Turning urban slums’ huge sanitation problem into opportunities for farming, taking a systemic approach to solving a complex of problems at the same time.

The Challenge: waste increase in urbanizing regions

Our rapid urbanization is claiming more and more land, putting added pressure on food systems and natural resources. Today, almost 60% of the world’s population lives in urban areas; a share expected to continue growing until 2050 when 68% of the global population is projected to live in cities.

The overall population increase and the growing number of people moving to urban areas will add 2.5 billion inhabitants to the world’s urban population by 2050, with almost 90% of this growth happening in Asia and Africa. Nigeria alone is projected to add 189 million urban dwellers.

As cities in emerging economies expand rapidly, they are often ill-equipped to handle their waste increase, not least their sanitation waste. Today, over one billion people worldwide lack access to safe and hygienic sanitation facilities. This seriously undermines their health and contributes to the spread of infectious diseases, causing about 700,000 deaths yearly, according to The World Bank. The bank estimates that annual waste generation from cities will increase by 70% to 3.4 billion tons by 2050, posing huge environmental and economic challenges globally.

Simultaneously, food security is a growing concern, due to insufficient agricultural yields. Many farmers in emerging economies lack access to efficient fertilizers and nutritious feed for their livestock. If taken care of systematically, human waste can contribute to solving these problems.

Sanergy, is a for-profit social enterprise registered in the USA, and based in Nairobi, Kenya, where they operate organic waste and sanitation management systems, upcycling and converting waste to organic fertilizers and animal feed.

Founded in 2011 by a team of MIT graduates, Sanergy is funded by several investors, foundations, and development agencies, among them the Bill & Melinda Gates Foundation, Tillväxtverket (The Swedish Agency for Economic and Regional Growth), FinnFund, FMO, Novastar Ventures, Acumen, and Echoing Green.

The Initiative: breaking a vicious circle

Instead of thinking of human waste as a problem and a painful cost driver, Sanergy treats this waste as a valuable input resource to strengthen fragile food systems and vulnerable societies. By providing Nairobi’s slum dwellers with specially equipped pay-per-use toilets, sanitation waste is utilized in a controlled and integrated production chain to promote local agriculture – based on a circular and holistic systemic approach.

Sanergy has developed insect-based methods to convert human waste into organic fertilizers and animal feed for commercial and smallholder farms. According to the organization, their work has helped increase horticultural farmers’ vegetable yields by 30%. Similarly, livestock farmers have seen a 30% weight increase in chickens, fish, and pork.

By offering affordable toilet solutions to urban slums and townships and controlling the waste streams through waste collection operations, Sanergy is poised to scale – in Kenya, East Africa, and beyond. Their Build-Collect-Treat&Convert model can be applied anywhere in the world, where human waste is not flushed out in water-based sanitation systems.



“The initiative is also considered a social innovation, its impact on urban slum populations beneficial from a health and employment perspective.”

In Sanergy’s current operation, black soldier flies are doing the dirty work. They break down the waste in a week and produce larvae that are harvested to be used as biofertilizers and as a protein source in poultry, pork and fish feeds. Before the flies can go to work, pathogens have to be removed from the matter, a continuous challenge, not least because of residues from increased use of pharmaceuticals.

Waste collection in townships and urban slums is usually done with little or no regard for health and safety or the environment. In addition to supporting local food production, Sanergy’s systems approach to waste collection contributes to creating jobs for youth in areas with high unemployment – approximately 40% in Kenya.

Nominate yourself or someone else, it takes three minutes and could change the world!