MidCoast Council in NSW is accelerating development of a temporary desalination plant at the Nabiac Aquifer water supply plant to provide emergency water to its community, which is at Level 4 water restrictions. The plant could be operating in two months.

“We’ve made the decision to ensure water security for the Manning - Great Lakes scheme, which supplies 90 per cent of our water users,” said Council’s Director of Infrastructure and Engineering Services, Rob Scott on January 6.

“We are currently seeking approvals from the NSW Government to proceed with a desalination plant, accessing the $1 million grant to kick start the project.”

“This amount of construction work would normally have taken 12 months or more to deliver. With the planning work we have already done and construction commencing onsite this week, we’re on track to commission the temporary desalination plant by March 2020,” said Scott.

The proposal involves hiring a mobile desalination plant already mounted in multiple shipping containers. The overall treatment system is a two-stage filtration process, with the second stage being reverse osmosis. This is the step that desalinates the water.

Extensive support infrastructure needs to be built before the shipping containers arrive onsite. This includes inlet and outlet pipelines to the river, vehicular access, storage tanks and the footings for the containers, as well as connections between all the container units.

Saltwater will be extracted from the Wallamba River, treated at the temporary desalination plant and provided to supplement the existing Manning and Great Lakes water supply. The existing Nabiac Water Scheme has infrastructure that can transfer water concurrently north to the Taree area and to Forster Tuncurry and surrounds.

Council will obtain the relevant licences to permit water extraction and discharge the concentrated saltwater through a reverse osmosis process.

A review of environmental factors has been produced, outlining measures to ensure minimal adverse impact from the plant’s temporary operations. The plan includes discharging only for a short period of time and monitoring water quality throughout the operation of the plant.

It’s estimated that a supply of around 17.5 megalitres per day would provide emergency water for all users of the Manning - Great Lakes supply, with the desalination plant providing up to 5.5 megalitres of water per day, added to an expected production of up to 12 megalitres from the Nabiac Aquifer.

Currently the average usage is hovering just above 20 megalitres per day, with the current water restrictions target being 17.

“If we can reduce our water usage to 17 megalitres per day, and with the responses we’ve outlined above, we will have enough water to get by during this prolonged drought,” said Scott.

Council’s modelling shows this reduction can be achieved with no outdoor water use.