Half-a-tonne fatberg blocks city sewer main

Workers have spent a whole day attacking a ‘‘fatberg’’ with picks, shovels and hoses in Gisborne. The half-a-tonne fatberg was made up of rags, wet wipes, condoms and solid fat – all things that should not be flushed down a toilet or sink. Fatbergs are usually found in sewers and are made up of solid waste. On Tuesday, the Kaiti sewer network, which serves Kaiti and outer Kaiti catchments, was overloaded with rain. The Gisborne District Council was forced to open an emergency sewer valve at the Gladstone Rd Bridge, and flows stayed high until the valve was closed on Wednesday. Senior wastewater operations engineer Phillip Dodds said there must have been a block in the network near Rutene and Wainui roads. Placing a camera down the pipes, workers found the problem in a sewer main near the Mobil Station on Hirini St – a 15-metre long fatberg, believed to weigh about 500 kilograms, had filled the top half of a pipe. Contractors started cutting it out using brute force and high-pressure water jetting, but high evening sewer flows yesterday saw work stop.