A new type of public toilet is helping people in Haiti make fertilizer from human waste, a project that may someday revive the country’s degraded farmland, curb disease, and create jobs.
Since 2006 the U.S. nonprofit Sustainable Organic Integrated Livelihoods (SOIL) has been installing public toilets in Haiti, where 80 percent of the population has no access to sanitation.
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Sanitation was the most successful health intervention in the modern world,” said SOIL co-founder and soil ecologist Sasha Kramer. But in Haiti, “poop getting into water is the leading cause of death.”
So far, SOIL has installed ecological toilets in camps of more than 20,000 people left homeless by the 2010 earthquake in Port-au-Prince. Facilities are also being supplied to 30 communities in northern Haiti. (See “Haiti Earthquake Anniversary: Pictures Show Slow Recovery.”)
But these aren’t just any toilets: Kramer and her colleagues constructed urine-diverting toilets, a type of ecological sanitation in which urine and feces are separated. The waste is then covered with a dry material to aid decomposition and is regularly collected.
“With seven billion people on the planet as of this week,” Kramer said, “technologies like this are more and more important for addressing the basic rights of a growing population and reducing the negative impact on the earth’s ecological systems.”
From Waste to Valuable Soil
Once a week SOIL workers drive through communities in a flatbed truck called the Poopmobile, collecting the toilet drums and replacing them with clean ones
The waste is then taken to a composting site outside the city, where workers mix the material with sugarcane bagas—a byproduct of making rum—to speed up the composting cycle.
“All the microbes get excited, they start reproducing like crazy,” said Kramer, who’s also an emerging explorer with the National Geographic Society. (The Society owns National Geographic News.)
The activity heats the compost to about 160 degrees Fahrenheit (71 degrees Celsius). This kills any disease-causing bacteria, which are adapted to the average human body temperature of 98 degrees Fahrenheit (37 degrees Celsius).
Workers check the compost temperature every two days, and “by the end of eight months, [we] end up with incredibly nutrient-rich soil,” Kramer said. Human waste may even be better than cow feces for compost, she added, since our meatier diets contain more plant-boosting nitrogen.
When composted properly to kill pathogens, human waste is a “very rich nutrient source that’s quite suitable for growing crops for human consumption,” said Serita Frey, a soil microbial ecologist at the University of New Hampshire in Durham.
“In the West, we’re quite squeamish about use of human waste in general as a fertilizer,” Frey said, but “throughout history it’s been used in Asia and other parts of the world as a soil amendment.”
Adding compost to farmland can also improve soil structure and stability, both crucial for preventing erosion, added Frey, who is not affiliated with SOIL.
That’s because, as bacteria and fungi decompose the material, they produce sticky glues that bind soil particles together to form stable clumps, she said.
Toilet Project a “Very Good Circle”
So far, the Haitian toilet project has yielded more than 100,000 gallons (400,000 liters) of compost, some of which is already being applied to experimental gardens and crops, Kramer said.
Some of these gardens are producing vegetables that provide food for residents in Cité Soleil, an extremely poor, densely populated area near Port-au-Prince, said Daniel Tillias, a Haitian community organizer for the peace group Pax Christi Haiti.
The rich compost could eventually be used to grow crops and replant trees across the impoverished Caribbean country, where decades of land overuse and deforestation have stripped soils of nutrients and led to widespread erosion.