Carbon footprint analysis and comprehensive evaluation of municipal wastewater treatment plants under different typical upgrading and reconstruction modes

Jinglin Wang; Nan Zhang; Shengjun Xu; Zhiping Shao; Cancan Jiang; Hongying Yuan; Cong Wang; Xiaoxu Zheng; Yongzhi Chi; Weijun Zhang; Dongsheng Wang; Xuliang Zhuang

doi:10.1016/j.scitotenv.2023.163335

Carbon footprint analysis and comprehensive evaluation of municipal wastewater treatment plants under different typical upgrading and reconstruction modes

Sci Total Environ. 2023 Jul 1:880:163335. doi: 10.1016/j.scitotenv.2023.163335. Epub 2023 Apr 6.

Authors

Jinglin Wang¹, Nan Zhang², Shengjun Xu³, Zhiping Shao⁴, Cancan Jiang⁵, Hongying Yuan⁶, Cong Wang⁵, Xiaoxu Zheng⁵, Yongzhi Chi⁶, Weijun Zhang⁷, Dongsheng Wang⁴, Xuliang Zhuang⁵

Affiliations

¹ Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; School of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin 300384, China; Yangtze River Delta Branch, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Yiwu 322000, Zhejiang, China.
² Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China.
³ Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. Electronic address: sjxu@rcees.ac.cn.
⁴ Yangtze River Delta Branch, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Yiwu 322000, Zhejiang, China.
⁵ Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
⁶ School of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin 300384, China.
⁷ School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China.

PMID: 37030360
DOI: 10.1016/j.scitotenv.2023.163335

Abstract

The issue of greenhouse gas (GHG) emissions resulting from the upgrading and reconstruction of municipal wastewater treatment plants (MWWTPs) along with improved water quality is receiving attention and research. There is an urgent need to explore the impact of upgrading and reconstruction on carbon footprint (CF) in order to address concerns that the upgrading and reconstruction will increase GHG emissions while improving water quality. Here we accounted for the CF of five MWWTPs in Zhejiang Province, China, before and after three different upgrading and reconstruction models - "Improving quality and efficiency" ("Mode I"), "Upgrading and renovation" ("Mode U") and "Improving quality and efficiency plus Upgrading and renovation" ("Mode I plus U"). The upgrading and reconstruction was found to not necessarily result in more GHG emissions. In contrast, the "Mode I" had a more significant advantage in terms of CF reduction (1.82-12.6 % reduction in CF). Overall, the ratio of indirect emissions to direct emissions (indirect emissions/direct emissions) and the amount of GHG emitted per unit of pollutant removed (CF_COD、CF_TN、CF_TP) decreased, while both the carbon and energy neutral rates increased significantly (up to 33.29 % and 79.36 % respectively) after all three upgrading and reconstruction modes. In addition, the wastewater treatment efficiency and capacity are the main factors that affect the level of carbon emission. The results of this study can provide a calculation model that can be used for other similar MWWTPs during the upgrading and reconstruction processes. More importantly, it can provide a new research perspective as well as valuable information to revisit the impact of upgrading and reconstruction in MWWTPs on GHG emissions.

Keywords: Carbon footprint calculation; Carbon neutrality; Energy for pollutant equivalent removal; Incineration-power generation; Municipal wastewater treatment plants; Upgrading and reconstruction.