There are more than 30.000 contaminated sites in Denmark and the Danish Regions, private industry and developers use many societal resources for site investigations and clean-up. In June 2013 new Danish legislation was passed in Parliament to address new EU requirements requiring groundwater and surface water to be managed as a single system. There are 2,500 former landfills in Denmark, which is expected to be a major challenge because they are situated close to surface water and contain a complex mixture of contaminants.
GEOCON will conduct field work on landfills because they have concentrated contaminant signals that are well-suited to the development of the geophysical methods. Geophysical methods are promising because they are non-invasive and cost effective supplements to traditional methods based on boreholes with water and sediment sampling. They can map the subsurface in three dimensions and provide detailed information on landfill bodies and leachate plumes. The methods will need to determine both small scale discharges (e.g. to streams) and larger scale transport of contaminant plumes in groundwater. While the GEOCON project will focus on landfills, the methods will be applicable to many other types of contaminated sites.
GEOCON considers three major technologies. The first technology is a subsurface heterogeneity mapping tool, required for performing high-quality geological characterization, joint inter-pretation of geophysical measurements, modeling of contaminant transport, risk assessment and clean-up of contaminated sites. The second technology considers flow field determination and detailed mapping of contaminant distributions. The project will combine state of the art field methods with the Point Velocity Probes (PVP), which are small cylindrical devices that measure groundwater velocities through a mini-tracer test. New approaches will provide high quality data for contaminant mass discharge estimation and uncertainty analysis. The third technology will be improved geophysical methods and models for data interpretation. It is hypothesized that it is possible to combine data from a small number of monitoring wells, knowledge of geology, and surface DCIP geophysics (induced polarization, IP,and resistivity, DC signals), to provide a cost effective tool for mapping contaminant plumes.