Comparative analysis of AOPs and biological processes for the control of VOCs industrial emissions

Volatile Organic Compounds (VOCs) emissions from a wide range of industrial plants have become a major issue in the framework of atmospheric pollution, due to their negative effects on human and environmental health. VOC-laden emissions are also responsible for odour annoyance. To comply with the stringent regulations and to avoid complaints from the population living near these plants, the most suitable treatment technologies should be identified and implemented. Chemical-physical off-gas treatments such as adsorption and scrubbing, are proven and tested technologies; however, they only promote the transfer of the contaminants from the gaseous to solid or liquid phase, and further treatments are thus required. Biological processes and advanced oxidation processes (AOPs), instead, are able to support the degradation and mineralization of organic compounds, resulting in more effective solutions. This study presents and discusses a comparative analysis of the biological processes and AOPs for the removal of VOCs, focusing on assessing their potential application for industrial waste gas treatment. A numerical procedure, based on the quantification of a set of parameters classified into clusters, was proposed to evaluate the most suitable process for the treatment of the VOC-laden emissions in the different industrial sectors. The results, based on a semi-quantitative ranking of the different identified parameters, pointed out the weaknesses and strengths of the investigated processes. AOPs entailed high elimination capacities, but the emissions of hazardous byproducts should be controlled and reduced. Biotechnologies have emerged as cost-effective and environmental friendly processes; however, the efficiencies of these processes are often limited by the presence of recalcitrant and toxic secondary metabolites.