Wastholm.com

The Row-bot has four tiny buoyant stabilizers for feet and two paddles that extend from the middle of its body. While the feet keep Row-bot afloat, the paddles send it skimming across the surface of a body of water. The device takes water into a cavity in its housing as it moves, where electrogenic bacteria digest pollutants found within the water. The byproducts of that digestion are carbon dioxide and electricity, which in turn fuels the Row-bot and keeps it moving.