Deep in the sprawling slum of Kibera, volunteers shovel a stinking pile of garbage into one end of a giant concrete oven while a queue of people clutching packets of tea and saucepans tries to ignore the acrid smoke wafting from the cooker.

"It might smell a bit but it doesn't make our food taste any different," says Virginia Wamaitha, as she pours sugar into her steaming pan of chai – the gently spiced tea loved by Kenyans. "It will taste just like chai should."

The garbage-burning oven is part of a UN-sponsored move to clean up Kenya's slums while preserving the country's dwindling forests, which are cleared to provide wood and charcoal for cooking. If successful, the pilot project could be a model as the world faces an explosion in urban living, and the waste it creates.

"It is only a pilot and we need many more cookers to clean up Kibera, but we have already seen a difference in the area we are targeting," says Pauline Nyota, of the Umande Trust, which works in slums to improve sanitation and runs the project. "The drainage ditches are much cleaner – just wastewater when before they were clogged with rubbish."

The first cooker's early success has prompted the country's biggest supermarket chain to pledge funding for 20 more.

How the oven works

Through trial and error, the developers of the oven used technology that can produce temperatures of up to 930 degrees F., enough to burn many of the hazardous pollutants.

It uses a superheated steel plate inside the incinerator box to vaporize drops of water. The oxygen released then helps burn discarded "sump" oil from vehicles – itself a pollutant in the slums – driving temperatures higher.

The process is simple enough to be controlled by locally trained volunteers.

Pots of pasta boil inside the oven, while chai simmers on hot plates above – all for a few shillings from Kibera's residents.

The project is the first of its kind, according to the United Nations Environment Programme (UNEP), which provided $10,000 for the launch.

Youth workers are paid a few shillings to go door to door collecting rubbish.

They are also allowed to use the cooker for preparing hot meals or to fill buckets with hot water for washing.

The target is for the cooker to consume half a ton of waste every day once it has finished trials in a month or so.

World's slums growing

Kibera's problems with waste are mirrored in Nairobi's other slums and are the result of rapid, unplanned expansion as families give up their rural way of life for the city.

It is a trend seen throughout the developing world.

Earlier this year the UN Population Fund reported that, for the first time, more than half the world's 6.6 billion inhabitants would live in urban areas by 2008.

Without adequate planning, warns its State of the World's Population 2007 report, there will be an explosion of slums, with the associated environmental damage and human disease.

Page: 1 | 2