ReOcean: An Active System for Removing Waste from the Oceans

Abstract

This work demonstrates the effectiveness of an active collection system which will remove macro-scale (>0.5 cm) waste from the Great Pacific Garbage Patch (and other similar garbage patches around the globe). The scope of this project is to simulate such a feat in a similar, scale model, proof-of-concept environment. The system will be composed of two classes of electric watercraft: a single central garbage scow (barge), and a set of two skimmers (smaller boats) which corral trash and relocate it to the garbage scow for removal from the sea. The central garbage scow picks up waste from the sea immediately in front of it and stows it in a holding bay. The skimmers contain a propulsion system to navigate and tow a screen which collects waste. Each controls one end of the trash collection screen which entraps waste near the water’s surface.

Across ten trials, the ReOcean system was able to successfully corral and transport an average of 39\% of an approximately 100 m$^2$ plastic patch during a single pass to the pick-up mechanism. Similarly, across ten trials the ReOcean system was able to successfully corral and transport an average of 41\% of an approximately 200 m$^2$ plastic patch while executing two passes to the pick-up mechanism. Finally, the pick-up mechanism successfully removed 90\% or more of all plastic it encountered across each of ten trials. The longest duration for a full-system test incorporating two passes and a total distance traveled of nearly 50 m was approximately 3.5 minutes.

Based on scale model performance, it is projected that a fleet of 21 full-scale ReOcean systems will successfully remove 72\% of all particles presently in the Great Pacific Garbage Patch of size 0.5 cm or larger (52,992,000 kg) within the next roughly 25 years at a present cost of \$197,445,585 - less than 60 cents per American citizen. Alternatively, a fleet of 42 full-scale ReOcean systems could be deployed to simultaneously execute a second pass of the Great Pacific Garbage Patch, ensuring the removal of approximately 92.2\% of all particles in the Great Pacific Garbage Patch of size 0.5 cm or larger (67,859,200 kg) within the next roughly 25 years at a present cost of \$388,629,774 - less than \$1.19 per American citizen. The removed waste could be re-purposed on an industrial scale to partially fund the continued operation of the cleanup.