Grantee Research Project Results

Final Report: Reclaiming Beneficial Biosolids : A PFAS Removal and Destruction Approach

EPA Contract Number: 68HERC25C0011
Title: Reclaiming Beneficial Biosolids : A PFAS Removal and Destruction Approach
Investigators: Carpenter, Alexis W
Small Business: AxNano
EPA Contact: Richards, April
Phase: I
Project Period: December 16, 2024 through June 15, 2025
Project Amount: $100,000
RFA: Small Business Innovation Research (SBIR) - Phase I (2025) RFA Text |  Recipients Lists
Research Category: Small Business Innovation Research (SBIR)

Description:

The purpose of this research was to develop a practical, feasible, and field-deployable solution for the removal and destruction of PFAS (per- and polyfluoroalkyl substances) from municipal biosolids. Current biosolids management practices, such as land application, landfilling, and incineration, either fail to effectively address PFAS or create additional environmental concerns.

In response to this challenge, AxNano, in partnership with EzraTerra, proposed integrating two advanced treatment technologies:

• Sintered Wave Technology (SWoT) for nondestructive PFAS extraction, and
• Supercritical Water Oxidation (SCWO) for complete PFAS destruction.

SWoT uses electrically heated air to liberate PFAS from biosolids, capturing and concentrating the PFAS in liquid and solid forms. SCWO then breaks the carbon-fluorine bonds in these concentrates, fully destroying PFAS compounds. This integrated, electricity-powered system is designed to remove PFAS while preserving the beneficial qualities of biosolids, producing reusable Class A material, water, carbon dioxide (CO₂), and inert salts, offering a sustainable alternative to current disposal-based methods. Independent testing has shown that SWoT can remove 99.999% of PFAS from industrial sludge, while SCWO achieves up to 99.999% PFAS destruction in both solids and liquids.

Phase 1 research focused on system performance, integration, and implementation. Activities included:

• Evaluated biosolids input and material compatibility with SWoT and SCWO.
• Validated PFAS removal and destruction using past pilot-scale data.
• Reviewed PFAS occurrence data from North Carolian Department of Environmental Quality (NCDEQ) and regulatory requirements under 40 Code of Federal Regulations (CFR) Part 503.
• Analyzed technology readiness and system-level integration.
• Identified potential pilot sites and engaged stakeholders for market insight.
• Conducted an abridged life cycle assessment to inform system design.

Summary/Accomplishments (Outputs/Outcomes):

This integrated solution addresses a major environmental challenge: the widespread presence of PFAS in biosolids. Traditional land application, landfilling, and incineration practices pose a risk of releasing PFAS into soil, water, and air. Our approach mitigates these risks, supports beneficial reuse, and reduces reliance on conventional disposal methods. Unlike current technologies, AxNano and EzraTerra offer complete PFAS destruction while preserving the value of treated biosolids.

Phase 1 confirmed the technical feasibility of the integrated SWoT–SCWO system:

• Technology Readiness: SWoT and SCWO components operate at TRL 6–7; integrated system is at TRL 7 pending pilot deployment.
• Performance: SWoT reduced PFAS in solids to non-detect levels; SCWO achieved >99.995% PFAS destruction in prior GAC project (AF SBIR FA864923P1125 7/21/2023-4/21/2025).
• System Compatibility: The concentrated PFAS liquid and spend GAC outputs from SWoT were found to be compatible with SCWO input requirements. Reuse of CO₂ from SCWO into SWoT was initially proposed but later determined infeasible due to insufficient CO₂ production.
• Commercial Path: Class A biosolid producers were initially expected to be high-paying customers, but this was not supported by market feedback. Producers facing high disposal and transportation costs due to state regulations, along with land application markets, were identified as more viable early targets. A pilot demonstration is the next critical step toward commercial deployment.

Commercialization:

The proposed system offers a cost-effective solution for biosolid producers (e.g., municipal wastewater treatment facilities) looking to decrease disposal costs and for biosolids receivers (e.g., landfills) seeking to better manage increasing volumes of biosolids and prevent landfill destabilization. As land application becomes less viable due to increasing regulatory limits, more biosolids are being diverted to landfills –which are not designed to handle such volumes. While biosolid processors showed interest, the system best aligned with the needs of producers and receivers by supporting compliance with evolving PFAS regulations while preserving the value of biosolids. Key commercial advantages include:

• On-site PFAS treatment lowers transportation and disposal costs by reducing the need to haul biosolids off-site.
• Destruction of PFAS eliminates reliance on landfilling, reducing long-term environmental liability.
• Production of PFAS-free, Class A biosolids creates a safe, reusable product with potential for re-sale.
• Regulatory compliance lowers operational risks and minimizes future liability exposure.

We estimated a total addressable market of $1.9 billion and a near-term opportunity of $50 million, this technology positions AxNano and its partner as leaders in sustainable PFAS management. Advancing the system from TRL 6 to 8 through pilot testing will support commercialization and create a viable, environmentally responsible alternative to incineration and landfilling.

Conclusions:

This treatment train represents a novel, electricity-powered alternative to traditional biosolid management approaches. SWoT’s ability to extract PFAS from supramolecular microemulsions and the use of real-time GeoRheo functional state analysis are unmatched in the current market. When combined with SCWO, the system ensures complete PFAS destruction, including precursors, without combustion or air pollution concerns.

With Phase I demonstrating feasibility and system compatibility, the project is well-positioned for Phase II pilot-scale deployment and commercialization.