Finding Solutions in Sources of Pollution
Synthetic fertilizers are commonly used in agriculture to accelerate crop growth, but they are expensive and contribute to greenhouse gas emissions (GHG) that drive climate change. The rising financial and environmental costs of conventional fertilizers heighten the need to build soil health, protect water quality and reduce dependency on fossil fuels and mined minerals.
A significant portion of regional fertilizer needs could be met by reclaiming the nutrients from human waste, which currently are mostly lost during wastewater treatment. Though vast quantities of nutrients flow through modern wastewater treatment systems, posing a pollution risk, only a fraction is captured for beneficial reuse.
Researchers led by Abraham Noe-Hays, research director at the Rich Earth Institute, are producing biochar – charcoal created from organic matter – from wastewater to develop safe, renewable fertilizers that enhance agricultural productivity, support soil health, reduce nutrient pollution and mitigate climate change through soil carbon sequestration.
Using Waste Management to Improve Soil & Water
This research responds to shortcomings in the existing practice of using biosolids, produced during the wastewater treatment process, for fertilizing farmland. Wastewater biosolids are rich in organic matter and nutrients, but they contain micropollutants including per- and polyfluoroalkyl substances (PFAS), also known as forever chemicals, from industrial processes, personal care products and many other sources. As a result, wastewater biosolids are increasingly sent to landfills, where they produce GHG emissions. By transforming biosolids into biochar, which can also be used as fertilizer, it may be possible to resolve the micropollutant and GHG concerns, although some fertilizer value is lost in the production process.
The researchers are studying various techniques to optimize the wastewater biochar production process to reduce micropollutants while retaining nutrients. In addition, they are evaluating biochar’s ability to filter contaminants out of other nutrient-rich liquid waste streams, and to bind nutrients to produce fertilizers even richer in nitrogen and phosphorus.
Finally, Rich Earth Institute is engaging with farmers, policymakers, soil health advocates, and other stakeholders to identify interests and concerns, develop informational resources, and support regulatory and planning processes to ensure the safety and appropriate use of wastewater-derived fertilizer.