Santos Energy is seeking approval for a new waste treatment plant at its controversial pilot coal seam gas field in northern NSW without identifying how it will dispose of the briny and potentially toxic end product.
The Santos venture at Narrabri, which has already cost the company about $1.2 billion, was drawn into the state election campaign when Opposition Leader Luke Foley declared a Labor government would not allow the gas field's exploration licence to be converted to a production licence if it won office.
The issue of CSG may prove key in several electorates on Saturday, including in Barwon in which the Santos field sits, with several long-standing Nationals candidates facing big swings against them for supporting the industry.
Mr Foley's move drew sharp criticism from the mining industry, which said Labor's concerns about possible contamination of the Great Artesian Basin were exaggerated.
The company has submitted plans to the Office of Coal Seam Gas for its Leewood Project Phase 2 that will serve its Narrabri CSG field. The proposed plant will process an average of more than one million litres of wastewater a day from its handful of exploration wells in the Pilliga East State Forest.
Naomi Hogan, a campaigner for the Wilderness Society, said the latest plans show that between now and 2018, Santos would need to dispose of about 500 million litres of concentrated brine.
Plans for a gas field of as many as 850 wells would require much more waste to be treated, she said.
"We're seeing this pattern where it's clear they don't have a plan of what they are going to do with the waste," Ms Hogan said. "They have no idea, yet they want all the CSG approvals anyway."
Santos says the water being processed from the wells is only half as strong as sea water and, if it contains other minerals, such as uranium or radon, they were only in trace amounts.
"We estimate that once treated, more than two-thirds of the produced water could be reused for activities including irrigation, construction and firefighting," said Peter Mitchley, general Manager for ENSW, Santos.
However, the company was yet to determine how it would dispose of the final waste.
"We are working with industry experts to develop salt handling solutions which will be put in place when the project moves into the development phase," Mr Mitchley said. "Until these plans are finalised, the concentrated brine that we produce will be stored in one of our newly constructed state-of-the-art ponds at our Leewood facility."
Mr Mitchley said the salts will be disposed of commercially or in a registered landfill "if and when we get to a sanctioned development project".
High-tech and high cost?
Stuart Khan, an associate professor at the University of NSW's School of Civil & Environmental Engineering, said the type of plant being proposed by Santos is a "top shelf" facility, "capable of treating water to a quality suitable for any use".
However, the planned reverse osmosis water purification process would be both costly to build and operate, Professor Khan said.
"Reverse osmosis plants are rare in inland environments," he said. "The reason is that the residual salts are the major management problem. That problem still seems unresolved in this case."
The problem would magnify when the project ramps up to production. Based on an average of about 100-150 wells operating at one time, the gas field would likely produce about 20,000 tonnes of salt requiring disposal each year for a quarter of a century, Professor Khan said.
Past issues
Ms Hogan said tests on the produced water at the site indicate toxic chemicals or heavy metals could be expected in the waste, along with the salt. Santos' predecessor in charge of the project – Eastern Star Gas – was earlier fined by the Environment Protection Authority over ammonium levels in its discharges.
The EPA last year fined Santos $1500 when leaks from one of its treatment ponds triggered a jump in uranium levels in aquifers below.
"You'd think that if they'd been operating in Queensland for so long that they'd know what to do with the waste products, but they don't have a plan," Ms Hogan said.
A spokeswoman for the Division of Resources and Energy (DRE), overseeing the Office of Coal Seam Gas, said the department "is currently carefully reviewing Santos' application and [Review of Environmental Factors] and is undertaking a rigorous assessment of the application".
"All decisions and reasons for decisions will be made publicly available once this assessment is complete," she said.
The EPA said it is up to Santos "to ensure its activities and procedures are carried out in accordance" with strict conditions of its Environment Protection Licence".
"If the company does not abide by the licence conditions, the EPA can then take regulatory action," a spokeswoman for the EPA said.
The agency has been asked to review and comment on the Santos proposal, the spokeswoman said.
AGL investigations
Separately, both the EPA and the Division of Resources and Energy said their two investigations into the discovery of toxic BTEX chemicals at AGL's pilot CSG gas field are yet to be completed.
Both agencies suspended AGL's Gloucester operations in January after the chemicals were found at the site.
"The investigations regarding AGL are ongoing," the DRE spokeswoman said. "It is important that the investigations are not rushed and that all matters are carefully considered."
