Effective Valorization of Anaerobic Digestate—A Sustainable Approach to Circular Economy
M. Dincă, Mariana Ferdeș, Bianca-Ștefania Zăbavă, M. Ionescu, Georgiana Moiceanu, G. Paraschiv
Abstract
Lately, anaerobic digestion has become a promising method for producing bioenergy from organic waste and is considered a model of the circular economy. At the same time, the concept of circular economy has gained particular attention in environmental policy agendas supporting the transition towards climate neutrality and the promotion of clean energy sources. Although the main objective of anaerobic digestion is to produce biogas, a significant part of the used substrate is converted into digestate, a by-product. Digestate is composed of organic and inorganic matter, which are considered dangerous contaminants for the environment if not properly treated, but also potential renewable resources if properly recovered. Digestate has enormous potential as an organic fertilizer, soil improver and landfill cover soil, but its disposal and use present significant challenges. The main aim of this review paper is to present the current routes for solid and liquid anaerobic digestate valorization according to circular economy principles and to highlight the relation between anaerobic digestion processes and circular economy models. It further focuses on the aspects regarding anaerobic digestate processing technologies, standards and regulations for digestate use and environmental benefits of its use as soil fertilizer.