Australia faces a significant challenge with its mounting food waste, which reached 31.2 million tonnes between 2020 and 2021. This waste stream poses substantial economic, environmental, and resource management burdens. In a comprehensive review published in Carbon Research, Chowdhury et al., explore a sustainable solution: converting food waste into biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More. Biochar holds promise for improving soil health, mitigating climate change, and fostering a circular economy in Australia.  

Food waste is a growing global concern, exacerbated by modernization, population growth, and urbanization. Projections suggest that global food waste could reach 2.1 billion tonnes by 2030. In Australia, the problem is particularly acute, with 31.2 million tonnes of food waste generated annually. This waste not only strains resources, with 2600 gigalitres of water used in its production, but also contributes to 3% of Australia’s annual greenhouse gas emissions, costing the economy $36.6 billion (AUD) annually.    

Thermochemical approaches, such as pyrolysisPyrolysis is a thermochemical process that converts waste biomass into bio-char, bio-oil, and pyro-gas. It offers significant advantages in waste valorization, turning low-value materials into economically valuable resources. Its versatility allows for tailored products based on operational conditions, presenting itself as a cost-effective and efficient More, offer an alternative to traditional waste management. Pyrolysis process can be more advantageous than other methods like gasificationGasification is a high-temperature, thermochemical process that converts carbon-based materials into a gaseous fuel called syngas and solid by-products. It takes place in an oxygen-deficient environment at temperatures typically above 750°C. Unlike combustion, which fully burns material to produce heat and carbon dioxide (CO2​), gasification More, which requires high energy, or incineration, which produces harmful emissions.  

Biochar offers significant potential benefits, particularly for Australia. It can improve soil health by increasing carbon content, enhancing texture, and improving nutrient availability. This is crucial for Australia, where soils often have low fertility. Additionally, biochar can reduce greenhouse gas emissions from agricultural land, addressing the significant contribution of agriculture to Australia’s methane emissions.  

The properties of biochar can be influenced by several factors, including the type of food waste used and the pyrolysis process parameters such as temperature, residence timeResidence time refers to the duration that the biomass is heated during the pyrolysis process. The residence time can influence the properties of the biochar produced.   More, heating rate, particle size, and pressure. For instance, higher pyrolysis temperatures generally decrease biochar yield while increasing its carbon content.  

Beyond soil improvement and climate change mitigation, biochar can contribute to a circular economy. It can be used as an adsorbent for pollutants and even as a component in construction materials, potentially reducing the environmental impact of the construction industry.  

Despite its potential, the widespread adoption of food waste-derived biochar faces challenges in Australia. These include the variability in food waste composition, the high moisture content of food waste, and the need for cost-effective large-scale production technologies. Future research should focus on optimizing biochar production, exploring new applications, and addressing potential environmental concerns, such as the impact of biochar on soil organisms.  

The conversion of food waste into biochar offers a sustainable pathway to address Australia’s waste management challenges, mitigate climate change, and improve soil health. While challenges remain, continued research, technological innovation, and policy support can help unlock the full potential of biochar in creating a more sustainable future for Australia.  

Source: Chowdhury, P., Chowdhury, T., Chowdhury, H., & Bontempi, E. (2025). Food waste to biochar; a potential sustainable solution for Australia: a comprehensive review. Carbon Research, 4(41).