||In 2003, the town of Greenville, Wisconsin was selected for the Round 2 U.S. Environmental Protection Agency (EPA) Arsenic Demonstration Program and a Kinetico Macrolite pressure filtration system was selected for its ability to remove arsenic. Well reconstruction prior to the planned arsenic study, however, resulted in changes in water quality that resulted in a decrease in arsenic to below the 10-ig/L maximum contaminant level (MCL) and an increase in radium to above the combined MCL of 5 pCi/L (at around 9 pCi/L). With the changes in water quality (high radium), the treatment process was modified to include the addition of hydrous manganese oxide (HMO) for radium removal. Between August 3, 2007 and April 19, 2010, system performance was evaluated in two phases. The first study conducted between August 3, 2007, and January 14, 2008, collected system operational, performance, and cost data on arsenic removal. Operational data included system pressures, flowrates, filter run lengths, and filter backwashing. Operation and maintenance (O&M) cost was tracked and analyzed per 1,000 gal of water treated. A special study that focused entirely on the systems ability to remove radium followed a year later between May 29, 2009, and April 19, 2010.