We barely give a second thought to the greasy monsters that lurk in sewers beneath our streets, growing larger every day. We might even feed them without realising it.
This might sound like the plot of a cheesy Hollywood film, but it’s the strange reality of a growing waste problem in the 21st century – and engineers, not film stars, are the heroes fighting back with new inventions to vanquish the fatberg monsters.
Fatbergs are rock-like heaps of waste that build up in sewer systems thanks to the unsavoury and lazy habits of humans. Cooking fat and oils poured down sinks congeal in the sewers, forming a thick layer around pipes. This fatty build-up stops sewage from flowing freely, which can cause it to back up. But it’s the addition of non-biodegradable solids such as wet wipes and nappies that, when mixed with the fat, create hard fatbergs capable of growing to the size of buses and completely blocking sewage systems. In short, it’s one disgusting recipe...