Deconstruction of waste personal protective equipment (PPE) using subcritical wet air oxidation

Abstract

Wet air oxidation (WAO) of the PPE mixture was performed at temperatures ranging from 300 °C to 350 °C, with initial air pressures of 30 bar and 60 bar, respectively. Total suspended solids (TSS) were reduced by up to 99%, while total chemical oxygen demand (tCOD) and soluble chemical oxygen demand (sCOD) were significantly reduced to 360 mg/L and 110 mg/L, respectively. The main products were volatile fatty acids such as acetic and propionic acids and ammonia nitrogen (NH3-N) with concentrations of up to 1117 mg/L, 975 mg/L, and 18 mg/L, respectively. Nitrogen and oxygen were the most abundant gaseous products, reaching 72% (w/w) and 14% (w/w), respectively. Semi-batch WAO treatments were carried out at 300 °C and 350 °C to achieve comparable waste reduction. The results suggest that non-catalytic WAO is a viable PPE waste management solution.