Biological Nitrogen Removal Database
A manually curated data resource for microbial nitrogen removal
Biological Nitrogen Removal Database
A manually curated data resource for microbial nitrogen removal
Influent:Groundwater
Denitrification system:Chemoautotrophic denitrification-Nitrate-dependent anaerobic ferrous oxidizing (NAFO)
Denitrifying reactor:Continuous-flow sand packed bed columns
Medium:Iron coated sand
Culture taken from:Activated sludge
Organism (s) cultured:nan
Respiration:Anaerobic
Electron donor:Ferrous iron
Electron acceptor:Nitrate
Input NO3-N (mg/l):nan
Nitrate removal rate (mg NO3-N/l/h):nan
Denitrification rate (gNO3-N removed/m3/day):nan
Microorganisms identified:nan
Molecular tools:nan
Major findings:Microbial denitrification based on nitrate removal was effective as a bioremediation strategy for the oxidation of ferrous iron and arsenite. It resulted in the enhanced immobilization of aqeous arsenic to the iron coated sand beads resulting in the formation of Fe(III) (hydr)oxide coated sands with adsorbed As(V).
Authors:Sun et al., 2009
Title:Arsenite and Ferrous Iron Oxidation Linked to Chemolithotrophic Denitrification for the Immobilization of Arsenic in Anoxic Environments
Pubmed link:None
Full research link:Link
Abstract:The objective of this study was to explore a bioremediation strategy based on injecting NO3? to support the anoxic oxidation of ferrous iron (Fe(II)) and arsenite (As(III)) in the subsurface as a means to immobilize As in the form of arsenate (As(V)) adsorbed onto biogenic ferric (Fe(III)) (hydr)oxides. Continuous flow sand filled columns were used to simulate a natural anaerobic groundwater and sediment system with co-occurring As(III) and Fe(II) in the presence (column SF1) or absence (column SF2) of nitrate, respectively. During operation for 250 days, the average influent arsenic concentration of 567 ?g L?1 was reduced to 10.6 (±9.6) ?g L?1 in the effluent of column SF1. The cumulative removal of Fe(II) and As(III) in SF1 was 6.5 to 10-fold higher than that in SF2. Extraction and measurement of the mass of iron and arsenic immobilized on the sand packing of the columns were close to the iron and arsenic removed from the aqueous phase during column operation. The dominant speciation of the immobilized iron and arsenic was Fe(III) and As(V) in SF1, compared with Fe(II) and As(III) in SF2. The speciation was confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results indicate that microbial oxidation of As(III) and Fe(II) linked to denitrification resulted in the enhanced immobilization of aqueous arsenic in anaerobic environments by forming Fe(III) (hydr)oxide coated sands with adsorbed As(V).