Debris balls found on several beaches along the New South Wales Central Coast earlier this year likely originated from a Sydney sewage treatment facility, according to the state's environmental authority. In August, over 40 kilograms of grey balls, ranging from one to four centimeters in diameter, washed ashore from Forresters Beach to The Entrance. This incident occurred more than six months after similar debris appeared on Sydney's beaches.

The Environment Protection Authority (EPA) is investigating the source of the debris. They collected samples from the Central Coast for comparison with materials from various wastewater facilities operated by Central Coast Council, Hunter Water, and Sydney Water. The analysis indicated that the local samples shared a "matching chemical signature" with material from Sydney Water's Malabar treatment facility.

This finding has prompted Sydney Water to conduct further investigations to identify potential sources of the debris within its system. Ben Armstrong, Principal Manager Environment at Sydney Water, expressed surprise at the distance the balls traveled. "To have them go so far up the coast is not what we were expecting," he said.

Armstrong noted that the Malabar facility has seen an increase in the amount of fat, oil, and grease entering its drains. "We're trying to find out where that could be coming from, if it is industry or illegal dumping," he explained. He added that the catchment area serves over 2 million people, extending to Liverpool and Glenfield.

As the investigation continues, efforts are being made to prevent further occurrences of the debris this summer. Armstrong stated, "At this stage, we're trying everything we can to stop that from occurring." He mentioned that some areas of the deep-ocean outfall are difficult to access, and they are exploring new methods to identify the source of the problem.

Sydney Water has also launched public awareness campaigns to educate residents about proper disposal practices. "Water, soap, and detergents are the only things we want to go into the sinks because fats, oils, and grease congeal in our pipes and can cause our system to overload," Armstrong said.

Jonathan Beves, a chemistry professor at the University of New South Wales, analyzed the debris that washed up on Sydney beaches and has requested samples from the Central Coast. He expressed surprise that the EPA could identify the source of the balls. "If there was some unique chemical or unique treatment they were using that wasn't used at other treatment plants, that might be something you'd be able to detect and exclusively trace to that plant, but I'm not aware of anything like that," he said.

Despite the unpleasant nature of the debris, Beves reassured the public that there is no significant health risk associated with it. "I don't think that there's anything to be particularly worried about from a health perspective. It's just unpleasant to be swimming in things that come out of a sewer," he stated. He noted that before the 1990s, swimming in contaminated waters was more common at Sydney beaches, as sewer outfalls were located closer to shore.