Pilot-scale vermicomposting of sewage sludge mixed with mature vermicompost using earthworm reactor of frame composite structure.

To improve the efficiency of sludge vermicomposting, a new cost-effective method is provided. It uses a new earthworm reactor with a frame composite structure for vermicomposting and reuses mature vermicompost to condition the sludge. Under the optimum conditions (proportion of earthworm droppings: 15%; thickness of sludge laying: 6 cm; moisture content of initial sludge mixture: 75%), the method of continuous operation described herein works well and presents three advantages compared with the traditional vermicomposting method: the short time required for vermicomposting (20.25 h); covering a small area (5 m2/t·d); and a low cost. In addition, the vermicompost obtained from sludge vermicomposting shows better stability and maturity (C/N: 14.96; GI: 86.42%; TOC: 188.5 mg/g; ash content: 516.2 mg/g). The investigation of the associated mechanisms, including 3D-EEM, TGA, SEM and microbial community analyses, revealed that the addition of mature vermicompost can speed up the progress of decomposition and humification of organic matter in sludge. The process of vermicomposting and adding mature vermicompost significantly modified the microbial community of sewage sludge, and the changes in microorganisms in vermicompost were related to the microorganisms in the earthworm gut. Copyright © 2020 Elsevier B.V. All rights reserved.

Citation

Xiuren Hu, Tong Zhang, Ganpei Tian, Limin Zhang, Bo Bian. Pilot-scale vermicomposting of sewage sludge mixed with mature vermicompost using earthworm reactor of frame composite structure. The Science of the total environment. 2021 May 01;767:144217

Mesh Tags

Substances

PMID: 33434844

search → result