The demand for more sustainable and climate-proof water management is increasing worldwide. Due to growing demand and drought in certain regions, the pressure on the extraction of drinking water is increasing. A solution to this problem is the decentralised purification of wastewater from residential areas, whereby (ideally, grey and black) wastewater is treated locally so that the water can be reused, for example for irrigating urban green areas.
Unfortunately, the decentralised purification systems used to date do not yet remove micro-pollutants, such as medicines. As a result, temporary underground storage or discharge into surface water will not be permitted in the future. Within the Project “Put BAK to work”, Desah and Bioclear earth are investigating whether we can develop an addition to existing technology that ensures that these contaminants are removed, in order to make the reuse of water at district level possible and to comply with all legal requirements, including those of the future.
BAK stands for Biologically Active Carbon. Activated carbon has been used for decades. The mechanism operates by causing toxic compounds to adhere to the large internal surface of activated carbon, which consists of a fine microstructure with numerous small pores. Over time, the activated carbon becomes saturated and must be replaced. The concept of an activated carbon filter is that it breaks down the undesired compounds and regenerates the activated carbon filter using specially selected bacteria.
The uniqueness of our approach is that we want to enable the controllability of the microbiological processes in activated carbon filters. We believe this can be achieved by applying a suitable pre-treatment technique. We want to compare different pre-treatment methods in order to select the most effective method. Therefore, the idea is that after a pre-treatment step, we can better regulate the processes in a BAK, for example by reducing the supply of bacteria from the wastewater or by adding specific micro-pollution-degrading bacteria at the most suitable place in the system. The ultimate goal is to create a well-manageable, controllable and low-maintenance filter system that can be used in decentralised wastewater treatment plants at a neighbourhood level.
If you would like to know more about the BAK project, please contact Maurice Henssen or Freek van den Heuvel.
This research is made possible by the North Netherlands Cooperation Agency, the European Regional Development Fund, the Province of Groningen, the Province of Friesland and the Municipality of Groningen. Project number OPSN0399