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Human Poop: An Unexpected Ally in the Fight Against Climate Change

By Office of Communication Services    Published on 10/30/2017 More stories >>

CTAHR's
Rebecca Ryals and postdoctoral researcher Gavin McNicol (in red) are partnering
with the Haitian NGO Sustainable Organic Integrated Livelihoods (SOIL).

CTAHR's Rebecca Ryals and postdoctoral researcher Gavin McNicol (in red) are partnering with the Haitian NGO Sustainable Organic Integrated Livelihoods (SOIL).

Whether you call it night soil or humanure, human feces, when released to the environment, can cause severe problems to human health. But if managed ecologically, it can potentially be a solution for climate change and sustainable development, as research by assistant professor Rebecca Ryals and postdoctoral researcher Gavin McNicol shows. The two are partnering with the Haitian NGO Sustainable Organic Integrated Livelihoods (SOIL) to research the impact of SOIL’s “ecological sanitation” (EcoSan) human-feces composting technique on greenhouse gas emissions, nutrient cycling, and pathogens.

EcoSan provides clean, dignified sanitation options in places without the widespread apparatus of plumbing systems and water-treatment plants that most in the US take for granted. EcoSan composting uses microbes’ natural ability to decompose organic waste at high temperature. This reduces the spread of potentially devastating intestinal-borne pathogens, like cholera. It transforms feces into pathogen-free, nutrient-rich compost: used as an agricultural soil amendment, it returns nutrients and organic matter to soils, which can boost crop yields while reducing the necessity for purchased, often imported, soil fertilizers made from non-renewable sources like petroleum. It may also increase plants’ health, making them more resilient to stresses.

EcoSan composting uses microbes’ natural abilityto decompose organic waste at high temperature.

EcoSan composting uses microbes’ natural ability to decompose organic waste at high temperature.

EcoSan is also potentially healthy for the planet. Dr. McNicol, an ecosystem scientist, explains how it could slow or mitigate climate change: like any composting process, it emits greenhouse gases, but it may emit significantly fewer than other waste-management strategies, and it requires relatively little energy consumption and few inputs. The researchers are quantifying these greenhouse gas savings to evaluate and compare EcoSan to other waste-management strategies. Applying compost to agricultural soils increases the amount of carbon stored in soil, lowering the amount of carbon dioxide (CO2) in the atmosphere. It may also provide resiliency in the face of climate change: soil enriched with compost gains increased ability to hold water and nutrients, acting as a buffer against drought and other problems of global warming.

Drs. Ryals and McNicol, both in the Natural Resources and Environmental Management department, have also helped to start a new Stajyè Klima ak Konpòs (Climate and Compost Fellows) program, with the aid of donations, to support Haitian research interns and a lab technician to further this collaborative research. And they’ve built a weather station at one of SOIL’s compost sites, offering continuous, publicly available information on local weather. Their international collaboration shows that the problems of global climate change require global solutions; as Dr. Ryals explains, “The best solutions to climate change are those that empower communities, improve livelihoods, and protect natural resources. Closing the poop loop does just that.”