To Wipe or Not to Wipe: Ensuring Equipment Cleanliness after Decontamination

At TerraTherm, our wellfield and process equipment can take a beating! Between high concentrations of hazardous chemicals, corrosive conditions, and elevated temperatures, piping and equipment generally need a bit of TLC before being put back into circulation for use at another site.

When TerraTherm is operating at sites with persistent organic pollutants such as polychlorinated biphenyls (PCBs) or dioxin/furans, decontamination becomes even more difficult and even more important.  Along with typical decontamination procedures such as steam cleaning and pressure washing, washing with a non-ionizing  detergent (e.g. Simple Green) is typically necessary. Additional rinsing of equipment with specialized products such as CAPSUR®, or solvents such as dichloromethane or diesel may be needed for equipment exposed to very high concentrations of contaminants. Since the majority of TerraTherm’s process equipment is comprised of non-porous materials, this approach of surface cleaning is effective.

In addition to more aggressive decontamination procedures, a quantitative or semi-quantitative test of cleanliness is also typically required when dealing with persistent organic pollutants. For example, when working at a site impacted by PCBs, any decontaminated equipment leaving the project site must be wipe tested and analyzed for total PCBs. A piece of equipment is deemed clean if the wipe (collected over 100cm2 surface area) detects less than 10 micrograms of total PCBs.[1]  Site specific acceptance limits for other contaminants of concern are established for a site on a case by case basis.

Wipe samples are often preferred over rinsate samples, since they are a direct measure of the surface cleanliness of the non-porous equipment. However, if solvents have been used, TerraTherm may choose to also collect rinsate samples to ensure that the solvent (used to remove the site contaminants from the equipment) has been rinsed thoroughly from the inner workings of the equipment.

Although the additional decontamination and wipe testing process can be time consuming, TerraTherm implements these procedures on any sites with persistent organic pollutants, as part of our commitment to safety and the environment.

Wipe Kit Components

Wipe Kit Components


Wipe testing equipment piping

Wipe testing equipment piping

For more information on this topic please contact Alyson Fortune at


[1] Refer to 40 CFR 761.123 for more information on PCB wipe test requirements

About Alyson Fortune

Ms. Fortune is responsible for managing thermal remediation treatability studies and project laboratory interactions, conducting reviews on laboratory data, maintaining complex field equipment monitoring systems (FTIR), and other data management functions.
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