Trillions of bacteria with a taste for turkey fat and cooking oil are released in sewers to eat the annual onslaught of Christmas dinner grease that risks blocking pipes

Yorkshire Water said it was deploying the "biological weapon" of bacillus bacteria -- commonly found in the human gut -- in its sewer network in an attempt to prevent blockages, which typically increase by 25pc over the festive season.

The company began pouring vats of water mixed with the bacteria down sewers at known trouble spots last week and is rolling out the treatment at 180 sites in Yorkshire.

Sewer blockages cost the water industry tens of millions of pounds a year, with many due to hot fat, oil and grease being poured down the drains and then solidifying. The fat also binds with non-biodegradable rubbish flushed down toilets, causing blockages which can make sewage flood back up into homes.

The fatty build-ups are usually cleared out manually with high-pressure water jets.

Patrick Killgallon, pollution manager at Yorkshire Water, said, "Having your home filled with waste from your toilet and sink is a very unpleasant experience, which no one should ever have to suffer, particularly at Christmas."

The company encouraged people not to "pour leftover fat down the plug hole or flush a make-up wipe down the toilet", but Killgallon said more than 6,000 fat-related blockages had already been removed from Yorkshire Water's network so far this year.

With the likely increase in fat over Christmas, the company was turning to "new and innovative methods".
Killgallon said the utility was confident that the  "'good bacteria, literally feasting on solidified fat" would be cost-effective and could potentially end all such blockages.

"Because these bacteria constantly multiply in the right environment, we can leave them to get on with their job in our sewers, seven days a week, 24 hours a day, without the need for regular dosing," he said.

Other water companies have conducted trials with different kinds of bacteria treatments but Anglian, which has experimented submerging "sock-like" containers of bacteria into sewage, said it had not yet been successful in sewer networks because of the "fluctuating conditions and levels of sewage".