A SYDNEY Water executive has defended a leak which caused more than 153 megalitres of raw sewage to flow into the Georges River, saying it was caused by a fault that had never occurred before.
Eric de Rooy, the organisation's general manager for service delivery, said the heavy rain on Friday, November 22, caused a "very big inflow" of sewage into the Glenfield Wastewater Treatment Facility and the extra pressure caused a valve to malfunction.
"Our safety devices then cut the power to the pumps, which were eventually completely submerged in water and that caused the sewage to flow into Bunbury Curran Creek," Mr de Rooy said.
He said there was nothing that could have been done to prevent the spill.
"The valves are checked regularly, this was just a unique failure due to flooding," he said. Residents are advised to avoid all contact with the waterway between the treatment facility and Liverpool Weir until further notice.
Signe Westerberg, a Liverpool-based member of The Greens, said the area should not experience these problems.
"We're not in the Dark Ages any more, there should be fail-safes in place to avoid this sort of thing," she said.
She said the damage the leak would do to the river was heart-breaking and a detailed investigation was required.
Mr de Rooy said staff worked around the clock to clean the sewage out of the 23-metre-tall pump station, which had been half-filled by the sewage and the pumps were then sent for cleaning.
Sydney Water also aerated the river by pumping dissolved oxygen into the water, to clean the waterway.
"The overflow into the river will be worked through the eco-system," Mr de Rooy said. "There will be no permanent damage to the river."
Liverpool councillor Peter Ristevski, the treasurer of the Georges River Combined Councils Committee, said Sydney Water would be asked to explain what happened.
"They will be receiving a stern warning from us to make sure this never happens again," he said.