Investigation of the self-cleaning ability of Lake Koumoundourou near Athens from oil pollution

This study was performed under a general project for the restoration of Lake Koumoudourou. This lake is situated next to the sea in the prefecture of Attica, with a large oil refinery installation and a military fuel depot nearby. The geological formations of the surrounding area are Quaternary alluvial deposits and fans, which overlie karstic limestone and dolomites of the Middle Tertiary to Lower Jurassic. This lake has been polluted by oil spills and leaks from both the refinery and the military depot, containing large amounts of different petroleum extracts. In addition, the aquifer has also been polluted by an underground pipe connecting these two installations as well as by percolated surface pollutants and leaks from the refinery tanks. The purpose of the experimental investigation was to determine the way to clean up the bottom of the lake and keep the water under European Union directive standards for bathing waters. To accomplish the target, a purpose built aquarium was constructed in the laboratory. Mud, water, algae, and fish were transported from the lake, and the investigation began after a 6-day period necessary for the aquarium to adjust. The simulation proved successful and the experiment resulted in 50% reduction of oil and chemical oxygen demand.