IN-SITU PHYTOREMEDIATION OF PFAS-CONTAMINATED SOILS TO RETURN FARMLAND TO USEFUL PRODUCTIVITY

Home Grown Fuel's goal is to bring products,services, and resources to farmers to remediatePFAS from their contaminated soil. We will workwith farmers, using their labor and equipment, to returntheir farmland to active and healthy production.Goals andAlignment Home Grown Fuels' goalsalignwith USDA's Strategic Goals as follows:Combat Climate Change. HGF's Combined Heating and Power (CHP) production facility, constructed with repurposed buildings at a closed paper mill in Millinocket, Maine, will be powered by renewable energy made from biomass and hydropower. The facility is anticipated to be net zero or near net zero emissions. The facility will initially produce 2,000 tons of biochar per year of biochar, sequestering carbon, and be available for sale as carbon credits to help industry and others reduce their carbon footprint.Equitable, Resilient, Prosperous. Removing contamination from farm soil will return the land to production for farmers and landowners. It will also help rebuild the grand list for the community and the State. In the United States, 20 million acres of farmland have been identified as contaminated with PFAS (USDA, National Agricultural Statistics Service, 2024).Equitable and competitive marketplace. Nineteen billion pounds of septic sludge have been spread on 5% of America's farmland since 2016. PFAS from the sludge has been found in soil, water, plants, and wild and domestic animals, exposing farm workers and landowners to cancer-causing PFAS chemicals (Moran, 2023).Provide safe, and nutritious food. Successful phytoremediation of contaminated cropland will facilitate the return of these fields to produce fresh, locally sourced food. These phytoremediation steps will combat the annual loss of an estimated 1 million acres of land in farms in the U.S., especially small and mid-sized family-run farms (USDA, National Agricultural Statistics Service, 2024).Expand opportunities for economic development and improve the quality of life in rural and tribal areas. Known PFAS contamination is identified by red dots in Figure 1, and tribal lands are represented by the blue plots. Disadvantaged communities, particularly tribal lands have been disproportionately impacted by PFAS contamination. As background, by combining and studying soil types, soil amendments, plants' uptake, and thermal destruction we created the roadmap to PFAS remediation on America's farms. What science has already proven is that biochar stimulates growth in plants. Also known is that certain plants can phytoextract PFAS from the soil. HGF is combining this knowledge to maximize the extraction of PFAS from the soil into the plant. We are using the contaminated biomass as the vehicle to remove PFAS from the soil and the farm. This approach not only aids in removing PFAS from the soil but also unlocks the intrinsic value of biomass for energy production, such as generating power and syngas, including ethanol. Using biomass to create energy is done at temperatures known to break the bonds of "forever chemicals" that make up PFAS. Biochar stimulates growth in plants and sequesters carbon. Plants phytoextract PFAS from contaminated soils. From the Journal of Hazardous Materials, July 2023, scientists from Chongqing University in China and North Carolina State University show Phytoextraction of PFAS by weeds is cost-effective and up to 41.4%wt of PFAS can be removed from soil (He et al., 2023; Nason et al., 2024). Dr. Yanna Liang, Phase I STTR PI of UAlbany, designed our experiments and is providing the analysis of our findings. PFAS is broad a category and results vary from study to study as we search for an answer to remediate PFAS from soil. We learned that one size does not fit all. We remind ourselves that we must take the next step and the next and the next until the direction becomes clear. Moving to field trials will eliminate some of the unknowns of the grow house and give us space and time to have controls for each step. HGF gained many insights from the work Dr Liang published in February of this year;A Comprehensive Trial on PFAS Remediation: Hemp Phytoextraction and PFAS degradation in harvested plants (Nason et al., 2024). Dr. Liang directed a study of phytoremediation using hemp with the Mi'kmaq Nation, Upland Grasslands, and researchers from several institutions including UAlbany. The study was conducted with community members at the former Loring Air Force Base in northern Maine. Two key initiatives in the Loring study are (1) hemp was proven to uptake PFAS, and (2) lab-scale hydrothermal liquefaction equipment was used to degrade the grams of harvested hemp tissue. Building on Dr. Liang's work with the Mi'kmaw Nation, and her work with us in Phase I as reported in our Interim Report, HGF is adding two additional components to our Phase II scope of work: (1) we will further study the stimulation of plant growth with biochar and organic nutrients to increase yield and uptake, (2) thermal destruction will be tested on a commercial scale. The environmental significance of the Mi'kmaq study was 28 PFAS were identified in the soil and 10 PFAS were found in the hemp tissue Three kinds of hemp were studied. Fiber hemp is an annual crop that grows quickly, takes up large amounts of water, has limited grazing by animals, and does not shed leaf matter back into the soil. Some PFAS were found in the leaves and others in the stalks. The destruction of hemp at Loring was performed on tissues in 15mL reactors and run in triplicate. The hemp was heated in the reactor to 300°C for a residence time of 2 hours. Degradation of PFAS by HTL was nearly 100% for carboxylic acids, but a portion of sulfonic acids remained. The study concluded the project had positive impacts and lowered the overall presence of PFAS at a very contaminated site. Home Grown Fuels oversaw the destruction of the biomass grown in our grow house. The biomass was put through a pyrolysis unit in an oxygen-starved container and processed at 750 degrees centigrade for twenty minutes. The resulting ash/char showed a non-detect to 500 PPT.Technical ObjectivesTechnical Objective 1: Establish how to maximize phytoextraction from farmland soils. Questions to be answered:What PFAS exists on farmland sites?What is the soil type?What phytoextraction plants will respond to the soil type and climate?What soil amendments with maximize the growth and at what dose?How do both the roots and shoots perform in phytoextraction?Technical Objective 2: Determine how to support the farmer to grow the phytoextractions plants. Questions to be answered:What labor can the farmer provide?What equipment does the farmer have on-site?What is the best plan for the farmer to undertake on his or her own?What seeds and soil amendments will be needed?What is the agreed-upon statement of work?What licenses will be necessary, for example, hemp?Technical Objective 3: Establish safety protocols. Questions to be answered:What precautions does the farmer need to take for personal safety?How should the equipment be handled and cleaned?What does the logistics team need to be safe?How can biomass be safely handled at the thermal destruction site?How is sampling handled in the field, from the plants and the product being ash?Technical Objective 4: Demonstrate the PFAS bonds have been broken. Questions to be answered:What temperatures do the PFAS bonds in the biomass break down?What are the temperatures in the boiler or the gasification system?What does the emissions stack test show?Is there PFAS in the ash?If yes, should the ash be landfilled?Technical Objective 5: Model how payments for PFAS remediation can subsidize the work of farmers. Questions to be answered:Who are the likely payors to remediate PFAS?How will the subsidies be delivered?How much energy can biomass generate?