Sydney Water ordered to clean Malabar treatment plant where fatberg is birthing poo balls | Pollution
New South Wales’ environmental watchdog has ordered Sydney Water to clean up oils from its Malabar wastewater treatment plant, a month after Guardian Australia revealed a huge oil mountain was responsible for the poop balls that blocked beaches last summer.
Sydney Water isn’t sure exactly how big the oil mountain is because it can’t easily reach the area where it accumulates. It could be the size of four Sydney buses.
Fixing the problem will require shutting down the ocean outflow 2.3 kilometers offshore for maintenance and diverting sewage into a “cliff face outfall” that will close Sydney beaches for “months”, according to a confidential report obtained by Guardian Australia using freedom of information laws.
The Sydney Water report from August 2025 acknowledges that this has “never been done” and is “no longer considered an acceptable approach”.
The Environmental Protection Authority (EPA) said on Monday it had issued Sydney Water with a pollution reduction program that “requires a number of significant works, including cleaning up oil from the Malabar deep ocean outlet baffle area, to reduce the likelihood of further balls of debris hitting the state’s beaches”.
“The requirements for Sydney Water include a range of short, medium and long-term actions, including the removal of solids, liquids and grease accumulation from a hard-to-reach baffle zone of deep ocean currents,” the watchdog said in a statement.
Sydney Water was also ordered to develop “a system to capture debris overflowing from sewers during severe wet weather events”; conduct “a study of the formation and erosion of debris balls to facilitate their tracking”; and “Consider AI or other technology to monitor debris pellet formation.”
NSW EPA operations manager Steve Beaman said Sydney Water “has a responsibility to ensure it does not pollute our beautiful beaches and this important work is a step towards that”.
“Debris balls are a complex problem and EPA will continue to regulate Sydney Water to protect our precious natural environment.”
August 2025 report reveals “working hypothesis is FOG” [fats, oils and grease] “Accumulation in the inaccessible dead zone between the Malabar bulkhead and the fall tunnel led to the release of debris balls, potentially leading to debris events.”
The bulkhead is usually underwater and can only be opened at low tide and low flows in the system. The report states that it is impossible to move safely beyond the stops. The huge fat mountain is thought to be in a 300 cubic meter chamber beyond the stops.
Sydney Water currently cleans the accessible section regularly, which in itself is “an extremely risky operation”. The report states that 53 tons of accumulated FOG, including debris balls, were cleared in April 2025.
Debris cannons first closed beaches in October 2024. A month later Sydney Water acknowledged that the balls “may have absorbed wastewater discharges already present in the water as they formed”, but insisted they “did not form as a result of our wastewater discharges”.
Later reporting by Guardian Australia revealed that this statement was untrue.
Earlier this month Sydney Water’s chief executive Darren Cleary admitted as much, telling the ABC: “In hindsight, the evidence clearly shows that it was most likely ocean current. So in hindsight, yes, the earlier statements were not factually correct.”
