The operation of a former gasworks in Copenhagen (Østre Gasværk) has given rise to significant pollution of soil and groundwater in the area with oil, tar and cyanides. Ramboll has conducted extensive studies of pollution and mitigation measures such as draining pipes and wells to prevent contaminated groundwater from spreading to the neighbouring areas and the harbour.
In 2001, a pilot project was conducted where water was cleaned before discharge into the sewer. Based on these pilot tests Ramboll planned and established a full-scale plant for the purification of the water, polluted with organic contaminants (tars). The water purification includes biological treatment in sand filters with the addition of pure oxygen and has a capacity of 10 m3/h. The area is now used for sports fields and recreational parks.
In 2005, Ramboll conducted a risk assessment of contamination spreading to the nearby water body by means of model calculations of pollution transport through the groundwater zone to the harbour and disper-sion calculations in the harbour itself.
Since 2001, Ramboll has handled the operation and monitoring of water treatment and optimized the system with the aim of getting permission from the local authorities to discharge the water into the harbour instead of into the sewer system.