An in-depth review of environmental protections for a common storm- water culvert repair practice — cured-in-place pipe (CIPP) repair — has revealed differing installation practices across states, water contamination incidents in 10 states and Canada, and lack of safety data for existing installation practices. Funded by six states, Purdue University researchers examined past wa- ter contamination incidents, environmental studies, industry practices, and construction specifications from 32 states. Creek, river, pond, and sometimes drinking water contamination incidents were found in 10 states: Alabama, California, Colorado, Connecticut, Florida, Georgia, Minnesota, Oregon, Vermont, and Washington. Of the 32 states that responded to the researchers’ request for infor- mation, only four states required water testing after the construction procedure, and the test methods used were often not the same. Nine states had no formal requirements to oversee or monitor the proce- dure’s environmental impacts. Andrew Whelton, Ph.D., associate professor of civil engineering and environmental and ecological engineering at Purdue, said many states and municipalities are beginning to re-examine how CIPP is used and lessen the potential harm to nearby water and air. “State transportation agencies want to repair their infrastructure with- Water quality impacts of cured-in-place pipe repair Review of common construction practice finds environmental contamination and need for improved oversight and monitoring. which is the equivalent of 19 football fields each piled with 10 feet of dirt. This included 80,000 cubic yards of mass excavation and haul off and the installation of more than 150,000 cubic yards of specialty and amended soils. The project involved creating nine acres of exposed ag- gregate walkways as well as constructing a new infrastructure of storm sewers, extensive underdrain systems, sanitary sewers, water mains, and underground electrical duct banks. More than 50 pieces of sitework equipment were commissioned, in- cluding bulldozers, high lifts, 300- and 400-size excavators, a tractor with 17-cubic-yard pans, and a directional boring machine. Smaller specialty equipment included conveyors and low-impact skid loaders. With the July 2018 opening of the reimagined Gateway Arch National
out having to worry about fish kills, drinking water contamination, or chemical incident cleanup,” he said. “There have been some significant incidents.” A popular method of repairing stormwater culverts under roadways, CIPP utilizes resin-impregnated fabric that is hardened inside a dam- aged pipe using pressurized steam, hot water, or UV light, creating a new plastic pipe inside the old, damaged pipe. The process, if not well controlled, can release a worrisome mix of hazardous chemicals into the air and water, although what exactly is discharged, and how that varies site to site, is just beginning to be un- derstood. “In 2014, waste produced at an Alabama culvert repair site was found to be acutely contaminated and dissolved a freshwater organism,” Whelton said. “While the technology has been around for 30 years, there are very few laboratory and field studies on possible environmen- tal effects.” Previous research found that the chemical plume created during the steam-based CIPP installation process released chemical vapors, not just steam. It also contained known air pollutants, suspected endocrine- disrupting chemicals, and known and suspected carcinogens. The California Department of Public Health issued a statewide notice about potential hazards after its own investigation and the prior study. As part of the review, Purdue graduate student Kyungyeon Ra stated that at one Colorado site, “People reported an odor in their drinking water.” Upon investigation, the community discovered high styrene levels in their drinking water, which were traced back to an upstream stormwater culvert repair gone wrong, she said. “We are continuing to investigate whether the 13 water contamination incidents we found are outliers or are typical of CIPP installations,” Park, visitors have new opportunities to access and experience the tall- est man-made monument in the Western Hemisphere. By weaving the international icon into the fabric of the region, the expansive park strengthens connections to downtown St. Louis and the riverfront while creating an inspiring urban oasis. Ultimately, it revital- izes an enduring symbol of St. Louis and the Gateway of the West for generations to come. MICHAEL PRANGER is vice president of operations at Castle Contracting, LLC (www.digcastle.com), which provides turnkey site preparation services, site utilities, earthwork, subsurface utility mapping, and trenchless technology directly to owners; general contractors; and mechanical, electrical, plumbing, and fire protection contractors. He can be reached at michael.pranger@ digcastle.com.
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july 2018
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