Hydro-Powered Hydrodemolition Solution
The Keeyask Generation Project is being constructed on the lower Nelson River, about 725 km northeast of Winnipeg, Manitoba. The 695 MW hydroelectric generating station, scheduled for completion in 2021, will be a source of renewable energy, producing an average of 4,400 GWh of electricity each year. The energy produced will be integrated into Manitoba Hydro’s electric system for use in Manitoba and for export. Throughout its construction, now in its 7th year, the project has managed a number of location-specific challenges.
One such challenge occurred in 2017 when water in a 60 cm pipe in the intake froze, damaging an 2.4 m-thick concrete pier. To minimize impact to the overall project, Keeyask managers opted to use hydrodemolition to remove the damaged section. The job required a specialized contractor, one able to leverage all of their experience and equipment to overcome environmental and logistical challenges, while delivering quality results.
Water Blasting & Vacuum Services Inc., an industrial cleaning specialist from Edmundston, New Brunswick, secured the contract based on a plan that provided not only the efficiency to complete the 140 m3 removal work on time, but recycled nearly 80% of the water. With Aquajet’s industry-leading technology, combined with years of experience, Water Blasting & Vacuum Services pushed the boundaries of hydrodemolition to work deeper and cleaner than any Canadian project to date.
While its first hydrodemolition machines were bought used and converted in-house to meet the cleaning challenges of mills and other industrial facilities, the company quickly realized the benefits of working with an original equipment manufacturer to increase precision, safety and efficiency.
With one of their pieces of Aquajet equipment – an Aqua Cutter 410A – they saw an 80% increase in efficiency.
That reputation put Water Blasting & Vacuum Services on the shortlist for the hydroelectric company in need of a specialized solution for an unexpected concrete removal job that threatened to delay the project.
Location was another key challenge. The construction site was approximately 4,000 km from the contractor’s headquarters, and limited access to the remote site needed to be carefully factored into any proposed solution. While project managers could provide access to water, power or other general construction supplies, getting specialty equipment or replacement parts presented a time-consuming challenge. The contractor needed dependable equipment and a fully stocked toolbox to limit any unnecessary downtime.
Strict environmental controls also limited contractors’ application choices. The project partners, known as the Keeyask Hydropower Limited Partnership – which includes 4 Manitoba First Nations and Manitoba Hydro – 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.
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 – one that promised maximum productivity while minimizing resource consumption and protecting the environment. 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.
Water Blasting & Vacuum Services arrived at the jobsite in March 2018. With temperatures averaging -29°C and dipping as low as -40°C at times, 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 maximize the hydrodemolition robot’s reach to 12 m. An extension kit allowed the contractor to make a 4 m-wide cut, as well. These enhancements greatly reduced the downtime frequent repositioning would have required.
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