Posted on December 12th, 2019
For environmental and public health agencies, one concern with PFAS is that they dissolve in water, which combined with their chemical properties, makes removing the chemicals through commonly used adsorbent technologies challenging and nearly impossible.
Detected in drinking water supplies across the country, the cancer-causing nonpolymer per- and polyfluoroalkyl substances have been in the news a lot lately. Because the molecules of PFAS substances contain tough carbon-fluorine bonds which generally increase their persistence, bioaccumulation, and toxicity, exposure to some of these chemicals have been linked to harmful health effects.
These compounds are generally not removed by common water treatment methods and technologies, meaning they remain in both biosolids and treated wastewater. Additionally, treated wastewater is often discharged to surface water, which may be a drinking water supply. Because these chemicals are not easily degraded by physical or chemical mechanisms once in the environment, PFAS mass is moved from one source to another and eventually reports to water.
The need for remediation of PFAS in drinking water is growing as a result of more regulatory attention to this class of highly persistent, mobile in groundwater, and bioaccumulative contaminants.
Using conventional drinking water treatment technologies at water treatment facilities may trap the chemicals, but they are vulnerable to clogging, and they collect the PFAS, which then needs to be disposed of. Now, researchers and chemists are not only developing new adsorbents that better target PFAS and don't clog as often, but also design innovative methods to completely destroy the molecules rather than merely sequestering them.
Accumulation of PFAS in the human body can have adverse health effects. In response, EPA researchers have been studying a variety of technologies to determine which methods work best to remove PFAS from drinking water.
Certain treatment technologies have been found to remove PFAS from drinking water. These technologies include:
These treatment technologies reviewed by the EPA can be used in drinking water treatment facilities, in water systems in hospitals or individual buildings, or even in homes at the point-of-entry, where water enters the home, or the point-of-use, such as in a kitchen sink or a shower.
Although there are several technologies engineered carefully with the consideration of specific wastewater chemistry, co-contaminant removals, and the pros and the cons of these treatment options, they are challenged because the carbon-fluorine bond is one of the strongest chemical bonds ever created. Multiple ionic states, variable isomers, differing alkyl group, are among factors specifically challenging for PFAS remediation.
Consequently, PFAS chemicals will be subject to data collection, studies, risk assessments, and possible regulations, so product- and waste-reduction practices should be considered immediately to reduce any potential consequences. Despite posing massive risks to public health they are not included in any major environmental laws, states and local communities being left without a clear plan to end their harmful exposures. Public health advocates and environmentalists say that the PFAS issue requires a national drinking water maximum contaminant level under the Safe Drinking Water Act specifications.