title: Characteristics of biofilm attaching to carriers in moving bed biofilm reactor used to treat vitamin C wastewater.
abstract: In order to investigate characteristics of biofilm attaching firmly to carriers in the moving bed biofilm reactor (MBBR) used for vitamin C wastewater treatment, experiments were undertaken with instrumental analysis methods. Scanning electron microscopy (SEM) micrographs of MBBR biofilms revealed that there were rod-shaped microbes and cocci in the biofilm, and microbes were embedded within medium substances and the biofilm matrix adhered firmly to carriers, leading to the formation of a smooth compacted surface at the base of the biofilm. Transmission electron microscopy (TEM) analysis revealed that extracellular polymeric substances (EPS) layer surrounded cell, sequestered inorganics to form a mixed structure, which ensured firm attachment of the biofilm to the carrier. X-ray diffraction (XRD) experiments and thermogravimetry analysis revealed that (i) the biofilm contained many inorganic substances, about 70.5%, and the inorganic substances contained multiple classes of inorganic with a high boiling point; (ii) inorganic elements such as calcium and phosphorous were selectively absorbed and accumulated in the biofilm as insoluble compounds with amorphous phases, rendering the biofilm highly resistant to detachment. Fourier-transform infrared (FTIR) spectroscopy showed carbohydrates were the main EPS.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu, People's Republic of China.
authors.forename: Xiao-bing
authors.initials: XB
authors.lastname: Hu
authors.forename: Ke
authors.initials: K
authors.lastname: Xu
authors.forename: Zhao
authors.initials: Z
authors.lastname: Wang
authors.forename: Li-li
authors.initials: LL
authors.lastname: Ding
authors.forename: Hong-qiang
authors.initials: HQ
authors.lastname: Ren
mesh_terms: D001205:Ascorbic Acid / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development*; D019149:Bioreactors / Q000382:microbiology*; D001711:Biotransformation; D002241:Carbohydrates / Q000032:analysis; D007287:Inorganic Chemicals / Q000032:analysis; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D017550:Spectroscopy, Fourier Transform Infrared; D013818:Thermogravimetry; D062065:Wastewater / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D001205:Ascorbic Acid; D002241:Carbohydrates; D007287:Inorganic Chemicals; D062065:Wastewater