title: Feeding behavior and trophic relationship of earthworms and other predators in vermifiltration system for liquid-state sludge stabilization using fatty acid profiles.
abstract: The sludge reduction capability (VSS reduction) of vermifilter (VF) was 14.7% higher than that of conventional biofilter (BF) due to the fact that there was a net loss of biomass and energy when the food web in VF is extended. Therefore, feeding behavior and trophic relationship of earthworms and other predators (leeches, lymnaeidaes and limaxes) in VF were investigated using fatty acid (FA) profiles for the first time. Compared with BF biofilm, microbial community structure of VF biofilm got optimized by earthworms that the percentage of protozoa increased from 14.2% to 20.4%. Furthermore, analysis of specific microbial FAs composition in each predator suggested different trophic level of predators resulted from their selective ingestion of different microorganisms, and earthworms were at the second high trophic level in VF food web. Overall findings indicated earthworms modified microbial community and extended the food web of VF and thus enhanced the sludge reduction.
authors.affiliation: The Institute of Biofilm Technology, State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Meiyan
authors.initials: M
authors.lastname: Xing
authors.affiliation: The Institute of Biofilm Technology, State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China. Electronic address: chunhui315@gmail.com.
authors.forename: Chunhui
authors.initials: C
authors.lastname: Zhao
authors.affiliation: The Institute of Biofilm Technology, State Key Laboratory of Pollution Control and Resources Reuse, 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.affiliation: The Institute of Biofilm Technology, State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Baoyi
authors.initials: B
authors.lastname: Lv
mesh_terms: D000818:Animals; D001419:Bacteria / Q000378:metabolism; D001673:Biodegradation, Environmental; D016000:Cluster Analysis; D017753:Ecosystem; D005227:Fatty Acids / Q000378:metabolism*; D005247:Feeding Behavior; D005374:Filtration / Q000379:methods*; D005658:Fungi / Q000378:metabolism; D009835:Oligochaeta / Q000502:physiology*; D011235:Predatory Behavior; D012722:Sewage / Q000737:chemistry*
chemical_list: D005227:Fatty Acids; D012722:Sewage
keywords: Excess sludge; Food web; Microbial community structure; Predator; Vermifilter