Socio–Environmental Cost Evaluation of Excavation Technology Compared with Trenchless Cured-in-Place Pipe Renewal for Small-to-Very Large Diameter Sewers: A Holistic Approach

Growing environmental concerns and urban infrastructure demands necessitate sustainable sewer rehabilitation methods. This study evaluates the socioenvironmental costs (SECs) of cured-in-place pipe renewal technology (CIPPRT) versus conventional excavation technology (ET) across sewer diameters ranging from 150 to 2,130 mm (6–84 in.). Environmental costs (ECs) represent monetized impacts from emissions, resource depletion, and ecological burdens over a project’s life cycle. Social costs (SCs) quantify public externalities such as traffic delays, business revenue loss, and community disruption. A comprehensive dataset was assembled by triangulating empirical bid-tab data from multiple U.S. agencies with peer-reviewed research, municipal technical reports, and full-scale case studies, enabling consistent quantification of material, energy, labor, and traffic impacts across more than 500 CIPPRT and 250 ET projects. Environmental emissions were assessed using the life-cycle assessment software (SimaPro 2024’s) life-cycle impact assessment method (ReCiPe 2016) Midpoint (H) across 18 impact categories and monetized. SCs were modeled using validated equations incorporating site-specific and literature-based parameters. ET’s ECs are 42% higher for small [150–250 mm (6–10 in.)], 52% higher for medium [300–525 mm (12–21 in.)], and 12% higher for large [600–1,500 mm (24–60 in.)] sewers, with dominance in 16 of 18 ReCiPe categories driven by excavation-related fuel use and hauling. Average SCs for ET were 108% higher than CIPPRT’s, primarily from prolonged lane closures, fuel consumption, and productivity losses. ET’s SCs increased exponentially with diameter, while CIPPRT’s remained nearly constant. Across the 150–1,500 mm (6–60 in.) range, CIPPRT reduces ECs by up to 34% and SCs by up to 55%. When environmental and social costs are combined, ET’s SECs exceed CIPPRT’s by 45%, 54%, and 16% for small, medium, and large sewers, respectively, while CIPPRT’s exceed ET’s by 23% for very large systems [1,600–2,130 mm (63–84 in.)]. For very large sewers, CIPPRT’s SECs are primarily driven by increased resin volume, curing energy, and transportation demands. Overall, CIPPRT achieves 40%–60% lower total SECs for diameters up to 1,500 mm (60 in.), confirming its sustainability and cost efficiency in urban sewer rehabilitation and providing a quantitative framework for municipal technology selection.