Spatial and Temporal Distribution of Greenhouse Gas Emissions From Municipal Wastewater Treatment Plants in China From 2005 to 2014. Issue 4 (4th April 2019)

• Record Type: Journal Article
• Authors: Yan, Xu; Qiu, Dezhi; Zheng, Shikan; Cheng, Ke; Han, Yunping; Sun, Jianhui; Su, Xianfa
• Is Part Of: Earth's future. Volume 7:Issue 4(2019)
• Page Start: 340
• Page End: 350
• Publication Date: 2019-04-04
• Subjects: greenhouse gas emission -- municipal wastewater treatment plant -- spatial distribution -- temporal distribution -- China; Environmental sciences -- Periodicals; Environmental sciences; Periodicals; 550
• DOI: 10.1029/2018EF001058
• Languages: English
• ISSNs: 2328-4277

Abstract

Abstract: Municipal wastewater treatment plants (MWWTPs) are considered significant artificial sources of greenhouse gas (GHG) emissions, in the forms of methane (CH4 ) and nitrous oxide (N2 O), during their normal operations. In this study, we used an emission factor method to determine the spatial and temporal distribution characteristics of GHG emissions from MWWTPs in China during the period 2005–2014; influencing factors and uncertainties were also analyzed. Our results show that total GHG emissions from Chinese MWWTPs increased from 326.54 to 1294.03 Gg CO2 ‐eq between 2005 and 2014, and that regional distribution was extremely variable. During this decade, the proportion of CH4 in the total GHG emissions decreased from 74.1 to 59.4% while that of N2 O increased from 25.9 to 40.6%. The observed increase in N2 O was probably due to the enhancement of wastewater discharge standards for nitrogen discharge, resulting in lower waterborne but higher atmospheric levels of nitrogen oxides. Our comparison of GHG emissions from wastewater discharging directly to the aquatic environment with that treated at MWWTPs in 2014 indicate that the latter disposal method resulted in an 18‐fold drop in GHG emissions. Regional economic development level and wastewater treatment capacity were the factors most closely related to GHG emissions from MWWTPs; the per‐capita protein supply was closely related to N2 O emissions. Plain Language Summary: The role of municipal wastewater treatment plants as sources of greenhouse gas for methane and nitrous oxide emissions is well known. With increasing urbanization and rising expectations of environmental protection in China, the municipal wastewater discharge volume and treatment rate are constantly increasing, which leads to an increase in treatment plant‐related greenhouse gas emissions to the atmosphere. However, an integrated and detailed investigation of atmospheric emission characteristics of these two important greenhouse gases from municipal wastewater treatment plants in China has not been reported to date. In this study, we established a comprehensive inventory of greenhouse gas emissions by municipal wastewater treatment plants for China in 2014. The spatial distribution and temporal variation characteristics of greenhouse gas emissions were investigated during the period 2005–2014. The total emissions increased from 326.54 to 1294.03 Gg CO2 ‐eq, and that the regional distribution was extremely variable. The regional economic development level and wastewater treatment capacity were the factors most closely related to greenhouse gas emissions by municipal wastewater treatment plants; the per‐capita protein supply was closely related to nitrous oxide emissions. The basic data of a significant component of Chinese carbon emissions from wastewater treatment sector was provided by this work. Key Points: GHG emissions from MWWTPs in China (excluding Hong Kong, Macao, and Taiwan) increased fourfold between 2005 and 2014 Treatment by MWWTPs would significantly decrease the GHG generation in comparison with discharging wastewater directly to the environment The regional economic development level and wastewater treatment capacity were the factors most closely related to GHG emissions by MWWTPs