Thermochemical processing of organic wastes for sustainable valorisation and energy recovery: A review of recent contributions to the field

This paper reviews the current knowledge on the thermochemical processing of organic waste for sustainable valorisation and presents its impacts on energy recovery. We focused on novel, low-cost, and highly efficient thermochemical methods for converting organic waste into energy. Thermochemical processes for waste management are reported as sustainable alternatives for energy recovery, while generating other by-products for various applications. Thermochemical methods include hydrothermal processes, pyrolysis, and gasification. Additionally, torrefaction has been extensively studied in recent years for the pre-treatment of feedstock. Combustion and incineration are not discussed in this review, as conversion of carbon-rich feedstock into energy and valuable chemicals through gasification has several advantages over them. Recent contributions in this field have focused on enhancing the specificity of thermochemical processes for the sustainable valorisation of organic waste into high-value products. Waste valorisation fulfils the concept of biorefineries and the use of renewable energy, which helps attain the Sustainable Development Goals. Since thermochemical processing offers excellent opportunities to transform waste into valuable resources, this review paper will also highlight these crucial aspects within the concept of circular bioeconomy.