Comparison of greenhouse gas emission accounting for a constructed wetland wastewater treatment system

The method of systems accounting as a combination of process analysis and input-output analysis is applied to assess the greenhouse gas (GHG) emissions of Longdao River constructed wetland (LRCW), a typical constructed wetland in northern China. An improved GHG emission assessment for the constructed wetland wastewater treatment is made in this paper by using a local embodied GHG emissions intensity database for the Beijing economy 2002. Results show that the indirect GHG emission of the case constructed wetland accounts for 82.31% of the total GHG emissions. More than half of the indirect GHG emission is caused by the electricity. 64.48% of the total GHG emissions happened during the operation stage. There is a great gap between the GHG emissions of the LRCW in this study and in former study, which can be attributed to the diverse economy structures and technology levels of Beijing economy and Chinese economy.