You Might Give a Shit About This Story

Let’s go back to 2011. The City of San Francisco has spent about $100 million US to retrofit the city’s aging sewer system. Then, City leadership makes the rash decision to spend $14 million on a plan to dump bleach into the sewers.

Yes, the city famous for hippies, open-mindedness and being one of the most granola places in North America had made the rash decision to stop a smell problem by dumping bleach on it.

What led to the decision? The rise of low-flow toilets. Californians are often the first to adopt new ways of life, and the state and the various municipalities are often quick to incentivize green technologies, from electric cars to wind energy.

So, by 2011, low-flow toilets were already the norm. But, they messed with the water-to-shit ratio in the pipes, leading to smelly sludge which jammed the sewers and leeched crappy odours through the city.

Now, what does what happened in the Bay Area 13 years ago have to do with Edmonton?

Well, over the past few months, Grovenor residents have been complaining to EPCOR about the bad smells coming out of the sewers. This is the site of a recent sewer rehabilitation project, as the 99th Avenue line brings wastewater from the west end all the way to the Gold Bar treatment plant. It serves more than 117,000 customers.

That’s a lot of shit. And it stinks. Urban Affairs is aware that questions were asked about the nature of what’s flowing through the pipes. Does our low-flow sludge smell a lot worse than our sewage from a decade ago, or longer?

“When wastewater is not moving quickly through the wastewater collection system, odours can become more noticeable,” wrote EPCOR’s Laura Ehrkamp in an email. “For example, there can be reduced flows in the system during times of the year when there is little rain or snow entering the system. Low-flow appliances help customers conserve water and, therefore, can reduce flows in the system compared to less efficient appliances.”

So, odours are more noticeable when the sewage is moving slowly, and low-flow appliances reduce the water flow in the sewers.

EPCOR told us that the utility is well aware of the complaints, and have already taken steps to mitigate the odours, “such as sealing some manholes to help reduce air venting, installing odour flaps and installing air monitoring near some manholes.”

I asked some folks in the development business about low-flow toilets — and the responses were similar; they are good for the environment, they allow for dense infill projects, because the old pipes can handle the addition of new living spaces. The big “but” was the sludge thing.

But, talking to people about the unintended consequences of green technology is like talking to people about what’s inside of Area 51. No one is going to publicly slam a widely accepted new technology. And, heck, we can all agree that reducing our water use is a good thing, even if we create pipes filled with guck that’s the consistency of Minute Maid concentrate. (I really just wanted to plant that mental image, because I am a bad person.)

No worries, because, in 2021, the University of Exeter published a study from Peter Melville-Shreeve, Sarah Cotterill, Alex Newman and David Butler on the effect of low-flush toilets on campus. Now, this was a study based on public washrooms in multiple university buildings, but what it found was that an auxiliary flushing system was needed for the women’s washrooms, to add water to the waste flow. There were still added blockages, mainly toilet paper dams. Men’s washrooms were better off, because having urinals near the flush toilets helped with the water flow.

Ehrkamp said that the Grovenor complaints go against a six-year trend. She stated that, since 2018, odour complaints in Edmonton have actually gone down by more than 52 per cent.

Despite the drop in complaints, smell is a big concern for the utility. EPCOR recently presented its 2025-27 spending plan to city council, and it includes $890 million for wastewater infrastructure. Of that, $220 million is earmarked for odour reduction. San Francisco can eat its smelly heart out.