The largest treatment plant in North America
Montreal鈥檚 daily production of wastewater ranges from 2.5 million m3 on dry days up to 7.6 million m3/day on rainy days. On average, we produce enough wastewater each day to fill the Olympic Stadium, and that water needs to be treated before it is returned to the Saint Lawrence River.
The water treatment plant that deals with the majority of the city鈥檚 water is the Jean-R. Marcotte plant in Pointe aux Trembles, at the eastern tip of the island. (Montreal also has a very small plant to treat the water on 脦le Notre Dame and 脦le Ste. H茅l猫ne.) The Jean-R. Marcotte plant is the largest in North America, the third largest in the world, and it deals with 50% of all water treated in the province of Quebec.
Photo: David Richfield. Wikipedia.org.
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Everyone lives downstream from someone else
Size isn鈥檛 everything, however, and in terms of wastewater treatment, Montreal is behind the times compared to many other cities. In fact, it was the last major city in North America to begin treating its wastewater. In addition, Montreal鈥檚 plant only carries out primary treatment of sewage, which removes solids and some nutrients but leaves behind bacteria, viruses, pharmaceuticals, heavy metals, and other contaminants.
Illustration: Genevieve Young
When the water leaves the Jean-R. Marcotte plant, all of those untreated substances are dumped back into the Saint Lawrence River, and downstream ecosystems are showing the effects. A by the Universit茅 de Montr茅al鈥檚 Chemistry Department showed that antidepressants in the water, although not harmful to humans, are affecting fish.
Photo: Brook trout: Universit茅 de Montr茅al.
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In addition, treatment of any kind may be bypassed when there are heavy rains and the collector system or pumps cannot handle the extra water. Why can't the collectors handle heavy rains? Because 63% of Montreal's territory still uses combined sewers, which funnel storm water into the same collectors receiving our residential and industrial waste water. When collectors cannot handle the extra volume of water, raw sewage is released directly into the waters surrounding our island city.
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It's time for cleaner water
In 2004, the , which puts us on a par with places that don鈥檛 treat their water at all. In 2008, the City announced that it wants to convert the Jean-R. Marcotte plant into an ozonation treatment facility, which would provide tertiary treatment of wastewater before it is released into the Saint Lawrence. Ozonation uses ozone, a powerful oxidizer, to disinfect water, and the City already uses ozonation to disinfect our drinking water at certain of its treatment plants. Ozonation effectively destroys bacteria and viruses in wastewater and it is believed to reduce the amount of pharmaceuticals, industrial chemicals, and personal care products left in the water. The ozonation process does this by causing the products to break down and decompose. The latest news is that the ozonation upgrade will be ready in 2015.
For more information, see the website.
For a unique look at Montreal鈥檚 sewer system, check out .