Prevention of Per- and polyfluoroalkyl substances (PFAS) Crop Contamination Through Management of Biosolids-Amended Soils

Commodities

Practices

The use of biosolids as fertilizer is an emerging strategy for sustainable agriculture by recycling essential nutrients, improving soil health and reducing reliance on synthetic fertilizers. However, the widespread presence of per- and polyfluoroalkyl substances (PFAS) in biosolids threatens the long-term viability of this management approach. When contaminated biosolids are applied to crop fields, PFAS can persist in soil, leach into groundwater, and accumulate in crops, raising concerns about food safety, environmental quality, and the health of agroecosystems. Addressing PFAS contamination is therefore essential to maintaining the role of biosolids in environmentally responsible agriculture.

This project will develop and optimize a modified alkaline thermal hydrolysis (MATH) treatment to remove PFAS from biosolids before land application, building on existing wastewater treatment infrastructure with minimal capital investment. Batch experiments will identify the optimal temperature, alkalinity, and residence time conditions to maximize PFAS desorption from biosolids into the aqueous phase while retaining key plant nutrients. The effectiveness of the MATH treatment will then be validated by growing soybeans (Glycine max) in MATH-treated versus untreated biosolids-amended soils.

By integrating contaminant removal with nutrient recovery, this research seeks to support the safe use of biosolids in agricultural systems, contributing to circular nutrient economies and reducing agricultural dependence on expensive synthetic inputs. The findings will provide critical insights into managing emerging contaminants in agroecosystems, helping to protect soil health, crop quality, and the long-term profitability of agriculture.

The primary goal of this project is to mitigate PFAS uptake by crops stemming from agricultural fields treated with biosolids by modifying current biosolids processing techniques. The following objectives are listed below to help achieve this goal:

Objective 1: Establish a theoretical foundation for the proposed research by evaluating current literature on PFAS behavior in biosolids and crop uptake. The goal for objective 1 completion is January 2027.

Objective 2: Optimize modified alkaline thermal hydrolysis process conditions to remove PFAS contaminants in biosolids within existing wastewater treatment infrastructure. The goal for objective 2 completion is August 2027.

Objective 3: Assess nutrient retention in treated biosolids to ensure viability as a synthetic fertilizer alternative. The goal for objective 3 completion is August 2027.

Objective 4: Evaluate and compare PFAS uptake across soybean tissue types grown in soils amended with treated versus untreated biosolids using EPA Method 1633A. The goal for objective 4 completion is July 2028.