[Study on greenhouse gas emissions from urban waste disposal system: a case study in Xiamen]

Waste disposal is one of the sources of greenhouse gas (GHG) emissions from urban human activities. According to the method recommended by IPCC Guidelines for National Greenhouse Gas Inventories 2006, a calculation model was established to assess GHG emissions of waste disposal in Xiamen. Then GHG emissions from waste disposal in Xiamen during the year of 2005-2010 were estimated, including solid waste landfill, solid waste incineration and wastewater treatment. The results showed that total GHG emissions quantified in carbon dioxide equivalents (CO2e) from waste disposal was 406.3 kt in 2005, and increased to 704.6 kt in 2010. Because of the improvement of wastewater treatment process and rapid increasing municipal solid waste (MSW), the main source of emissions was from wastewater treatment turning to solid waste landfill. GHG emissions from solid waste landfill accounted for about 90% of total emissions from solid waste disposal process in 2005, and the proportion decreased to 75% in 2010. GHG emissions (quantified in CO2e) from waste water treatment reached the highest value 325.5 kt in 2007. Chemical raw materials and chemical industry have been the highest CH4 emission industry during 2005-2010, which accounted for more than 55% of total CH4 emission from industrial wastewater treatment.