Trenchless Technology

Fall Canada 2018

Trenchless Technology is the premier communications vehicle for the trenchless industry. Through our multiple platforms, readers receive insights into the trenchless industry, as well as keep connected to the latest news, products and projects.

Issue link:

Contents of this Issue


Page 24 of 39

W W W.T R E N C H L E S S T EC H N O LO GY.C O M/C A N A DA 25 " BCIP allows us to show the tech- nology and results in live situations, so future clients can see actual re- sults," Joseph says. "Customers want to see these innovations in real -life situations outside of the lab." Bleeding the Line Like many of the other watermains in the North Bay system, the Graham Drive line was heavily tuberculated leading to capacity and water qual - ity issues, as well as leaks and breaks due to corrosion and aging . Because the line is a dead-end it suffered from sub -par chlorine concentrations making water quality a major issue for the users. To help combat this the City in- stalled a bleeder line at the end of the pipe, which on its initial installation was only meant to run on a timer. In reality, because the water quality was so poor, the bleeder ran approximate- ly 23 hours a day, seven days a week. Not only is this a waste of clean wa- ter at a considerable cost , it was also running into a sanitary line, where the city incurred additional retreat- ment costs. In North Bay 's scenario the use of the Tomahawk System provided a cost savings from its original plans for the watermain on Graham Drive. Before Joseph approached the City about using the system, its original plan was to add a loop to the end of the line connecting it to an adjacent neighbourhood. " We were in the process of trying to work out an easement with one of the companies at the end of the line and we were going to loop through to an adjoining system in a residential area. Then we were presented with this option from Logistique Saint- Laurent ," says Domenic Schiavone, director of Public Works for North Bay. " When we looked at the cost of the loop, it involved a lot of rock re- moval . We opted to try the trenchless technology." Schiavone estimates that the loop line would have cost the city $500,000 at the least . With this trenchless option and its BCIP fund- ing , North Bay handled the bypass and excavation of the lining pits, pro - viding a considerable savings. At this time the bleeder is still on the line, but it only runs for 20 minutes about every two hours and Schiavone is op - timistic that it will be removed from the line all together. Tomahawk in Action The Tomahawk System requires two vehicles — an abrasive and coat- ing delivery trailer and a positive dis- placement vacuum truck to provide the airstream — and a four-person crew to handle the work. Following the Tomahawk Cleaning and inspec- tion with the Tomahawk Scout CCTV camera, the same trailer and vacuum truck rigging is used to move the Blu- Kote through the line. Any residual BluKote is collected in a material out- let and does not make its way into the vacuum truck. BluKote is an AWWA Class 1 non- structural liner that meets NSF/ANSI 61 certification for drinking water. The two -part resin is poured into the line at the trailer end and the vacuum truck sucks the resin, along with the Distributive Body (DB), through the pipe. The DB is tethered to a winch in the trailer and helps distribute the BluKote evenly throughout the line. Because the system uses the airstream, BluKote also fills pits and joints and evenly wraps around ser- vice connections. " We can line 100 mm, 150 mm and 200 mm lines, which make up about 75 per cent of the distribution pipes in North America," says Brian Thoro - good, general manager, Envirologics. " The North Bay project also allowed us to test lining a longer stretch and lining in both directions." Because the pilot projects and lab tests were completed on shorter sec- tion of lines, Thorogood says that the North Bay project offered Envirolog- ics and Logistique Saint-Laurent the opportunity to test the length that can be lined. Preliminary tests indi- cate that 107 m of 150 mm diameter watermain can be lined without in- terruption. The team was able to line up to a 115 m stretch of a 135 m sec- tion. To cover the entire length the equipment was turned around and lined in the opposite direction. " We also lined it from both direc- tions because we know there is a limit to the length that can be lined, because we have to mix the mate- rial onsite and pour it in and begin fighting a cure time," Thorogood says. " We wanted to try lining from both ends because if we have a longer pipe that we knew we couldn't apply in one shot , we wanted to make sure we could line it from both ends." When looking at the video, Joseph says that you cannot see where the sections meet indicating an even coating . To line more than 115 m the crew will adjust the DB and modify the airflow and that was tested on the other BCIP projects. The team also lined through some abandoned valves with no problem and through PVC transitions where the watermain was repaired over time. They also found that all leaky services to the watermain must be repaired prior to application as any moisture in the watermain inhibits proper bonding . According to Joseph, the crew took all of this information learned and has used it on the subsequent BCIP lining projects in Huntsville, Ontario; and Sherbrooke, Saguenay and Alma, Quebec. At the end of the project the water- main was disinfected and the team is confident that it has inhibited further corrosion of this watermain, as well as restored the water quality and hydraulic capacity of this line for years to come. Mike Kezdi is associate editor of T renchless Technology Canada .

Articles in this issue

Archives of this issue

view archives of Trenchless Technology - Fall Canada 2018