NEWS RELEASE: Des Moines Water Works begins operation of Nitrate Removal Facility because of nutrient spikes in raw source water
For immediate release:
June 9, 2022
Contact: Jennifer Terry,
DES MOINES – While Des Moines Water Works’ finished drinking water continues to meet Safe Drinking Water standards, elevated nitrate concentration in raw source waters has caused the drinking water utility to start operation of its nitrate removal facility on Tuesday (June 7).
Des Moines Water Works utilizes various processes and strategies to manage source water challenges, including nitrate, to provide safe drinking water to 600,000 central Iowans. The spikes in nitrate concentration can be largely attributed to upstream land-use practices in which excess nutrients leave the soil and enter Iowa’s rivers, lakes and streams. The U.S. Environmental Protection Agency’s Safe Drinking Water Standard for nitrate is 10 milligrams per liter (mg/L). Nitrate levels in the rivers and the shallow alluvial groundwater Des Moines Water Works uses are above 9 mg/L. After deploying other strategies, the nitrate removal facility is now needed.
“This is a delicate time – we are at that point where we are monitoring the nitrate level closely, and it is an hour-by-hour decision on which sources of water to use and how to blend the water source in order to reduce nitrate levels,” said Ted Corrigan, CEO/General Manager of Des Moines Water Works, Iowa’s largest drinking water utility, which provides drinking water to one-fifth of the state’s population.
DMWW’s nitrate removal facility initially started operating in March 1992. The nitrate removal facility was last used in 2017. Drier conditions the past few years have limited the flow of nutrients into Iowa’s streams, lakes and rivers, which has led to lower levels of nitrate in raw source water. It can cost up to $10,000 a day to operate the nitrate removal facility.
The nitrate removal facility captures the nitrate ions in the water, similar to how a home water softener removes calcium and magnesium ions. Nitrate removal waste is diverted to Des Moines Metropolitan Wastewater Reclamation Authority (WRA) where is treated through controlled biological environments within the WRA facility. In addition, a beneficial reuse product called biosolids is produced for land application on agricultural fields in the Des Moines River Watershed (Polk and Jasper Counties).
“While we are able to do the work downstream to remove nitrate to comply with drinking water standards, there is a financial cost to our ratepayers to do so,” Corrigan said. “The real solution is upstream. The landowners there are the solution-holders. They have the ability to make changes to the way they use their land in order to keep nutrients on the land and in the soil, which is where they belong.”