BORDERS residents have been warned against tipping fats, oils and grease down the sink.

It comes after Scottish Water discovered St Boswells’ waste water site contaminated with used cooking oil.

Alan Aitchison, of Scottish Water, said: "The amount of cooking oil which entered our works at St Boswells was significant.

"We now have to empty and carry out extra cleaning of a number of tanks, and we will have to transport the contaminated sludge to Galashiels Waste Water Treatment Works where it will be disposed of and correctly treated, in a way which is non-harmful to the environment.”

When fats, oils and grease (FOG) are poured down a drain, they contribute to the build-up of 'fatbergs' – congealed lumps of fats and non-biodegradable waste, such as baby wipes and sanitary items – which can cause internal and external flooding, as well as environmental damage.

Mr Aitchison said: "Everything you dispose of down sinks and toilets will all end up in the drains and sewers – and we urge everyone to think twice about how they dispose of fats, oils, grease and other products such as wipes and cotton buds that aren’t biodegradable that can potentially lead to sewer blockages that will impact our water courses and environment."

Mr Aitchison said the amount of oil found at the St Boswells treatment facility means a deep-clean is necessary.

He added: "Toilet paper is the only biodegradable material that should be disposed into the sewer collection system – all other items should be bagged and binned for disposal."

Scottish Water handles more than 100 burst pipes nationally per year, some of which are caused by FOGs.

An FOG factfile has been created by Scottish Water:

  • Fat, oil and grease may not appear harmful but as it cools it congeals and hardens
  • This can cause blockages to the inner lining of drainage pipes, which can lead to waste water flooding into gardens and properties and cause a health hazard to wildlife and the local environment
  • In extreme cases blocked sewers can spill into burns, rivers, streams, coastal waters and beaches which can cause environmental damage
  • Scottish Water deals with 35,000 blockages every year – at a cost of £6.5 million to attend and clear
  • The waste water drain which runs from your house to the public sewer is usually only about four inches wide - less than the diameter of a DVD.