How a favela in Rio got its clean water back, for $42,300

RIO DE JANEIRO (AP) — Butterflies and waxbills flit through the Enchanted Valley just outside Rio de Janeiro’s Tijuca Forest National Park. There are fruit trees, a nearby waterfall and a commanding view out over the Atlantic Ocean. But for decades something was spoiling the idyll: the stench of raw sewage.

Electricity arrived in the late 20th century to the low-income Enchanted Valley community – which drew its name from a nearby residential project – but the utility never connected it to the city’s sewage network. Waste was contaminating the local environment and putting residents’ health at risk.

So the community set out to solve the problem on its own by building a biodigester and artificial wetland to process all sewage generated by all of its 40 families.

It started full operations in June, and is the first independently built biosystem for an entire Brazilian favela, according to Theresa Williamson, executive director at Catalytic Communities, a nonprofit that supports the underserviced communities. And it could serve as an example for rural hamlets across Brazil. According to official data, 45% of Brazilians' sewage isn’t collected.

The Enchanted Valley project is years in the making. The president of the local residents’ association, Otávio Barros, brought a group of tourists to a waterfall downhill in 2007 and, when they wanted to bathe in its waters, he told them they couldn’t; all the community’s sewage flowed through that cascade. The seed of an idea was planted, though, and he started drumming up support.

“It was harder back then to make people aware, show that everyone would benefit,” he told The Associated Press as he walked through the community.

He found allies among researchers of Pontifical Catholic University of Rio de Janeiro, where he had been...