One of the most common questions we get about Hydrodemolition is: What do you do with the wastewater?
At the heart of Aquajet is a focus on developing innovative solutions for everyday jobsite challenges, including wastewater treatment. That’s why we offer our fully automated, high-volume Ecoclear water treatment system that removes suspended solids and neutralizes the pH.
The system effectively tackles wastewater on Hydrodemolition jobs across the globe. Here are three success stories right here in North America.
When general contractor Arguson Projects Inc. embarked on a multiyear, multimillion dollar parking garage renovation in Toronto, they quickly found the suspended slabs in the parkade were heavily contaminated with road salt, resulting in significant corrosion-related deterioration and cracking. They brought in Conterra Restoration to remove 200,000 square feet (18,581 square meters) of material from the second and third levels of the 39-year-old, open-air parkade.
Due to the size of this Hydrodemolition job, it required more than 10 million gallons of water. The EcoClear presented significant cost and carbon savings compared to alternatives, such as hauling wastewater out with a vacuum truck. Water was routed through existing drains and a system of clear stone filtration to a catch pit near the staging site. From there, it was pumped through the EcoClear on its way to the sewer. The EcoClear reduces suspended solids to 50 ppm or less, which proved to be true for the Conterra crew, who saw total suspended solids as low as 15 ppm.
The EcoClear provided a similar solution for a highly sensitive project at a hydroelectric plant about 400 miles north of Winnipeg, Manitoba. A 24-inch pipe in the intake froze, damaging an 8-foot-thick concrete pier. A Canadian industrial cleaning specialist secured the contract based on their plan that provided not only efficient removal of 4,944 cubic feet (140 cubic meters) of concrete, but also recycled nearly 80% of the water.
The project had strict environmental controls paired with a remote location that made hauling water in and out costly and inefficient. As a result, the contractor in charge of removal used the EcoClear as part of a closed-loop system. The system featured two 21,000-gallon water tanks providing water to the Aqua Cutter 710V for the concrete removal. Wastewater was then pumped to the EcoClear, treated and pumped back to the holding tanks for recirculation. In a 12-hour shift, the crew used about 40,000 gallons of water, collecting and recycling about 80% of it. In total, the EcoClear processed a whopping 1.3 million-plus gallons of water.
This takes us to our final project example — beneath the roadway of the Fort McHenry Tunnel in Baltimore. The ongoing Hydrodemolition job entails the removal of 4 miles of old conduit within the tunnel wall and installation of new conduit that houses 15,000-volt cables, along with 26,000 cubic feet of concrete removal and repair. Contractor Freyssinet Inc. turned to the EcoClear to treat the project’s wastewater which has been a critical component during the job.
The worksite, located beneath the roadway in a tunnel below the Patapsco River, enables only limited access for the Freyssinet crew. While a fleet of three Aqua Cutter 410As performs Hydrodemolition in the tunnel basement, the EcoClear remains on the roadway above, treating water. The work is done overnight while the roadway is closed. To accommodate this schedule, the compact, self-contained EcoClear is mounted on a lowboy, so it can be towed away after each shift and the road reopened to traffic.
The Freyssinet team retains, treats and recirculates essentially all water in their closed-loop system. As a result, they use one 5,500-gallon tanker truck per shift as their water source and recycle the water five times, saving significant time and money.
Currently, not every project has strict guidelines concerning wastewater management. However, as demand for Hydrodemolition grows and the industry evolves, contractors who proactively tackle responsible wastewater management will lead the way and achieve the greatest success. Your day may bring new puzzles to solve, but how to treat wastewater won’t be one of them.