Greenhouse gas emissions from leachate treatment systems in typical municipal solid waste incineration power plants...

With waste incineration emerging as the primary waste management approach in China, greenhouse gas (GHG) emissions from leachate treatment have become an increasingly critical environmental concern. This study provides the first comprehensive, field-based assessment of GHG emissions from leachate treatment systems across seven typical municipal solid waste (MSW) incineration plants. The determined emission factors (EFs) were 0.0267 ± 0.0302 kg N₂O-N kg^-1 TN_inf and 0.0002 ± 0.0002 kg CH₄ kg^-1 COD_inf, which are approximately double the IPCC default values for industrial wastewater treatment. In 2022, GHG emissions from incineration leachate treatment reached 1965.2 kt CO_2-eq, accounting for 2.2% ± 0.9% of national wastewater treatment emissions. Including leachate from landfills and biological treatment increased the total to 2632.7 ± 1024.8 kt CO_2-eq. Uncertainty analysis indicates that inter-facility variability dominates overall uncertainty (77.1%), highlighting the inadequacy of applying a single national EF for accurate accounting. This study identifies leachate treatment as a significant yet underreported source of GHG emissions, underscoring an urgent need to update GHG inventories with leachate-specific EFs and formulate N₂O-targeted mitigation strategies.