What a big fat mess lurking underground

Fat in manhole on Chorley Road
Fat in manhole on Chorley Road

THIS is the monster “fatberg” which lurked beneath one of Wigan’s busiest roads.

United Utilities workers discovered the giant lard blockage, which engineers say was one of the worst they have ever seen, during repairs to the sewer pipes below Preston Road, Standish.

Many people don’t think twice about pouring fat and oil down the drain with hot water and washing up liquid, but it’s a real problem

Daivd Stock

So damaging was the ‘berg, they were forced to close the main road into the town for three weeks while repairs were carried out.

David Stock, who looks after the sewer network in Wigan for United Utilities and supervised the repair process, said: “The sewer was completely blocked with fat and grease which caused pressure to build in the pipe, and eventually it burst.”

The sewer runs uphill so to clear the monster blockage it had to be pumped.

But because it is a sealed pipe which operates under pressure without the usual manholes to check flows, the fat was only discovered after two repairs had already been completed.

The road was initially closed on January 27 and it was expected to take a week to fix.

But, after a number of other fatty discoveries, there were significant delays and it remained closed with diversions put in place.

United Utilities says it deals with around 28,000 blockages on the North West’s sewers every year. One of the biggest fatberg problems in the UK came in 2013 when a sewage worker took three weeks to defeat a toxic 15-tonne ball of congealed fat the size of a bus that came close to turning parts of the London borough of Kingston upon Thames into a cesspit.

United Utilities is determined to avoid a repeat problem and is now going to write to the 30 households and businesses served by the pipe in Standish to explain the problems caused by pouring fatty waste away down the sink.

Mr Stock added: “Many people don’t think twice about pouring fat and oil down the drain with hot water and washing up liquid, but it’s a real problem.

“The fat only travels so far before it cools down and coats the inside of the pipes and over time you get a fatberg. The consequences in this case were horrendous for all the drivers who use Preston Road.”

The company says the best thing to do with fatty waste is scrape it into the bin.

Many businesses and restaurants that produce a lot of waste oil can get it taken away and recycled into biodiesel.