Canadian contractor pushes limits of hydrodemolition with Manitoba ProjectPublished 2/12, 2020 at 14:15
More than 640k north of Winnipeg, the Keeyask Generation Project is underway. During the seventh year of construction, a problem occurred when water in a pipe in the intake froze, damaging a concrete pier. Keeyask managers opted to use hydrodemolition to remove the damaged section using a specialised contractor to overcome environmental and logistical challenges, while delivering quality results. Water Blasting & Vacuum Services Inc., a Canadian industrial cleaning specialist, secured the contract based on a plan that provided not only the efficiency to complete the 140m3 removal work on time, but recycled nearly 80% of the water.
Water Blasting & Vacuum Services first hydrodemolition machines were bought used and converted in-house to meet the cleaning challenges of mills and other industrial facilities. The company quickly realised the benefits of working with an original equipment manufacturer to increase precision, safety and efficiency. “Our old equipment kept the team safe and got the job done, but with most plants slowing down for routine maintenance during the same few months, we needed to find a way to maximise efficiency,” said Luc Laforge, president and owner of Water Blasting & Vacuum Services. With one piece of Aquajet equipment, an Aqua Cutter 410A, Laforge saw an 80% increase in efficiency when dealing with a routine scrubber cleaning application.
The power and efficiency of the 410A and additional Aquajet equipment, including a 710V, allowed the company to branch out into hydrodemolition, hydromilling and other applications, greatly increasing the company’s service offerings. Over time, a reputation for delivering creative solutions and timely, high quality results with minimal environmental impact propelled the company to the forefront of the Canadian hydrodemolition industry.
The hard won reputation saw Water Blasting & Vacuum Services win the contract to provide specialist hydrodemolition work at the Keeyask Generation Project that would test the company and its equipment. “The project had a lot of challenges to overcome,” said Maurice Lavoie, general manager at Water Blasting and Vacuum Services and site manager for the project. “The remote location left us with no access to technicians or spare parts if something were to go wrong. On top of that, we would be dealing with sub-zero temperatures. You had to have a lot of confidence in your team and your equipment to even submit a bid.” Strict environmental controls also limited contractors’ application choices. The project partners, the Keeyask Hydropower Limited Partnership, had made environmental protection a cornerstone of the overall project. So, while the original brief specified hydrodemolition as an acceptable process, the contractors would need to ensure all wastewater was properly collected and treated.
“Whatever technique we used, we had to ensure there would be no negative impact on the surrounding environment,” Lavoie said. “Limiting environmental impact is always an important part of any project for our company, but, when combined with this project’s remote location, we knew there would be additional challenges. From previous experience on a jobsite in Labrador, we knew hauling water in and out was an option, but it was costly and inefficient. Treating the water onsite and reusing was the most economical and environmentally friendly solution. And with the Aquajet EcoClear we already had the right machine to make it work.”
The EcoClear water filtration system, in combination with Water Blasting & Vacuum Services’ extensive experience and expert logistics, allowed the contractor to present a revolutionary solution to project managers. Water Blasting & Vacuum Services purchased the EcoClear system in 2017 as a more efficient and cost effective alternative to hauling wastewater with vacuum trucks for offsite treatment. The system neutralises water pH and reduces turbidity to allow safe release back into the environment. For the hydroelectric power project, rather than treating and releasing the water, Water Blasting & Vacuum Services proposed using the EcoClear as part of a closed loop system that would recycle the water back to its Aqua Cutter 710V. It would be the company’s first time using the EcoClear to recycle water on such a large scale, but Lavoie and his team were confident the EcoClear and 710V would make the perfect pairing to tackle the challenging application. “This project put our people and equipment to the test. There were a lot of firsts, but we knew we had the experience and the support of the Aquajet team to take our plan from theory to reality,” Lavoie said
Clearing a Path
Water Blasting & Vacuum Services arrived at the jobsite in March 2018. With temperatures averaging -29o a hoarding system and heaters had to be set up around the demolition site to provide shelter and keep the pumps operating. In addition to the EcoClear system and 710V, the contractor used a spreader bar and additional tower sections to maximise the hydrodemolition robot’s reach. The enhancements greatly reduced the downtime that frequent repositioning would have required with additional lance sections used to increase efficiency.
Steve Ouellette, lead supervisor at Water Blasting &Vacuum Services, was put in charge of the closed loop system with two 95,000l tanks providing water to the Aqua Cutter 710V. Wastewater was directed to a low point then pumped to the EcoClear. Once the water was treated, it was pumped back to the holding tanks for reuse. In a 12h shift, Water Blasting & Vacuum Services removed an average of 4m3 of concrete and used an estimated 181,000l of water. Of this, roughly 20% of the water was lost during the hydrodemolition process due to evaporation and absorption into the concrete. However, Water Blasting & Vacuum Services was able to collect and recycle the remaining 80% with the EcoClear system. Over the course of the project, the EcoClear processed roughly 6M/l of water.
Water Blasting & Vacuum Services worked with project managers to integrate demolition into the complex timeline of the overall project, completing the work in two multi week phases. Lavoie and his team operated the Aqua Cutter daily for almost an entire 12h shift, working in 3.6m wide sections to completely demolish the wall. A separate crew would come on at night to remove rebar and debris. The process was repeated for approximately 41 days of blasting and a total of 53 days onsite.
Water Blasting & Vacuum Services completed demolition in May 2018. Thanks to a revolutionary and expertly executed plan, as well as innovative equipment, the removal did not disrupt the timeline of the overall project. “Projects like that are once in a lifetime,” Laforge said. “Thanks to a dedicated team with the experience and daring to take on the impossible and innovative equipment, we were able to find a unique solution that allowed us to push the boundaries of hydrodemolition and be part of such an important construction.”