Queensland and Coal-Seam Gas Water

Over the last two years, Queensland, Australia's water situation seems to have been growing from strength to strength. Abundant rainfalls have helped to bring reservoir levels up from a low of 16% in 2007 to more than 90%. And now, there is the strong possibility of a new water source: coal-seam gas water.

Coal-seam gas, also known as coalbed methane, is natural gas that is found in the cracks in coal. Water is a by-product of coal-seam gas extraction, and in Queensland, up to 420megalitres per day (approx 90mgd) of brackish water is expected to be produced if proposed coal-seam gas operations go ahead. The Queensland government has reportedly legislated against simple evaporation of this water, so companies have been looking into various methods of treating it.

One option has been to treat the water to potable standards by reverse osmosis. This could contribute close to 15% of Queensland's daily water needs. However, there have been strong protests from farmers concerned that the extraction of water could draw down the water table and pollute the underground aquifers that they currently get their water from. With the 2008 demise of water reuse plans due to strong public opposition still fresh on people's minds, one cannot help but wonder how this will pan out.

Perhaps in anticipation of the public outcry, Santos, one of the coal-seam gas companies, is going in a slightly different direction. They are spending A$50mil to plant 2 million Chinchilla hardwood gum trees on a piece of land close to the gas site. These trees are particularly tolerant to the brackish water, and could later be harvested or used for carbon sequestration. More importantly, Santos estimates that this will cost about half that of an equivalent reverse osmosis plant.


Main Source:
Gas Boom's Watery Legacy