A pilot project has been performed that has seen the bed of a Danish lake successfully oxygenated thanks to the use of electrodes.

Oxygen depletion and algae in lakes is seen as a big problem in both Denmark and Europe, with just over 75 percent of lakes being affected according to an article on dtu.dk. The catalyst for this percentage is down to the discharging of wastewater, which contains high levels of phosphorus. This in turn lowers oxygen levels within a lakebed and kickstarts the growth of algae in the process.

However, Professor Stefan Trapp and his team from DTU Environment have carried out a method that can lower levels of phosphorus in a lakebed. Performed in a small section of Lake Søllerød in Denmark, the method involves steel meshes which form an electric battery.

“The two meshes are connected by a wire and form a kind of electric battery. As they break down dead plants and fish, the bacteria at the bottom of the lake release electrons that are caught by the steel mesh and travel to the surface mesh, where oxygen is present and can absorb the electrons,” says Karl Haxthausen of DTU Environment, who is a researcher behind the project.

“In this way, the bacteria can break down the dead organic matter as if oxygen was present. And in fact, the whole process takes place without producing unwanted methane. The removal of electrons also changes the chemistry at the bottom of the lake, causing the phosphorus to bind to the sediment and thus resulting in its immobilization.”

Results showed up to a 94 percent reduction of phosphorus within the selected section of the lake. Looking forward, the team will aim to execute this method on a larger area size.