It may seem off-putting to some, but human waste is full of nutrients that can be recycled into valuable products that could promote agricultural sustainability and better economic independence for some developing countries.
Cities produce and must manage huge quantities of wastewater. Researchers at the University of Illinois at Urbana-Champaign have developed a model to clarify what parts of the world may benefit most from re-circulation of human-waste-derived nitrogen, potassium and phosphorus from cities and back into farm fields. They report their findings in the journal Nature Sustainability.
“We grow our crops in the field, apply nutrient-rich fertilizers, eat the crops, excrete all of the nitrogen, phosphorus and potassium and then those nutrients end up at the wastewater treatment plant,” said Jeremy Guest, a civil and environmental engineering professor and study co-author. “It is a very linear, one-directional flow of resources. Engineering a more circular nutrient cycle would create opportunities that could benefit the environment, economy and agriculture.”