In the four weeks that Ocean Cleanup's System 001 is working in the Great Pacific Garbage Patch (GPGP), the organization of Boyan Slat has suffered a setback. The waste plastic collected by the system escapes from the system again.
"We are working on the causes and the solutions to solve this," says Slat. Because this is the first test, Ocean Cleanup was prepared for 'surprises'. The organization itself says that, although no waste plastics are currently being harvested, they are positive and expected to be close to a solution.
First observations of Boyan Slat's 'System 001'
After System 001 (named ‘Wilson’) arrived in the GPGP it was immediately put into the operational U-form. Since then there has been a change of crew and that change brought a new group of team members to the system that had a different purpose. Team 1 had as its main task to get ‘Wilson’ in its U-shape and Team 2 now focuses on the observations, on data analysis and on the collection of plastics.
The most important first observations were:
- For the most part, the system behaves as predicted; The density of the plastic in the GPGP is in line with the expectations, but due to the short period in the GPGP this is too limited a dataset, so this cannot yet be fully verified.
- No interaction with sea creatures has been observed.
- Small particles are also floating in the system, but measurements of their quantity are still required.
- Plastic remains in the system for a relatively short time.
Simple sustainable solution but complex
The technique is based on simple principles, but the dynamics are complex. There may be several reasons why the plastic does not stay within the system. "We have concluded that the system sometimes seems to go too slowly (to be able to catch plastic there must be a difference in speed, the system has to move faster than the plastic, ed.) And sometimes the movement is opposite and the plastic goes harder than the system. Even if only with a very small difference, the system must always go faster than the plastic to be able to function. " An assumption now is that the forces of the wind on the system oscillate the two ends of floater (the long floating tube) like the fins of a fish. This leads to a movement against the wind, which slows the system down.
It is also possible that the vibrations at the ends of the U-shape create a kind of ripple that repels the waste plastic as it approaches the mouth of the U-shape. Slat: "We think that the first solution we try might solve both causes, we tested a scale model and made computer models, but because this phenomenon was never observed before, we did not have a ready-made solution to be carried out because the materials are on board the ship on the site and we will tackle the speed difference by making the U-shape sixty to seventy meters wider."
"Theoretically, this will have two effects on the speed of the system: first, the surface of the system is exposed to wind and waves, which are the driving forces. due to the moving ends, "says Slat. In order to achieve the increase of the wingspan, the connection cables of the system are made longer. "We are going to run it at different stages until we hopefully achieve the desired effect." Because a larger span is likely to have a negative effect on the system's ability to rotate quickly when the wind direction changes, we don’t want to increase the span to much.
Before it can be scaled up, System 001 must first function. While working outside with the implementation of the first possible solution, the team is working on data analysis and testing alternative solutions.
https://www.whatsorb.com/waste/combing-plastic-waste-out-of-polluted-oceans--will-boyan-slat-face-competition-
By: engineersonline.nl