Josie Taylor | June 14, 2022
Des Moines Water Works has had to begin operating its nitrate-removal system for the first time in five years after finding elevated nitrate concentrations in their water. The level of nitrate in the utility’s water supply fluctuates, and is attributable to excess nutrients on upstream farmland running off the land and entering Iowa’s rivers, lakes and streams.
The U.S. Environmental Protection Agency’s Safe Drinking Water Standard for nitrate is 10 milligrams per liter, and the nitrate levels in the rivers and groundwater used by the Des Moines Water Works have recently peaked at more than nine milligrams per liter.
The Water Works’ nitrate removal facility initially began operating in March 1992, but was last used in 2017. Drier conditions the past few years have limited the flow of nutrients into Iowa’s waterways, which has led to lower levels of nitrate in raw source water.
Use of the nitrate-removal system is significant because of what it means in terms of water quality and because of the expense. It can cost up to $10,000 a day to operate the nitrate-removal system, the Des Moines Water Works says.
The Des Moines Water Works is Iowa’s largest drinking water utility and provides drinking water to one-fifth of the state’s population.