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 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.”