NI Water makes 'fatberg' busting appeal in run-up to Christmas

Repairing the sewer after a blockage - NI Water crews at work

NI Water has spent an estimated £5m in the past two years dealing with 40,000 blockages in Northern Ireland's sewers.

In the run-up to Christmas, the company has made an impassioned plea to the public to avoid "fatbergs" and keep drains clear.

The message is not to pour cooking fat, oil and grease down the sink as it solidifies and blocks the sewer.

In the past, huge "fatbergs" have blocked pipes and caused considerable disruption.

Last year, a giant lump of fat weighing about as much as five sports cars was cleared from a Chelsea sewer in London.

In August 2013, a fatberg the size of a double decker bus was found under the streets of south-west London.

The one found in November of that year under Belfast's Ormeau Road was smaller but, nevertheless, caused disruption.

Up close and dirty: a clogged sewer

Alec McQuillan, head of Wastewater at NI Water, said: "Fat, oil and grease in its liquid form may not look harmful, but once in the drains, it is. Even when hot water or soap is poured down the sink - the fat, oil and grease will still harden. Detergents and bleach may also appear to work, but this is only temporary.

"When a drain becomes blocked and overflows, the consequences can be devastating.

"We can all play a part in maintaining the sewerage infrastructure from restaurants, pubs and hotels right through to home owners and industrial outlets."

One way to dispose of fat, oil and grease is to let it cool and solidify and then scrape it into the rubbish.