Solar-Powered Autonomous System for Oil Spill Recovery andBiodiesel Production in the Danube River

Navigable waterways are essential for transportation, trade, and regional development, yet they are increasingly affected by oil pollution generated by intensive maritime traffic and industrial activities. Oil contamination threatens aquatic ecosystems, reduces water quality, and affects biodiversity and economic activities dependent on river systems. This study proposes an innovative and sustainable solution for oil spill mitigation through the development of a solarpowered autonomous or semi-autonomous boat designed to collect oil from the water surface and convert the recovered waste into biodiesel.The proposed system integrates floating collection arms, an oil–water separation unit, a filtration system, and a hybrid solar-electric propulsion system that enables energy-efficient and environmentally friendly operation. The concept is tested for potential deployment on the Danube River, one of Europe’s most important navigable waterways, particularly in areas affected by oil pollution from commercial vessels.The system performance is evaluated based on oil recovery efficiency, separation and filtration performance, and improvements in water quality parameters. Results indicate that the system could recover up to 80–90% of surface oil, while separation and filtration processes may achieve efficiencies above 95% and 98%, respectively. In addition to reducing pollution, the recovered oil can be processed into biodiesel, supporting circular economy principles and contributing to sustainable waterway management.