Fatberg ahead

Why fatbergs are no laughing matter. By Richard Leigh

At the time of writing, ‘Fatty McFatberg’ found in Whitechapel, east London is the biggest fatberg that has ever been recorded. The gigantic fatberg weighs approximately 130 tonnes, blocks a 250-metre stretch of sewer and is about the same size as two football pitches. Fatbergs represent the dark underbelly of living in major cities across the world. And it is not a coincidence that London, one of the largest and most populous cities on the planet, holds consecutive records for finding and excavating the biggest fatbergs.

Over the course of this article we will explain why fatbergs are a menace, why modern day society is to blame, how to remove a fatberg, and the pressures it exerts on drainage as a whole.

Sinister fatbergs
Fatbergs are no laughing matter. They are huge lumps of congealed fat, sanitary products, condoms and wet wipes. They are made up of all the things that don’t break down when you flush them down the toilet or pour them into your sink. They are commonly found in major cities such as London, Birmingham, Glasgow, Sydney and New York, where the stress on the city’s sewage network are far greater than in rural areas.

Besides from being totally disgusting, fatbergs have an alarming impact on sewage and the surrounding infrastructure in which they are formed. They have the potential to completely block drainage systems, preventing waste from getting to facilities for treatment and purification. In some cases, when they get big enough, fatbergs can cause raw sewage to spill out from our sewers onto street level.

They also cost millions to manage and excavate. According to Thames Water, the utilities company spends approximately £1 million a month taming these underground beasts. It’s the same in the US, with the mayor of New York City saying they’ve spent $18 million on excavating fatbergs over the last five years.

Is modern society to blame?
Blocked drains and clogged sewers are a problem as old as the sewers themselves. Many cultures adopted different approaches to tackling the issue, with the Romans sending slaves into the depths of their sewers, to clean and remove blockages.

The fatberg issue has only really escalated as our society has modernised and grown. As mentioned previously, fatbergs are born when grease, fat or oil is tipped down a sink and when wet wipes are flushed down a toilet. Unlike toilet paper, wet wipes do not break down when flushed down the loo. Instead when you put the two together, you have the perfect conditions to make a baby fatberg. In London, large portions of the sewage system are from the Victorian-era and with London’s population continuing to grow, our sewage systems just can’t keep up.

When you analyse the areas where fatbergs have formed and have been excavated, a pattern begins to emerge. In Whitechapel, where ‘Fatty McFatberg’ was excavated, a large proportion of fast-food restaurants failed to have a grease trap installed or adequately set up to capture excess grease and fat from cooking and food.

Thames Water surveyed hundreds of restaurants across the capital. And according to its data, as much as 90 per cent of restaurants don’t have adequate systems in place. This information comes as little surprise to Stephen Pattenden, Thames Water’s sewer network manager. He said: “We’re not suggesting anyone pours the contents of a fat fryer down the drain, but it’s more about the gunk that comes from dirty plates, pots and pans.”

He added: a “simple, well maintained grease trap” was enough to prevent kitchen waste from entering sewers.

How to remove a fatberg
Removing a fatberg from a sewer is a big job and requires a lot of manpower, specialist machinery and above all, a very strong stomach. First, the fatberg and the surrounding sewers must be surveyed to identify the scale of the problem, how far it has spread and the mass of the fatberg. This is usually done with CCTV surveying technology, which provides HD quality pictures.

Once the survey is completed, project managers put together a plan and a team to tackle the mass of rubbish the old fashioned way – with shovels and other digging equipment. Sometimes, it’s difficult to cut through with a shovel, so you need top-of-the-line jet vacuumation equipment to cut through the tougher to remove chunks of fatberg.

Bits of the fatberg are then carried to the surface and placed into waste disposal tanker to be shipped to recycling facility for processing. Some fatbergs even get turned into biofuel.

Drainage and trenchless technology
Removing fatbergs is only part of the story when companies like Lanes for Drains come in to remove fatbergs. More than often, the sheer size, weight and volume of a fatberg can actually damage sewage systems.

In the case of the 2013 fatberg found in Kingston upon Thames, once the fatberg had been excavated, it took engineers six weeks to actually repair the surrounding sewage system. This a huge undertaking and requires the expertise of workers from a wide range of disciplines, including civil engineers. Usually, in a project like this, civil engineers would be forced to rip up an entire street corner, to access the damaged area. But trenchless technology has changed this.

In particular, Cured-In-Place-Piping (CIPP) UV lining technology rehabilitates sewage facilities from 225mm to 2500mm in diameter. The technique involves inserting a piper layered with a special type of resin into the sewer or drain. Once inside, the liner is turned inside out by the operator and is forced through using water or air pressure. An ultraviolet light train then dries the resin in the pipe, binding the pipe together, fixing the problematic pipe or sewer system without the need for excavation.

Remember, bin it, don’t flush it
If you’re looking for a key takeaway from this article, please let it be ‘Bin it, don’t flush it’. By changing the behaviour of people when it comes to dropping wet wipes, fats, oils and grease down the toilet or your sink, we hope the number fatbergs and broken or damaged sewers beneath our feet begin to disappear

Richard Leigh is Group Development Director, Lanes for Drains. Lanes for Drains has been fighting fatbergs since 1992. The company offers 24/7 responses to drainage emergencies with removal, rehabilitation and renewal as well as consultancy and waste management services. Recently, Lanes for Drains has launched their ‘Fatberg Fighters’ campaign, which is set to help young children understand the problems our sewage facilities face when disposing of wet wipes and FOG incorrectly.