'Monster fatberg,' mix of wet wipes, diapers and oil, clogs up London sewer

The "fatberg" has blocked a sewer in east London. (Thames Water)

An enormous "monster fatberg" weighing the same as 11 double-decker buses has clogged up a sewer in east London and will take about three weeks to clean out, officials said Tuesday.

The rock hard mass of wet wipes, diapers, fat and oil in a stretch of Victorian-era sewers under Whitechapel Road is more than twice the length of two soccer fields, according to Thames Water.

“This fatberg is up there with the biggest we’ve ever seen," said Matt Rimmer, Thames Water’s head of waste networks. "It’s a total monster and taking a lot of manpower and machinery to remove as it’s set hard."

A workman in protective clothing prepares to go into the sewer. (Thames Water)

The underground beast weighing about 130 tons is about 10 times larger than the last monster clog found underneath London streets in 2013, according to the agency.

Thames Water said it will take specialist workers about three weeks to chip away at the mass, using "high-powered jet hoses" to break it down, and then suck out the muck with tankers.

“It’s basically like trying to break up concrete," Rimmer said. "It’s frustrating as these situations are totally avoidable and caused by fat, oil and grease being washed down sinks and wipes flushed down the loo.”

Workers are "painstakingly removing" 20 to 30 tons per shift, with shifts running between 8 a.m. and 5 p.m. seven days a week.

Once full removed, the remnants of the "fatberg" will then be taken away for disposal at a recycling site.