Which remediation technique involves heating soil to desorb PCBs, typically performed off-site?

Which remediation technique involves heating soil to desorb PCBs, typically performed off-site?

• A. Ex situ thermal desorption
• B. In situ bioremediation
• C. Phytoremediation
• D. Excavation and disposal

Answer: (A)

Ex situ thermal desorption works by heating contaminated soil to release PCBs from the soil particles. When the soil is excavated and treated in a dedicated unit, the heat desorbs the PCBs, turning them into vapor that is captured and treated before release or disposal. This approach is off-site because the heating and vapor treatment occur in a facility away from the original location, rather than treating the soil in place. After treatment, the cleaned soil can be returned to the site or disposed of, depending on the cleanup goals. Other common methods don’t use heating to drive desorption. In situ bioremediation relies on microbes to break down contaminants where the soil sits, which is often less effective for PCBs due to their persistence. Phytoremediation uses plants to stabilize or extract contaminants but is slow and typically not focused on desorbing PCBs with heat. Excavation and disposal simply removes the contaminated soil and places it elsewhere, without heating to desorb the contaminants.

Ex situ thermal desorption works by heating contaminated soil to release PCBs from the soil particles. When the soil is excavated and treated in a dedicated unit, the heat desorbs the PCBs, turning them into vapor that is captured and treated before release or disposal. This approach is off-site because the heating and vapor treatment occur in a facility away from the original location, rather than treating the soil in place. After treatment, the cleaned soil can be returned to the site or disposed of, depending on the cleanup goals.

Other common methods don’t use heating to drive desorption. In situ bioremediation relies on microbes to break down contaminants where the soil sits, which is often less effective for PCBs due to their persistence. Phytoremediation uses plants to stabilize or extract contaminants but is slow and typically not focused on desorbing PCBs with heat. Excavation and disposal simply removes the contaminated soil and places it elsewhere, without heating to desorb the contaminants.