A Contribution to Environmental Protection Through the Valorisation of Kitchen Biowaste

The worldwide interest in Renewable Energy Sources (RES) is gathering momentum. Anaerobic Digestion (AD) process is steadily growing, as more people are setting up bioreactors in order to produce biogas and digestate. AD process is the fermentation of solid biowaste in the absence of oxygen and is zero emission, i.e. it is CO2 neutral. The aim of this work is to test HomeBiogas 2.0, i.e. a revolutionary equipment that used the kitchen biowaste from the canteen of the agricultural institute of Marsala (Trapani, Italy). This equipment works as a continuous flow bioreactor: the waste is fed in one end, while biogas and digestate come out from the other. The process continuously took place at an average temperature of 18 ℃ ca. The liquid digestate was sanitised by running through three chlorine tablets, in order to reduce the amount of active bacteria in this effluent. Therefore, the digestate was immediately used as a liquid biofertiliser for the soilless cultivation of tomato, strawberry, aubergine and pepper plants, inside a greenhouse. HomeBiogas 2.0 had a disposal capacity of 1.7 t of organic waste per year, equal to approximately 4.8 kg per day. During the testing period, this equipment produced 525 L of biogas and 7.78 L of liquid digestate per day. Sicily and the other islands of Mediterranean Sea are optimal environments for the operation of the tested equipment, that is an example of circular bioeconomy implementation.