Anaerobic digestate management for carbon neutrality and fertilizer use: A review of current practices and future opportunities

Biogas production, a low-carbon energy source, has led to heightened focus on sustainable management of its by-product, anaerobic digestate. The unprocessed digestate poses environmental and safety risks, including greenhouse gas emissions and potential soil contamination. Thus, the development of comprehensive, globally applicable guidelines for sustainable digestate management is crucial. The unique aspect of this review lies in the proposed guidelines, addressing micropollutant presence, prioritizing nutrient conservation, and aligning with carbon neutrality and Sustainable Development Goals. The review methodology involves an exhaustive study of existing literature and innovative valorization methods for anaerobic digestate, including biological, chemical, thermal, and mechanical processes. The review emphasizes the importance of enhancing digestate quality before soil application, thus reducing environmental contamination and improving fertilization properties. This review notably contributes to the understanding of sustainable anaerobic digestate management in the context of carbon neutrality and process circularity, offering valuable insights for future research and practical applications.