Reducing Environmental Impacts in Soil Remediation: A Comparative Life Cycle Assessment of Cement and Alternative Binders in Solidification/Stabilization

Contaminated soil remediation is of increasing importance due to the environmental and health risks associated with hazardous pollutants. Solidification/stabilization (S/S) is a widely adopted remediation technique; however, its environmental performance is often limited by the high demand for Portland cement. This study evaluates the environmental impacts of a conventional cement-based S/S system and an alternative formulation incorporating ground granulated blast furnace slag (GGBFS), washed fly ash (W-FA), and marble sludge (MS) using a comparative Life Cycle Assessment (LCA). The assessment was performed using SimaPro 9.3, the Ecoinvent v3.9 database, and the ReCiPe 2016 Midpoint (H) method, within a cradle-to-gate system boundary. Particular attention was given to developing a transparent and reproducible life cycle inventory, integrating primary operational data with background datasets for all material and energy flows associated with the remediation process. The results show that replacing a substantial portion of Portland cement with industrial by-products reduces Global Warming Potential by approximately 27%, while smaller reductions of approximately 20% are observed for ozone formation, human health and ozone formation, and terrestrial ecosystems, respectively. Conversely, the Green S/S formulation shows higher impacts across most of the remaining midpoint categories, including ionizing radiation; terrestrial, freshwater, and marine ecotoxicity; human toxicity; eutrophication; resource scarcity and water consumption. These increases reflect upstream elementary flows and processing requirements associated with the alternative binder constituents included within the adopted cradle-to-gate system boundary. Overall, the results demonstrate that the environmental performance of the alternative formulation is characterized by clear category-specific trade-offs rather than a uniform reduction across impact categories. The findings highlight the potential of industrial by-products to reduce cement-related climate impacts while emphasizing the need for a multi-impact life-cycle perspective when evaluating alternative S/S formulations for contaminated soil remediation.