Flushing out better environmental outcomes

12 December 2018

New technology and infrastructure built at the Northern Territory’s largest wastewater treatment plant is already achieving improved environmental outcomes.

After 18 months of construction and 65,000 work hours, the new Leanyer Sanderson Waste Stabilisation Ponds Inlet Works was officially opened today by Northern Territory Deputy Chief Minister the Honourable Nicole Manison.

Support of local industry has been a strong focus of the project with 90 per cent of the work being delivered locally by 15 Northern Territory contractors.

The facility is screening 15 million litres of wastewater daily from Royal Darwin Hospital, 50,000 houses, schools and businesses across Darwin’s northern suburbs and is expected to remove 45 tonnes of bathroom products and 50 tonnes of grit annually.

Power and Water Corporation Chief Executive Michael Thomson said the $16.2 million inlet works are parallel to the wastewater stabilisation ponds.

“As raw sewage passes through the inlet works it removes pollutants that should not be flushed down the toilet such as wipes, litter, sanitary products and grit,” Mr Thomson said.

“These pollutants do not easily break down in the ponds’ natural treatment process and are the major contributor to the development of surface scum and blockages in the treatment pond system.”

The inlet works also consolidate the most odorous components of the system at a central location where it can be better managed through extraction and biological treatment.

Since commissioning of the inlet works began late last month, initial operations had already resulted in a significant reduction in surface scum accumulating at the ponds.

“Environmental protection is important to us. The planning, management and design of this new facility is focussed on reducing impact on the natural environment,” Mr Thomson said.

“The great early results of this pre-treatment system show it is improving the overall sewage treatment process and the quality of wastewater discharged to Buffalo Creek while also reducing odour.”

At its maximum capacity, the inlet works will be able to receive and effectively screen 250 litres of wastewater per second.

“The capital project will deliver operational efficiencies including a reduction in the treatment plant maintenance budget,” Mr Thomson said.

“Previously, every week our employees were manually removing surface scum caused by the accumulation of unwanted bathroom products that ended up at the facility.”

A major sustainable benefit this project achieves is that by removing bathroom products and other rubbish from the process, the sludge that accumulates in the ponds, which would otherwise go to landfill, can in future be repurposed for composting, land rehabilitation and mining uses.

Mr Thomson said while the major infrastructure upgrade to the 46-year-old sewage treatment plant would play an important function in the treatment of Darwin’s wastewater, it was also important to remind all Territorians that they have a crucial role to play in sustainable wastewater management.

“Toilets aren’t a rubbish bin. What you flush down the loo impacts the environment,” he said.

“Only the three Ps, pee, poo and toilet paper should go in the toilet. Put wet wipes, nappies, ear buds and all other bathroom products in the bin.”

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