It is often said by those who work in development that simply improving sanitation around the world could effect huge change. More than a third of the global population doesn't have access to clean safe toilets and running water. In the Kenyan capital Nairobi, a new project is turning waste into useful organic products. The BBC's Nancy has this report.

Stanley washes his hands in a reluctant stream of water pouring out of a tap molded onto a small white plastic drum. We're standing next to one of the toilets he operates charging less than one US cent per use. It looks freshly painted, a bright blue with white and yellow branding conspicuous in these otherwise grey muddy part of Mukuru, an informal settlement in Nairobi. He says the toilet has changed much more than just the landscape.

There used to be a lot of wastes.

Stanley's is one of more than seven hundred so-called "fresh life toilets" in Nairobi's urban settlements. They are made by the company Sanergy as part of a fresh approach to old problems. By linking a shortage in proper sanitation facilities to a shortage in local fertilizer, the hope is to create one solution for two problems.

At the company's workshop a carpenter is making doors for more toilets. All the toilets made here are waterless. There is no need for water to flush with. Sawdust is used instead. This compensates with a lack of piped water in the settlements and helps with the next step, a crucial step treating the waste.

These people produce over ten thousand tons of waste every day.

I'm standing in the treatment facility where all the waste collected from the "fresh life toilets" is brought. All around me is piles of treated waste. Now this is the final stage before it's packed and then sent off to different trial farms across the country.

Sanergy treats about twenty-five tons of waste each week. But as Sara explains, getting people used to the idea of products from human waste is taking some effort. And fertilizer isn't the only byproduct. No waste is wasted here. Some of it is fed to the larvae of black soldier flies who remove the pathogens and turn the waste into protein, producing a nutritious feed for animals. The reusing of waste benefits the environment.