title: Responses of anaerobic granule and flocculent sludge to ceria nanoparticles and toxic mechanisms.
abstract: Effects of CeO2-NPs on anaerobic fermentation were investigated from the processes of acidification and methanation with anaerobic granule sludge and anaerobic flocculent sludge as the targets. Results showed that acidification process was more sensitive to CeO2-NPs than methanation process. Both types of sludge produced less short-chain fatty acid compared to the control, with a reduction of 15-19% for the flocculent sludge at the dosage of 5, 50 and 150 mg CeO2-NPs/g-VSS, and a reduction of 35% for the granular sludge at 150 mg CeO2-NPs/g-VSS. CeO2-NPs caused no inhibition to methanation process. Most of CeO2-NPs distributed on the surface of sludge as revealed by fluorescence labeled CeO2-NPs. The toxicity of CeO2-NPs to anaerobic sludge did not result from reactive oxygen species. Physical penetration and membrane reduction may be important toxic mechanisms.
authors.affiliation: Key Laboratory of Water and Sediment Sciences of Ministry of Education,; State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China.
authors.forename: Jingyun
authors.initials: J
authors.lastname: Ma
authors.forename: Xiangchun
authors.initials: X
authors.lastname: Quan
authors.forename: Xiurong
authors.initials: X
authors.lastname: Si
authors.forename: Yachuan
authors.initials: Y
authors.lastname: Wu
mesh_terms: D000693:Anaerobiosis / Q000187:drug effects; D001704:Biopolymers / Q000032:analysis; D002563:Cerium / Q000633:toxicity*; D005110:Extracellular Space / Q000737:chemistry; D005227:Fatty Acids / Q000378:metabolism; D005427:Flocculation / Q000187:drug effects; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008697:Methane / Q000378:metabolism; D050296:Microbial Viability / Q000187:drug effects; D053758:Nanoparticles / Q000633:toxicity*; D017382:Reactive Oxygen Species / Q000378:metabolism; D012722:Sewage / Q000382:microbiology*
chemical_list: D001704:Biopolymers; D005227:Fatty Acids; D017382:Reactive Oxygen Species; D012722:Sewage; D002563:Cerium; D007770:L-Lactate Dehydrogenase; D008697:Methane
keywords: Acidification; Anaerobic flocculent sludge; Anaerobic granule sludge; Ceria nanoparticles; Methanation