Chemical Emissions from Plastic Manufactured in Water Infrastructure
Abstract
In-situ pipe repair technologies such as cured-in-place-pipe (CIPP) and spray-on plastic lining have been used for rehabilitating damaged sanitary sewer, storm sewer, and drinking water pipes. These technologies sometimes require minimal work space and are less costly than pipe removal and replacement. However, utilities, regulators, and health officials have raised environmental, occupational, and public health concerns regarding chemical emissions into water. The overall goal of this thesis was to understand the potential and magnitude of chemical emissions due to in-situ plastic manufacture. In the present work, two separate studies were conducted and are presented as two independent chapters. In Chapter 1, Chemical emissions were investigated at four ultraviolet (UV) light cured-in-place-pipe (CIPP) storm water culvert installation sites. Samples of an uncured resin tube, styrene-based resin CIPPs, materials released into the air, water, and on the ground, as well as standing and rinse waters were analyzed. Real-time photoionization detector monitoring and odors showed that chemicals were emitted into air. Particulates emitted into the air during CIPP cutting contained fiberglass, polymer, and contaminants with state water quality standards that leached into water. The uncured resin tube contained more than 70 compounds, and 19 were confirmed with analytical standards. Compounds included known or suspected carcinogens, endocrine disrupting compounds, hazardous air pollutants, and others compounds with little aquatic toxicity data available. Compounds (14 of 19) were extracted from the new CIPPs, and 11 were found in water samples. Acetophenone and phenol were not detected in CIPPs, but were found in water samples, and have been found by others at thermal cure resin CIPP installation sites. Aqueous styrene (2.31 mg/L), dibutyl phthalate (12.5 µg/L), and phenol (16.7 µg/L) levels exceeded the most stringent state water quality standards chosen in this study. New CIPPs contained a significant amount volatile material (1.0-6.8 wt%). Recommendations are described that can reduce chemical emissions, improve worksite and environmental protection practices including water and air monitoring, and proposed future research is also described. In Chapter 2, available chemical leaching and drinking water quality impact literature for polymer coating technologies was reviewed. The study’s objectives were to (1) review polymer coating technologies and chemistry being used; (2) compile and review current state of knowledge for water quality impacts; (3) identify knowledge gaps and provide prioritized recommendations for future research. Three major types of resins have been used for portable water pipeline coating: epoxy (EP), polyurethane (PU) and polyurea (PEUU). Few studies have been conducted in the U.S to evaluate the water quality impacts (EP: 10, PU: 2, PEUU: 2). NSFI 61 test determines that contaminants leaching from the lining materials to drinking water are within the acceptable limits, and all polymeric coating products must gain NSF 61 certification before the application for drinking water pipe interior coating. However, previous published studies indicated that NSFI 61 certification may not be a sufficient validation of polymeric coatings. The variability of water quality across the U.S, presence of disinfectant in drinking water, various chemicals that may leach into water, microbial regrowth and the difference between field coating application and laboratory coating application have not been considered in NSFI 61 test. To improve understanding of polymeric coating technology, additional work is needed to determine the compounds that could be released and their magnitude. As more information becomes available, NSFI 61 test should be upgraded.
Degree
M.S.
Advisors
Whelton, Purdue University.
Subject Area
Environmental engineering
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