A Better Toilet

For A Cleaner World

Reinventing The Toilet

The sanitation technology paradigm is under review, as past approaches are not sufficient or affordable to close the sanitation coverage gap. The Bill & Melinda Gates Foundation (BMGF) is at the forefront of the sanitation revolution, as it works to stimulate technology and sanitation market development. In 2011, BMGF launched the bold Reinvent the Toilet Challenge (RTTC) program to promote the development of radically new innovations to address the sanitation challenge on a large-scale. The RTTC is premised on the fact that ground-breaking improvements are required in toilet design and fecal sludge management to close the urban sanitation gap. The RTTC is focused on reinventing the flush toilet, a break-through public health invention that has not changed substantially since the first flush toilet patent was issued in 1775. The Foundation has called on grantees to design a standalone toilet unit without piped-in water, a sewer connection, or outside electricity, with facility costs targeted at less than five cents per person per day. RTTC is also working to improve waste handling from collection and treatment.

The Gates Foundation diagram above depicts the Sanitation Value Chain, a solution that starts with the individual and toilet, followed by storage, transportation and treatment of human waste, and ends, ideally, with safe, usable byproducts such as fertilizer, fuel or clean water. A range of Gates Foundation RTTC grantees are working on different stages of the sanitation value chain.

Duke University is an RTTC grantee working with other teams to address on-site sanitation solutions through the development of a better toilet. Duke University is working in partnership with RTI and Colorado State University, to develop an integrated toilet system. Duke’s technology approach combines electrochemical disinfection for liquid waste processing and recovery, and biomass energy conversion to process solid waste. The system is designed to be energy neutral, requiring no external sources of power or linkage to piped sewerage systems.

The Duke/RTI system now under development separates liquid from solid, and the solid waste is then convectively dried and delivered to a combustion system. The waste heat from the combustion system is converted to electricity using thermoelectric modules which, in turn, power the entire toilet. The liquid waste is disinfected by electrochemical oxidation and the by-products can be used for toilet rinse, crop irrigation, or other non-potable applications. The toilet is designed to be self-cleaning, low maintenance, and low cost.

Why We Care

Improved sanitation in the developing world is a global need, but a neglected priority. The Millennium Development Goals (MDGs) include a sanitation target to reach 75% coverage of improved sanitation by 2015, but it remains one of the MDG goals most far out of reach. Currently, 2.5 billion people do not have access to improved sanitation and nearly 1.1 billion resort to open defecation (MDG Report, 2012). Even in urban areas, more than 2 billion people in the developing world lack access to services and infrastructure for the safe disposal of human waste (The World Bank, 2003).

Open defecation poses significant health and environmental risks. Open defecation also creates vulnerability, particularly for women and children who are exposed to a loss of dignity, abuse or harassment while defecating in the open.

Globally, poor sanitation contributes to 1.5m child deaths each year from diarrheal disease; in India alone, diarrhea kills 1 child per minute (UNICEF/WHO, 2009). Diarrhea is a major cause of death for children and chronic diarrhea hurts child development by impeding their health, nutrition and hinders vaccine absorption. Those who suffer from the lack of this most basic of human needs also tend to be victims of poverty, ill health, and an overall poor quality of life.

Urban sanitation is a particular challenge, and as often received less attention in international sanitation programming — until today. When urban sanitation is neglected, the health, environmental, and aesthetic consequences are particularly large because of space constraints and population densities. In addition to the health and environmental impacts of inadequate sanitation, poor performance in sanitation service provision has had a significant impact on economic potential. In many parts of the developing world, cities have become engines of the economic growth, and the prospects for long-term prosperity are hindered by the inability to build basic infrastructure and close the sanitation coverage gap.

Sanitation is a critical intervention needed to improve living conditions among the world’s poor and to reduce or prevent diarrhea and other seriously debilitating conditions, especially among children.

Sanitation is a problem we can solve.