STAGE one of AGL’s Gloucester Gas Project will produce up to five tonnes of salt per day during peak production.
AGL’s manager of hydrogeology John Ross said the salt would be the only by-product from the desalination plant proposed by the company to deal with the produced water from its coal seam gas operations.
Spruiking AGL’s extracted water management strategy for stage one of the project last week, Mr Ross said the company would install four container-sized portable water treatment facilities on property it owns between Stratford and Craven.
The plants will have sufficient capacity to deal with up to two megalitres of produced water a day.
AGL expects to recover about 98 per cent of the water used in its operations.
Mr Ross said the desalinated water would be stored for reuse or made available for other purposes, including irrigation or aquaculture.
He said there was the possibility that some water could be made available to local landholders or other industries, but emphasised the company would not have large quantities of water for long periods of time.
“We estimate the maximum amount of produced water that we will need to put through the reverse osmosis process to be about 1.1 megalitres per day,” he said.
“That’s with all 110 wells installed and over an 18 month period around year two of the project.”
He said there was a possibility some desalinated water may be released back into the Avon River during year two of production, but said for the majority of the project no water would enter the catchment.
“Beyond year three we’ve calculated we have enough storage to contain the water,” he said.
“The maximum amount of water that we would release is about 0.7 megalitres per day in year two and that would only be when the river is in high flow.
“It would probably be less than 0.1 per cent of one per cent of the amount of water in the river at that point.”
Mr Ross admitted the EPA would most likely require AGL to mimic the quality of the water already in the Avon River if it did need to release water back into the catchment.
He said the desalinated water would have a salt content of no more than 300 parts per million per litre.
The amount of salt by-product produced from the desalination process would peak in year two with an expected 1900 tonnes of salt per annum, or five tonnes a day.
The average for the whole project was 400 tonnes per annum, Mr Ross said.
The salt would be bagged and trucked to landfill in the Hunter or Sydney area.
“They’re not large quantities of salt. We think they’re manageable,” Mr Ross said.
“And if we can find local uses for the salt even better.”
Mr Ross stressed the extracted water management strategy was merely a concept in its current form and significant analysis and feedback would be required before the plan could be approved.