In Italy, in the last decade, intensive source separation of biowaste (food waste, and green park waste), has been extended also to medium/large towns and metropolitan areas, attaining best-practice performances in terms of quantity and quality of the collected biowaste. Among these cases, it is worth mentioning the high performances achieved since 2014 by Milan (Lombardy) with 1.4 million inhabitants, recovering about 90 kg per person per year of food waste, very high compared to other European cities.

Using the trend recorded in the last 10 years in Italy, by 2025 about 9 million tons of organic waste will be collected separately, reaching 145 kg per-capita and per-year. Anaerobic digestion (AD), regarded by EU waste legislation as ideal recycling operation in the framework of the circular economy is currently considered the most feasible technology for the treatment of organic streams to produce renewable energy.

In a typical AD process, in fact, biomethane is the final product obtained from the transformation of volatile fatty acids, produced during dark fermentation. However, since different microorganisms with specific biochemical pathways are involved in the AD process, many other valuable products with a wide spectrum of possible valorization, can be obtained. At the same time renewable energy production is one of the Regional Objectives, considering that the production target set by the Lombardy region is 15.5% for renewables, while the Italian objective is much lower (11.3%).