Integrating anaerobic digestion and composting to boost energy and material recovery from organic wastes in the Circular Economy framework in Europe: A review

In the global context of raw materials and energetic crisis, recovering energy and materials from organic wastes becomes mandatory in Europe to meet the principles of Circular Economy. This manuscript reviewed the state of the art and highlighted research gaps of integrated anaerobic digestion and composting (IADC) to treat organic wastes. Biogas produced through anaerobic digestion and high-quality compost produced through composting can lessen the environmental effect of organic waste management while also sustaining it economically. In addition, the IADC allows for removing most of the common organic contaminants with high efficiency. Main research gaps and future challenges that still need to be addressed are represented by the need (i) for more full-scale studies providing environmental and economic sustainability assessment, (ii) to boost organic waste degradation during the anaerobic step, (iii) to evaluate the degradation pathways of contaminants during the treatment, and (iv) to spread the technology through policy actions.