In January 2019, the sewers of the British resort town of Sidmouth were at risk of being clogged. The culprit was a giant fatberg, a large mass that builds in the sewers comprised typically of grease, fat and wet wipes. Beyond being as disgusting as you can imagine, fatbergs are a problem in sewers the world over and have proven to be costly as sewerage workers break down the blockages.
To understand the real horror of the Sidmouth fatberg, you need to fully appreciate the size of it. This wasn't just a pipe blockage caused by a bit of waste build-up. This fatberg was reported to have been 64 metres in length – or to put it another way, the size of six double-decker buses end to end.
This fatberg was so big that workers are still cutting it up and removing it as part of an eight-week project. Thankfully, it was identified in time to prevent the blockage from affecting bathing water.
The cost of careless flushing
In the UK, 80,000 fatberg blockages are reported annually, costing Thames Water around £1 million each month. To better appreciate the scale of how badly Britons are carelessly abusing sewerage systems, consider that at Christmas it was believed that approximately two Olympic-sized swimming pools worth of turkey fat was tipped down the drain.
And locally, the problem isn't much better. Queensland Urban Utilities, which looks after the Brisbane City Council and four nearby council regions, reported last year that it had cleared more than 360 fatbergs from sewers over recent a 12-month period. That's a significant portion of the 4000 blockages in QUU sewer pipes each year, costing $1.5 million.
Because you're curious: the longest fatberg found by QUU was approximately 7 metres long and 60 centimetres wide. It was found in the inner-city suburb of Bowen Hills and needed to be removed by a crane.
According to New York City's 2018 State of the Sewers report, NYC has actually seen a 6% reduction in reported sewer back-up issues. This can, in part, be attributed to enforcement of stricter rules of disposal of commercial cooking oils in the city.
The unflushable flushables
One of the biggest issues causing fatbergs is the increasing number of wipes that are clogging up the sewers. While these are predominantly baby wipes, there has also been an increase in the number of wet wipes being used by adults on the toilet. While many of these are advertised as being 'flushable', the reality is that it still takes far longer for the wipes to break down compared to toilet paper.
According to Sydney Water:
- 1 in 4 people in Sydney are flushing wet wipes.
- 72% of people who flush wet wipes are unsure or think they're biodegradable.
- The key demographic of flushers are males aged 15–44.
- 75% of sewer blockages involve flushed wet wipes.
Following on from the UK's 'Bin it, don't block it' campaigns, Andrew Rowntree, the waste water treatment manager at South West Water (who handled the Sidmouth blockage) has advised that people only flush the Three Ps. "That is pee, paper and poo. Nothing else," he advised.
Upgrading London's aged sewerage system is underway. You can learn more about the efforts to build a system that meets the needs of modern times in the documentary Five Billion Pound Super Sewer, airing on Sunday, 17 March at 7.30pm on SBS and available to stream afterwards at SBS On Demand.