Students win prize with device that turns plastics into toilets

A new 3D printer design could help turn discarded plastics into composting toilets and components for rainwater collection systems.

The device, built by students from Washington University in Seattle, was the winning entry for an international contest to use 3D printing to produce technologies for the developing world.

The 3D4D Challenge competition, sponsored by UK charity, presented its $100,000 (£62,000) prize to three undergraduate members of a 3D printing club; the prize will fund the formation of a non-profit company to develop the technology in Oaxaca, Mexico.

Matthew Rogge, who presented the project at the competition final, came up with the idea while building irrigation and sanitation systems with the US Peace Corps in Ghana, Panama and Bolivia. Frustrated by the problems of building custom parts with limited resources, he read up on 3D printing and decided to embark on a postgraduate engineering course on his return to the US.

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The Big Red machine, printing out the base of the boat the team used to test the technology

The printer designed by the team, nicknamed Big Red, uses shredded plastic as a feed, melting it and extruding it through a nozzle, working something like a giant icing piping machine.

The team, which comprises members of the Washington Open Object Fabricators (WOOF) student club at the university, recently used Big Red to print a boat from shredded milk cartons, which it then entered in a Seattle race for boats made from recycled drinks containers; the team came second.

This technology is the basis for the team’s entry in the 3D4D Challenge competition. Rogge proposed using giant 3D printers, whose size enables them to print using uneven shredded plastic that might not be completely clean without clogging, to print compositing latrines and components for rainwater catchment systems designed to fit rain barrels without leaking, unlike current systems, which are often cobbled together from ill-fitting plumbing components.

‘I feel lucky to have the chance to start making our ideas into reality,’ Rogge said. ‘There is great potential here to improve people’s quality of life while taking plastic out of the waste stream.’