title: Enhanced anaerobic digestion of waste activated sludge of low organic content in a novel digester.
abstract: A novel digester, termed an internal circulation anaerobic digester (ICAD), was developed to intensify sludge digestion. It consists of reaction zone, settling zone, thickening zone, riser and downcomer. Internal circulation in the digester is intensified by backflow biogas. The mesophilic ICAD treating thermal pretreated waste activated sludge with volatile suspended solids (VSS)/suspended solids (SS) of 0.45-0.49 was conducted in this study to reduce and stabilize the low organic content sludge. The results showed that the VSS removal rate and biogas rate reached 46.0% and 0.72 m(3)/kg VSS(fed) at hydraulic retention time (HRT) of 15 days. VSS/SS and soluble chemical oxygen demand (SCOD) of the effluent sludge ranged from 0.39 to 0.41 and 274 mg/L to 473 mg/L, respectively, under various HRTs from 10 to 27 days. The degradation ability of ICAD derived from the improved mass transfer by internal circulation and long solid retention time at short HRT is compared with continuous stirred tank reactor.
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China E-mail: wu_jing@mail.tsinghua.edu.cn.
authors.forename: J
authors.initials: J
authors.lastname: Wu
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China E-mail: wu_jing@mail.tsinghua.edu.cn; Department of Civil Engineering, College of Engineering and Informatics, NUI Galway, Galway, Ireland.
authors.forename: Y
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China E-mail: wu_jing@mail.tsinghua.edu.cn.
authors.forename: Z P
authors.initials: ZP
authors.lastname: Cao
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China E-mail: wu_jing@mail.tsinghua.edu.cn.
authors.forename: Z H
authors.initials: ZH
authors.lastname: Li
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China E-mail: wu_jing@mail.tsinghua.edu.cn.
authors.forename: Y Y
authors.initials: YY
authors.lastname: Hu
authors.affiliation: Laboratory of Reactions and Process Engineering, Université de Lorraine, CNRS, 1, rue Grandville, BP 20451, 54001 Nancy cedex, France.
authors.forename: H Z
authors.initials: HZ
authors.lastname: Li
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China E-mail: wu_jing@mail.tsinghua.edu.cn.
authors.forename: J E
authors.initials: JE
authors.lastname: Zuo
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China E-mail: wu_jing@mail.tsinghua.edu.cn.
authors.forename: K J
authors.initials: KJ
authors.lastname: Wang
mesh_terms: D000693:Anaerobiosis; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D012722:Sewage / Q000737:chemistry*
chemical_list: D012722:Sewage