Water quality


 

The Deschambault Smelter discharges very little water because of how its network is designed.  A few times a year, it must discharge surplus rainwater that has accumulated in its reservoirs into the Belle-Isle River, which has only a moderate flow. As a result, the process is managed using a dynamic system that ensures the quality of the water in this small river is respected.

 

The Bécancour Smelter has a settling pond where process water and recovered rainwater are sent prior to being discharged into the St-Lawrence River, a very large body of water. The Bécancour Rod Plant’s wastewater is discharged into the Bécancour River, close to its junction with the St-Lawrence.

 

Unlike the other two smelters, the Baie-Comeau Smelter does not have a buffer between the rainwater it gathers and the St-Lawrence River.  The water is discharged directly into the Anse au Moulin, whose sediments were contaminated by previous discharges from the smelter before the installation of a dry cleaner at the Söderberg plant, the discontinued use of PCB contaminated oil, and the subsequent cleaning of the discharge pipes in the 1980s. The quality of the water is now good in the Anse au Moulin, and a rehabilitation impact study is currently underway.

 

Discharges from the Bécancour Rod Plant flow into a ditch in the Bécancour industrial park, not far from where it flows into the St. Lawrence.

 

None of our facilities have water intakes located in proximity to discharge points, and none of the receiving bodies of water have protected status.  In 2012, all the parameters measured at our four plants remained stable or improved their average annual results compared to previous years.

 

The Bécancour Smelter recorded one non-compliance in 2011 when the casthouse exceeded the discharge limit for C10-C50 hydrocarbons.  This was an isolated incident attributable to a wastewater treatment issue in the cooling system at the casthouse.  The average annual level of hydrocarbons recorded at the discharge outlet in 2011 remained well below the established limit.

 

However, the Baie-Comeau Smelter did record an exceedence of the daily limit for C10-C50 hydrocarbons in February.  An investigation is underway to identify and eliminate all sources of contamination.  One source has already been identified at the electrical substation (a cracked holding tank) and corrected.

 

A major breakdown at a heat exchanger at the rod plant in July resulted in the discharge of approximately 25 m³ of emulsion into the ditch adjacent to the plant, which was immediately recovered.  A large capital investment project was launched in 2012 to automate control of the water and blow-out system, which will allow part of the wastewater to be re-circulated within the plant.