'Fatbergs' are taking over city sewers - scientists are fighting back

Reeking coagulations of grease and debris are clotting sewers around the world on a colossal scale. Cities are deploying new technologies to control this modern menace. Beneath the bustle of pedestrians and traffic on London's Whitechapel Road, something truly horrific was taking shape. It weighed more than 130 tonnes – the same as 11 of the city's famous red double decker buses – and breathed toxic fumes. This subterranean monster had been growing unnoticed in the Victorian-era sewer running underneath the busy street, until workers carrying out a routine inspection bumped into its rock-hard flank. Now, a team wielding pickaxes, high-pressure water jets and clad head-to-toe in protective clothing, were preparing to tackle the putrid beast. Their foe? A stomach-churning agglomeration of fat, oil, grease, wet wipes, sanitary products and condoms, known as a "fatberg". This unholy concoction turns out to be "a magical mixture" that hardens like concrete, says Richard Martin, head of treatment improvement at Southern Water, a water company responsible for sewers in the southeast of England. These hideous clogs menace cities around the world. Formed from material that householders and