Theme: 07. Per- and Polyfluorinated Alkyl Substances (PFAS)

Topic Area: 7b. Ex Situ PFAS Treatment Approaches

Formatted Title:

Cleaning PFAS from a Former Manufacturing Building: A Visual Approach

Background/Objectives:

Background/Objectives. Per- and polyfluoroalkyl substances (PFAS) were identified on building surfaces in a vacant manufacturing facility that previously used PFAS in the manufacturing process. Sampling was conducted to determine which surfaces and areas of those surfaces were impacted. Bench testing of cleaning methods identified hot water pressure washing with the select use of a non-chlorinated degreaser as the most effective cleaning method for addressing PFAS residues on hard building materials such as concrete, steel, and metal siding. With the goal of limiting risks associated with PFAS impacts and allowing for redevelopment of the facility, an evaluation of corrective action alternatives was completed. Removal and disposal of soft building materials, such as insulation, and cleaning of hard surfaces were selected.

The project required close coordination with the state regulatory agency to develop a cleaning standard for the work. Sample results of soft building materials, visual inspections, and wipe samples from remaining surfaces conducted during bench testing supported establishing a visual standard where visible residues were removed. The visual standard was supported by a sitewide assessment of PFAS mass which indicated that more than 95% of PFAS mass would be removed during the cleaning work. The proposed visual standard was approved by the state regulatory agency and was used to guide full-scale implementation.

Approach/Activities:

Approach/Activities. Bench testing of cleaning methods was conducted on various surfaces and surface conditions (i.e., surfaces with varying degrees of impacts were tested) to verify that the selected cleaning approach would be suitable for the entire building. Wipe samples were collected after the various cleaning methods to attempt to quantify removal. Bench-testing results were documented in analytical and photographic detail to support a visual cleaning standard for full-scale implementation.

The full-scale implementation required developing a detailed documentation and inspection procedure. A 3-D survey scan and PowerApps were used to develop a site-specific inspection form and database for conducting visual inspection. The building was subdivided into specific areas for inspection by Barr and the state regulatory agency. Photos of each inspection area were collected and stored within PowerApps for compilation in the remedial implementation report.

Results/Lessons Learned:

Results/Lessons Learned. Verification of cleaning hard surfaces impacted with PFAS can be done using different methods, but the verification method should consider the objectives of the project, the relative mass of PFAS being mitigated by cleaning activities, the risk of residual impacts (if any), and the implementability of verification methods during project execution. Development of a cleaning standard and inspection approach for PFAS should be done in close coordination with the governing regulatory agency since no standards currently exist for building material surfaces. Conducting bench-scale testing to establish a visual standard and detailed inspection procedures allowed for the cleaning of a former manufacturing facility that removed the majority of mass, limited the risk of impacts from residual impacts, and provided the means to prepare the site for redevelopment.

Alec Danielson

Affiliation

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(Group 1, Poster Board #197) Cleaning PFAS from a Former Manufacturing Building: A Visual Approach