Grantee Research Project Results

Final Report: Destruction of PFAS Using Hydrodynamic Cavitation

EPA Contract Number: 68HERC20C0022
Title: Destruction of PFAS Using Hydrodynamic Cavitation
Investigators: Servi, Amelia T
Small Business: Creare LLC
EPA Contact: Richards, April
Phase: I
Project Period: March 1, 2020 through August 31, 2020
Project Amount: $99,980
RFA: Small Business Innovation Research (SBIR) - Phase I (2020) RFA Text |  Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , SBIR - Clean and Safe Water

Description:

The goal of this project is to  develop  an inexpensive and scalable method to destroy  per- and polyfluoroalkyl substances (PFAS) in groundwater. PFAS contamination of groundwater is pernicious and widespread, potentially contaminating the drinking water of up to 110 million Americans. PFAS chemicals have been shown to be hazardous to human health, and are associated with an increased risk of kidney, breast, and testicular cancer, immune dysfunction, and harm to the endocrine system, reproductive system, and fetal development. A major source of this contamination is aqueous film forming foam (AFFF) which was used for decades for firefighting and is still in use at military bases today. PFAS are also found in a wide range of consumer products including food packaging, non-stick cookware, stain, or water-resistant clothing, carpets, and upholstery, cleaning products, personal care products, and others. They are called “forever chemicals” because they never break down in the environment, so concentrations build up over time, contaminating soils, groundwater, and drinking water.

Currently, options to destroy PFAS are limited and expensive. The dominant method for removing aqueous PFAS is sorption using granular activated carbon (GAC) or ion-exchange resins. This method results in contaminated GAC or resin which must be incinerated at high temperature (>1100°C) to destroy the PFAS. This incineration step is energy-intensive and may produce toxic byproducts, including shorter chain PFAS, carbon tetrafluoride, and hexafluoroethane, that are released to the atmosphere and eventually make their way back into soil and water in nearby communities. The C–F bonds in PFAS are among the strongest of chemical bonds, so the ability to break them is especially critical for any technology that aims to destroy PFAS. Therefore, improved technologies that successfully destroy PFAS and break the C–F bonds are needed.

Our approach is to use an innovative flow process to generate extremely high local temperature and pressure conditions which can destroy PFAS in water. These conditions are intense enough to produce hydroxyl radicals that react with C1 fluororadicals to break the C–F bonds in PFAS.

In this Phase I project, Creare demonstrated that our process is a feasible approach for PFAS destruction. We designed and built a proof-of-concept PFAS destruction reactor. We then tested our reactor with perfluorooctanesulfonic acid (PFOS) as a representative PFAS chemical and sent samples to an independent certified lab for analysis with EPA Method 533 to determine the PFOS concentration and breakdown products as a function of reaction time. We measured  the rate of PFOS destruction and also identified the byproducts of the destruction reaction.

Summary/Accomplishments (Outputs/Outcomes):

Creare successfully demonstrated that our process destroys PFOS. During Phase II we will build on the Phase I tests and use the results to design and build a larger scale pilot plant to be built in Phase II.

Conclusions:

Initial results indicate that we can successfully destroy PFAS. This Phase I project has been a critical demonstration of a novel technique capable of degrading PFAS chemical in situ, rather than simply removing the PFAS for later disposal and destruction.

Creare has begun developing relationships with potential industry partners as well as the New Hampshire Department of Environmental Services to commercialize this technology. Because our process is easily scalable and holds potential to destroy other contaminants beyond PFAS, it is appropriate for treatment of many aqueous water sources. Systems could be sized for point-of use treatment for household, municipal, or military drinking water systems. The process could also be used to destroy PFAS in a concentrated waste stream created when regenerating GAC beds, ion-exchange resins, or other methods that filter out PFAS but do not actually destroy it. Creare’s process may also be suitable for treating some aqueous industrial waste streams containing PFAS and possibly other chemicals before release to the environment.