Turning Wastewater into Fertilizer Could Aid Sustainability

Gurian works with undergraduate students to
measure ammonia concentration in water samples.

Recovering nitrogen from wastewater could provide a more sustainable source of fertilizer than traditional industrial methods, according to a new study led by Patrick Gurian, PhDprofessor of civil, architectural and environmental engineering. The study found that removing ammonia from wastewater through a process called air-stripping and converting it into fertilizer emits far less greenhouse gas and uses much less energy than standard methods.

“Recovering nitrogen from wastewater would be a desirable alternative because it creates a ‘circular nitrogen economy,’” Gurian said. “This means we are reusing existing nitrogen rather than using energy and generating greenhouse gas to harvest nitrogen from the atmosphere.”

The life cycle analysis indicated air-stripping is cost-effective even at low ammonia concentrations. While it would produce smaller quantities than industrial production, the method provides an eco-friendly way to reuse nitrogen. The study suggests water treatment plants could invest in capturing phosphorus as well to support agricultural recycling of both key nutrients.

Overall, Gurian concludes that recovering nitrogen and phosphorus from wastewater could play a role in more sustainable food production while also creating potential revenue streams for utilities. The method presents an important step toward reusing the massive amounts of nitrogen needed to sustain agriculture worldwide.