This week, UK officials announced they'd found a 15 tonne blob of fat inside a London sewer pipe. The so-called "fatberg" blocked 95% of the sewer and threatened to force raw sewage back through pipes into people's basements and city streets.
That begs the question: could "fatberg" happen in Toronto?
Yes, yes it could. When you pour grease and oil down the sink, it flows into the sanitary sewer system. It congeals, collects debris, and forms blockages. The problem is so bad that the City of Toronto has a by-law that requires every restaurant operator in the city to use a grease trap. The traps collect fat before it hits the sewers - but only when they are installed and maintained properly. City inspections in 2009 and 2010 revealed that nearly 1 in 3 Toronto restaurants do not have grease traps at all (pdf report).
If blockages get bad enough, real sewage has nowhere to go except back into buildings or out into city streets. That puts sewage and other sanitary waste into city waterways, jeopardizing public and environmental health.
No one has ever reported a bus-sized fatberg blob to Lake Ontario Waterkeeper, but we know that grease is a big problem. That's why the City's by-law was created in the first place. Fines for non-compliance are as high as $100,000.
Grease in the sewers isn't just a Toronto problem, either. Two years ago, bacon fat built up in a Halifax sewer, causing sewage to back up into people's basements. Metro Vancouver spends more than $2-million a year cleaning up mini fatbergs.
It's an important reminder that everything you dump down the drain eventually ends up in the pipes beneath us. And, when we fail to act responsibly, local waterways suffer and cities spend a fortune trying to solve the problem.