Abstract: A typical chlorinated hydrocarbon contaminated site in Tianjin was taken as the research object, and the full-life-cycle environmental impacts of two soil remediation schemes were evaluated based on engineering measured data and the life cycle assessment (LCA) method. The survey area of the site is 49 691.52 m2, with soil pollution involving 5 types of pollutants such as tetrachloroethylene and trichloroethylene, and groundwater pollution involving 4 types of pollutants such as trichloroethylene and vinyl chloride. The total remediation earthwork volume is 39 236.7 m3, and the groundwater remediation volume is 10 118.0 m3. The remediation target values were determined based on the health risk assessment model in HJ 25.3—2019 Technical Guidelines for Risk Assessment of Soil Contamination of Land for Construction, combined with the risk control values calculated inversely using plot exposure parameters. By quantifying indicators such as material consumption, energy consumption, and solid waste generation, the carbon emission characteristics and environmental benefits of the two schemes were compared and analyzed. The results showed that there were significant differences in carbon emission intensity (in terms of carbon dioxide equivalent) per cubic meter among different remediation technologies. In-situ chemical oxidation (ISCO) had the lowest intensity (0.38 t/m3), cement kiln co-processing (CKC) had the highest intensity (0.57 t/m3), while thermal-enhanced soil vapor extraction (TE-SVE) (0.54 t/m3) and in-situ thermal desorption (ISTD) (0.49 t/m3) were in the middle. Scheme 1 adopted the combined technology of ISTD + ISCO, with a total carbon emission of 32 301.52 t and a remediation cost of 94.585 4 million yuan. Scheme 2 adopted the combined technology of CKC + in-situ TE-SVE + ISCO + groundwater pump-and-treat, with a total carbon emission of 27 050.41 t, which was 16.3% lower than that of scheme 1, and the remediation cost was 69.994 0 million yuan, which was 26.0% lower than that of scheme 1, reflecting the remediation advantages of “low carbon + high efficiency”.

Key words: carbon emission accounting, life cycle assessment (LCA), chlorinated hydrocarbon contaminated sites, green and sustainable remediation (GSR), classification-based remediation