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 implementation of various protective measures including: 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 work is underway to evaluate ways to address the contaminated sediments.
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.
A few times a year, the Deschambault Smelter must discharge surplus rainwater that has accumulated in its reservoirs. The surplus rainwater is discharged into the Belle-Isle River, which has only a moderate flow. As such, the process is managed using a dynamic system that ensures the quality of the water in this small river is respected.
In all cases, no water intakes are located in proximity to discharge points, and none of the receiving bodies of water have a protected status. All 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.
The Baie-Comeau Smelter recorded two exceedences of the daily limit for C10-C50 hydrocarbons, one in April and the other in December. The root causes are under investigation.