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Carolina Ospina-Betancourth

Use of nitrogen fixing microbial mixed cultures for wastewater valorisation.


Project supervisors

  • School of Engineering
  • School of Natural and Environmental Sciences
    • Prof Ian Head

Project description

Nitrogen (N2) is a problem. Nitrogen fixed by the Haber Bosch process (HBP) is increasing in cost. This has raised interest in alternative ways to produce it to meet agricultural demands. Fertilisers cause environmental problems related to eutrophication, greenhouse gasses and soil acidification. Sludge from wastewater treatment plants contains free-living N2 fixing bacteria (NFB). This is a potential inoculum for a nitrogen-fixing bioreactor. The energy contained in low nitrogen wastewaters could act as a carbon source to feed the bioreactor.

There has been very little research on nitrogen-fixing bioreactors. Specific fixing rates of NFB from wastewater sludge are not established. This project will explore a biotechnological solution for residue valorisation. We will use N2 fixing bioreactors inoculated with wastewater sludge and fed with low nitrogen wastewaters. Fixed N2 and selected sludge could potentially be used as a biofertiliser. We could also modify the technology by making use of wastewaters with higher N2 content. I will elucidate the microbial ecology in the bioreactors through molecular biology techniques.