Over the years, many instances of “fatbergs” have made headlines — massive FOG-based sewer clogs requiring a lot of manpower to remove.

The latest large sewer clog is not of the FOG variety, however. Rather, the blockage in a London sewer estimated to weigh as much as a blue whale consists of concrete.

“Normally blockages are caused by fat, oil and wet wipes building up in the sewer, but unfortunately in this case it’s rock-hard concrete. It’s in there and set to the Victorian brickwork, so we need to chip away at it to get it removed,” says Alex Saunders, operations manager for Thames Water.

The 330-foot-long, 115-ton “concreteberg” is the largest of its kind that Thames Water has ever seen. Work is beginning this week on removing the blockage, which is expected to take at least two months. Workers will be using a range of tools, including jackhammer pneumatic drills and high-pressure jetters.

“This is not the first time damage has been caused by people pouring concrete into our sewers but it’s certainly the worst we’ve seen,” Saunders says. “It is very frustrating and takes a great amount of time and effort to resolve. We’re now doing everything we can to deal with it as quickly as possible, making sure our customers don’t have to suffer because of this mindless abuse of our network.”

According to the utility, an investigation into how the concrete got into the sewer is underway.

Source: Thames Water