Turning Australia’s food waste into biochar: a sustainable solution for climate and soil
image: Food waste to biochar; a potential sustainable solution for Australia: a comprehensive review
Credit: Piyal Chowdhury, Tamal Chowdhury, Hemal Chowdhury & Elza Bontempi
Australia produces over 31 million tonnes of food waste each year, creating serious challenges for both the environment and the economy. Researchers at the University of New South Wales and their international partners have reviewed how converting food waste into biochar, a carbon-rich material produced by heating organic matter without oxygen, could help tackle the country’s waste crisis while improving soil fertility and fighting climate change.
Traditional waste management options, such as landfilling, composting, and anaerobic digestion, each present drawbacks. Landfilling leads to methane emissions and environmental risks, composting requires substantial space, and anaerobic digestion has high costs and technical barriers. The study highlights pyrolysis, a process that converts food waste into biochar, as a promising alternative. Not only does pyrolysis divert waste from landfills, but it also produces a useful soil amendment that can help Australian farmers deal with declining soil health, drought, and climate impacts.
Biochar’s physical and chemical properties depend on how it is made. The review found that factors such as temperature, residence time, and moisture content all influence biochar’s yield and quality. Higher temperatures create biochar with more pores and greater surface area, important for retaining water and nutrients in soils. Chemical activation methods make biochar even more effective, enhancing its ability to capture heavy metals and improve soil fertility.
Applying biochar to farmland can significantly increase soil carbon and water retention. Studies cited in the review show that biochar derived from vegetable and fruit waste can raise soil organic carbon by up to 90 percent. In Australia, where soils are often low in nutrients and highly sensitive to climate change, using biochar offers a pathway to boost agricultural productivity. The material can also be used in construction materials, offering lighter, stronger concrete in some cases.
Biochar’s benefits go beyond soil health. By locking carbon in the soil for decades, biochar production helps Australia reduce greenhouse gas emissions from both agriculture and waste disposal. The researchers note that using biochar in crops like corn and wheat can cut emissions of carbon dioxide, nitrous oxide, and methane by substantial margins.
Despite these advantages, challenges remain before biochar can be widely adopted. Food waste varies in composition, making it difficult to predict biochar quality and yields. The high moisture content of food waste can complicate storage and processing. The authors suggest solar-powered pyrolysis and government investment as practical solutions for scaling up production and reducing costs.
The Australian government’s National Food Waste Strategy aims to cut food waste by half by 2030, and biochar could play an important role in meeting this milestone. The review calls for coordinated research, investment, and policy support to overcome technical barriers, ensure environmental safety, and create new markets for biochar products. Key areas for future research include optimizing production methods, understanding biochar’s long-term impact on soil biology, and broadening its usage in agriculture, construction, and energy storage.
By turning food waste into biochar, Australia can address waste issues, support sustainable farming and construction, and make a real contribution to global climate goals.
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Journal reference: Chowdhury, P., Chowdhury, T., Chowdhury, H. et al. Food waste to biochar; a potential sustainable solution for Australia: a comprehensive review. Carbon Res. 4, 41 (2025). https://doi.org/10.1007/s44246-025-00207-7
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About Carbon Research
The journal Carbon Research is an international multidisciplinary platform for communicating advances in fundamental and applied research on natural and engineered carbonaceous materials that are associated with ecological and environmental functions, energy generation, and global change. It is a fully Open Access (OA) journal and the Article Publishing Charges (APC) are waived until Dec 31, 2025. It is dedicated to serving as an innovative, efficient and professional platform for researchers in the field of carbon functions around the world to deliver findings from this rapidly expanding field of science. The journal is currently indexed by Scopus and Ei Compendex, and as of June 2025, the dynamic CiteScore value is 15.4.