Imagine a dry, cost-effective, pipe cleaning solution that removes tuberculation, corrosion, biofilms and old tar-based liners, then dries and inspects the pipe in same-day return-to-service conditions. Many would consider an all-in-one cleaning process difficult to deliver, yet Envirologics Engineering Inc. has created a technology that can do just that without the need for service bypass.
Established in 2008, Envirologics Engineering Inc., focuses on the development and operations of the innovative pipe cleaning, preparation and inspection technology called the Tomahawk System.
The patented (and patent-pending) Tomahawk System, deploys abrasives of various calibers in a high-volume, low-pressure airstream to clean the interior of dirty, congested water mains and industrial pipes. The pipe is left clean and dry, setting the stage for a strong bond with any subsequent lining process. This system operates by using a standard vacuum truck to create the airstream for cleaning and to capture the debris, ensuring a safe, dust-free worksite. Removing internal deposits restores the pipe’s hydraulic capacity, improves water quality and reduces the electrical pumping power required to move fluid through the pressurized pipe. The system takes less time than traditional cleaning methods and requires no water for cleaning or flushing out the scale and debris.
Envirologics general manager Brian Thorogood, P.Eng., said that The Tomahawk has been used in numerous municipalities to clean and prepare water mains for various lining contractors. “This has helped us better understand the in-field conditions, which has led to improvements in our technology and propelled us from development to commercial deployment,” he said.
Over the past three years, Envirologics has completed cleaning projects in numerous Canadian and U.S. cities and has achieved some outstanding results. “Municipalities will like that the process is dry, which greatly reduces the amount of waste generated and that both ends of the pipe are closed, eliminating public viewing of the undesirable waste that comes out of these pipes,” says Thorogood.
The trenchless Tomahawk System onsite cleaning and preparing watermains prior to application of a liner.
2014 Pilot Projects:
The Tomahawk System set the standard for an all-in-one pipe cleaning, drying and inspection system by achieving excellent results in the following locations:
1. St. John’s, New Brunswick – 780 m of 150- and 200-mm bitumen lined, structurally sound 1955 cast iron (CI) pipe.
2. Waterloo, Ontario – 135 m of 6-in. unlined and tuberculated CI pipe.
3. Quebec (Montreal and Quebec City area municipalities) – 880 plus 300 m of 60- to 80 year-old, heavily tuberculated, cast iron pipe.
4. Victoria, British Columbia – 480 m of 150 mm and 200 mm of 1908 vintage, tuberculated, CI pipe.
All unlined cast iron pipes, including those that were congested with up to 40 percent tuberculation, were thoroughly cleaned and returned to a healthy state. Pockets of graphitic corrosion were removed to ensure the liner could bond directly to metal. Moreover, service connections were fully cleaned and dried around the outer circumference, thus providing ideal conditions for a continuous liner bond to ensure years of leak free performance.
This was the first time that Tomahawk was used to clean CML (cement-mortar-lined) pipe. The pipe was quickly dried, and the biofilm was gently removed using a low-caliber abrasive. What was unexpected was the need to also remove tuberculation, which had formed over the years both at service connections and at pipe joints, due to exposed metal. The combined abrasive caliber and air velocity settings were tailored to provide the balance needed to remove the tuberculation without destroying the integrity of the underlying cement liner. Any sharp concrete edges were rounded smooth, reducing stress concentrations within the finished liner. After cleaning, the CML liner was left largely intact, and the cement was “prepared” and dried, ready for a smooth, continuous lining application.
According to Thorogood, “Envirologics success with gently removing deposits, biofilms and drying CML instills confidence in our ability to do the same for asbestos cement pipe in preparation for a liner application. We also have the ability to capture any asbestos fibers that might be released into the airstream to ensure air quality and customer safety. We are currently looking for a beta site to validate this process as this would provide municipalities with a viable solution for the cleaning and encapsulation of aging AC pipe for decades of continued service.”
Envirologics also had the opportunity to remove tuberculation and old bitumen lining materials from both 150-mm and 200-mm diameter CI pipe sections. The liner was fully removed from all pipe sections to ensure an excellent bond was achieved upon being lined by Trenchless Solutions of Moncton, New Brunswick. This was carried out under same-day return-to-service conditions.
According to Thorogood, “To make things really interesting, two pipe sections were cleaned and lined each day on two consecutive days without a service bypass in-place. That is four pipe sections totaling 403 meters in length, cleaned, lined and returned to service over two, 10-hour working days.” The street was largely undisturbed during the process except for the small access pits located approximately 80 to 120 meters apart.”
2014 presented another first for Envirologics, cleaning pipe under an active railway line. “You need to be confident in your capability when working in locations such as this where mistakes are unforgiving. Not having a traveling, mechanical cleaning head that can get stuck in the pipe during cleaning operations further solidifies this technology as an excellent choice,” says Thorogood.
Blaire Melvin is with Envirologics.