title: [Measurement of the effective diffusion coefficient of dissolved oxygen by microelectrodes].
abstract: Mass transfer of oxygen inside biocarrier is a key factor determining the performance of simultaneous nitrification and denitrification. Measurement of the effective diffusion coefficient of dissolved oxygen (DO) in a spherical biocarrier was introduced. Based on a diffusion-reaction model, the effective diffusion coefficient of dissolved oxygen (DO) was calculated by curve-fitting the depth distribution of DO measured by microelectrode. At the filling rate of 25%, simultaneous nitrification and denitrification is achieved in the continuous flow reactor with organic removal loading of 5.6 kg/(m3 x d). The effective diffusivity coefficient of DO is calculated to be 0.017 2 m2/d, which means the turbulence diffusion prevailes against the molecular diffusion inside the biocarrier.
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, China. zhouxh02@mails.tsinghua.edu.cn
authors.forename: Xiao-Hong
authors.initials: XH
authors.lastname: Zhou
authors.forename: Han-Chang
authors.initials: HC
authors.lastname: Shi
authors.forename: Miao
authors.initials: M
authors.lastname: He
mesh_terms: D000332:Aerobiosis; D019149:Bioreactors; D004058:Diffusion; D008839:Microelectrodes; D009584:Nitrogen / Q000737:chemistry / Q000378:metabolism; D010100:Oxygen / Q000737:chemistry / Q000378:metabolism*; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods*; D018508:Water Purification / Q000295:instrumentation / Q000379:methods*
chemical_list: D009584:Nitrogen; D010100:Oxygen