You can get rid of blue-green algae using an extract from the seeds of the tropical ‘miracle tree’ Moringa oleifera. This was discovered by high school students in Eindhoven. Wageningen UR’s blue-green algae team are now researching this new way of making life difficult for the algae.
But how it works, exactly, and what the active substance is, is still not known. Research is now going on. The Ethiopian Masters student Getahun Tolla heard about the experiments and was immediately enthusiastic, says Lurling. He imported seeds, roots and leaves from the tree from his country, and went to work to test how long the extract from the seeds worked and to try to isolate the active substance. But Lurling doesn’t think that a miracle cure for blue-green algae has now been discovered. ‘You need rather large amounts. But on a small scale in the tropics it should work well. De Moringa is common in the tropics and is drought-resistant.’ Still, it only tackles the symptoms, Lurling thinks. The Wageningen research focuses primarily on tackling the root of the algae problem by ‘dephosphating’ the water. Lurling’s group uses the ‘flock & lock’ method for this: phosphates are driven to the bottom of the water by a method known as flocking, and the bottom is then covered (locked) using modified clay so that the phosphate cannot escape again. Lurling says good results are obtained with this method.