Our sewage treatment systems are lacking

Montréal’s plan to dump 8 billion litres of untreated sewage into the St. Lawrence River made its way into the election campaign and out the other end with little discussion and minor stalls by Environment Canada. There is now a team of scientists looking at the issue for Environment Canada (several years after they received the file) and will publish a report November 2. Mayor Coderre, meanwhile, is unimpressed with the hold-up on work to be done on the conduit. This isn’t the first time that raw sewage has been dumped into a major water body. In fact it is a regular occurrence. But it is something that is clearly no longer acceptable in the public’s eye.

This release of untreated sewage is part of the work being done on the Bonaventure Expressway. This upgrade will ensure the system will be able to handle wastewater for years to come, and the city of Montreal is adamant that this dump is exceptional and essential to ensuring safe treatment of wastewater in coming years.

For decades our society believed that dilution is the solution for most pollution. The atmosphere, our lakes, rivers and oceans were so large that we couldn’t ever imagine that we would be able to affect them in any real manner. This idea has proved difficult to get rid of as we continue to assume that natural systems will clean and treat our increasing large and complex waste products. In fact it is the sum of everyone’s actions that are the results to analyse.

Dilution isn’t the solution, accumulation is the complication.

The Canadian context

Statistics Canada provides data on sewage treatment in Canada and at first glance it seems that our state of water treatment is reasonably good. Approximately 97 per cent of residential sewage in Canada is deemed as treated. That means just 3 percent is being dumped directly into surface water (rivers, lakes or rivers). This is, however, a little misleading, when those number are broken down by type of treatment, we see that in fact our treatment levels are lower than we would expect.

When looking at wastewater treatment there are three levels of treatment. Primary treatment is simply removing solids. Secondary treatment removes solids and treats to remove organic compounds. Finally, tertiary treatment does the first two plus removes toxic chemicals and medications.

If we look more closely at the data in Canada we see the picture is a little more complicated:

  • 03 per cent — is untreated
  • 16 per cent — primary treatment
  • 53 per cent — secondary treatment
  • 15 per cent — tertiary treatment
  • 13 per cent — Septic Systems or Haulage (this is then treated at local treatment plants)

(2009 Environment Canada data)

Montreal’s situation

As can be seen, this dump in Montreal is not strange. Rather it is something that should bring attention to a Canada wide issue. Our sewage treatment systems are lacking. Many systems combine sewage and rainwater so with large rains the systems don’t have capacity to treat all the sewage; many systems still only do secondary treatment leaving medications and other chemicals in the water.

Many lakes and rivers are recovering worldwide as wastewater is being properly treated but this is a slow process. The opposite is also happening as larger amounts of sewage are being produced worldwide and the requisite systems aren’t being developed.

This dump should bring attention to the fact that Montreal must and will upgrade its wastewater treatment. This is unfortunately one of those situations where we have to be pragmatic and understand that the negligible damage this sewage dump will cause is necessary to maintain and improve a wastewater treatment system that will ensure a cleaner and healthier St. Lawrence.

This issue should also bring to light the fact that this progress is happening slowly in Montreal and across Canada. Our systems are old, weak and treating water at unacceptable levels.

EcoJustice, a Canadian non-profit, highlights the weaknesses in the Canadian sewage treatment systems in regular published reports. The Canadian government made a plan to address the need to improve our wastewater systems but the regulations are weak, far in the future and without a great deal of financial support. We still flush in a world where billions of litres of untreated water can go back into local ecosystems. With an (apparent) influx of infrastructure money coming to cities across the country, dealing with our sewage to protect our drinking water, our recreation areas and the surrounding flora and fauna needs to be a priority.

Originally published on at The Suburban


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