Madison, Wisconsin: Water Resources Center, University of Wisconsin–Madison
The project was undertaken to determine if Radium (Ra) coprecipitates with iron (Fe) and manganese (Mn) during in situ oxidation of groundwater and whether there are locations in Wisconsin where the coicidence of these elements in aquifers would make the process a viable treatement option. Concentration of Fe and Mn in public groundwater supplies are sufficiently high to be nuisances and warrant removal in many locations. However, in situ oxidation tratement is effective only in unconsolidated Quaternary deposits. Known occurrences of high Ra (>5 pci/liter) have been mapped, but are extremely spotty. The only area where high Fe and Mn coincides with known high levels of 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 from the bedrock aquifers, aerated, and injected in the glacial aquifer. Other areas of the state might have suitable conditions for in situ treatment, but Ra data are too sparse to tell.