The new “green latrine” designed by Caitlyn Butler of the Civil and Environmental Engineering Department is attracting widespread media coverage. Butler is currently field-testing her new latrine, which purifies human waste, turns it into compost for farming, and generates electricity. Her multipurpose invention is officially called a “Microbial Fuel Cell Latrine.” Butler traveled to Ghana in May to install a pilot version of her device. Articles on Butler’s revolutionary invention have appeared in Physorg.com, Fuel Cell Works magazine, Electronic Products, the Springfield Republican, the Amherst Bulletin, and the Hampshire Gazette. Butler’s innovation was also featured last week on the UMass Amherst News Office website and posted on the campus email newsletter, In the Loop: Engineer builds ‘green latrine’ that makes compost and generates electricity.
Butler believes her inexpensive green latrine can be deployed throughout places such as rural Africa, transforming the way human waste is treated in areas where sanitation facilities are poor or nonexistent. At the same time, the device can play a key role in preventing waterborne diseases, including diarrhea.
“This would be a centralized resource for the whole community,” explains Butler. “Its purpose is a combination of removing the harmful components of human waste and generating electricity for the villagers.”
In Ghana, Butler worked with her two graduate students, Cynthia Castro and Joe Goodwill, collaborators Mark Henderson and Brad Rogers from Arizona State University, and many residents of the small farming village of Agona Nyakrom to install the first working model of her Microbial Fuel Cell Larine in the field. Together they proved that it takes a whole village to raise a good latrine, and in turn the whole village will benefit.
“You get a lot or resources out of this system,” notes Butler. “The latrine produces electricity. It makes compost. And you protect the ground water source. So you get a lot back for a small investment.”
In the long term, when her latrine is deployed more widely, it will address two persistent problems throughout the developing world.
The first problem is that, when human waste leaches into underground water, deadly pathogens that cause waterborne diseases such as diarrhea spread throughout the aquifer. High nitrogen concentrations contained in the waste can also damage healthy water systems as well as cause nitrate-poisoning in infants and the elderly. Butler’s microbial latrine would neutralize all those issues.
The second problem is that many rural areas of Africa have limited electricity, and Butler’s fuel cell would generate enough electricity to power a light within the latrine, thus allowing villagers access throughout the night.
Butler’s project and her Ghana trip were funded by a $100,000 grant from the Grand Challenges Exploration program supported by the Bill & Linda Gates Foundation in this collaborative project between engineers from UMass Amherst and Arizona State. (August 2012)