My PhD research was all about residential water consumption, and I completed it surrounded by engineers working on all sorts of practical water-related projects, so I have a longstanding interest in urban infrastructure. But I’ve never heard of anything like this.
John Vidal’s story on London’s fatberg, published in The Guardian, Wednesday 7 August 2013, describes a bizarre consequence of the combination of high-density urban living with dodgy waste disposal. Used oil and fat poured down sinks and drains over many years generated a 15-tonne ball of congealed fat that blocked 95% of a sewerage main in the borough of Kingston upon Thames. Workers needed three weeks to clear it with high-powered water jets. According to a Thames Water spokesman, “it’s a heaving, sick-smelling, rotting mass of filth and faeces. It’s steaming and it unleashes an unimaginable stink.”
Fatbergs aren’t just disgusting, they represent a missed opportunity. Fat is very energy-dense, and is easily converted into biodiesel to run vehicles or generate electricity. Boris Johnson is reportedly pressing for waste fat to power a fifth of London’s bus fleet (which is appropriate as the fatberg was the size of a bus …)