A remote beach on the southern tip of Hawaii’s Big Island is known for its trash: In a typical year, volunteers collect around 20 tons of plastic waste from the area as currents wash up old toothbrushes, plastic bottles and other single-use packaging, and mounds of fishing nets.

This spring, a team of engineering students visited the beach to test a new tool for cleanup—essentially, a giant vacuum for the sand. The machine, called the Hoola One, sucks a mixture of sand and plastic into a tank that separates particles by weight, so plastic can be filtered out. Clean sand and rocks weigh more and sink to the bottom, where they can be returned to the beach. In about a minute, the Hoola One can process around three gallons of sand.

In April, the students delivered a prototype of their machine to the beach—driving it off-road through a lava field to get there—and then spent two weeks testing the machine. After some tweaks to the vacuum system, everything worked. The students are still waiting for test results that will show how well the machine captured plastic of a certain size and, critically, whether it had any impact on tiny wildlife living in the sand. Should the vacuum be a real success, we could very well be seeing more of them on beaches around the world.