Revealed: Main culprits that made up monster fatberg
In total, 36 tanker loads – each 3,000 gallons – of debris were excavated and removed by a dedicated team of seven specialists.
Cooking fats and hygiene products played a pivotal role in the formation of the giant fatberg found lurking under a seaside town, scientists say.
The 64-metre monster – greater in length than the Tower of Pisa – was discovered under The Esplanade in Sidmouth, Devon, just before Christmas last year.
A team of scientists from the University of Exeter were asked to carry out an extensive “autopsy” of the fatberg to try to solve the mystery of how it was constructed and whether it posed any environmental risks.
The scientists were given four samples from the fatberg, each weighing around 10kg, after South West Water workers spent eight weeks removing it from the sewer.
In total, 36 tanker loads – each 3,000 gallons – of debris were excavated and removed by a dedicated team of seven specialists.
The fatberg was taken to a local sewage treatment works where it was fed into the anaerobic digester and produced energy to power the plant.
The university team found that the samples they received were mostly made of animal fats – consistent with domestic food preparation – 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 its presence in the sewer, while increasing the risk of a blockage, did not pose a chemical or biological risk to the environment or human health.
Synthetic biology expert Professor John Love, who led the project, said: “Analysing the fatberg samples in such a short timeframe was an exciting challenge requiring the expertise from a number of specialised scientists.
“We worried that the fatberg might concentrate fat-soluble chemicals such as those found in contraceptives, contain now-banned microplastic beads from cosmetics and be rich in potentially pathogenic microbes, but we found no trace of these possible dangers.
“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.
“The microfibres we did find probably came from toilet tissue and laundry, and the bacteria were those we would normally associate with a sewer.”