FATBERGS AND HOW TO GET RID OF THEM
AS A METAPHOR for our 21st-century consumer culture it couldn’t be more damning. “Fatbergs” – huge, rock-hard masses of congealed waste – are the silently growing menace beneath our streets… and they’re only getting bigger and more dangerous.
This week it was revealed that the world’s largest fatberg has been discovered in the sewers of Whitechapel, east London.
At 240 metres long, the monstrous mound of grease, oil, wet wipes and nappies stretches the length of Tower Bridge and weighs 130 tons – the equivalent of 11 double-decker buses, a blue whale, or 520,000 packets of lard. And it is entirely man-made.
The sheer scale of the subterranean slimeball has astonished those tasked with destroying it. According to Matt Rimmer, Thames Water’s head of waste networks: “This fatberg is up there with the biggest we’ve ever seen. It’s a total monster and taking a lot of manpower and machinery to remove as it’s set hard. It’s basically like trying to break up concrete.”
Workmen dressed in special protective suits are now attempting to break up the fatberg, using high-powered jets as well as shovels. The waste is then sucked into tankers and taken for disposal at a recycling plant. So huge is it that the whole operation is expected to take at least three weeks.
If it had not been discovered, there was a danger that the sewer could have become blocked completely, backing up toilets above ground and spilling raw sewage into the streets and people’s homes.
“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,” says Rimmer. “We check our sewers routinely but these things can build up really quickly and cause big problems with flooding as the waste gets blocked. A lot of the fat comes from food outlets but the wipes and sanitary items are far more likely to be from domestic properties.”
The sheer size of this fatberg may be unprecedented but experts reckon that it is a problem that will only get worse. As the use of wet wipes and disposable nappies has increased, and a lack of awareness of the dangers of pouring cooking oil and grease down the sink persists, our ageing sewers are simply unable to cope.
MOST of our underground waste infrastructure was built by the Victorians about 150 years ago. And if they remain something of a miracle of engineering – in London alone there are around 550 miles of sewers, with a further 13,000 miles of local pipes connected to them – they are now struggling to handle the demands we are placing upon them.
Fatbergs are formed when oil, grease and fat, which do not break up in water, meet flushed wet wipes, nappies and other sanitary products. The wipes do not disintegrate like traditional toilet paper but remain floating on top of the waste water, absorbing and collecting the globules of oil and grease.
There then follows a kind of “snowball effect” – as more fat is collected, more is attracted… and as the glob grows in size, it hardens
and solidifies. If it is not discovered it will only continue to grow until it reaches the monstrous size of the fatberg now underneath east London.
They would also seem to be a growing phenomenon. Waste engineers are called to 6.7 million blocked drains each year in the UK, and Thames Water says it spends as much as £1million every month clearing blockages from its sewers in London and the Thames Valley.
And as they are getting more frequent, they’re also getting larger. When a 15-ton congealed leviathan of lard was sucked from the sewers of Kingston, south-west London, in 2013, Thames Water waste contracts supervisor Gordon Hailwood declared: “We have never seen a single, congealed lump this big clogging our sewers before. We reckon it has to be the biggest such berg in British history. The sewer was almost completely clogged with more than 15 tons of fat. If we hadn’t discovered it in time, raw sewage could have started spurting out of manholes across the whole of Kingston.”
Within two years, however, a 40-metre fatberg snapped sewer pipes in Chelsea, and another twice as long had to be removed from Shepherd’s Bush. As recently as last June, Northern Ireland Water spent six weeks breaking down 100 tons of fat, oil and grease from the sewers of Belfast.
The problem is not unique to the UK either. The New York Times estimated that clearing “grease backups” costs the city $4.65million (£3.5million) a year; and in Australia a spokesperson for Queensland Urban Utilities reckons they have to remove about 120 tons of wet wipes from the sewers of Brisbane every year.
This latest mountain of congealed waste eclipses them all, however.
At the moment, clearing up fatbergs is a time-consuming, labourintensive – not to mention disgusting – process, with the material having to be broken up largely by hand before being taken to landfill, or, when possible, recycled.
However, with fatbergs a growing problem, water firms are keen to find alternative uses for the waste. This spring, Thames Water announced it was joining forces with renewables firm Argent Energy to explore the possibility of converting the congealed greases into a fuel that is environmentally friendly.
Describing the scheme as a “nobrainer”, Simon Brum, strategic recycling manager at Thames Water, said: “We have a problem with fatbergs. Previously what we’ve done is either extract the fatberg out of the pipes and send to landfill, or break it down and put it back through the system. Now we’re looking to see if we can use fatbergs in a clever way.”
Some of it could even end up at the Museum of London. Director Sharon Ament said adding the fatberg to its collection “would raise questions about how we live today and also inspire our visitors to consider solutions to the problems of growing metropolises”. For the moment, however, the focus remains firmly on prevention. “The sewers are not an abyss for household rubbish,” says Rimmer. “Our message to everyone is clear: bin it, don’t block it.”