Recycling agricultural, municipal and industrial pollutant wastes into fertilizers for a sustainable healthy food production

This work was focused on recycling different typology of pollutant wastes (olive pomace and orange residues; municipal wastes and sulphur residue of hydrocarbon refining processes) with the triple objectives of limiting wastes in landfill, reducing greenhouse gas emission and producing organic-mineral fertilizers. The environmental risks and benefits of the whole process have been considered. The specific objectives were: 1) innovation in waste management techniques by reducing the accumulation of different typology of wastes using a unique process 2) verifying efficiency of the obtained organic-mineral fertilizers on soil and plant growth 3) improving soil and crop quality relating wastes to food, economy and environment. Sulphur-based pads improved soil quality mostly when contained orange residues. Onion and Garlic grew better in presence of sulphur-based pads (+20%), and mostly when pads contained orange residues (+45%). Onion and Garlic quality, in terms of antioxidant compounds and antioxidant capacity, increased in presence of sulphur-based pads (+30%) mostly when orange residues were present in the pads (+90%). In short, in addition to the environmental advantages, numerous economic benefits coming from the decrease in the production and use of chemical fertilizers, the reduction of costs for landfilling and the gain rising from the sale of the new fertilizers produced, emerged.