University of SaskatchewanHARVEST
  • Login
  • Submit Your Research
  • About
    • About HARVEST
    • Guidelines
    • Browse
      • All of HARVEST
      • Communities & Collections
      • By Issue Date
      • Authors
      • Titles
      • Subjects
      • This Collection
      • By Issue Date
      • Authors
      • Titles
      • Subjects
    • My Account
      • Login
      JavaScript is disabled for your browser. Some features of this site may not work without it.
      View Item 
      • HARVEST
      • Electronic Theses and Dissertations
      • Graduate Theses and Dissertations
      • View Item
      • HARVEST
      • Electronic Theses and Dissertations
      • Graduate Theses and Dissertations
      • View Item

      Coupled iron reduction-ammonium oxidation (Feammox) in alkaline soils polluted with nitrogen

      Thumbnail
      View/Open
      BROCKAMP-THESIS-2021.pdf (2.096Mb)
      Date
      2021-02-22
      Author
      Brockamp, Rachel Lynn
      ORCID
      0000-0001-5700-0851
      Type
      Thesis
      Degree Level
      Masters
      Metadata
      Show full item record
      Abstract
      Although nitrogen fertilizers help stimulate plant and microbial growth in N-limited soils, the use of excess N fertilizers to improve agricultural yield in Canada can cause adverse side effects of groundwater and surface water pollution, greenhouse gas production, soil acidification, and human health issues. Two N-removal pathways currently used to treat N-polluted wastewater and groundwater include denitrification and anaerobic ammonium oxidation (anammox). This study explored a novel anaerobic N-removal pathway that converts ammonium (NH4+) to inert nitrogen gas (N2) or nitrite (NO2-) while reducing Fe(III) to Fe(II), a.k.a. iron ammonium oxidation (Feammox) via a 118-day anaerobic incubation which included four sequential biostimulation experiments. The goal of the incubation was to identify Feammox in neutral-alkaline soil samples from a N-polluted site in Alberta by stimulating the bioremediation of NH4+. This was done amending the soils with vitamins and sources of NH4+ and Fe(III). The treatments for the anaerobic controls and soil slurries included one or more of the following: ammonium chloride (A), 2-line ferrihydrite (FH), and ferric citrate (FC). Amendments were added to these treatments in four sequential Feammox biostimulation experiments: 1) FC, FH, and A, 2) FC and FH, 3) FC and A, and 4) vitamin and molybdate solutions. The soil slurry with ferric citrate and NH4Cl amendments (S-FCA) had the most notable dissolved NH4+-N loss during the 118-day incubation, particularly when FC and A were added concurrently, i.e. a decrease of 14 ± 1.7 mg L-1 dissolved NH4+-N in the first experiment and a decrease of 13 ± 6.5 mg L-1 dissolved NH4+-N in the third experiment. S-FCA also exhibited signs of Fe(III) reduction throughout the incubation. In the incubation all samples generated minimal dissolved NO2- (0-2 mg L-1). Following the 118-day incubation the S-FCA treatment was subcultured to reproduce results; however, the subcultures did not show notable NH4+ loss, possibly due to dilution or N mineralization. Overall, this study showed a correlation between concurrent ferric citrate and NH4Cl amendments and dissolved NH4+-N loss in near-neutral anaerobic conditions; however, it did not provide clear evidence of Feammox. Additional experiments are necessary to isolate Feammox.
      Degree
      Master of Science (M.Sc.)
      Department
      Soil Science
      Program
      Soil Science
      Committee
      Siciliano, Steven; Peak, Derek; Stein, Lisa; Farrell, Richard
      Copyright Date
      January 2021
      URI
      http://hdl.handle.net/10388/13269
      Subject
      Nitrogen, pollution, fertilizers, bioremediation, iron, ammonium, oxidation, soil
      Collections
      • Graduate Theses and Dissertations
      University of Saskatchewan

      University Library

      © University of Saskatchewan
      Contact Us | Disclaimer | Privacy