Background

Shellharbour City Council needed to upgrade its Dunmore Recycling and Waste Disposal Depot to combat rising disposal costs.

Landfill on the site generated wastewater called leachate, which had previously been managed via 200,000L storage tanks and trucking the wastewater offsite for treatment and disposal via a third-party provider. This was a high cost exercise as Council were trucking out tens of thousands of litres per day.

A commissioned report into the disposal options for the site showed that onsite pre-treatment and connection to sewer would be a more economical and sustainable option for Council.

Aerofloat’s industrial wastewater experience, and its critical thinking led to it being awarded the contract, and successfully delivered the project.

The Aerofloat Solution

Aerofloat provided an effective leachate treatment solution at Dunmore Recycling and Waste Disposal Depot for Shellharbour City Council.

Aerofloat installed three large concrete tanks, comprising an anoxic reactor, nitrifying reactor and a sequence batch reactor (SBR). To complete the build, activated sludge recycle pumps were installed between the reactors to ensure consistent concentrations in the reactors. Chemicals optimised the process performance, including Sucrose as a carbon source and Caustic Soda for pH correction. Excess biosolids were pumped to a thickening tank for disposal.

Understanding the nitrification and denitrification process was extremely important in treating the leachate. The high ammonia levels were effectively treated to ensure a high quality effluent prior to discharge to sewer. Aerofloat’s leachate treatment system was designed to achieve an effluent quality suitable for discharge to Sydney Water’s sewer, with a design capacity of around 65m3/day and an average ammonia concentration of 1250mg/L.

“From the beginning, Aerofloat critically analysed the process design by leveraging its in-house knowledge and experience in treating industrial wastewaters. Once the civil works and large tanks were constructed, Aerofloat made the build seem simple, despite being a very complex project.”

James Brumpton, Shellharbour City Council Project Manager.

The plant was contained within a concrete bund and included a purpose-built mezzanine floor to ensure all the critical mechanical and electrical systems were safely positioned. The system was also installed with an automated PLC system with a HMI interface and offered remote-monitoring capabilities.

The Results

Aerofloat was able to seed the plant with biomass prior to practical completion, thereby enabling the biosolids to acclimatise. This fast-tracked the plant’s ability to treat and discharge effluent to sewer.

Aerofloat provided a cost-effective and workable leachate treatment solution at Dunmore Recycling and Waste Disposal Depot. The plant achieved results beyond the initial scope, managing peak loads of 2000mg/L of ammonia and still achieved strict Sydney water ammonia and nitrogen discharge limits.

Shellharbour City Council’s Project Manager, James Brumpton, said that Aerofloat exceeded expectations – allowing Council to make strong financial savings earlier than expected.

“Aerofloat exceeded expectations on this project and delivered ahead of schedule. They brought forward hot commissioning of the plant so we could start treating leachate sooner, which which reduced our operating costs earlier than expected,” said Brumpton.

Aerofloat’s execution of the project and its ability to help Council to continue to save on costs ensured terrific feedback from Shellharbour City Council.

“As part of the process of assessing contractors at the completion of each project Aerofloat certainly scored highly – often exceeding expectations on those criteria,” said Brumpton.

Aerofloat’s engineers continued to support the relationship well beyond the capital project by maintaining the plant and offering ongoing chemical supply.