Grantee Research Project Results

Final Report: Degradation of Per-and Polyfluoroalkyl Substances (PFAS) from Water Using Thermal Plasma Arc Discharge

EPA Contract Number: 68HERC24C0011
Title: Degradation of Per-and Polyfluoroalkyl Substances (PFAS) from Water Using Thermal Plasma Arc Discharge
Investigators: Jorjadze, Vasily
Small Business: IM Technologies, LLC
EPA Contact: Richards, April
Phase: I
Project Period: December 1, 2023 through May 30, 2024
Project Amount: $100,000
RFA: Small Business Innovation Research (SBIR) - Phase I (2024) RFA Text |  Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , PFAS Treatment , Water Treatment

Description:

Sustainable access to drinking water is a major public health issue and thus one of the great challenges for the 21st century. Over development, inadequate management of wastewater, climate change, and seasonal variation of weather make fresh water a scarce commodity. One obvious path to overcome this issue is to reuse water. However, to be reused in a meaningful way requires processing wastewater with advanced water treatment technologies. Of alarm are emerging contaminants of micropollutants from household products and industrial applications.

Per- and polyfluoroalkyl substances (PFAS) are contaminants of emerging concern in the United States and worldwide. They have been used in a wide variety of household and industrial applications, including firefighting foams, and have found their way into the groundwater contaminating our drinking water supplies. Extremely high levels of these contaminants are also prevalent at many DoD sites.

This project investigated a new approach to degrade PFAS simultaneously by exploiting a thermal plasma arc discharge system. The plasma arc discharge is submerged in water to create ions and free electrons by sustaining a current of many hundred amperes through the water. The interaction of plasma discharges with water creates multiple phenomena that have applications in water treatment. These include the generation of chemically active components including hydroxyl radicals, hydrogen peroxide, ozone and other active compounds, energetic electrons and ions, UV light, ultrasound waves and cavitation, and more. Since these phenomena are created simultaneously, the collective effectiveness can be much higher and lead to synergistic contributions from short-living active species, charged particles and UV light.

Thermal plasma technology can be implemented to effectively decompose PFAS compounds, which are notoriously resistant to conventional treatment methods. Unlike traditional approaches that may only capture or contain these contaminants, thermal plasma technology actively breaks down the strong carbon-fluorine bonds in PFAS molecules, transforming them into non-hazardous substances. Hence, it addresses the critical challenge of permanently removing PFAS from water sources, rather than merely relocating the pollution. The innovative application of thermal plasma to environmental remediation represents a significant advancement in the field, offering a potentially transformative solution to a pervasive and growing global issue of water contamination.

Summary/Accomplishments (Outputs/Outcomes):

A simple controlled approach was implemented to evaluate the effectiveness of thermal plasma discharge in water.  The investigation demonstrated that at sufficient energy density levels, near complete PFAS degradation is possible.  More than 90% degradation levels were demonstrated at sufficient energy density levels, while further analysis of the treated water revealed anticipated Fluorine content supporting degradation claims.  A relationship between relative PFAS degradation percentage and energy density (energy per unit volume of water) was constructed that can form the basis of understanding operational adaptation of the thermal plasma process as a modular and scalable approach to water treatment.   Next generation thermal plasma reactor system for in-line and continuous treatment of water were conceptualized considering logistical experience garnered during the Phase I effort.

Conclusions:

Implementation of thermal plasma technology demonstrated that “forever chemicals” are degradable.  A unique trend of relative PFAS reduction versus energy density was obtained that points to 100% reduction to carbon and fluorine.   

PFAS causes diverse effects on the environment and finally on human life, affecting in the most negative way. Therefore, the requirement to have water, where PFAS concentration is at low ppt (part per trillion) level, is of significant interest to the US Government, city municipalities, hospitals and clinics, water producing companies and many more. Key interest exists for clean-up of the contaminated sites, where PFAS containing material is manufactured, military areas, fire-fighting teams training areas, as firefighting foams are containing significant amount of PFAS and are subject of intense spilling and penetration into a ground water.

The introduction of plasma technology highlights an innovative direction in the field, aiming to create a reactive environment that breaks down PFAS molecules into harmless byproducts. This suggests a trend towards technologies that not only remove but also chemically transform PFAS to ensure they are not simply displaced but effectively neutralized.