Cheap, simple composting toilet concept receives funding from Gates Foundation
November 8, 2011
Whatever you call it - lavatory, privy, latrine, crapper, loo or dunny - most of us take the humble toilet for granted. But in many parts of the world the absence of sanitary waste disposal is not just inconvenient, it can kill you. When effluent is not properly disposed of it can enter waterways and cause diseases such as hepatitis, dysentery, trachoma, typhoid and cholera. According to the World Health Organization (WHO) up to 5 million people suffer from cholera every year.
Flushable toilets, including composting toilets, are expensive, require complex sewage infrastructure and massive amounts of water. This is not an option for many developing regions.
Enter Marc Deshusses, a Duke University environmental engineer who has envisioned an innovative yet simple waste disposal system designed specifically for Third World countries that can be constructed from everyday items.
According to Deshusses, for less than $100 and a day's work a single family in an undeveloped country can construct a solid waste disposal system that processes the waste, requires no electricity or additional energy and destroys harmful pathogens.
In the system Deshusses is developing, the waste is directed to a chamber, most likely constructed of PVC pipe. Once sealed in the chamber, an oxygen-free, or anaerobic, environment is created and bacteria digest the waste. As a byproduct of this digestion, methane gas is produced. Instead of the methane escaping into the environment, the new approach captures and burns it, creating enough heat to kill the bacteria and viruses most commonly found in effluence.
Deshusses suggests that additional organic materials, such as leftover food scraps or animal waste, might also need to be added to boost the amount of organic matter and therefore increase the methane produced.
"The system works much like septic tanks used in many rural communities," Deshusses said. "However, in septic tanks, the methane produced is released into the environment, which a lost opportunity as well as an environmental liability. As a greenhouse gas, methane is 25 times more potent than carbon dioxide."
"People in countries that lack proper sanitation for their sewage desperately need a disposal method that is cheap, simple to implement and maintain, and reliable," Deshusses said. "We believe the proposed system could represent a major advance in environmental and health protection for developing countries."
The Duke University program has active projects throughout the Third World as part of Engineers Without Borders (EWB).
Deshusses says he and a team of Duke researchers will use the grant to perfect and test the system in the laboratory before producing a prototype to field-test in 18 months time. If successful, Deshusses hopes to test the device in up to five additional countries to be identified with the assistance of the Gates Foundation.
The Foundation's Grand Challenges Explorations program awarded 110 such grants on November 7, 2011. One of their focus projects is to reinvent the toilet. As the following Gates Foundation video cheerfully remarks, "Reinventing the toilet - let's get our sh*t together and do it". Yes lets!