WARNING: Some readers might find the descriptions in this story disturbing. Discretion is advised.
HALIFAX – Last week a downtown Halifax manhole cover was lifted skyward by a dense lump of floating fat, oil and grease. It was a fatberg.
The term was coined in London, England when sewer maintenance crews discovered fat flushed down drains was congealing along pipe walls. Eventually the walls thicken and the flow is reduced, then the clogged sewers overflow during heavy rains.
The same thing is happening now in Halifax.
“The problem is residents and business are pouring fat, oil and grease down the drain,” said James Campbell, spokesperson for Halifax Water. “That’s material that should not be going down the drain.”
Fatbergs aren’t easy to fix. Crews have to lower custom robots down manholes, which squeeze into narrow pipes. The robots send back live video showing what’s in the sewer.
Paul Kohoot is the man who sits at a control panel to watch what the robot sees.
“In this section of pipe you can see the liquids are risen,” he said, pointing to the screen. “Something is blocking it ahead here.”
Ahead of the robot, there is a mound of white and brown lumps.
“Chunks of fat and grease,” Kohoot explained.
The robot then backed out of the sewer to allow a vacuum truck in.
“The vacuum truck will use a jet of water to try to blast that fat away and vacuum it up at the same time,” said Campbell.
These two trucks cost Halifax Water nearly $1 million. Officials say the investment is worthwhile because the fatberg problem isn’t going away.
“So-called flushable wipes or dental floss, or tampon applicators, or condoms — these are all things that should not be going in the sewer system,” Campbell said. “People are treating their drains like garbage cans and they’re not.”
Cleaning the 60-metre section of pipe took the Halifax Water crew about one hour.
With thousands of kilometres of pipes beneath city streets, that’s just the tip of the fatberg.