Ideal Carbon Utilisation (ICU) - Sweden Water Research

Ideal Carbon Utilisation (ICU)

This is Elin Ossiansson's PhD project. Elin is an industrial PhD student working for Sweden Water Research, VA SYD and Chalmers University of Technology.

PHD PROJECT In municipal wastewater treatment, easily available carbon is needed as energy source for bacteria that remove nutrient from the water. At many wastewater treatment plants, ethanol or methanol is added to the wastewater in order to enhance nitrogen removal, but this is expensive and has a high climate impact. As opposed to chemical addition, utilisation of the already existing carbon in the wastewater requires degradation (hydrolysis) of particulate carbon to enable uptake by bacteria. If the nutrient removal is to obtain enough carbon source. The carbon that cannot be used in the biological nutrient removal will we oxidised, which requires oxygen and thereby energy.

Wastewater contains enough carbon to make treatment plant net producers of energy.  The particulate carbon can be removed prior to biological treatment, and used for biogas production. This is energy efficient because it both reduces the energy requirement in the biological treatment, and increases biogas production. However, the carbon that remains in the wastewater needs to be sufficient for the biological nutrient removal.

In the project Ideal Carbon Utilisation (ICU), we study a novel pre-treatment with the potential to optimise the carbon utilisation for both nutrient removal and biogas production. A pilot plant with wastewater filtration and hydrolysis of the filter sludge has been operating for two years at Källby wastewater treatment plant in Lund.

Supervisor: Frank Persson, Chalmers University of Technology

Co-supervisors: Michael Cimbritz, Lund University Faculty of Engineering, David Gustavsson och Simon Bengtsson, VA SYD

  • To gain operational experience and process knowledge from pre-treatment of wastewater with filtration and filter sludge hydrolysis at pilot scale
  • Study the hydrolysis-fermentation of filter sludge at ambient temperature, and assess the possibility to cover the need for carbon source in the biological nutrient removal
  • Study how the wastewater composition affects the potential for carbon source production