Industrial-scale incineration of polyvinylidene fluoride (PVDF)

Thermal treatment is a promising method for the mineralization of per- and polyfluoroalkyl substances (PFAS) contained in waste. However, its efficiency is often constrained by the requirement for high temperature and the challenge of controlling hydrogen-fluoride (HF) emission in the flue gas. This study investigates the performance of an industrial-scale thermal treatment configuration for polymeric PFAS and evaluates the Destruction Efficiency (DE) and Destruction and Removal Efficiency (DRE) achieved during the thermal treatment of polyvinylidene fluoride (PVDF). Industrial trials were carried out in a hazardous waste incinerator with materials containing polyvinylidene fluorides (PVDF) mixed with polyethylene (PE 98% / PVDF 2%). The thermal treatment was performed in a rotary kiln and in a Secondary Combustion Chamber (SCC) with an average conventional and typical combustion temperature of 950°C and an average residence time of 2.3 seconds. Trials were performed with a calcium based reagent injection into the SCC and with PVDF injection rates in the kiln from 0,5 to 5 kg/h. The US OTM-45 method was used for the PFAS emissions measurements at two sampling points: at the boiler outlet and at the stack. The findings demonstrate that the industrial thermal treatment configuration tested achieved DE and DRE values equal to or exceeding 99.99% and 99.9999%, respectively, for all PVDF injection rates investigated. Furthermore, the PFAS concentrations at both sampling points were systematically below the quantification limits and were comparable to those observed in the blanks without PVDF injection, and the HF regulatory emission limit (1 mg/Nm³ dry at 11% O₂) was fully respected with concentrations below 0.08 mg/Nm³.