Treatment Process

Fleur Drive Treatment Process (Click to enlarge.)  Maffitt Treatment Process (Click to enlarge.)

Des Moines Water Works' Fleur Drive facility is a 100 Million Gallons per Day (MGD) surface water treatment facility that pumps a daily average of 43 MGD. It draws water from three sources: the Raccoon River, Des Moines River, and an infiltration gallery. The infiltration gallery is a large horizontal well that lies in sand and gravel sediment adjacent to the Raccoon River. It yields approximately 15 MGD of clean, naturally filtered river and ground water. The remaining demand is supplied from either the Raccoon or Des Moines River. River selection is based primarily on source water quality and the ability to treat substances in the water. Treatment strategy and design must accommodate rapid changes in river quality and water demand. To best understand the treatment process, follow the illustration as you read how the water is treated.

Powdered activated carbon is fed into the river water for removal of man-made and natural organic chemicals. The water is then pre treated to remove dirt and debris and combined with water from the infiltration gallery system. The combined water then flows into softening basins. The pH of the water is adjusted before the final filtering process. The water is passed through layers of sand and various sizes of gravel to remove any remaining particles. Des Moines Water Works activates its nitrate removal facility to remove this contaminant from your water during periods of possible nitrate level increases. After this final phase, fluoride is added to aid in the prevention of tooth decay and chlorine is added as a disinfectant to kill bacteria. The clean water is stored in a clear well until pumped into the pipes of the distribution system.

Des Moines Water Works laboratory and water production staff collect and test water samples from throughout the system several times a day. These tests ensure that the proper chemical levels are maintained and that the water remains free of unwanted contaminants.