On July 14, 2021, the Saint-Gobain Performance Plastics (Saint-Gobain) facility in Merrimack completed the installation and commenced operation of the regenerative thermal oxidizer for the control of per- and polyfluorinated compounds (PFAS) emissions from their manufacturing facility. Comprehensive stack testing utilizing the services of Barr Engineering Co. (Barr) to collect the samples and Eurofins TestAmerica to perform the analysis was conducted the week of September 7-10, 2021. NHDES personnel were on site during the entire stack test to confirm that production and stack test methods conformed with the stack test plan submitted prior to the test. During the stack testing, samples were collected for analysis of PFAS, hydrogen fluoride, regulated toxic air pollutants (RTAPs), and volatile organic compounds (VOCs). Barr submitted a report of the findings from the testing to NHDES for review on November 9, 2021. A copy of the Barr report with the Eurofins TestAmerica lab reports is available here:
While the NHDES Air Resources Division is still in the process of reviewing this report, Saint-Gobain states in the report that the RTO has demonstrated the following parameters:
- The outlet concentrations of PFOA and PFOS are below the emission limits that are contained in the permit (0.45 lb/yr and 0.57 lb/yr respectively);
- Emissions of hydrogen fluoride and other RTAPs meet the ambient air limits for each RTAP which are listed in Env-A 1400;
- Many of the PFAS measured during the test are being destroyed by the RTO;
- The RTO was operated at the required temperature and inlet flow rates established in the permit; and
- The stack test was conducted with the emission units operating at conditions between 90 and 100 percent of maximum production rate or capacity.
Additional stack samples were taken during this testing and have been sent to EPA Office of Research and Development (ORD) for further stack test methods development. A final report from EPA ORD has not been received.