Coal Seam Gas Water Treatment and Reuse Options

Coal seam gas is a major resource currently developing in the Surat Basin, Queensland, Australia. The major by-product of this process is brackish water that requires treatment and disposal – or reuse.All of the disposal and reuse options for CSG water require treatment to near potable water standard, or higher. The use of reverse osmosis at high recoveries has been found to be most cost effective. The resulting water can be used for pasture or crop irrigation, and coal washing. Disposal of desalinated water to a waterway is generally not accepted on environmental grounds.Across the Surat Basin, the water treatment process produces a brine stream, which amounts to over 1,000t/d of dry salt. As the Surat basin is over 300km from the Pacific Ocean this poses a major challenge. Options range from ocean outfall, secure landfill through to a commercialisation project in which the brine is refined to merchant grade products.