WP5: Removing micropollutants and microplastics by biofiltration - Sweden Water Research


Biofilters as an option for decentralized treatment for wastewater, CSO and stormwater

WP5: Removing micropollutants and microplastics by biofiltration

Previous laboratory experiments with sandfilter columns have shown biofilter reactors being effective for removal of organic micropollutants from waste- and stormwater. The removal rate is dependent on the pollutants retention time in the system, the surface area of the media, and activity of the microbes.

Activated sludge is used to grow the biofilm for enhancement of degradation, as it along with sorption is known important process for removal. Additionally the behavior of microplastic in the system will be investigated since it has not thoroughly been studied before.

Biofilter Pilot plant

The pilot plant is located at BIOFOS Wastewater Treatment Plant, Avedøre, Copenhagen, Denmark.


Biofilters can have a polishing effect on polluted waters thus the aim is to explore and develop an intensified system for decentralised treatment of waste- and stormwater for removal of micro-pollutants and -plastics.


Determine consequences and borders of long-term use of a biofilter thereby optimize processes effecting the removal of micropollutants. Furthermore, we will go into details with kinetics, removal rates, and transformation products under different operational conditions.

First results

Natural logarithm of inlet/outlet concentrations versus Hydraulic Residence Time (HRT); fitted to single first-order kinetics.


  • Gain understanding on the relevant processes control
  • Improve the design: enhanced surface/volume ratio
  • Optimize the processes

Contact information

Key person

Nadia B. Nord, AU

Other participants

Ulla E. Bollmann, AU
Jes Vollertsen, AAU
Dines Thornberg, Biofos


Kai Bester, AU, kb@envs.au.dk


Prof. Kai Bester, kb@envs.au.dk Aarhus University, Dep. of Environ. Sci., Frederiksborgvej 399, DK-4000 Roskilde