A 200 tonne fatberg that was clogging a sewer underneath Liverpool city centre has finally been cleared after two workers developed a new way to get rid of it.
The huge pile of fat, grease and many other types of waste was 250 metres long and had caused internal flooding to properties on Bankhall Lane, Birchall Street and Foster Street.
Workers had to come up with a new method to get rid of the fatberg after traditional methods failed, ultimately coming up with a process that “literally ate it away from the inside out”.
Sammy Nelson, from United Utilities, and Stuart Ashton, from Sapphire Utility Solutions, eventually developed a hybrid technique to get rid of the fatberg and restore water flow to the sewer.
They first drilled a hole right the way through the centre of the fatberg using a clean water technique known as auger boring.
Then they fed a steel rope line through the hole where they hung a specially adapted jet machine used to clear sewer blockages.
Using the steel rope they moved the jet machine backwards and forwards inside the fatberg.
Mr Nelson, who is a wastewater programme delivery manager for United Utilites, said: “Together we came up with the idea of using guided directional drilling equipment to drill through the fatberg and then allow a cable to be run through which would allow jetting to be carried out.
“We then reconfigured a cutting jet to run along the cable through the centre of the fatberg like a ‘Zip Wire’ – this was done to great success and within a couple of weeks flow was restored to the sewer.”
Mr Nelson said the work was carried out in half the time it would have taken to replace the sewer system, the next option, and cost a third of the price with far less disruption.
A new UV cured chemical resistant structural liner has now been installed to prolong the life of the sewer and stop flooding issues from occurring in the future.
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