title: A kinetic study of autohydrogenotrophic denitrification at the optimum pH and sodium bicarbonate dose.
abstract: In this study the kinetics of autohydrogenotrophic denitrification was studied under optimum solution pH and bicarbonate concentration. The optimal pH and bicarbonate concentration were firstly obtained using a design of experiment (DOE) methodology. For this purpose a total of 11 experiments were carried out. Sodium bicarbonate concentrations ranging of 20-2000 mg/L and pH values from 6.5 to 8.5 were used in the optimization runs. It was found that the pH has a more pronounced effect on the denitrification process as compared to the bicarbonate dose. The developed quadratic model predicted the optimum conditions at pH 8 and 1100 mg NaHCO(3)/L. Using these optimal conditions, the kinetics of denitrification for nitrate and nitrite degradation were investigated in separate experiments. Both processes were found to follow a zero order kinetic model. The ultimate specific degradation rates for nitrate and nitrite remediation were 29.60 mg NO(3)(-)-N/g MLVSS/L and 34.85 mg NO(3)(-)-N/g MLVSS/L respectively, when hydrogen was supplied every 0.5h.
authors.affiliation: Faculty of Engineering, Department of Civil Engineering, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Shahin
authors.initials: S
authors.lastname: Ghafari
authors.forename: Masitah
authors.initials: M
authors.lastname: Hasan
authors.forename: Mohamed Kheireddine
authors.initials: MK
authors.lastname: Aroua
mesh_terms: D000704:Analysis of Variance; D052818:Autotrophic Processes / Q000187:drug effects*; D001673:Biodegradation, Environmental / Q000187:drug effects; D006859:Hydrogen / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007700:Kinetics; D008954:Models, Biological; D009566:Nitrates / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000187:drug effects; D010100:Oxygen / Q000302:isolation & purification; D017693:Sodium Bicarbonate / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D009566:Nitrates; D009573:Nitrites; D006859:Hydrogen; D017693:Sodium Bicarbonate; D009584:Nitrogen; D010100:Oxygen