Environment

Santos coal seam gas waste-water pond leaked briefly during commissioning

One of Santos' four waste-water holding ponds near Narrabri leaked briefly during its commissioning phase but none of the water leached into the environment, the company said.

A leak in the seal in the first layer of the pond was detected in February last year during the construction phase and contractors quickly repaired the fault, said Peter Mitchley, Santos's manager of energy for NSW.

​"There was no loss of fluid from the pond," Mr Mitchley said. "It proves the detection system works, and the second and third layers prevented the water going anywhere."

Questions about the detection of water between the main linings of one of the four ponds – each capable of holding 150 million litres – were raised at a local consultation meeting last month in Narrabri by Tony Pickard, a local resident opposed to the CSG project in the Pilliga Forest.

Mr Pickard said he had been told by a local Santos operations manager during a tour of the site in November that the fluid was "rainwater" and not from the pond.

It is understood a small amount of rainwater had also been found between the primary and secondary layers during construction when the liner was incomplete and prior to produced water being stored in the pond.

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Santos said on Tuesday that the leak was found when the pond was about one-third full, and the waste water was then drained to allow the repairs to take place. The amount leaked was in the order of 2000 litres a day.

"Why the heck didn't they get back to me with the answer?" Mr Pickard said. "They all tell you they want to get to the information out there ... but you've got to put them in a corner to get it."

The NSW Environment Protection Authority said it carried out regular inspections at the Leewood ponds site and would continue to do so.

"We have no evidence of any leak from the water treatment ponds into the environment," a spokeswoman said. "The EPA is satisfied that the construction of the ponds at Leewood represent best practice. The construction includes double liners and a leak detection system."

"As long as the secondary liner is not breached and the leak detection system and sump collection system work as intended – which is part of our regular inspection regime - the EPA is confident that the environment will be protected," the spokeswoman said.

The EPA warned Santos in May last year that it had to improve the operations and transparency at the proposed $2 billion project after two incidents in 2013 and 2015.

The earlier incident involved the contamination of an aquifer – possibly the first of its kind in Australia – after a separate set of waste water ponds leaked and mobilised heavy metals including uranium.

Santos, meanwhile, has secured approval for its brine disposal management plan to handle the salts generated during its exploration phase. The plant can handle as much as 31.9 tonnes of salt per day.

The Division of Resources and Energy approved the plan in November after consulting the EPA, as part of the current Review of Environmental Factors.

Mr Pickard said the approval appears to contradict statements made by Santos to a community consultation meeting last March that a separate Review of Environmental Factors – a form of environmental impact statement – would be needed for the brine treatment works. 

The public had wanted to know more about what would be in the salts, where they would be stored and how they would be disposed, he said.

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