Bench scale incineration of polychlorotrifluoroethylene

Polychlorotrifluoroethylene (PCTFE) was incinerated under Municipal Waste Combustion (MWC) conditions to determine if targeted poly- and perfluoroalkyl Substances (PFAS) were emitted. A bench-scale incineration system was custom built to thermally gasify solid PCTFE, incinerate under controlled conditions, and collect effluent gases using an aqueous impinger sampling train and gas canisters for subsequent analyses. Incineration was conducted at 1150 °C and 850 °C, temperatures used in the US and Europe, respectively, with the gas composition that mimics the post combustion zone of municipal waste combustors. The aqueous impinger samples were analyzed for targeted PFAS using EPA Method 537 with laboratory modification, while the non-aqueous gaseous effluent was analyzed for products of incomplete destruction (PIDs) using EPA OTM-50. Neither PFAS nor gaseous PIDs were detected at 1150 °C. At 850 °C, 198 - 228 μg/L of perfluoroethanoic acid and 117 - 142 ng/L of perfluoropropanoic acid were detected. Also, 4.96 - 5.06 ppb of trifluoromethane and 49.0 - 54.7 ppb of chlorotrifluoromethane were detected in the gaseous mixture. For PFAS analysis, only the PFAS compounds defined within the analytical methods were analyzed. Calculations showed that PFAS destruction efficiency (DE) at 1150 °C was high (>99.9999%) whereas at 850 °C DE was reduced to 99.9% mainly due to the formation of perfluoroethanoic acid. These PFAS DEs corresponded to emission concentrations (ng/m³) of 51.2 and 67,468 at the high and low temperature conditions, respectively. Data shows the Global Warming Potential (GWP) impact from greenhouse gases emitted at 850 °C was insignificant compared to CO₂. The Ozone Depletion Potential (ODP) of the observed PIDs at 850 °C was also insignificant compared to other emission sources.