Senior Honors Projects, 2010-current

Preferred Name - First Author

Rivas Bolivar, Andy

Date of Award

Spring 2017

Document Type

Thesis

Degree Name

Bachelor of Science (BS)

Department

Department of Engineering

Advisor(s)

Adebayo A. Ogundipe

Elise M. Barrella

Kyle G. Gipson

Abstract

Water conveyance systems play a critical role in modern developed areas. Polymer pipes have been used for about a century, and their convenient physical properties have positioned polymers as the leading material in the piping industry. Having such influence in the market means that changes in current material selection and manufacturing could lead to significant reductions in the footprint associated with their products. Currently, there are no comparative lifecycle assessments that evaluate the different polymer selections commercially available, which makes it hard to determine what products have the least impact on the environment. Understanding how such impacts are relative to each other could lead to conscious customer material selection, and therefore, a reduced negative influence on impact categories such as human health, global warming, ecosystems quality, and natural resources depletion.

This study considered nine commercially available materials used for water conveyance: Chlorinated Polyvinyl Chloride (CPVC), Polybutylene (PB), High Density Polyethylene (HDPE), Cross-Linked Polyethylene (PEX), Polyvinylidene Difluoride (PVDF), Acrylonitrile Butadiene Styrene (ABS), Polyvinyl Chloride (PVC), Unplasticized PVC, and Polypropylene (PP). Two different groups were created to understand impact: products used for waste water conveyance (ABS, PVC, UPVC, PP, HDPE, PEX) and those used for drinking water distribution (CPVC, PB, HDPE, PEX, PVDF). To conduct this study, the LCA software tool Simapro 8.0.2 was used to model a cradle-to-gate comparative approach that took into consideration raw material extraction, polymerization, and processing of polymer resins to manufacture pipes. The Ecoinvent 3.01 libraries were used to compile empirical data from the pipe industry in countries all around the world, which was evaluated using the Impact 2002+ and EPD 2008 LCA methods. External Environmental Product Declarations (EPD) played an important role as complementary sources of information for data not available on the Ecoinvent libraries.

Material impact was measured using various impact categories, and no material demonstrated lowest impact across all categories. Category prioritization would play a critical role in deciding materials based on what impacts are considered “more important” than others. Since no categories were prioritized in this study, footprint trends were used to provide the most appropriate material recommendation. In the wastewater group, PP demonstrated the lowest impact through most categories, while in the drinking water group, PB exhibited the lowest impact in all but one category. HDPE/PEX made a good second choice within both the drinking and wastewater group categories, while the rest of the materials seemed to have considerably higher impacts. Although data limitations encountered while developing the comparative assessment led to making some assumptions, the results from the study provide a good basis to recommend PB, PP, HDPE, and PEX as the most environmentally conscious material selections, without considering regional or national context.

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