The Division of Resources and Energy has given the oil and gas giant until June 5 to address “inaccuracies” in its proposal to build a desalination plant at its Leewood site or the “application will be refused”.

Santos proposes to treat the 500,000 litres of saline-rich water extracted daily from coal seams in the Pilliga to a standard suitable for use in irrigation, as well as for dust suppression, drilling, construction and firefighting.

But in assessing the application for the treatment plant, which would operate for a maximum of five years during the $2 billion Narrabri Gas Project’s appraisal period, several agencies have identified serious shortcomings.

The Department of Primary Industries (DPI) said it had “major concerns” about the project and feared it had a “high risk of having significant adverse impacts and potential loss of the agricultural capacity of the lands affected by the proposal”.

“The proposed soils on the irrigation site are highly unsuited to irrigation and pose a significant risk of failure for this proposal,” the DPI’s report said.

Chief among the NSW Environment Protection Authority’s concerns was Santos’s lack of a clear plan to deal with about 500 million litres of “highly concentrated brine” to be kept in Leewood’s storage ponds.

“The EPA understands that at a proposed rate of 0.5 megalitres of brine produced per day, the storage capacity available at Leewood would be exhausted after the third year of operation,” the report stated.

“In the absence of a detailed commitment for the lawful disposal of brine, the EPA has concluded that this issue presents a significant environmental risk and is unable to support this proposal in its current form.”

Other concerns raised in the government reports included inaccuracies in the irrigation project’s design and modelling and the lack of information about benzene, toluene, ethylbenzene and xylenes (BTEX) chemicals and heavy metals.

Anti-coal seam gas campaigners in Narrabri have seized upon the reports, which they say identified “shocking inadequacies” in the company’s planning, as proof the controversial 850-well project should not proceed. 

“That this application from Santos is its best effort under these high-stake conditions demonstrates that this industry is not, and can never be, safe or sustainable,” said People of the Plains president Sally Hunter.

“The gross inadequacies in Santos’s Leewood wastewater treatment proposal are further evidence that fundamental questions regarding the functioning of this industry remain unanswered.”

But Santos NSW general manager Peter Mitchley, who said the company would meet the June 5 deadline, stood by its proposal.

“The irrigation water will meet Australian and NSW irrigation standards and is, for all intents and purposes, potable drinking water,” he said.

“The irrigation activity will be carried out on 98 hectares of Santos-owned land. The proposed activity is clearly of very low environmental risk.

“We note the questions from the various agencies and third-party commentators. This is part of the usual government planning process to ensure all the views (are) collated for consideration before a final determination is made.”