University researchers create toilet that converts human urine to fertilizer

Tuesday, January 31, 2017 - 5:50pm

Out of all of the national rankings the University of Michigan makes each year, a new project could shake things up: The University, they say, is "number one" at number one.

Last week, University researchers contributed to a project some dub “peecycling,” installing a toilet and a urinal in the G.G. Brown Engineering building on North Campus that recycles human urine to fertilizer.  

The initiative, funded by a $3 million grant from the National Science Foundation, created a split-bowl toilet design that collects urine from the toilet in a tank. The urine is then treated and filtered to be used as a fertilizer in the University’s botanical gardens. Solid waste from the toilet is sent to a treatment plant.    

From a user's perspective, researchers said, the split-bowl toilet is not much different than a traditional toilet. Anthropology Associate Prof. Rebecca Hardin, one of the project leaders, said there is almost no difference in user experience.

“At this point, the technology doesn’t look much different than a normal bathroom infrastructure,” she said.

Hardin led the project with Nancy Love and Krista Wigginton, both professors of civil and environmental engineering.   

The professors and researchers created many goals for the project. They hoped to utilize urine’s nutrients effectively to reduce water pollution, but also create a fertilizer that is safer than many synthetic fertilizers.

"We believe our work will take urine-derived fertilizer to a point where it's safer than synthetic fertilizers and biosolids," Love said in a Michigan News article.

The launch of the new toilets coincided with the announcement of a survey analyzing users’ opinions on the new technology. The survey is presented on tablets in the bathroom toilet users can give immediate feedback. The team is working on “how to most effectively convey this technical information to the public to try to advance acceptance and instruction,” Love said.     

“None of this is going to go anywhere if people have negative impressions of this technology,” Love said.

By using the survey to gauge user experience and opinions about the new toilet technology, the leaders of the project plan to introduce these toilets in other regions of the United States.

“There will be many related types of surveys in the project as we expand uptake potential of the project in New England, the Upper Midwest and possibly a third area,” Hardin said.

Urine recycling first began in 2014 when researchers from the University’s School of Engineering, the School of Public Health and the School of Natural Resources collaborated with researchers from the Rich Earth Institute in Vermont and researchers from the University of Buffalo. Since then, the team examined and tested ways to filter urine to create an effective plant fertilizer.

“We had been doing trial runs where we took urine collected from festivals and events and then we used the collected urine and we’d been using them to apply to crops,” Love said. “During two seasons of field visits, we grew carrots and lettuce and tracked the way technology killed the bacteria and viruses.”

Since the launch of the new technology, researchers are recognizing the toilet could be a step in developing ways to promote sustainability on campus, especially as the University plans to launch the School for Environment and Sustainability in July.  

“One other exciting aspect is that it is kind of the harbinger of the times to come for sustainability on campus,” Hardin said. “In July, we will be launching the School for Sustainability and Environment, and that will foster more bridge building across units.”  

Love said she was appreciative of the University’s willingness to help with the project.

“It’s been interesting because on campus we’ve had no resistance, we've had extensive enthusiasm,” she said. “This is promising from the perspective of a campus.”