Agro-Food Wastewater Management in Calabria and Sicily (Southern Italy): A General Overview and Key Case Studies

The choice of the most suitable management system for wastewater of agro-food industries is a difficult task for firm owners, since the convenience of each system depends on the specific case. This overview discusses advantages and constraints of the main systems for wastewater of oil mills, citrus industries and wineries in Sicily and Calabria (Southern Italy). Intensive depuration, lagoons, constructed wetlands, energy valorization, reuse for agronomic purposes, valorization in biorefineries are the main focus of this discussion. Some examples of successful case studies in agro-food wastewater management on the real scale are proposed. It has been highlighted that, while the treatment in centralized activated sludge plants is viable for agro-food industries in large urban areas, depuration in lagoons or constructed wetlands are good options for firms in rural areas. Agronomic utilization is feasible in industries with enough land to irrigate, adopting proper application protocols to avoid soil degradation and crop damage. Anaerobic digestion is promising, but only when agro-food wastewater is blended with other substrates (agricultural or animal residues). The possible extraction of value-added compounds is potentially interesting, but the biorefinery processes are not technically mature and generally not convenient as far as now.