Sydney’s ‘Poo Ball’ Problem: Fatberg Forces Beach Closures and Triggers Urgent Action

Sydney, Australia is grappling with a significant environmental challenge: a massive fatberg lurking beneath its Malabar wastewater treatment plant. This accumulation of fats, oils, and grease (FOG) is believed to be the source of unsightly and unsanitary “poo balls” that have repeatedly forced the closure of popular beaches, prompting a pollution reduction program ordered by the New South Wales Environment Protection Authority (EPA).

The Scale of the Problem

Sydney Water is working to address the fatberg, estimated to be as large as four buses, but its exact size remains unknown due to its location in a difficult-to-access area of the sewer network. The blockage is situated in a tunnel at the Malabar Water Resource Recovery Facility. The fatberg is thought to be located in a 300 cubic meter chamber beyond a bulkhead door that is usually underwater.

From Mysterious Debris to Identified Source

The issue first came to public attention in October 2024 when debris balls began washing ashore on Sydney beaches. Initially, authorities investigated potential sources like oil spills, but analysis by the University of New South Wales revealed the balls contained human feces. Sydney Water initially stated the balls did not originate from its wastewater discharges, but Managing Director Darren Cleary later admitted this was inaccurate.

EPA Orders Remedial Action

On February 23, 2026, the EPA issued a pollution reduction program requiring Sydney Water to remove fats from the Malabar plant and develop a system to capture debris during severe weather events. The program includes short, medium, and long-term actions, such as removing accumulated FOG from the hard-to-access bulkhead area. Sydney Water had already removed 53 tonnes of FOG and debris balls in April 2025.

Challenges and Proposed Solutions

Accessing the fatberg presents significant challenges. The area is considered a “hazardous” and “inaccessible dead zone.” Shutting down the ocean outfall – which extends 2.3km offshore – for maintenance and diverting sewage to a “cliff face discharge” would necessitate closing Sydney’s beaches for months, a solution deemed unacceptable in a report from August 2025.

Sydney Water is now exploring the use of remote equipment and methods to inspect and remove the blockage. The EPA has mandated at least 18 inspections of the area over the next three years, starting in April 2026.

Future Prevention and Monitoring

Beyond removal efforts, Sydney Water has been ordered to develop a system to capture debris during wet weather and conduct a study into the formation and weathering of debris balls to improve tracking. The agency is similarly considering the use of artificial intelligence (AI) and computational fluid dynamics to remotely monitor for debris ball formation within the plant.

These initiatives align with Sydney Water’s $3 billion Malabar system investment program, aimed at upgrading infrastructure to support population growth and reduce discharges from its ocean outfalls.

EPA Executive Director of Operations Steve Beaman emphasized Sydney Water’s responsibility to protect the region’s beaches. “Debris balls are a complex problem and the EPA will continue to regulate Sydney Water to protect our precious natural environment.”