Sustainable food waste management: a critical review on biochar production and applications

Abstract

As per the FAO's estimation (Food and Agriculture Organization, USA), approximately 1.3 billion tons of food are wasted yearly, accounting for around 33% of global food production, releasing millions of tonnes of greenhouse gas (GHG) emissions on a global scale. The predominant techniques for handling food waste involve landfilling, incineration, and composting, all of which come with substantial emission-related challenges and are considered unsustainable. In contrast, advanced thermal processes such as pyrolysis and gasification have proven to be environmentally sustainable alternatives and can convert organic food waste into valuable resources such as H₂-rich gas, bio-oil, and biochar. Among these products, biochar stands out due to its numerous benefits, encompassing energy generation, carbon sequestration, climate change alleviation, soil enhancement, and wastewater treatment. This paper presents a state-of-the-art review of food waste biochar (FWBC) production and application. FWBC applications as carbon capture adsorbents, fuel, catalysts, and supercapacitors and in wastewater treatment, along with modelling and optimisation/life cycle analysis, are also reviewed. The literature review highlighted that FWBC has immense potential for carbon capture, wastewater treatment and as a catalyst. However, the research is lacking in industrial applications of biochar, and such data are scarce. Furthermore, biochar modifications improve biochar characteristics, which rely greatly on chemical processes. The paper concludes by proposing future perspectives and potential directions for the sustainable utilization of food waste through biochar production and application. The conversion of food waste into biochar holds immense potential to significantly advance the cause of sustainable food waste management.