title: Operation performance and granule characterization of upflow anaerobic sludge blanket (UASB) reactor treating wastewater with starch as the sole carbon source.
abstract: Long-term performance of a lab-scale UASB reactor treating starch wastewater was investigated under different hydraulic retention times (HRT). Successful start-up could be achieved after 15days' operation. The optimal HRT was 6h with organic loading rate (OLR) 4g COD/Ld at COD concentration 1000mg/L, attaining 81.1-98.7% total COD removal with methane production rate of 0.33L CH4/g CODremoved. Specific methane activity tests demonstrated that methane formation via H2-CO2 and acetate were the principal degradation pathways. Vertical characterizations revealed that main reactions including starch hydrolysis, acidification and methanogenesis occurred at the lower part of reactor ("main reaction zone"); comparatively, at the up converting acetate into methane predominated ("substrate-shortage zone"). Further reducing HRT to 3h caused volatile fatty acids accumulation, sludge floating and performance deterioration. Sludge floating was ascribed to the excess polysaccharides in extracellular polymeric substances (EPS). More efforts are required to overcome sludge floating-related issues.
authors.affiliation: Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, Sendai, Miyagi 980-8579, Japan. Electronic address: luxq@epl1.civil.tohoku.ac.jp.
authors.forename: Xueqin
authors.initials: X
authors.lastname: Lu
authors.affiliation: National Institute for Environmental Studies, Onogawa 16-2, Tsukuba, Ibaraki 305-0053, Japan. Electronic address: zhenguangyin@163.com.
authors.forename: Guangyin
authors.initials: G
authors.lastname: Zhen
authors.affiliation: Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, Sendai, Miyagi 980-8579, Japan.
authors.forename: Adriana Ledezma
authors.initials: AL
authors.lastname: Estrada
authors.affiliation: Graduate School of Environmental Studies, Tohoku University, Sendai, Miyagi 980-8579, Japan.
authors.forename: Mo
authors.initials: M
authors.lastname: Chen
authors.affiliation: Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, Sendai, Miyagi 980-8579, Japan.
authors.forename: Jialing
authors.initials: J
authors.lastname: Ni
authors.affiliation: Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, Sendai, Miyagi 980-8579, Japan.
authors.forename: Toshimasa
authors.initials: T
authors.lastname: Hojo
authors.affiliation: Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, Sendai, Miyagi 980-8579, Japan.
authors.forename: Kengo
authors.initials: K
authors.lastname: Kubota
authors.affiliation: Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, Sendai, Miyagi 980-8579, Japan; Graduate School of Environmental Studies, Tohoku University, Sendai, Miyagi 980-8579, Japan. Electronic address: yyli@epl1.civil.tohoku.ac.jp.
authors.forename: Yu-You
authors.initials: YY
authors.lastname: Li
mesh_terms: D000085:Acetates / Q000378:metabolism; D000693:Anaerobiosis; D056804:Biofuels; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D005227:Fatty Acids / Q000378:metabolism; D008697:Methane / Q000378:metabolism; D012722:Sewage; D013050:Spectrometry, Fluorescence; D013213:Starch / Q000378:metabolism*; D014865:Waste Disposal, Fluid / Q000295:instrumentation* / Q000379:methods*; D062065:Wastewater / Q000737:chemistry
chemical_list: D000085:Acetates; D056804:Biofuels; D005227:Fatty Acids; D008697:Methane; D012722:Sewage; D013213:Starch; D062065:Wastewater
keywords: Extracellular polymeric substances (EPS); Granular sludge; Methane; Starch; Upflow anaerobic sludge blanket (UASB)