title: Effect of nitrate concentration, pH, and hydraulic retention time on autotrophic denitrification efficiency with Fe(II) and Mn(II) as electron donors.
abstract: The role of electron donors (Fe(2+) and Mn(2+)) in the autotrophic denitrification of contaminated groundwater by bacterial strain SY6 was characterized based on empirical laboratory-scale analysis. Strain SY6 can utilize Fe(2+) more efficiently than Mn(2+) as an electron donor. This study has shown that the highest nitrate removal ratio, observed with Fe(2+) as the electron donor, was approximately 88.89%. An immobilized biological filter reactor was tested by using three levels of influent nitrate (10, 30, and 50 mg/L), three pH levels (6, 7, and 8), and three levels of hydraulic retention time (HRT; 6, 8, and 12 h), respectively. An optimal nitrate removal ratio of about 95% was achieved at pH 6.0 using a nitrate concentration of 50 mg/L and HRT of 12 h with Fe(2+) as an electron donor. The study showed that 90% of Fe(2+) and 75.52% removal of Mn(2+) were achieved at pH 8.0 with a nitrate concentration of 50 mg/L and a HRT of 12 h. Removal ratio of Fe(2+) and Mn(2+) is higher with higher influent nitrate and HRT. A weakly alkaline environment assisted the removal of Fe(2+) and Mn(2+).
authors.affiliation: School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China E-mail: sjf1977518@sina.com; State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: Jun-Feng
authors.initials: JF
authors.lastname: Su
authors.affiliation: School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China E-mail: sjf1977518@sina.com.
authors.forename: Jing-Xin
authors.initials: JX
authors.lastname: Shi
authors.affiliation: School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China E-mail: sjf1977518@sina.com.
authors.forename: Ting-Lin
authors.initials: TL
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Ma
authors.affiliation: School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China E-mail: sjf1977518@sina.com.
authors.forename: Jin-Suo
authors.initials: JS
authors.lastname: Lu
authors.affiliation: School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China E-mail: sjf1977518@sina.com.
authors.forename: Shao-Fei
authors.initials: SF
authors.lastname: Yang
mesh_terms: D052818:Autotrophic Processes; D019149:Bioreactors / Q000382:microbiology; D058440:Denitrification; D004583:Electrons; D005296:Ferrous Compounds; D060587:Groundwater; D009566:Nitrates / Q000737:chemistry*; D009589:Nitrogen Oxides
chemical_list: D005296:Ferrous Compounds; D009566:Nitrates; D009589:Nitrogen Oxides