title: Effect of earthworms on the performance and microbial communities of excess sludge treatment process in vermifilter.
abstract: Previous studies have shown that the stabilization of excess sludge by vermifiltration can be improved significantly through the use of earthworms. To investigate the effect of earthworms on enhancing sludge stabilization during the vermifiltration process, a vermifilter (VF) with earthworms and a conventional biofilter (BF) without earthworms were compared. The sludge reduction capability of the VF was ∼85% higher than that of the BF. Specifically, elemental analysis indicated that earthworms enhanced the stabilization of organic matter. Furthermore, earthworm predation strongly regulated microbial biomass while improving microbial activity. Denaturing gradient gel electrophoresis (DGGE) analysis showed that the most abundant microbes in the VF biofilms and earthworm casts were Flavobacterium, Myroides, Sphingobacterium, and Myxococcales, all of which are known to be highly effective at degrading organic matter. These results indicate that earthworms can improve the stabilization of excess sludge during vermifiltration, and reveal the processes by which this is achieved.
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.forename: Zhibo
authors.initials: Z
authors.lastname: Lu
authors.forename: Jian
authors.initials: J
authors.lastname: Yang
authors.forename: Meiyan
authors.initials: M
authors.lastname: Xing
authors.forename: Fen
authors.initials: F
authors.lastname: Yu
authors.forename: Meiting
authors.initials: M
authors.lastname: Guo
mesh_terms: D000818:Animals; D001483:Base Sequence; D001673:Biodegradation, Environmental; D018441:Biofilms; D016000:Cluster Analysis; D058645:Denaturing Gradient Gel Electrophoresis; D004602:Elements; D005374:Filtration / Q000295:instrumentation*; D008969:Molecular Sequence Data; D009835:Oligochaeta / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012722:Sewage / Q000382:microbiology*; D018508:Water Purification / Q000295:instrumentation* / Q000379:methods*
chemical_list: D004602:Elements; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D010088:Oxidoreductases