In-situ Removal of Fe, Mn, and Ra from groundwater

This project was undertaken to determine if radium coprecipitates with iron and manganese during in situ oxidation of ground water and whether there are locations in Wisconsin where the coincidence of these 3 elements in aquifers would make the process a viable treatment option.  Concentration of Fe and Mn in public ground-water supplies are high enough to be nuisances and warrant removal in many locations/  However, in situ oxidation treatment will be effective only in the unconsolidated Quaternary deposits.  Known occurrences of high Ra (>5pci/l) have been mapped, but are extremely spotty.  The only area high Fe and Mn coincides with known high Ra is a region between.  Marathon and Adams Counties, although the Fe and Mn are highest in the glacial aquifer and the Ra is in the crystalline and sandstone aquifers.  In situ oxidation could be effective in this region and is already in use at Rib Mountain.  For the overall area defined, Ra-rich water would need to be drawn form the bedrock aquifers, aerated and injected in the glacial aquifer.  Other areas of the state might have a suitable condition for in situ treatment, but the Ra data are too sparse to tell.

Determination of the effectiveness of radium coprecipitation was largely unsuccessful because of extremely low Ra recovery levels in the lab experiments. Discussion in this report will emphasize the development of radiochemical processes for the determination of low-level radium activity in water samples along with the tracer (²²⁵Ra).  The associated problems or difficulties and the results of the recovery of radium from the sample will also be discussed.