Master’s thesis proposal autumn 2020: Biofilm modelling of the partial denitrification and anammox process



Municipal wastewater treatment plants possess the capacity to be energy-positive through allocation of organic carbon to biogas production. This is, however, in direct conflict with the need of readily available organic carbon source in the traditional biological nutrient removal (BNR) processes. The anaerobic ammonium oxidation (anammox) process is autotrophic, but dependent of a nitrite provider. Inhibition of nitrite oxidising bacteria (NOB) have shown to be difficult in cold and weak municipal wastewaters. Instead, heterotrophic partial denitrification seems to be a better nitrite provider. Partial denitrification coupled to anammox (PDA) is a novel process and only one study has investigated fermented sludge as a carbon source for the PDA process. The PDA process coupled with preceding partial nitrification has the potential of decreasing the aeration need up to 50% and organic carbon need up to 80% compared to conventional nitrification-denitrification.

VA SYD is a municipal joint authority, operating several wastewater treatment plants (WWTPs) in southern Sweden. VA SYD and its R&D company Sweden Water Research want to explore the possibilities implementing the PDA process in the next generation of wastewater treatment plants.


The main objectives of this project are (i) to set-up a model of a nitrification biofilm process with a following one-stage PDA biofilm process, and (ii) to calibrate and validate the model by using data from the literature and a parallel ongoing lab-scale study at Lund University.


First, a literature review, about biofilm process modelling and the nitrification and PDA processes, is performed. Thereafter, the model is built in MatLab. The model is calibrated and validated using existing data. Simulations show process performance e.g. regarding process rates and nitrous oxide emissions. A comparison is also made with a conventional activated sludge plant, by modelling, investigating differences in energy usage, biogas production and space requirements.


Contact the one of the supervisors for the project:

  • Ulf Jeppsson, senior lecturer, Lund University (
  • Ramesh Saagi, postdoc, Lund University (
  • David Gustavsson, research leader, VA SYD/Sweden Water Research (