High hopes for Blue Diversion toilet

Home Technologist Online High hopes for Blue Diversion toilet

The award-winning toilet innovation Blue Diversion combines the best of high- and low-tech solutions in a bid to solve sanitation problems that threaten the environment and the health of 2.5 billion people.

Retrofit of an existing pit latrine with two Blue Diversion toilets.

In industrialised parts of the world, the flush toilet may seem like the ultimate fix to sanitation problems. But in developing regions that lack reliable water supply, sewerage and waste treatment infrastructure, new solutions are needed to provide sustainable and affordable sanitation for more than 2.5 billion people who don’t have access to a proper toilet.

One solution could be the Blue Diversion: “an appealing, affordable and safe solution for washers as well as wipers”. Developed by Swiss researchers and Austrian designers, the ‘blue loo’ is a grid-free, dry toilet with separate urine and faeces collection and a closed water cycle.

Reinvented toilet with in-built water recycling

In response to the Bill & Melinda Gates Foundation’s Reinvent the Toilet Challenge, the team from the Swiss Federal Institute of Aquatic Science and Technology (Eawag) and the Austrian design firm EOOS developed what they call ‘a radically new toilet.

Featuring an in-built water recycling process, the toilet is designed to overcome the hygienic problems of existing dry toilets. The system provides water for cleaning of the toilet bowl, hand washing and other personal hygiene practices.

After use, the water is biologically purified on-site by gravity-driven filtering through ‘the heart of the system’ – a membrane that removes infectious agents such as bacteria and viruses. Chlorine produced by solar-powered electrolysis prevents the re-growth of undesirable bacteria in the recycled water.

The toilet’s system for collecting urine and faeces is equipped with semi-centralised recycling plants, which allow the nutrients and other compounds in the waste material to be reused for production of fertilisers and energy.

Combining high- and low-tech

Instead of pitting the high- and low-tech approaches against each other, Blue Diversion combines the advantages of both, according to the developers.

“We are situated between the very ‘high-tech’ toilets, which you can hardly imagine in a slum, and the more ‘low-tech’ toilets, which build on known technology,” said project leader Tove Larsen after showcasing Blue Diversion at the Reinvent the Toilet Fair in India. “People liked that we had considered every aspect from human psychology to technical functionality. Personally, I think that this is our main strength.”

The project has received massive support both locally and internationally, enabling the toilet to be produced at an industrial scale, following a business model to ensure the concept will also work in countries with poor infrastructure.

The first working models have been tested under tough, real-life conditions in Uganda and Kenya, where the engineers learnt valuable lessons from local users. While some aspects such as the water purification system work really well, other aspects need to be improved, particularly the electronics set-up.

The team is continuing to optimise the system and to test newly developed prototypes, while also looking for an industrial partner and investors to enable mass production of Blue Diversion.

Award-winner – and next sanitary revolution?

In March 2014, the International Water Association awarded Blue Diversion the prize for the most innovative project in the applied research category in the Europe/West Asia sector. With that, the toilet qualifies for the worldwide competition at the World Water Congress in Portugal in September.

The Blue Diversion Toilet is also exhibited in the prestigious Architecture Venice Biennale, where this year’s guiding theme is ‘Fundamental Elements of Architecture’. According to deputy project leader Christoph Luethi, Blue Diversion was “selected as an example of a ’21st century outhouse’ that seeks to push the frontiers of technological innovation beyond the flush-and-forget solution invented 240 years ago”.

“While the Blue Diversion toilet has not been industrialised yet, witnessing it in this historical context of centuries of sanitary development gives hope that we’re on to something bigger – the next sanitary revolution,” Luethi wrote in a blog post.

by Lillian Sando


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