Optimizing the Path Towards Plastic-Free Oceans

Increasing ocean plastic pollution is irreversibly harming ecosystems and human activities. The Ocean Cleanup (TOC) is a Dutch NGO dedicated to cleaning oceans from plastic pollution. Among its initiatives, TOC operates a plastic collection system in the Great Pacific Garbage Patch, an accumulation area twice the size of Texas and located between Hawaii and California. In ‘Optimizing the Path Towards Plastic-Free Oceans,’ den Hertog, Pauphilet, Pham, Sainte-Rose, and Song design a routing algorithm that leverages data on weather conditions and plastic dispersion models to determine an optimal trajectory for their system, maximizing plastic collection. Unlike conventional routing problems, the trajectory directly impacts future plastic distribution, creating non-linearities that make standard dynamic programming unsuitable. To address this, they devise a tailored algorithm based on a relaxation-induced search and a customized branch-and-bound scheme. Validated on one year of ocean data, their algorithm results in a 60% increase in plastic collection compared with current strategies.