What You Need to Know about GAC Filters

At Encore Earth, our focus is eliminating PFAS chemicals from all water, not just the drinking water. But we do know it has to start somewhere, and we want to support those who are working hard to stop it from getting to your kitchen sink. It’s important for everyone to remember that this is only the first step in taking on a much bigger challenge.

How are Treatment Plants Removing PFAS?

Currently, water and wastewater plants have a treatment for removing nutrients like phosphates and nitrates from the water, and for getting rid of contaminants such as pharmaceuticals and heavy metals. However, when it comes to removing PFAS compounds, also knowns as “forever chemicals,” the water must be treated with very specific solutions. Removing PFAS compounds from water is a new regulation, and the standards and allowed levels are still being determined by the EPA. Anyone who has read the news lately, however, knows that PFAS chemicals can cause many serious human and environmental problems.

Granular Activated Carbon

Currently, one of the best options for wastewater treatment plants is to filter PFAS out of the water using activated carbon. Activated carbon absorbs organic and synthetic compounds, like PFAS, as it passes through the filters in the plant. Activated carbon is an effective adsorbent because it’s a very porous material and provides a large surface area that contaminants get absorbed into. The most common type is called a Granular Activated Filter (GAC). GAC filters are made from organic material with high carbon contents like wood and coal, and are used in granular (or powdered) form. An example would be black charcoal, in the sense that it has become so popular for removing toxins. GAC filtration has been shown to effectively remove PFAS from drinking water and works when it is used in a flow-through filter mode after particulates have been removed. However, those particulates need to go somewhere safe, because after absorbing the PFAS, they too have PFAS in them.

How Much PFAS Do They Remove?

The EPA has said that GAC filters can be 100% effective “for a period of time” but that seems to depend on a variety of factors. These factors include the depth of the bed of carbon, flow rate of the water, which PFAS need to be removed, water temperature, etc., which makes this solution very complicated. Granular activated carbon filters are also know to work well on certain, long-chain PFAS chemicals (ie. PFOA and PFOS) , but aren’t as good at capturing the short-chained (and sometimes, more recently developed) compounds such as PFBS and PFBA. This is due to lower absorbency rates.

How Long Do They Work?

Like all filters, GAC filters get clogged up and need to be changed or cleaned. The benefit of GAC filters is that they can be reused. Because PFAS compounds have to be heated up to an extreme temperature to be destroyed, the filters need to go through a process of thermal regeneration in order to be used repeatedly. Unfortunately, they begin to lose effectiveness over time, and slowly allow more and more PFAS to get into the drinking water. This means in addition to cleaning the filters, they’ll need to be continuously replaced, which can be very costly. Furthermore, the regeneration process is very energy intensive, and is not necessarily environmentally-friendly.

What Happens to the “Leftovers?”

A major concern that we focus on at Encore Earth is this questions: what happens to the filters, the waste that’s rejected from the filters, and that “brine” or sludge that’s sent away from the treatment plant once the drinking water part passes through? The reality is that all of the waste that now has concentrated PFAS in it ends up being sent right back to the land or returned to the plant at returned activated sludge. For the sludge that is sent to landfills, this concentrated hazardous waste sits in the heap until eventually it begins to leach out and is sent right back to the water treatment plant to re-contaminate the water.

What is not sent to landfills is used as fertilizer or injected as liquid into agricultural land, where the PFAS compounds travel up the plants and transfer to crops that are sold in stores or fed to livestock.Because PFAS compounds are not biodegradable, they then contaminate consumers who drink milk or eat vegetables or other produce from locations where sludge was spread on the land. Sometimes, if a treatment plant is near an ocean, the PFAS contanimated brine is actually sent directly into the ocean, using “dilution” as the treatment method. This is one reason why polar bears in the Artic have been tested and found to have PFAS compounds in their bodies.

How Can We Stop This PFAS Spread?

Even though our drinking water is beginning to be treatment for PFAS chemicals, there is still so much work that needs to be done to stop the cycle of these harmful chemicals. When it comes to waste treatment, we need to work together to stop PFAS contaminated sludge from being sent to landfills or to agricultural land so that it no longer contaminates our food, environment and our bodies.

Using our patent-pending process, Encore Flow, we’re stopping the endless PFAS cycle with our energy efficient, carbon negative, environmentally friendly solution. Many water treatment plants in the US are working hard to increase filtration against PFAS chemicals, but there’s a missing piece, and that’s where we work. The Encore Flow process ensures that the filters, backwash and all of the concentrated PFAS brine and sludge that’s leftover is destroyed forever. And our solution works in wastewater treatment plants without the need for specialized filtration or expensive equipment. Our Encore Flow process stops PFAS compounds from returning back into our ecosystem and makes the planet a healthy environment once again.

How Can You Help?

If you or someone you know is working hard to help keep your community safe from the PFAS compounds that plague our world, reach out to us at Encore Earth, and let us know how we can connect and help them solve this problem with our solution! We’re talking with many people in the government, cities, states, and local wastewater treatment plants and advocates to solve this problem today and return balance to our planet.