Oil is less dense than water and therefore the oil escaping the sea bed travels up to the water surface. Dr. Fivos Andritsos and his colleagues from the Joint Research Center in Ispra, Italy have now developed a reservoir which can be applied on top of the leakage. The invention is called DIFIS and stands for “Double Inverted Funnel for the Intervention on Ship wrecks”. The system stores the oil underwater until a tanker arrives to take it on board. The reservoir is situated in a depth of around 30-50 meters below the surface. This means the system is also operational during heavy sea storms. Currently, the tropical storms in the Gulf of Mexico are one of the major problems the engineers facing as they are working to keep the BP-leakage under control.
The Maritime Research Institute Netherlands (Marin) already built a scale model of this solution. It´s 12 meters tall and in a deployment test, the folded dome with the oil reservoir opened successfully over the oil spill of a tanker wreck, even in strong currents. The structure was then tested in extreme storm conditions simulating waves twelve meters high. Below the water, the buffer bell and the dome hardly moved.
The only difficulty lies in the installation of DIFIS. The mooring lines which hold the light and flexible structure are connected with weights which have to be applied exactly around the source of the oil spill. In anchoring, the folded structure opens like a tent over the leak. The uprising oil gets directed into a kind of inverted funnel, where it is channeled, along with sea water, through a long, flexible riser tube into the buffer reservoir close to the sea surface. The reservoir then collects the oil in a depth of around 30-50 meters below the sea surface until it gets unloaded by a shuttle tanker.
Compared to traditional methods DIFIS is designed to be cheap and flexible. It will be of general applicability as long the trapped pollutant does not dissolve and is of lower density than sea water. All simulation results and extrapolations confirmed the soundness of the concept and the economic feasibility from depths between 500 and 2000 meters. As the ongoing disaster in the Gulf of Mexico shows that traditional technologies fail in great depths, DIFIS could become a promising new solution to fight similar disasters in the future.