At some point, many of us have without thinking have emptied fat or grease down our kitchen sinks. Repeating this carelessness on a regular basis can over time restrict the flow of wastewater from our homes to sewer lines resulting in blockages and back-ups from the sewers. Fats, oils and grease (FOG) when poured or flushed down sinks, drains or toilets enter the sewer system where they cool, harden and subsequently stick to the inner walls of sewer pipes. If untreated, the build-up of FOG in a pipe can harden until it completely blocks the diameter of the pipe. When it hardens, it is both difficult and costly to remove FOG obstructions. The build-up of FOG can be a major problem in town centres or areas with multiple restaurants, takeaways or pubs since there is more grease heading down into the sewers to create the deposits. In some areas where the FOG build-up is extreme, Fatbergs can emerge.

In the sewer pipe, the fats in the grease get broken down into their component parts – glycerol and fatty acids. The fatty acids bind with calcium found in the sewers to create a compound which resembles a soap-like compound. This ‘soapy’ compound collects on the ceiling of the pipes when sewer levels rise to form stalactite structures. The net effect is extremely detrimental to the sewer network particularly when it ends up in Waste water Pumping Stations and Treatment Plants. Fatbergs can like their namesakes grow to a remarkable size. In recent years, reports suggest that two Fatbergs were discovered in London’s sewer network weighing 15 and 17 tonnes respectively.

Heavy rainfall will compound the problem of FOG build-up and result in flooding and extreme blockages. In one case, the build-up was so severe that it blew manholes covers upwards spewing sewage and waste outwards.

In simple terms, don’t empty fats, oils or grease down the sink or drain. If you are a food service operator, it is recommended to regularly check out the health of your drains through a CCTV survey and frequent cleaning. The McAllister Group is a drain specialist and have dealt with FOG problems across Ireland and the UK. If you have any concerns or problems, please call us today. The imagery below was recently taken at one of our out-of-hours call outs and was captured in the news: –

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