Despite its scientifically proven low-carbon credentials, is coal seam gas extraction far from environmentally friendly due to its tendency to cause groundwater contamination?
By: Ringo Bones
The energy firm Santos in New South Wales, Australia was picketed back in January 28, 2016 by local farmers due to its coal seam gas extraction schemes contaminating the local farmland’s groundwater source, but the energy firm’s “environmental impact” was already a concern almost two years ago. Back in March 24, 2014, leaks of water containing high levels of radioactive uranium from coal seam gas wastewater pond operated by energy firm Santos in New South Wales put the spotlight yet again on an industry already wracked by controversy. Most concerns over coal seam gas have to date focused on “fracking” – fracturing deep rock strata to get gas in coal seams – but as the incident shows, waste produced by coal seam gas wells and brought to the surface is another major environmental issue.
According to the New South Wales Environmental Protection Authority, the March 2014 incident resulted in the contamination of the groundwater aquifer downstream of the leak that tested 20 times the acceptable levels of uranium for drinking water. This is concerning given the long timescales and effort involved in groundwater clean-up and the fact that the region affected is an area of recharge for the Great Artesian Basin.
The type of wastewater that resulted in groundwater contamination in this incident – called “produced” or “co-produced” water – is generated in large quantities by all coal seam gas wells and it is usually of poor quality, containing potentially harmful levels of salts, radionuclides, metals and other contaminants. It appears that in this case such water was inappropriately stored in a leaky dam, allowing it to infiltrate and migrate into the underlying aquifer.
The only viable way to rectify this is to use reverse osmosis to remove the contaminants and release the treated water into local streams but the method can be potentially cost prohibitive in some situations. Some contaminants – such as boron – are harder to remove and are retained in the treated coal seam gas extraction produced water. In some cases, methane can also remain in the water after it leaves the treatment plant, adding concerns of “fugitive emissions” given that methane is 20 times more potent than carbon dioxide as a greenhouse gas. And this methane in the water has resulted in scores of sensational videos uploaded to You Tube where homeowners’ tap water catching fire after a lit match is brought close to a turned on faucet highlighting the environmental concerns of fracking.