Solution Bonaventure: the results

10 October 2018

The Solution Bonaventure is an environmental project to protect the St. Lawrence River from groundwater contaminants in the sector of the Bonaventure Expressway.

In the west sector, which includes land along the Bonaventure Expressway up to the approach of the Champlain Bridge across from Île des Sœurs, groundwater that drains to the river contains contaminants such as ammonia nitrogen, polycyclic aromatic hydrocarbons (PAHs) and dissolved metals.

To address this problem, the Corporation started work on a containment system consisting of a hydraulic barrier with 32 wells installed along the riverbank. Through active pumping, this barrier will intercept contaminated groundwater and carry it to an on-site treatment system.

Today, the treatment system cleans “every 10 days the equivalent of an Olympic pool of juice trash saturated PAHs, dissolved metals and ammonia nitrogen that harm the fish.” Journal Métro

The east sector includes the section of the Bonaventure Expressway between the Clément Bridge and Victoria Bridge. Here, testing has detected free-phase petroleum hydrocarbons (diesel) contaminated with polychlorinated biphenyls (PCBs). These hydrocarbons float at the top of groundwater.

In the east sector, the Corporation is built a retaining wall to contain and capture PCB-contaminated hydrocarbons. Two pumping stations at each end of the wall collect the contaminants, which will then be disposed of as per the applicable legislation.

The East Sector, which has been in operation since August 2018, is showing excellent results, as the 128 extraction wells can hold and pump about 10,000 liters of contaminated water every month.

Thanks to this system, hydrocarbons will be contained and captured before they migrate to the river.

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