Diverting urine away from municipal wastewater treatment plants and recycling the nutrient-rich liquid to make crop fertilizer would result in multiple environmental benefits when used at city scale, according to a new University of Michigan-led study.
Doing a comprehensive analysis of the environmental impacts of urine recycling compared to conventional fertilizer production may seem like an odd topic, but to Gregory Keoleian, Director of the Center for Sustainable Systems a the Univerisity of Michigan, it makes perfect sense. “Both conventional wastewater treatment and fertilizer production are carbon intensive processes said in an interview with Sarah DeWeerdt. “Flushing urine, with its valuable nutrients [nitrogen, phosphorus and potassium] down toilets for processing in energy intensive wastewater treatment plants makes no sense.”
The researchers found that urine diversion and recycling (which they call “peecycling”) can lead to significant reductions in greenhouse gas emissions, energy use, freshwater consumption and the potential for fueling algal blooms in lakes and other water bodies. The data they gathered from peecycling pilot projects in Vermont, Virginia and Michigan indicate that the benefits of improved wastewater management and avoiding synthetic fertilizer production far outweigh the costs of urine collection, processing and transport.
None of this means that peecycling is coming soon to a bathroom near you. As you can imagine, changing our existing infrastructure so that we can collect, store and process urine presents many challenges. But it’s a great example of how researchers and engineers are working together to bring us a more sustainable future.
