Potential of non-thermal plasmas for helping the biodegradation of volatile organic compounds (VOCs) released by waste management plants

This paper aims at investigating the feasibility of applying a non-thermal plasma (NTP) to treat the gaseous effluents released by mechanical-biological treatments of waste (MBTs) and overcome the typical issues of biofilters, whose removal efficiency is limited during acclimatization of bacteria, peaks of concentration of contaminants or unstable airflow rate. A dielectric barrier discharge was applied to two different mixtures of volatile organic compounds (VOCs) and air. Each mixture was intentionally chosen to represent real emissions from specific processes that make use of biofiltration as technology for air pollution control (APC). In addition, both the mixtures contain VOCs that are typical constituents of the waste air released by MBTs of waste. Within the range of power applied to the discharge, all the initial VOCs were removed by 95-100%. The byproducts formed at medium-low energy were characterized, the CO2 selectivity and the energy yield were calculated. Interestingly, the byproducts generated are more polar than the initial compounds and, thus, their solubility in water is higher. NTPs can be considered as a promising technology for pre-treating VOCs in facilities where biofilters are used as the main APC system, since placing an NTP treatment upstream of a biological treatment can definitely help biodegradation.