LI C J， HUANG S， CHEN B G， et al. Carbon footprint analysis and assessment of municipal wastewater treatment based on life cycle assessment ［J］. Journal of Henan Polytechnic University（Natural Science）, doi：10.16186/j.cnki.1673-9787.2025080038.

Received：2025-07-22

Revised：2025-09-20

Online：2025-11-05

Carbon footprint analysis and assessment of municipal wastewater treatment based on life cycle assessment

Li Chengjie^1，2， Huang Sen³， Chen Baoguang⁴， Zhao Aiping⁵， Guo Xiaoming^1，2，

Jiang Fengcheng^1，2， Wang Mingshi^1，2

(1. Shandong Hi-Speed Construction Management Group Co., Ltd., Jinan 250098，Shandong，China；2. School of  Qilu Transportation, Shandong University, Jinan 250002，Shandong，China;3. Shandong Provincial Communication Planning and Design Institute Group Co.， Ltd.， Jinan 250101，Shandong，China)

（1. School of Resources and Environment， Henan Polytechnic University， Jiaozuo 454000， Henan， China； 2. Henan Key Laboratory of Coal Measure Unconventional Resources Accumulation and Exploitation， Jiaozuo 454000， Henan， China； 3. China Classification Society Quality Certification Co.， Ltd. （CCSC）， Beijing 100006， 4. Witep Tech Co.， Ltd.， Zhengzhou 450041， Henan， China； 5. Kangda Environmental Protection （Jiaozuo） Water Co.， Ltd.， Jiaozuo 454000， Henan， China）

Abstract: Objectives The present study addresses gaps in existing wastewater treatment carbon‑footprint research—namely the omission of CO₂ emissions originating from fossil‑derived organic carbon in influent wastewater that are released during biological treatment by activated sludge， and the lack of comprehensive life‑cycle–level evaluation of carbon‑reduction pathways. We develop an improved carbon‑accounting model to identify the key emission sources across the full process of representative A/A/O （anaerobic/anoxic/aerobic） wastewater treatment plants， and we propose integrated， system‑level mitigation strategies. Methods Taking a typical wastewater treatment plant as an example， a life cycle assessment （LCA） method was applied to establish a system encompassing four unit processes： primary treatment， biological treatment， advanced treatment， and sludge treatment. Using the eFootprint software along with the CLCD and Ecoinvent databases， the carbon footprint was quantified. A novel aspect included the accounting of CO₂ emissions derived from fossil-origin organic carbon in wastewater during biological treatment via the activated sludge process. Based on one year of actual operational data， a sensitivity analysis was conducted to identify key influencing factors. Results The total plant carbon footprint was found to be 5.11×10⁻¹ kg CO₂e/m³. The carbon footprint of the four unit processes was ranked as follows： biological treatment> sludge treatment > advanced treatment> preliminary treatment. Biological and sludge treatment together accounted for 73% of the total， identifying them as the primary carbon emission units. From an inventory perspective， the contributions were ranked： electricity consumption>material consumption>pollutant emissions>direct emissions. Electricity and material consumption were the core influencing factors， with indirect emissions collectively accounting for 82%. Conclusions Based on the carbon footprint accounting model constructed in this study， which incorporates fossil-derived CO₂ emissions， biochemical treatment and sludge treatment have been identified as the key units for emission reduction， with electricity consumption and material consumption being the primary focuses for management. Accordingly， short- and long-term coordinated emission reduction strategies are proposed： short-term measures include improving equipment energy efficiency， optimizing operational processes， and adopting low-cost material alternatives； long-term strategies involve process upgrades， implementing intelligent control systems， and optimizing the energy mix. This approach provides actionable pathways for carbon emission reduction in wastewater treatment plant.

Key words：life cycle assessment （lca）； wastewater treatment； carbon footprint； carbon emissions； carbon mitigation pathways； unit process analysis

CLC: X24；TK09