Energy and Nutrients’ Recovery in Anaerobic Digestion of Agricultural Biomass: An Italian Perspective for Future Applications

Abstract

Anaerobic digestion (AD) is the most adopted biotechnology for the valorization of agricultural biomass into valuable products like biogas and digestate, a renewable fertilizer. This paper illustrates in the first part the actual situation of the anaerobic digestion sector in Italy, including the number of plants, their geographical distribution, the installed power and the typical feedstock used. In the second part, a future perspective, independent of the actual incentive scheme, is presented. It emerged that Italy is the second European country for the number of anaerobic digestion plants with more than 1500 units for a total electricity production of about 1400 MWel. More than 60% of them are in the range of 200 kW–1 MW installed power. Almost 70% of the plants are located in the northern part of the Country where intensive agriculture and husbandry are applied. Most of the plants are now using energy crops in the feedstock. The future perspectives of the biogas sector in Italy will necessarily consider a shift from power generation to biomethane production, and an enlargement of the portfolio of possible feedstocks, the recovery of nutrients from digestate in a concentrated form, and the expansion of the AD sector to southern regions. Power to gas and biobased products will complete the future scenario.

Energy Assessment of Sorghum Cultivation in Southern Ukraine

“…For sorghum silage, specific methane yields range from 52 to 84 m 3 /t (fresh mass) [85,86]. Thus, if sweet sorghum is cultivated on marginal lands, biomethane production can reach 162.4 million tons.…”

Model-Based Assessment of Giant Reed (Arundo donax L.) Energy Yield in the Form of Diverse Biofuels in Marginal Areas of Italy

“…Seventy-five percent of materials used to feed the biogas plants derive from agriculture, whereas the remaining 25% are from municipal wastes. In this context, while Emilia-Romagna accounts for 252 biogas plants and 6 for biomethane production, in Sicily there are only 14 biogas plants and none producing biomethane [39].…”

Correlations between the Composition of Liquid Fraction of Full-Scale Digestates and Process Conditions

“…The development of biogas plants from agricultural waste in Europe was particularly due to its energy policy to implement Clean Energy Package including Renewable Energy Directive. This policy aims to achieve a 32% share of renewable energy from total energy consumption by the year 2030 [1][2][3]. In consequence, this leads to a huge production of biogas plant byproducts, digestate, a renewable resource [4] which requires post-treatment for nutrient recovery to meet the latest European Union regulation proposal on fertilizers [3,5].…”