Lead poisoning has become synonymous with the name of Flint, Michigan. While lead poisoning is not a new problem, the Flint crisis definitely helped the latent matter reach the national forefront, and rightly so, because addressing the problem is key to securing healthy body and brains for the next generation. Lead poisoning affects kids more than adults because their bodies absorb lead faster and better, resulting in children with lower intelligence levels, not to mention other problems such as learning disabilities, seizures etc. Since lead is one of the oldest plumbing materials, a lot of our city water infrastructure is bound to have lead pipelines. The problem is now to ascertain where these pipelines are, and to replace them before another crisis like Flint forces us out of our stupor. As much as 70% of cities in the United States were using lead pipes for conveying potable water in the 1900’s and since then it has been well known that lead is poisonous. It is easy to replace the lead pipes above ground, like those within homes, but finding and replacing lead pipes underneath should be a priority. While digging up an entire stretch of road, disrupting and uprooting an entire city to replace these pipes is not possible, trenchless rehabilitation methods have brought much relief by way of eliminating the need to dig up anything at all. Many methods like cured-in-place pipe (CIPP), sliplining, pipe bursting, pipe pulling, etc. have revolutionized the underground rehabilitation industry.
Dangers of Lead Contamination
Ironically lead has been known as poisonous since Roman times, since they were the first to use lead pipes for their plumbing needs, and yes plumbing is not a new concept at all. Lead is cheap, and making lead pipes was cost effective because it is stable and can be easily molded; however the effects of lead on the health of the Roman people was evident to them. Like we all know by now, humans react to a crisis only when it gets out of hand, and so it was with Flint. According to Harold Babbitt, a professor of Sanitary Engineering, lead is quiet soluble in water and hence its use in the supply of potable water should at least be restricted. Massachusetts State Board of Health has conducted tests that show lead contents up to 3 to 5 parts per million (ppm) in water, which is quiet high, but an increase in lead content from 50 to 100% when that water has been standing in lead pipes. Surprisingly a content of 0.5 ppm is considered dangerous to health.
Lead can affect body systems in adults but more so in young children because when lead enters the body it is distributed to the liver, kidney, bones, and even to the brain. It has been found that lead present in an expectant mother’s blood can cause exposure to the fetus. Not only that, it can cause miscarriage, premature birth, minor malformations in the baby, and even stillbirth. Children exposed to lead contamination can be effected in permanent ways by affecting the development of the brain and nervous system because they absorb 4-5 times more than adults would. Adults experience high blood pressure, kidney damage, increased risk of stroke and cancer, brain damage etc. To prevent this damage, lead has to be eliminated from our water supply system because water is something that cannot be dismissed from our daily life.
Trenchless Technology to Replace Lead Pipes
With miles of pipes running under our feet, it will be a nightmare to find and replace lead pipes in our cities. However; thanks to trenchless technology, many cities have successfully replaced their lead pipes using trenchless rehabilitation methods with minimal disruption to vehicles, pedestrians, and homeowners. Here are a few examples of cities that have adopted trenchless rehabilitation methods to replace their lead pipes.
The City of Toronto council approved a Lead water service replacement program in 2007 to replace over 65000 lead water services over the next nine years. They opted to use trenchless rehabilitation methods to carry out this large scope of work. It helped them prevent unnecessary work by identifying 353 services that had already been upgraded but not recorded in the city database and discovered and replaced 238 lead connections that had not been identified.
The City of Saskatoon has approved a lead water pipe replacement initiative this year that will see the replacement of over 900 lead pipe services connecting homes and offices.
Holland has been replacing its lead water pipes for some years now using the traditional open trench method. Pipe pulling using trenchless technology was later adopted because the open trench method was causing a lot of disruption on the surface to road users and home owners. The trenchless method proved to be a success and also time and cost efficient.
Methods of Lead Pipe Replacement
Old and deteriorated pipes can be easily replaced or repaired depending on the extent of the damage. Since lead water pipes are known to cause lead poisoning in adults and children, it is necessary that these pipes be replaced. Some excellent methods to repair lead pipes are CIPP, sliplining and pipe bursting.
CIPP involves using a liner soaked with a resin prior to installation. It is designed to fit the size of the host pipe and is usually made of fiber reinforced fabric or non-woven polyester. The liner is inserted into the host pipe and expanded till it fits the pipe diameter. Hot compressed air or steam is used to cure and set the liner in place. CIPP lined pipes make the host pipe as good as new and increases the lifespan of the pipe to many decades.
Sliplining involves slipping a smaller diameter pipe within the host pipe and sealing the annular spaces and ends with grout. Though the original flow is marginally reduced, this method improves flow characteristics because of the use of materials such as high density polyethylene (HDPE), fiber reinforced plastic (FRP) and polyvinyl chloride (PVC), which possess qualities that prevent the buildup of material on the inside surface, and are resistant to corrosion and abrasion from chemicals and solid particles that may be present in the flow.
Pipe bursting literally means bursting the pipe. A conical bursting head slightly larger than the diameter of the host pipe is inserted and pulled through. A new pipe made of materials such as HDPE and PVC, slightly smaller than the diameter of the bursting head is pulled in behind it. As the bursting head shatters the host pipe with its rotation, the fragments are pushed into the soil surrounding the pipe, and the new pipe is installed simultaneously.