Groundwater restoration in the depleted wellfields....

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Phase 1 groundwater restoration of a depleted uranium in-situ leaching wellfield begins by pumping water out of the wellfield and through ion exchange columns . Barium chloride (BaCl2) and ammonium sulfate (NH4)2SO4 are added to precipitate the radium. The radium is precipitated as a co-precipitate with barium sulfate. After removal of the radium, the now clean wastewater is sprayed on a field in a process called land application. This process removes large quantities of water from the uranium depleted aquifer creating a cone of depression which draws in clean water from outside of the mine area. This is called groundwater sweep.
This flowsheet depicts Phase 2 of the groundwater restoration process. Water is pumped out of the wellfield through an ion exchange column to recover any remaining uranium. The water is then pumped through a reverse osmosis unit and injected back into the aquifer via injection wells to restore groundwater quality. Reject water from the reverse osmosis unit is treated with barium chloride to remove radium, mixed with fresh water, and sprayed onto a field. Spraying treated waste water onto a field is called land application.
Irrigation area Irrigation area used to dispose of waste water pumped from mined out wellfields. This aerial view to the right is of an irrigation (land application) area where treated water from wellfield restoration is applied to the land to grow a crop. In this manner, treated wastewater can be removed from the wellfield and used. The wellfield restoration process is described in the Phase 1 and Phase 2 restoration flowsheets. These drawings and photograph are courtesy of Power Resources, Inc.