The NSW Environment Protection Authority (EPA) says it is confident that pollution from a leaking leachate pond at Lake Macquarie City Council's Awaba Waste Management Facility has not migrated off-site, despite high ammonia levels detected in groundwater since at least 2017.
Multiple independent environmental audits since 2017 have reported non-compliance issues with the leachate pond. The most recent audit, published in December 2024, found the site non-compliant due to suspected leachate interaction with groundwater, posing potential harm to the environment.
The council's 2025 Soil, Water and Leachate Management Plan Update, approved in October 2024, confirmed ongoing leachate migration to groundwater, with elevated levels of ammonia, total dissolved solids, and total petroleum hydrocarbons detected near monitoring points closest to the leachate ponds.
Groundwater testing at site MP22, adjacent to the leachate pond, recorded ammonia levels ranging from 1,030 to 1,470 milligrams per litre in 2025, far exceeding the Australian and New Zealand guideline of 0.9 mg/L for fresh and marine water quality. Sites MP3 and MP4, south of the pond, recorded ammonia levels between 4.26 and 13 mg/L.
Surface water testing at site MP15, near an unnamed watercourse at the facility's south-eastern corner, showed ammonia levels of 1.99 to 3.59 mg/L in 2025—almost four times the recommended guideline. However, the EPA stated that off-site monitoring since 2017 has shown no leachate-affected groundwater outside the landfill boundary.
An EPA spokesperson said the agency has been working with the council since 2017, when a small tear in the leachate dam lining was reported. In December 2024, the council provided new data showing elevated levels of iron, potassium, bicarbonate alkalinity, calcium, sodium, chloride, and ammonia in surface water at one monitoring station. The EPA will meet with the council to discuss further monitoring and next steps.
