Turbidimeters at the Outfalls: A Major Step Forward

Turbidimeters have been successfully installed at the outfalls. This is a major step forward for Complexe Jonquière, which now has technology to detect colours and prevent contamination of the Saguenay River with red water.

The pilot project was launched last year, with several prototype tests carried out during the initial phase. The implementation phase at the four sites was completed last spring. Turbidimeters are a simple and effective technology designed to measure turbidity in industrial manufacturing processes. The continuous measurements provide data to help control the process.

“One of the benefits of installing turbidimeters is that a great deal of data can be recorded to analyse the root causes of changes in the water,” said Marc-Olivier Nepton, Development

Coordinator, Vaudreuil Operational Centre. “It will now be possible to correlate events and their effects on the water.”

François Thériault, Manager, Technical Services at Vaudreuil, added, “We were already carrying out analyses every day to help control 80 to 90% of the elements. The PH reading provides an indicator for virtually all the components of the water but does not detect the presence of bauxite, which left us vulnerable to the risk of contamination. Since there was no technology in place to detect bauxite, we had to rely on the vigilance of the workers who, under certain conditions—for example, in the evening—could not really perceive a change in the colour of the water.”

Water is a living environment that is constantly changing, sometimes very quickly. Many factors affect water’s turbidity, i.e., its relative clarity due to the content of suspended matter that absorbs, scatters, and reflects sunlight, clouding the water and changing its colour. Turbidity is in fact the opposite of clarity. It is an important ecological factor.

Rio Tinto is actively committed to minimising the environmental impact of its operations and is taking steps to achieve its environmental goals. Nicolas-Alexandre Bouchard, Principal Advisor, Technical Services, said, “We are becoming increasingly aware of environmental issues and the colour of our effluents. We take compliance very seriously, and this is also reflected in the thoroughness of our procedures. The turbidimeters that we installed are an additional tool to control 100% of the events and make sure that our effluents are compliant, and our processes are clean.”

Several people were required to implement the turbidimeters, including the Continuous Business Improvement team which consists of Charles Tremblay, Process Engineer; Pascal Boivin, Electrical Technician; and Denis Lavoie, Process Technician.