Over the past years the number of aquifer thermal energy storage (ATES) systems has grown considerably due to the growing demand for sustainable energy. Especially in urban areas these aquifer storages systems for heat and cold are a good alternative for fossil fuels. In the Netherlands approximately 2000 ATES systems are operational. During the summer cold water is extracted from the soil and used for cooling buildings. The heated water is pumped back into the soil and stored for later use. During the winter the stored water is used to warm up buildings. In our ATES plus system we use this water circulation system to improve groundwater quality.
The development of ATES plus is an initiative of Bioclear earth in cooperation with Brabant water, T&K Service, the Municipalities of Den Bosch, Apeldoorn and Tilburg, the Province of North Brabant, Hydreco, IF Technology, University of Wageningen and the Department of Waterways and Public Works. The aim of this project is to add a new functionality to existing and new aquifer thermal energy storage systems: improving groundwater quality. In urban areas chlorinated hydrocarbons are still found in the groundwater regularly. These substances are a threat to the groundwater quality: drink water extraction areas and surface water. Furthermore these pollutions can be an obstacle for further development of the area such as residential building.
In our ATES plus technology we add dechlorinating bacteria to the circulating water in the storage unit. These bacteria break down the chlorinated hydrocarbons in the soil. This technique can be applied to existing and new ATES systems and has no negative side effects on the efficiency of the system. Using ATES plus is more efficient and cost effective compared to traditional remediation, which may help municipalities to decide to execute remediation projects that were perceived as too costly in the past. There is another big advantage of this system: ATES plus can also be implemented on locations that were regarded unsuitable in the past because of the risk of spreading the contaminated groundwater. Doing so, we can combine generating sustainable energy while simultaneously improving groundwater quality, which is a fixed (stringent ?) goal of the European Water Framework Directive.
Since early 2016 we have started pilot projects is Apeldoorn and Den Bosch, in which we tested the effective degradation of pollution by injected dechlorinating biomass under heat/cold storage conditions. From the one time injection on and over the past 8 months all contamination passing the activated zone is completely degraded in Apeldoorn , with just one injection of bacteria. All contamination, floating through the bacteria enriched zone, is completely broken down without reinjection of bacteria or adding carbon sources, which is often necessary in traditional bioremediation. The first economical evaluations show that this enormous improvement of groundwater quality can be achieved for a relatively small additional price.
Meanwhile we have started a new pilot project in Utrecht and will also start a project in Copenhagen (Denmark) in March of 2018.
The biomass that is used in the ATES plus is cultivated in a reactor system that was specially constructed for this purpose. Thanks to this reactor we are able to cultivate large volumes (up to 10 m3) of dechlorinating bacteria with a high density(up to 108 cells/ml). With these quantities we can provide several ATES systems at the same time. Another big advantage of this concept is that by not adding any carbon sources, well clogging can be prevented.
Would you like to know if your situation is suited for ATES plus?
Please contact Maurice Henssen.
