A new scheme for low-carbon recycling of urban and rural organic waste based on carbon footprint assessment: A case study in China

Organic waste treatment is a major driver of global carbon emissions, thus its low-carbon utilization is essential yet unclear. Through a life cycle assessment of organic waste data from 34 provincial-level regions in China, we have determined that the synergistic and integrated utilization scheme (URIRP) with organic fertilizer and biochar as the primary products can reduce the annual life cycle carbon emissions from 6.9 Mt CO2e to 2.83 Mt CO2e. This reduction can offset 6% of the carbon emissions from the electricity industry mainly through carbon sequestration by application of biochar-based fertilizer, and fossil fuel displacement by bio-energy. Moreover, URIRP can promote the recycling of N and P, reduce annual emission of air pollutants by 866 Mt, and increase topsoil organic matter content by 0.25‰ and economic efficiency by 135%. These findings indicate that URIRP could realize sustainable management of UROSW with significant environmental and economic benefits, and contribute to the realization of China’s carbon neutrality goal.