In Africa's largest slum, uncollected waste has long posed an insurmountable health hazard but an ingenuous new energy-generating incineration programme could help contain pollution.
The UN-sponsored project in Kibera -- a sprawling shantytown in Nairobi -- recycles waste to fuel a giant cooker, in this poor neighbourhood where many never have a hot meal or warm water to bathe in.
"It's true that the idea is funny but we saw something that we did not expect," said Debrah Wanjiku, a 23-year-old mother of two as she explained how the "community cooker" works.
A recent study by the United Nations Environment Programme (UNEP) on a waste dump in another Nairobi slum, Korogocho -- reportedly the largest in sub-Saharan Africa -- documented the alarming impact the uncontained waste can have on human health and the environment. It notably recorded levels of toxic cadmium and mercury up to 10 times higher than emergency thresholds in developed countries.
Kibera's community cooker project seeks to offer a low-cost sustainable solution that reduces waste levels, improves residents' food hygiene and diet and preserves the natural habitat.
The project, which could be expanded to other slums on the continent, is the first of its kind, said UNEP, which is headquartered in Nairobi and funded the 10,000 dollars (7,500 euros) needed for the launch.
The sea of waste in Kibera's narrow streets has started to ebb since a twice-weekly collection was started.
Unemployed youth were enrolled to pick up the trash, a daunting task for which they receive 10 shillings (around 15 US cents) each time. The sum is modest but not negligible in a country where two-thirds of the population live on less than a dollar a day.
Recyclable waste such as hard plastics, metals and glass are sold while biodegradable items and some plastics such as the polyethylene used to manufacture soft drink bottles are incinerated after a two-day drying period.
Every waste collector retains ownership of the trash and can gain free access to the incinerator, whose integrated oven and burners can then be used to make tea or bake bread.
The initial goal is for the cooker to consume half a ton of waste a day, allowing users to prepare cooked meals rarely affordable to the most destitute in Kibera and improving sanitary conditions by heating water for nearby public baths.
"We are overlooking the fact that we are using waste because the benefit for the community is much higher," said Tom Wainaina, a 32-year-old collector from Kibera's Laini Saba area, where the cooker was installed.
"We want to have a clean environment and to stop the spreading of diseases" such as typhoid, cholera and various forms of diarrhea," added one of his colleagues, 22-year-old Meshack Nganyi.
"We have a lot of children dying of these diseases and it has become expensive to treat people," he said.
The project is in its infancy and developers have already spotted the need for improvements, including elevating the incinerator's combustion temperature to produce less noxious smoke and provide protective gear for the collectors.
It is part of UNEP's larger Nairobi River Basin Project launched in 1999 to improve the capital's badly polluted river system, said the agency's programme officer Henry Ndede.
"The degradation of the environment of the Nairobi rivers is reaching a critical stage.
"With the increasing of population now to more than three million people, the waste problems have actually overwhelmed the ecosystem," he said, adding that the city now generates 3,000 metric tons of waste a day.
Ndede noted that 70 percent of the city's population live in informal settlements -- or slums -- often located in the river valley and with no sanitation systems.
"Invariably, they throw out all the rubbish they have into the river, it could be plastic, bottles, (car) batteries with all the heavy metals in them, everything really goes into the river."
He estimated that up to another three million people living downstream, from the capital right to the Indian Ocean, are also exposed to the slums' pollution.
"What the stove has done is basically to make rubbish into something you can use," UNEP chief Achim Steiner told Kibera residents on a recent visit.
"That is one way in which being environmentally sound can also change the quality of your life here," he said.