People for the Plains contested the ruling made by the NSW Land and Environment Court in August, but the appeal was dismissed.

The group unsuccessfully argued the Leewood coal seam gas water treatment plant was unlawful, because it had been allowed to proceed without an Environmental Impact Statement (EIS) or public consultation.

Petroleum exploration developments are not required to submit an EIS.

People for the Plains said the government should classify the Leewood water treatment plant as a “waste or resource management facility” and therefore as an independent project. 

People for the Plains spokesperson Sally Hunter said the state’s laws were not strong enough to protect the environment against coal seam gas.

“We’re very disappointed with this outcome,” Ms Hunter said.

“If the law says that a gas company can build a 500-million litre coal seam gas water treatment plant without doing an Environmental Impact Statement, then we’re afraid the law is not strong enough to protect our community, or the environment.

“This is a large-scale industrial facility in our local environment. Despite this legal outcome, we still believe the local community should have the right to have a say,” she said.

“The Leewood wastewater storage is connected to the much broader 850-well Narrabri Gas Project proposed by Santos for the Pilliga forest.”

Despite the loss, People for the Plains vowed to continue fighting the development.

“With the Environmental Impact Statement now on public exhibition, the community will be redoubling its efforts to protect the Narrabri region from dangerous coal seam gas,” Ms Hunter said.

A spokesperson for Santos welcomed the decision.

“This reverse osmosis plant is similar to those used across the world and will be used to treat salty ground water produced by Santos’ exploration and appraisal operations to a very high standard,” they said.

“All of the different government departments were satisfied with the sustainability and safety of the plant.”