Seeking sanitation for the world’s poorest
One-third of the world’s population is without access to proper toilets. To address this problem, a team from Eawag has developed a new kind of latrine.
“Today, 6 billion people worldwide own a mobile phone, but only 4.5 billion have decent toilets.” Kristele Malegue, coordinator of the Water Coalition - an NGO that campaigns for clean water — sums up the situation in one sentence: one third of the world’s population is without access to proper sanitary facilities, and one billion people defecate in the open. “This shortage, which is still taboo in society, is a real scandal. It has serious consequences for people’s health, nutrition and education, the economy and the environment,” continues Kristele Malegue. Each year, 1.5 million children die from the effects of diarrhoea caused by drinking water contaminated with faecal matter.”
To address this problem, Swiss researchers from Eawag and the Vienna- based design firm EOOS have designed a new kind of latrine, “Blue Diversion,” as part of the “Reinvent The Toilet Challenge ( RTTC)” set by the Bill & Melinda Gates Foundation. “Flush toilets, which are commonly used in industrialized countries, seem to be the ideal solution. However, it is difficult to install them in developing countries. In many locations, infrastructures such as sewers and water treatment plants simply don’t exist, and there is often not enough water available for flushing. Pit latrines have seen very little progress over the course of history, and do not meet hygiene requirements,” points out Christoph Luthi, project manager at Eawag. “We wanted to design a radically different type of toilet, without the need for hefty infrastructures, at the same time as offering spot-
‘Elimination of pathogens and
To look at, Blue Diversion resembles a squat toilet made out of blue plastic, with two holes: one for urine and the other for feces. “The purpose of separating these is to facilitate the elimination of pathogens and save water,” explains Christoph Luthi. Through a nitrification process, the urine is converted into fertilizer in situ. However, what makes it radically different is the integrated independent water circuit. “We have fitted our toilets with a shower head to clean the pan and also ensure anal hygiene, as practiced in a great number of countries, as well as a sink to wash the hands,” continues Christoph Luthi. “Whenever the water flows, a valve automatically shuts off the urine and feces tanks. This enables almost all of the liquid to be recuperated.”
Subjected to internal biological treatment, this dirty water is disinfected by a gravity- driven membrane filter. A solar-powered electrolysis system then produces chlorine, preventing undesirable bacteria from forming. “This patented system is capable of treating 1.5 litres per hour, which is perfectly adequate because the appliance contains 60 liters in total. You can even drink the water produced, although we don’t recommend it because you’d then need to refill the tank,” continues Christoph Luthi. “One to two liters are lost per week, based on normal use.”
Prospects for Further Service
In 2013, the first prototype of Blue Diversion was successfully tested in Uganda, working with Makerere University. “The appliance was very well received by people during the trials in Kampala,” continues Christoph Luthi. “This first trial also allowed us to identify certain defects. We have since reduced the height of the toilet and improved the system’s hydraulics.” A new prototype is currently being tested in Nairobi, Kenya. Blue Diversion was awarded the 2014 Prize for Innovation by the International Water Association (IWA).
“We are now looking for industrial partners and investors so that we can produce the units in greater quantities,” continues Christoph Luthi. “Mass production will reduce the cost. The objective is to achieve a selling price of US$500 per appliance, for a projected lifetime of ten years.”
Is this too expensive for the countries in question? “The lack of toilet facilities mainly affects SubSaharan Africa, where just 30% of the population has access to decent toilets, but it doesn’t stop there. In India, almost half of the population is forced to defecate in the open, and even in Europe 20 million people are still without quality facilities,” points out Kristele Malegue. “One appliance won’t address everyone’s problems. Different approaches need to be devised to suit the situation.”
Consequently, Blue Diversion could come in useful in remote areas. “The main need is in Africa and India,” confirms Christoph Luthi, “but we can also see our toilets being useful elsewhere, particularly in mountain huts and remote villages, which will never be connected to the waste water sanitation network. What’s more, some countries are also interested in the water purification system we have developed, without the toilets, because it produces drinking water.”
Meanwhile, the researchers are currently looking into what can be done with the feces. “At the moment, our system only converts the urine into fertilizer. The actual stools have to be disposed of, which poses a problem due to the pathogens they contain,” explains Christoph Luthi. “We are working on a system to burn this solid residue which, I hope, will be operational by the end of 2015.”
The “Blue Diversion,” a toilet model that provides low-tech solutions to hygienic problems, is seen in this picture.