Fertilizer production contributes to GHG emissions, and runoff from fields can cause pollution. Rising fertilizer prices also put financial pressure on farmers. Furthermore, international conflict is disrupting supply chains, making fertilizer availability and price inconsistent.
Wastewater biosolids, produced during the wastewater treatment process, are rich in organic matter and nutrients that can be used as fertilizer. Yet, these biosolids often 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 often sent to landfills, where they produce GHG emissions. However, the amount of micropollutants can be greatly reduced by transforming biosolids into biochar, which can also be used as fertilizer, although the production process causes a loss of nutritional value.
Researchers led by Abraham Noe-Hays, research director at the Rich Earth Institute, are studying a variety of techniques to optimize the wastewater biochar production process to reduce the amount of micropollutants in the biochar while retaining nutrients. Additionally, they are evaluating biochar’s ability to filter contaminants out of other nutrient-rich liquid waste streams by binding nutrients to produce fertilizers even richer in nitrogen and phosphorus.
Finally, the Rich Earth Institute is engaging with farmers, policymakers and other key stakeholders to identify core concerns, needs and recommendations relating to wastewater-derived fertilizer, after which they will co-create strategies to address these perspectives through education, policy and technical development.