title: Effect of earthworms on the biochemical characterization of biofilms in vermifiltration treatment of excess sludge.
abstract: In this study, the biofilms formed in a vermifilter (VF) with earthworms and a conventional biofilter (BF) without earthworms were compared to investigate the effects of earthworms on the characteristics of biofilms during an excess sludge treatment period of 4months. Typical macrographs and micrographs of the biofilms showed that the feeding and casting actions of earthworms remarkably modified the VF morphology. Elemental analysis and fluorescence spectra indicated that earthworms enhanced the stabilization of organic matter by accelerating the mineralization and humification of organic materials during vermiconversion. In addition, bacterial communities inhabiting the VF biofilm showed that earthworms increased both bacterial diversity and metabolic activities in the film, as revealed by automatic testing bacteriology (ATB) expression and sequencing data. These results demonstrate that earthworms influence the structure and biochemical characteristics of biofilms and enhance their bacterial diversity and functions for improved sludge stabilization.
authors.affiliation: Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Yang
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.forename: Meiyan
authors.initials: M
authors.lastname: Xing
authors.forename: Zhibo
authors.initials: Z
authors.lastname: Lu
authors.forename: Qiong
authors.initials: Q
authors.lastname: Yan
mesh_terms: D000818:Animals; D001419:Bacteria / Q000235:genetics / Q000302:isolation & purification; D001483:Base Sequence; D001673:Biodegradation, Environmental; D018441:Biofilms; D017931:DNA Primers; D005374:Filtration / Q000379:methods*; D009835:Oligochaeta / Q000378:metabolism*; D012722:Sewage; D012988:Soil Microbiology; D013050:Spectrometry, Fluorescence
chemical_list: D017931:DNA Primers; D012722:Sewage
keywords: Biochemical characterization; Biofilm; Earthworm; Sludge stabilization; Vermifilter