In March of this year, Governor Brown of California imposed the state’s first mandatory water usage restriction due to the ongoing four year drought which is now reaching “near-crisis proportions” according to an April 1, New York Times article written by Adam Nagourney. The governor is requiring a 25% reduction this year in water usage from the states 400 local water agencies which, combined, serve 90% of its population. Is this the beginning of a water restriction trend for California and other states being affected by drought conditions? Although many solutions are needed in the war on drought, new trenchless technologies exist today the can help prevent the massive amount of water losses common to the operation and maintenance of our aging underground water mains in cities throughout North America.
When considering our urban utility service infrastructure, it is often easy to overlook underground piping. Since it is generally out of sight, it is usually out of mind, until there is a problem. Old metallic water mains become congested with tuberculation and corrosion which restrict the flow of water and can produce poor water quality. The corrosion process also reduces the pipe’s structural properties which may lead to leaks or breaks. Unfortunately, many leaks can remain undetected for years, wasting thousands of gallons of fresh water. Also, to compensate for reduced flows through old congested pipes, utilities are forced to increase network pressures which can produce a pipe failure at its weakest section. The result is a significant water release event and has become common place in many cities today.
As the squeeze continues for most municipal budgets, every chance to stretch dollars must be considered. Few municipalities have annual programs in place to attempt maintenance or renewal of their aging, leaky water infrastructure. The majority of drinking water pipe failures are from piping that was installed pre 1950, and has operated beyond its 50 year design life span. Jim Lary, a NACE certified corrosion engineer, estimates there are over 250,000 water main breaks per year in the US alone. The national cost can be more than one billion dollars to repair. Compounding the problem, the amount of piping installed post 1950 is dramatically more than that installed before 1950. Now, pipes that were installed in the 60’s and 70’s are reaching the end of their design life. Some estimates predict that rehabilitating the North American water distribution network to an acceptable level will require more than a trillion dollars of work over the next twenty years.
Approximately 70% of buried pipes are in good structural condition, according to PICA, a pipeline assessment company based in Edmonton, Alberta. Even at the end of their design life, with regular maintenance, pipes can continue to function. However, while they are often left to operate beyond their design life, the chance of developing leaks or failure increases. It is during this ‘extra life’ that municipalities are forced with the decision to replace or rehabilitate. Replacement is most common and comes with a heavy price. However, rehabilitation options exist and new innovative approaches offer advantages over replacement. Today’s trenchless renewal options are among the least costly, lowest impact, and quickest to restore pipes back to full service while extending life by up to 50+ years. Trenchless water main rehabilitation can be a significant contributor to reducing the number of leaks, breaks and unnecessary water releases in our water distribution network.
For added consideration, areas in drought conditions are more susceptible to fires. Older, tuberculated water mains restrict the flow of water which can make the difference between saving a structure from fire or not. The more the distribution system has been cleaned and rehabilitated, the better assurance of adequate water supply to all areas is available where, and when, it is needed most.
Most trenchless water pipe solutions require a clean and prepared pipe to host one of a variety of renewal or life extension methods. While most trenchless options limit the amount of environmental impact regarding greenhouse gas emissions and ground displacement, the process generally consumes a large amount of clean water. These wet cleaning methods are not ideal when you consider that experts are predicting the shortage of water is only going to get worse according to a Feb 13, 2015 BBC article titled “US at Risk of Mega-Drought Future”. Every aspect of water usage will be under increasing scrutiny as water conservation efforts take effect. This will be especially true when alternative waterless options are available as is the case with water main cleaning.
Common methods for cleaning buried pipe are with power boring and flushing, high pressure water flushing, or scraping and flushing. Each of these options requires a large amount of water to either dislodge internal corrosion and tuberculation or flush it from the pipe. In addition to this, all the water is displaced into the access pit and needs to be either captured and taken to a processing plant or pumped into a nearby sanitary sewer. Tens of thousands of gallons of clean water can be wasted in the process of cleaning the pipe.
In most situations, trenchless rehabilitation projects will install a fully structural class 4 liner to fully replace the pipe. Based on the break history, age, and condition of the pipe it may be possible, instead of installing a more expensive class 4 liner, to coat the pipe with a class 1 barrier coating. This option can be significantly less than the cost of a class 4 liner and can return the host pipe to full flow capacity while protecting it from further internal corrosion.
The patented and patent-pending Tomahawk™ technology requires NO WATER to clean old deteriorated pipes. Using a standard vac truck, Tomahawk injects dry abrasive materials in a high-volume, low-pressure air stream to clean corrosion and tuberculation from the interior of the pipe. The process also removes old tar or bitumen liners which may be present and contribute to poor water quality. The pipe is left clean and dry, in compliance with SSPC-SP/Nace No. 3, Commercial Blast standard. Using the Tomahawk Scout™, a patent-pending CCTV camera with integrated abrasive deflector, service connections in the pipe can be “target” cleaned to a SSPC-SP/Nace No. 2 standard. This degree of cleaning is crucial for maximum liner bond around any service connection to ensure leak free liner performance. This level of cleaning is not offered by any other mainstream cleaning methods and helps ensure excellent bond for all pipe rehabilitation technologies. The dry process also reduces waste generation by up to 98% and virtually eliminates downtime required for the disposal of waste. The process is completely enclosed, so there will be nothing for curious residents to see during operation. With a fully cleaned and prepared pipe, the pipe may be analyzed with a pull through Ferroscope to determine the remaining wall thickness along the entire pipe. The on-site engineer can then determine which class of liner should be installed into the main.
With the specific liner installation options available on site at the time of inspection, the cost and time savings to the municipality can be substantial. With these savings, more infrastructure can be renewed for less, and taxpayer money can go further to work toward conserving water and improving water quality.
According to Brian Thorogood, P. Eng., General Manager of Envirologics, the developers of the Tomahawk System, “We have seen a steady increase in the number of inquiries for Tomahawk because of its dry cleaning capabilities, especially from arid and more environmentally savvy municipalities who don’t want to deal with large amounts of wet waste.”
For more information about the Tomahawk pipe cleaning system, please visit www.envirologics.ca. For Tomahawk pipe cleaning services inquires, please visit www.evancoenviro.com or call 1-800-267-9810