Iowa City Treats Radium Through Hydrous Manganese Oxide
Farley, Iowa was in need of a new water plant for the treatment of multiple wells containing iron and radium. When considering technology options, the city chose a Hydrous Manganese Oxide (HMO) technology over other available treatment options due to a number of cost-saving opportunities. One of the key benefits included reduced operating expenses due to the elimination of brine waste. Due to their extensive HMO expertise, Tonka Water, a U.S. Water Brand was selected to assist Farley with designing a system that best aligned with the needs of the community. Over a span of several years, two new treatment plants were commissioned, the first plant in 2017 and a second plant in 2019.
Both treatment systems feature Tonka Water, a U.S. Water Brand’s OptaCell™ Plus pressure filter. Each system utilizes horizontal pressure filters with an isolated cell design, containing the Simul-Wash™ backwash system. These features were selected for additional cost savings and increased operational efficiency. The Simul-Wash backwash system enhances filter cleaning and significantly reduces backwash waste, while the isolated cell design provides operational flexibility, by allowing cells to remain in service while other cells are offline for maintenance. Both plants include fully integrated plant controls, providing full system responsibility.
The treatment process consists of a chemical addition, including pre-formed HMO followed by pressure filtration using Tonka Water’s non-accumulative IMAR™ media. During the chemical addition, radium absorbs onto the HMO particles. Water then passes through an OptaCell pressure filtration system, removing sulfide particles and the HMO particles. The pre-formed HMO process is operator friendly, with uniform mixing and proper feeding of the pre-mixed HMO slurry solution. The TonkaBlend™ HMO delivery system supports the standardization of this process, allowing the operator to easily make a consistent concentration of stabilized HMO solution and feed the slurry solution while minimizing chemical handling.
The HMO treatment process has been highly effective for both plants, with both facilities meeting current EPA primary standards for radium and secondary standards for iron. Tonka Water, a U.S. Water Brand is proud to have assisted the community in meeting their drinking water goals.