Highly porous carbon adsorbent used to remove organic contaminants, including long-chain PFAS, from water. GAC concentrates the contaminant onto the carbon: it is a containment-and-transfer step, not a destruction technology.
Granular activated carbon is the workhorse adsorbent of drinking water and groundwater treatment. It is produced from bituminous coal, coconut shell, or wood, and activated by steam or chemicals to develop an internal pore network with surface area above 1,000 square metres per gram. Contaminated water passes through vessels filled with the carbon granules; organic molecules adhere to the pore surfaces by adsorption and stay there while treated water exits.
A typical PFAS GAC vessel achieves long-chain PFAS removal greater than 99 percent at empty bed contact times of 10 to 20 minutes. GAC works well for PFOA, PFOS, and other long-chain compounds but is markedly less effective for short-chain PFAS such as PFBA, PFBS, and GenX, which break through earlier. Service life on PFAS-impacted groundwater is typically 6 to 24 months depending on co-contaminants, after which the spent carbon must either be reactivated at temperatures above roughly 800 degrees Celsius or disposed of as PFAS-bearing waste.
Because GAC concentrates rather than destroys PFAS, every GAC installation creates an obligation: the spent carbon contains the captured PFAS mass and must be sent to a destruction process. That liability is the reason regulators and procurement teams increasingly distinguish between separation steps (GAC, ion exchange) and destruction steps (high-temperature thermal, SCWO, electrochemical).
GAC also removes taste and odor compounds, chlorine, volatile organic compounds, and petroleum hydrocarbons, which is why it appears in municipal drinking water plants, pump-and-treat systems, and industrial discharge polishing. In remediation system design it frequently sits downstream of a primary treatment step as a polishing barrier, or upstream as a protective barrier for more sensitive media such as ion exchange resin.
Also known as: GAC, activated carbon, activated charcoal, GAC filter, carbon adsorption.
A GAC (granular activated carbon) filter is a treatment vessel filled with highly porous carbon granules. As contaminated water flows through, organic contaminants including PFAS, solvents, and petroleum compounds adsorb onto the carbon surface. GAC is the most widely used adsorbent in drinking water and groundwater treatment.
Yes for long-chain PFAS such as PFOA and PFOS, where GAC routinely achieves over 99 percent removal. It is much less effective for short-chain PFAS (PFBA, PFBS, GenX), which break through the carbon bed earlier. GAC captures PFAS; the spent carbon still requires high-temperature reactivation or destruction.
On PFAS-impacted groundwater, typically 6 to 24 months depending on influent concentrations, co-contaminants, and flow rate. Operators track breakthrough with scheduled effluent sampling and replace or reactivate the carbon before contaminants pass through.
GAC consists of larger granules (typically 0.4 to 2.5 mm) used in fixed-bed vessels and reactivated for reuse. Powdered activated carbon (PAC) is a fine powder dosed directly into water or slurry systems and used once. GAC suits continuous flow-through treatment; PAC suits batch or emergency dosing.
No. GAC adsorbs and concentrates contaminants onto the carbon. The captured mass remains on the spent carbon, which must be thermally reactivated above roughly 800 degrees Celsius or sent to a destruction process. This transfer step is why separation technologies are increasingly paired with a verified destruction step.
PFAS (Per- and Polyfluoroalkyl Substances): treatment approach
A family of thousands of synthetic fluorinated organics — including PFOA, PFOS, GenX, PFHxS, and AFFF constituents — defined by C-F bonds that resist conventional treatment and require destruction technologies to close a site.
An ex-situ soil treatment process that heats contaminated soil to volatilize and separate organic contaminants from the soil matrix, after which the liberated vapors are captured and treated, usually in a high-temperature oxidizer.
A thermal desorption configuration where the heat source contacts the soil directly inside the rotary unit, delivering high heat-transfer efficiency and supporting higher treatment temperatures.
A thermal desorption configuration where heat is conducted through the wall of the treatment vessel without combustion gases contacting the soil, producing a concentrated, lower-volume vapor stream suitable for condensation and recovery.
Treatment that heats contaminated soil and groundwater in place, typically with electrical resistance, thermal conduction, or steam injection, to volatilize and recover contaminants without excavation. Used where excavation is impractical or where the contaminant zone sits beneath active infrastructure.