Source of ‘disgusting’ grime balls that closed Sydney beaches revealed

The investigation notice required Sydney Water to undertake oceanographic modelling of the dispersion of the balls, complete a sampling and analysis program at its sewage treatment plants, and assess its deep ocean outfall systems at Bondi and Malabar and its sewage pipe network to find the fault and prevent a recurrence.

The EPA has established a wastewater expert panel to provide independent scientific advice to the EPA and other agencies, to be chaired by Professor Stuart Khan, head of civil engineering at the University of Sydney.

Sydney Water acting executive general manager water and environment services, Louise Beer, said in a statement it was important to note that all coastal treatment facilities were operating normally and the organisation was compliant with regulatory standards.

“As we could not find any faults with our system, we conducted widespread sampling and analysis of the debris balls at Sydney Water’s laboratories and appointed an independent oceanographer to determine the potential geographic origin of the debris balls,” Beer said.

The Sydney Water statement says the balls probably came from 10 or more separate discharge events from multiple locations rather than a single origin point.

The state-owned corporation suggested the debris balls might have formed due to an “increased load of fats, oils and greases in the wastewater system over time” and reminded Sydneysiders to keep them out of drains and put them in the bin instead.

Avoid touching debris balls or other pollution on beaches and report new finds to your local council or EPA’s Environment Line on 131 555.