Purification of produced water from coal seam natural gas wells using ion exchange and reverse osmosis

摘要

A method and apparatus are provided for treating produced water to lower the total dissolved solids of the water for safe discharge to the environment. The produced water is passed through a weak acid cation resin in H+ form to remove cations in the produced water and then preferably through a decarbonator to remove formed CO2 and to provide a first discharge stream. The cation loaded resin is then regenerated using a dilute acid, preferably diluted with produced water, to regenerate the resin to the H+ form. The resultant acid regenerated waste stream is discharged to a reject deep well. The acid regenerated resin is then rinsed, preferably with produced water, to remove residual salts to form a residual salt containing rinse stream. This salt stream is passed into a reverse osmosis unit to form a high salt containing reject stream which is discharged to a waste deep well and a low salt containing product discharge stream which may be safely discharged to the environment.