Two years ago, an off-grid closed-system toilet known as the Diversion won an award at the Bill & Melinda Gates Foundation's "Reinventing the Toilet" fair. Created by the Swiss Federal Institute of Aquatic Science and Technology (Eawag) and now called the Blue Diversion, it recently also won the title of Most Innovative Project (Europe/West Asia), as bestowed by the International Water Association. So, what makes it so special? Well, for one thing, the same water that flushes it is subsequently used in its hand-washing sink.

Here's how the Blue Diversion works ...

Feces, urine, and flush water are separated right below the toilet bowl. The first two items are then stored in sealed compartments, for subsequent use as fertilizer. The water, because it's used more to rinse out the bowl than to actually transport the waste, isn't as contaminated as what goes down a regular toilet's pipes. It's still pretty disgusting, though, so it's pumped into a filtration system in the back wall of the setup.

There, it passes through a bioreactor that neutralizes organic matter and ammonia, along with an ultrafiltration membrane that blocks pathogenic organisms such as bacteria and viruses. Any remaining trace amounts of organic matter and ammonia are then neutralized by an electrolysis unit, which also produces chlorine to disinfect the water.

From there, gravity carries the water down to be used in the sink, in a bidet-style shower head, or to rinse out the bowl once again. According to Eawag, the same water is good for about 50 uses per day. Power for the pumps, electrolysis unit and electronics are provided by a top-mounted photovoltaic panel.

Although the whole water-reuse thing may still sound kind of ... yucky to some people, the Blue Diversion has reportedly been successfully field-tested in Uganda and Kenya. Eawag is currently looking for industrial partners to help with large-scale production, and hope to sell it for use in developing nations and off-grid locations for about US$500 per unit.

... and should you not be into squatting, a sit-down version is due to come out next year.

Sources: Eawag, Blue Diversion