EPA Creates Database To Find Thermal Treatment Processes For Remediating PFAS
By U.S. EPA
Per- and polyfluoroalkyl substances (PFAS) are a group of synthetic chemicals that have been in use since the 1940s. PFAS are found in a wide array of consumer and industrial products. Due to their widespread use and persistence in the environment, most people in the United States have been exposed to PFAS. There is evidence that continued exposure above specific levels to certain PFAS may lead to adverse health effects.
In addition to being widespread and potentially harmful to human health, the carbon/fluorine bonds in PFAS are very difficult to break. One type of treatment that can result in the destruction or breakdown of the PFAS compounds is thermal destruction. However, just as there are many varieties of PFAS, there are a variety of thermal treatments. Thermal treatments can include:
- Calcination, a type of incineration performed on solid materials
- Pyrolysis, a process that decomposes materials at moderately elevated temperatures in an oxygen-free environment with the goal of producing a material for beneficial reuse (e.g. biochar, syngas).
- Gasification, a process similar to pyrolysis but uses small quantities of oxygen, taking advantage of the partial combustion process to provide the heat to operate the process
- Granular activated carbon reactivation, which first involves passing PFAS contaminated water through granular active carbon, or GAC. The GAC can then be thermally reactivated, removing the adsorbed contaminants and allowing the GAC to be recycled and reused
- Hydrothermal processing, a process which uses high-temperature and high-pressure water to degrade PFAS compounds
- Incineration, a process which uses high temperature and oxygen to degrade PFAS compounds
- Indirect thermal desorption, a process which removes PFAS from contaminated media through indirect heat without combustion
- Smoldering, a process which uses a slow, flameless form of combustion to degrade PFAS
Because there are so many forms of PFAS and treatment options, EPA researchers have developed a centralized database to record reliable references. EPA's PFAS Thermal Treatment Database (PFASTT) is an easy-to-use online tool that provides referenced information on the use of different thermal treatment processes for the remediation of PFAS. It was designed for use by utilities; federal, state and local agencies; scientific researchers; and others interested in the thermal treatment of PFAS. These groups could use PFASTT when making decisions for effective PFAS treatment processes, plan for future treatment plant upgrades, recognizing research needs, and more.
PFASTT includes information for 70 publications involving thermal treatment of 58 different PFAS substance. The treatment and contaminants information in the PFASTT is gathered from literature sources focused on bench-, pilot-, and full-scale studies of thermal treatment of PFAS-laden media. The literature comes from peer-reviewed journals and conferences, other conferences and symposia, research reports, theses, and dissertations.