LEIXu-yang,ZHANG Zhi-hua,CUIGuang-yu,et al.Effect of Earthworms on Stabilization Path of the Composting Process for Municipal Sludge[J].China Water & Wastewater,2023,39(21):13-20.
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Effect of Earthworms on Stabilization Path of the Composting Process for Municipal Sludge

China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU] volume: 第39卷 Number: 第21期 Page: 13-20 Column: Date of publication: 2023-11-01
Author(s):
LEI　Xu-yang1;  ZHANG Zhi-hua1;  CUI　Guang-yu2;  LIU　Yan-juan3;  HOU　Su-xia1;  LI　Bo1
（1. Department of Resource and Environmental Engineering， Hebei Vocational University of Technology and Engineering， Xingtai 054000， China； 2. School of Environment and Energy， Peking University Shenzhen Graduate School， Shenzhen 518055， China； 3. Schcool of New Materials and Chemical Engineering， Tangshan University， Tangshan 063000， China）
Keywords:
earthworm;  municipal sludge;  composting;  stabilization path;  PCR-DGGE
Abstract:
At 20 ℃, Eisenia foetida was used to treat municipal sludge with a particle size of 5 mm. The influence of earthworms on the stabilization path of municipal sludge composting process was studied by examining the changes in physicochemical indicators, and the changes in microbial population structure were explored using PCR-DGGE technology. The results indicated that the change trend of both the earthworm treatment group and control group were essentially identical. As composting time increased, organic matter (OM) decreased significantly, dissolved organic carbon (DOC) initially increased and then decreased, NH4+-N increased significantly, NO3--N in the control group remained low while it sharply rose after 50 days in the earthworm treatment group. At the end of composting, OM and DOC were considerably lower in the earthworm treatment group than those in the control group (p<0.05), whereas NH4+-N and NO3--N were notably higher than those in the control group (p<0.05). Principal component analysis (PCA) revealed that both groups’ stabilization process was characterized by degradation of organic matter, accumulation of DOC, ammonification and nitrification in order. Earthworms only accelerated municipal sludge’s stabilization rate but did not alter its stabilization path. The results of PCR-DGGE analysis revealed that both the earthworm treatment group and the control group exhibited a dominance of microorganisms involved in lignin, cellulose, chitin, and other refractory organic matter at the end of composting. Additionally, there was an enhanced relative abundance of Mortierellales within the system which contributed to a reduction in plant pathogens present in the compost products. Earthworms facilitate changes in the environmental conditions promoting microbial population turnover without disrupting its overall structure.
Last Update: 2023-11-01