title: Optimizing vermifilter depth by process performance collaborated with the evolutions of microbial characteristics during sewage sludge treatment.
abstract: The present study focuses on optimizing filter depth on sludge reduction in a four-stage vermifiltration during the course of treating excess sludge continuously. The results indicated that when the filter depth exceeded 75 cm, though the fourth stage can further advance the sludge reduction, its contribution for the total sludge reduction was lower than 10%, while the aerobic bacteria, especially the dominant bacteria (Proteobacteria and Bacteroidetes), kept a high similarity as the filter depth varied. Furthermore, earthworm activities attributed to aerobic bacteria being preferentially selected in the system, positively supporting the organic decomposition. As far as economic cost and process performance are concerned, a 75-cm vermifilter was recommended to efficiently and economically achieve the required standard for sewage sludge reduction and stabilization.
authors.affiliation: The Institute of Biofilm Technology, 1239 Siping Road, Shanghai, China.|Key Laboratory of Yangtze River Water Environment, Ministry of Education, 1239 Siping Road, Shanghai, China.|College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
authors.forename: Gege
authors.initials: G
authors.lastname: Yang
authors.affiliation: The Institute of Biofilm Technology, 1239 Siping Road, Shanghai, China. xingmeiyan@tongji.edu.cn.|Key Laboratory of Yangtze River Water Environment, Ministry of Education, 1239 Siping Road, Shanghai, China. xingmeiyan@tongji.edu.cn.|College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China. xingmeiyan@tongji.edu.cn.
authors.forename: Meiyan
authors.initials: M
authors.lastname: Xing
authors.affiliation: School of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai, 201418, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.affiliation: The Institute of Biofilm Technology, 1239 Siping Road, Shanghai, China.|Key Laboratory of Yangtze River Water Environment, Ministry of Education, 1239 Siping Road, Shanghai, China.|College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Yang
mesh_terms: D000332:Aerobiosis; D000818:Animals; D041963:Bacteroidetes / Q000235:genetics; D001673:Biodegradation, Environmental; D005374:Filtration; D064307:Microbiota; D058889:Molecular Typing; D009835:Oligochaeta; D020560:Proteobacteria / Q000235:genetics; D012722:Sewage / Q000382:microbiology*
chemical_list: D012722:Sewage
keywords: Filter depth; Microbial community structure; Microbial diversity; Microbial respiration; Sludge reduction