Cause of huge Devon fatberg measuring twice the size of blue whale revealed

A monstrous fatberg discovered underneath a seaside town was mainly caused by cooking fats and hygiene products, it's been revealed.

The 64-metre beast - twice the size of a blue whale - made up of hardened fat, oil and wet wipes, was discovered by South West Water under the Esplanade in Sidmouth just before Christmas last year.

This fatberg is thought to be the biggest found so close to the sea and is certainly the largest Devon or Cornwall has ever seen.

Work to remove the fatberg started in February and lasted over eight weeks, despite challenging conditions.

It was finally concluded in March.

Scientists from the University of Exeter were asked to carry out an extensive 'autopsy' to solve the mystery of how the fatberg was created - and if it posed any environmental risks.

The team were given four samples, each weighing around 10kg, after South West Water workers spent eight weeks removing it from the sewer.

It was then taken to a local sewage treatment works where it was fed into the anaerobic digester and produced energy to power the plant.

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Tanker loads - each 3,000 gallons - was excavated and removed.

64m

The fatberg measured as long as two blue whales.

The giant fatberg was found blocking a sewer in underneath the esplanade in Sidmouth seaside town. Credit: South West Water

The University team found the samples were mostly made of animal fats - consistent with those used in domestic food preparation.

That was then combined with household hygiene products such as wet wipes and sanitary products, as well as natural and artificial fibres from toilet tissues and laundry.

They also discovered the fatberg contained no detectable levels of toxic chemicals - meaning it did not pose a chemical or biological risk to the environment or human health.

Professor John Love, a synthetic biology expert who led the project, said they were worried it could have contained chemicals such as those found in contraceptives, microplastic beads - which have now been banned - and be rich in potentially pathogenic microbes.

We were all rather surprised to find that this Sidmouth fatberg was simply a lump of fat aggregated with wet wipes, sanitary towels and other household products that really should be put in the bin and not down the toilet.

Professor John Love

In order to undertake the analysis fatberg samples were melted to see what they revealed.

The teams also used state-of-the-art equipment to study the fats, particles, fibres and microbiological DNA found.

Scientists from the Greenpeace laboratory, based at Exeter's Streatham Campus, also looked at the chemical composition of the fatberg for their own analysis.

They found:

  • The fats found were more likely to come from domestic food preparation, rather than commercial food outlets.

  • The chemicals were those found in personal care products, rather than pharmaceuticals or pesticides.

  • There was no evidence of harmful viruses or bacteria.

Although we deal with around 8,500 blocked sewers every year, the Sidmouth fatberg was by far the largest discovered in our service history.

Andrew Roantree, South West Water
The fatberg is 64 metres long, which spans the distance of more than six double decker buses Credit: South West Water