title: Long term effect of MnO2 powder addition on nitrogen removal by anammox process.
abstract: This study examined long-term effect of MnO(2) powder (average diameter of 4-7 μm) on nitrogen removal in anammox process. Two lab-scale up-flow anammox reactors were operated for 380 days, one with and one without MnO(2) powder addition. During the period when only substrate concentrations varied, the maximum nitrogen removal rate in the reactor with MnO(2) addition reached 920.9 g-N/m(3)/d. This value was 2-folds higher than that (464.6 g-N/m(3)/d) of the reactor without MnO(2) addition. The crude enzyme activities of the anammox biomass from the two reactors was measured as 0.531±0.019 and 0.298±0.007 μmol cytochrome c reduced/mg protein/min, respectively. Transmission electron microscopy observation demonstrated more undefined particles existing inside anammox bacterial cell in the reactor with MnO(2) powder addition. Furthermore, filament-like structures inside anammoxosome were observed, which formed a net-like structure with particles as the connecting nodes. The experiment results demonstrated that MnO(2) improved nitrogen removal performance of anammox process.
authors.affiliation: Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, PR China. qscyj@mail.dlut.edu.cn
authors.forename: Sen
authors.initials: S
authors.lastname: Qiao
authors.forename: Zhen
authors.initials: Z
authors.lastname: Bi
authors.forename: Jiti
authors.initials: J
authors.lastname: Zhou
authors.forename: Yingjun
authors.initials: Y
authors.lastname: Cheng
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.forename: Zafar
authors.initials: Z
authors.lastname: Bhatti
mesh_terms: D018533:Biomass; D019149:Bioreactors; D017895:Manganese Compounds / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D009584:Nitrogen / Q000302:isolation & purification*; D010087:Oxides / Q000737:chemistry*; D011208:Powders
chemical_list: D017895:Manganese Compounds; D010087:Oxides; D011208:Powders; C027424:manganese oxide; D009584:Nitrogen