The St Andrews Prize for the Environment

University of St Andrews


2012 Finalist



Providing Sustainable Sanitation in Urban Slums

2.6 billion people worldwide lack access to adequate sanitation. The resulting diarrheal disease kills 1.5 million children each year. The high population density combined with the lack of infrastructure makes the sanitation crisis particularly acute in slums, where populations will double to 2 billion by 2030. The lack of proper waste removal and treatment options also creates a tremendous source of environmental pollution. With few viable options, the 8 million people in Kenya’s slums are forced to discharge 4 million metric tons of untreated human waste into the surrounding soil and waterways. In these areas that lack basic water and sewage infrastructure, solving the sanitation crisis requires more than just building toilets.

Sanergy takes an innovative systems-based approach to building out the entire sanitation value chain.

Our sustainable sanitation cycle features 3 parts:

  1. Build – Throughout the slums, we build a dense network of small-scale high-quality sanitation centers close to homes. Developed by our team of engineers, our toilets cost only $200 to manufacture at our workshop in Nairobi, compared to existing options that cost $500-$25,000. The toilet is hygienic, affordable and accessible. We franchise each toilet to local entrepreneurs and provide training and business support. Each toilet is designed for 100 uses per day, and at $0.06 per use, operators can make up to $1200 in income per year.
  2. Collect – The waste from our toilets is collected into double sealed containers, rather than commonly used pits and septic tanks that drain into waterways. Each day, Sanergy employees collect the full containers of waste from the operators and provide clean empty containers. The full containers are brought to our central processing facility.
  3. Convert – Sanergy is sustainable by converting this waste into high-margin products like electricity, which will be sold to the national grid, and organic fertilizer, which will be sold to farms.

We are combining technical ingenuity with business model innovation at each stage of the sanitation value chain to create a practical solution that effectively addresses the social, environmental, political, and economic realities in Kenya’s slums. At each step, Sanergy creates jobs and opportunity while addressing serious social, economic, and environmental needs.

As of March 2012, we have 20 operational franchises in Nairobi’s slums providing sanitation to more than 1,000 users daily. We are safely collecting more than 2 metric tons of human waste and we are converting it into fertilizer and biogas. By 2015, Sanergy will provide hygienic sanitation to 466,620 residents through a network of 6,060 franchised sanitation centers throughout the Kenya’s slums.

The St Andrews Prize will be catalytic in helping us design, prototype, and manufacture the next generation of our toilets that will improve user experience, material safety and durability while fully addressing needs of women during menstruation, mobility impaired residents, and very young children.

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