Making modifications on a small scale structure 10 miles offshore is relatively easy. In contrast, making corrections on a large scale structure 1000 miles offshore would be an entirely different challenge – at a different cost. Therefore, The Ocean Cleanup deployed a 100 meter-long barrier segment in the North Sea, 23 km off the coast of The Netherlands on the 22nd of June 2016. It was the first time our design was put to the test in open waters and the tests conducted gave valuable insights to our engineering team. After 10 weeks, we took the barrier back to shore.
Our passive cleanup system uses the natural ocean currents to collect and concentrate plastic. By placing long, floating screens in the Great Pacific Garbage Patch between Hawaii and California, we can clean up the accumulated plastic and prevent it from breaking down into even more harmful microplastic over time. Our design needs to withstand harsh weather conditions and constant wear and tear. Since our technology is the first of its kind, we believe the best way to move forward is to test often and fast and make iterative improvements based on these tests.
OBJECTIVE AND SET-UP
To investigate the durability of our design, we deployed a system segment in the North Sea. At this test site, conditions during a minor storm are more severe than those in exceptionally heavy and rarely occurring storms in the Pacific Ocean.
The objective of the North Sea prototype was twofold;
- Test the boom design on a small-scale for survivability in extreme conditions and for its plastic capturing abilities
- Gaining experience as an organization in the ocean deployment of a cleanup array
During an inspection of the North Sea prototype in August, we noticed the two outermost air chambers were bent out of shape - they did not follow the gentle U-shape of the boom. Thanks to underwater footage we were quickly able to diagnose the problem. It turned out this was caused by failing shackles – the ones connecting the barrier to the permanent mooring system.
After our diagnosis, we continued to closely observe the situation for some time, monitoring the status of the prototype while continuing to execute plastic capturing tests during the quieter periods in between the storms.
After close to two months, having been subjected to large waves and high winds, we noticed the barrier suffered increased damages, after which we decided to disconnect and take the barrier back to shore.
ITERATING TOWARDS EXECUTION
The data gathered is used to help engineers develop a system fully resistant to severe conditions of the ocean once deployed in the North Pacific. Thanks to the North Sea prototype test, we also learned how the chosen material proved to be suboptimal for the purpose. The results of this test were a strong support in making the conclusion not to move ahead with inflatable floaters that were derived from standard oil-collection booms, but rather turn to rigid HDPE pipes instead.
Watch the Prototype Unveil Event
June 22nd, 2016
Prototype installation by Boskalis