Ocean waste : "The Manta" is to ensure less waste in the world's oceans in 2025

Swiss record-breaking sailor and adventurer Yvan Bourgnon has unveiled a multi-functional research catamaran called "Manta" that aims to de-litter the oceans. Thanks to a combination of four complementary collection devices, the Manta can capture floating macro litter as small as ten millimeters and as deep as one meter.

For larger waste, such as fishing nets, cranes serve on the starboard and port sides. In addition, two smaller boats - called "mobula" after the Japanese devil ray - with a capacity of five to ten cubic meters of waste can be used: the smaller one in calm waters, the other also in stronger currents or higher waves.

In the catamaran, the waste collected in collection carpets is lifted out of the water by inclined conveyor belts with a suction system and goes onto conveyor belts, where it is separated manually. Metals, glass and aluminum waste are separated out, placed in two lifting containers of 40 tons each and later recycled locally on land. Organic waste ends up back in the sea. Plastic waste passes through a shredder and can be pressed into pellets. However, Frederic Silvert, a specialist in the Manta technology, points out that the material must be dry and - unlike household waste - desalinated and dechlorinated before further processing.

Then a plant converts the collected, sorted plastic that can no longer be recycled into electricity. Pyrolysis melts the material conveyed through a screw without a combustion process, producing syngas. The captured syngas enters a combustion chamber, and the resulting steam powers a generator and eventually a turbine that supplies electricity to all onboard equipment.

The plan is to achieve energy autonomy of 50 to 55 percent. With this technology, the Manta will have a recycling capacity of 3.5 tons per hour in the future. Annually, this is expected to add up to 5,000 to 10,000 metric tons of plastic to be fished off at those locations that are considered the main sources of waste into the oceans - especially river mouths in Africa and Asia. But the objective is also to be flexible and open to areas that have been affected by natural disasters, explains Frederic Silvert.

The catamaran is still in the planning stage, and according to Bourgnon, only a third of the costs have been covered. Nevertheless, he sees his project as the start of "a new generation of ships" with a different CO2 footprint. He expects the current eco-catamaran to reduce CO2 emissions by 75 percent. Of course, the Manta's operations will have to prove whether the concept is viable: The first trip to Southeast Asia is scheduled for 2025.