A Cheap, Easy Fix to Rio’s Sewage Problem | Source: The Atlantic, Aug 4 2016 |
The reason so much sewage is flushed directly into Rio’s Guanabara Bay, city officials have argued, is that it’s too difficult to lay pipes in much of the city. The favelas are crowded and carved into steep mountainsides.
Barros uses cups to demonstrate how the biodigester works. (Olga Khazan / The Atlantic)
They can be dangerous. Environmental activists, meanwhile, contend there’s not enough government will behind sanitation projects.
But there is one solution that gets around these issues: A cheap, seven-foot, cement dome that treats sewage with little more than some rocks, plants, and, well, coprophagic bacteria.
I learned about this contraption, called a biodigester, on a December reporting trip to Rio. On a scorching hot day, I took a cab up a mountain in the city’s northern zone, where I met Otavio Barros, the leader of the Vale Encantado community.
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April 17, 2011 – Desperately poor Haiti is finding a cheap source of fuel in recycling human excrement, a move that could help put a dent in a cholera epidemic and slow the country’s pervasive deforestation.
The “biodigester“, which converts organic waste to biogas and a liquid fertilizer rich in nutrients, requires little infrastructure: toilets linked to a sealed, brick-lined well connected to a basin. Seventy of these devices are up and running, while another 70 are in the works.
Deprived of air, the bacteria thriving in human excrement eat 85 percent of the refuse while producing methane gas, explained Martin Wartchow, pointing his lighter above a small tube hanging out of the rank. A powerful flame was immediately set ablaze.
“The remaining 15 percent of organic waste is thrown out with the excess water in a green area where they biodegrade,” continued the hydrologist, who is working with the Brazilian nongovernmental group Viva Rio in Port-au-Prince.
“Not a single chemical product is used and at the end of the line, the water we collect is completely clean.”
The engineer plunged his hand in a basin filled with filtered, clear and, incredibly, odorless liquid. “We even raise fish here.”
Recently completed at a Viva Rio center that hosts over 600 young Haitians each day, the installation is due to be linked to a cafeteria under construction to replace wood coals.