ORCID Identifier(s)

ORCID 0009-0009-2928-3503

Graduation Semester and Year

Spring 2025

Language

English

Document Type

Thesis

Degree Name

Master of Science in Civil Engineering

Department

Civil Engineering

First Advisor

Vinayak Kaushal, Ph.D., P.E.

Abstract

Underground infrastructure development has a significant impact on society, leading to continuous technological advancements. With the rising environmental concerns, novel technology is leaning towards adapting to sustainable practices for pipeline rehabilitation. Conducting a comparative study of environmental impacts produced by pipe renewal and replacement processes is a vital step towards sustainable development of underground infrastructure. Open-cut Pipeline Replacement (OCPR) is the conventional method used for pipeline rehabilitation, which involves the excavation of the ground surface to place a new pipe underground or replace an existing one. This process includes the trenching of ground, followed by surface reinstatement through backfill. The procedure requires removal of debris to enable smooth removal and replacement of the sewer pipe, thereby requiring more resources and increasing its overall environmental impact. Cured-in-Place Pipe (CIPP) renewal is a popular trenchless technology, involving the insertion of a liquid thermoset resin-saturated material into an existing pipe through air or water inversion, or by mechanically pulling-in and inflating the tube. Using hot water, steam or ultraviolet (UV) light, the liner material is cured inside the host pipe, leading to the production of CIPP product. The primary objective of this thesis research is to compare the environmental impacts from conventional open-cut pipeline replacement (OCPR) and trenchless cured-in-place pipe (CIPP) renewal method for small diameter sanitary sewers using midpoint approach. Further, this study aims to (1) conduct a comprehensive literature review from 1990 through 2025 (35 years), about environmental impacts from OCPR and CIPP methods, (2) categorize, systematize and visualize the literature review data using VOSViewer software and Microsoft Excel-OpenAlex combination, and (3) identify the factors influencing environmental impacts caused by both alternatives. Four case studies on sewer rehabilitation projects from around the US were selected to quantify the environmental impacts of OCPR and CIPP renewal for small diameter sewer pipes ranging between 8-12 inches. The comparative life cycle assessment (LCA) was performed using two midpoint impact assessment methods of SimaPro software, namely TRACI 2.2 and ReCiPe 2016 Midpoint (H). The results show that CIPP renewal reduces environmental impact by 56%, with global warming reduced by 71%, fossil fuel depletion by 72%, acidification by 54%, smog formation by 67%, and respiratory effects by 52%. A similar approach can be used to perform LCA of other pipe sizes, varying project and environmental conditions, different resins, curing methods, and liner thicknesses for CIPP, soil types, and pipe materials. This research develops an LCA framework to quantify and compare environmental impacts from OCPR and CIPP. Project and utility owners, cities, municipalities, decision makers, and contractors commonly take into consideration only the construction costs and sometimes overlook the LCA aspects while making a choice between open-cut and trenchless pipeline installation. Therefore, this study will be helpful for project owners and contractors to facilitate their decision-making process to select a more sustainable pipe rehabilitation method.

Keywords

Life cycle assessment, Open-cut pipeline replacement, Trenchless technology, Cured-in-place pipe (CIPP), Pipeline renewal, Wastewater applications, SimaPro, Midpoint approach, Environmental sustainability, Emissions

Disciplines

Construction Engineering and Management

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