition experiments through analyzing physicochemical properties,especially changes of MBC and DHA in the comparison between two groups of sludge-with and without addition of earthworms. The dewatering sludge with 80.6% water content was regulated into 5 mm particles for the study while the species of earthworms Eisenia foetida were chosen for the experiments. The results indicated that the sludge with earthworms showed less variation of pH values, significantly higher electrical conductivity(EC) and dissolved organic carbon (DOC)at the end of experiments, but only organic matter(OM)was apparently lower than the compared sludge without earthworms. However, higher values of MBC were found in sludge with earthworms during the first 30 days, then much less than in sludge without earthworms from 40 days until finishing the experiments. The analytical results of DHA proved that there was no big difference between the two groups of sludge during the first 30 days. Nevertheless, DHA value in sludge with earthworms appeared to be stable with 2.98~6.40 mg (TPF)·g^-1·h^-1 after 40 day treatment, which was obviously lower than in sludge without earthworms. In addition,the correlation analysis evidenced that significantly positive relationships existed for DHA,MBC and OM in the decomposition treatment. This study verified that the presence of earthworms could stimulate the microbial numbers at the beginning of vermicomposting and accelerate the degradation of organic materials in sewage sludge treatment. As a result, the final products became more stable with relatively lower values of both MBC and DHA.