For over 20 years the Des Moines Water Works has filtered nitrates out of the river water it uses to supply drinking water for the public. Then it discharges the brine wastewater containing the nitrates back into the Raccoon River. Last week officials of the utility announced they plan to end the controversial wastewater dumping by late summer.

Related: Iowa Supreme Court may decide fate of Water Works lawsuit

WATER WORKS: For years the Des Moines utility has filtered out nitrates from river water it uses for the public water supply, then dumps the wastewater containing the nitrates back into the river. The dumping will stop by late summer.

The practice of discharging the potentially harmful chemicals into the river has stirred controversy as the Water Works is pursuing its federal lawsuit against upstream drainage districts. In its lawsuit, the utility says tile drainage systems (and indirectly farmers) are responsible for channeling high concentrations of nitrates from farm fields into the state’s streams and rivers. Farmers and others who oppose the lawsuit say if Water Works officials are worried about nitrates, why do they dump them back into the river?

Disposing wastewater downstream is no longer an option
The Water Works has been filtering out nitrates and disposing of the wastewater this way for at least 20 years under a permit approved by the Iowa Department of Natural Resources. But the latest state standards and monitoring show excessive levels of previously unregulated pollutants are in the discharge, in addition to nitrates.

The Iowa DNR recently identified excessive concentrations of sulfate and chloride in the liquid discharge from the Water Works nitrate filtering process. These pollutants pose a greater threat to aquatic life than the nitrate levels, according to the DNR. The compounds at high enough levels would be toxic to fish, bugs and other life in the stream, says Adam Schnieders, water quality coordinator with Iowa DNR.

The DNR last May renewed a five-year permit for the Water Works’ discharge pipe in the Raccoon River, under the condition that the Water Works reaches compliance as soon as possible on the sulfate and chloride levels. DNR set a deadline of April 2020. Thus, dumping the brine waste back in the river where it flows on downstream is no longer a cost-effective option.

Criticized for putting nitrates back into river
Farmers, farm organizations and other opponents of the Water Works lawsuit have criticized the utility for targeting upstream nitrate sources while it returns nitrates into the river. Water Works CEO Bill Stowe counters that argument by pointing out that the utility’s permit gave it permission. He also emphasizes that the Water Works isn’t putting additional nitrates in the river, just the nitrates it had to initially remove to comply with federal guidelines to make the drinking water safe.

Under the new disposal plan, the Water Works nitrate removal facility will be connected with the sewer system on the southwest side of Des Moines which will provide treatment of the brine waste. The connection is being designed now and construction is expected to start in late spring. Stowe says it should be operational by late summer.

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Discharge water will be sent to sewage treatment plant
The $1.3 million project will create an underground pipeline running under the Raccoon River, to the sewer treatment facility. The Water Works will pay a surcharge for the Des Moines Waste Water Reclamation Authority to treat the discharge water coming from the Water Works nitrate filtering facility.

Related: Des Moines Water Works sets nitrate removal record in 2015

The federal government has limits on the acceptable amount of nitrates in drinking water, and says excessive levels can be harmful to infants. “When nitrate levels exceed those limits in our source water, we filter them out,” explains Stowe. A chemical ion-exchange process removes the excess nitrates, creating the brine waste the utility puts back into the river.

Officials are convinced this is best route to take
The Des Moines regional sewage treatment plant will remove some but not all of the nitrates in the brine solution the Water Works will send to it.

Royce Hammitt, operations manager for the Des Moines Metro Wastewater Reclamation Facility, says bacteria will break down about 40% of the nitrates into a gas that will be released into the atmosphere or mixed with bio-solids from the sewage treatment plant and applied to farm fields. About 60% of the nitrates will end up in the Des Moines River. The sulfate and chloride will have a similar outcome. However, the advantage is the toxicity of the discharge coming from the sewage treatment process will be neutralized as the compounds are diluted with large quantities of water.

Why not apply the Water Works discharge to farmland?
Stowe says the Water Works studied other disposal options, including application of the nitrate discharge water to farmland, before deciding to connect the Water Works discharge with the sewer system. Sending the discharge water to the city’s sanitary sewer system is the least-costly alternative.

The larger issue in all of this, Stowe says, is the continued concern about high nitrate concentrations in both the Des Moines River and the Raccoon River source water. And the outdated nitrate removal facility at the Des Moines Water Works.

Water Works board approves plan to repair and upgrade
In late February, the board of trustees who oversee the Des Moines Water Works approved a five-year capital improvement plan that includes $241 million in Water Works system maintenance and expansion. About $70 million of that amount, plus $10 million in year six, is designated for upgrading the Water Works nitrate removal system.

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Stowe and his staff previously estimated the cost of building a new nitrate removal facility equipped with the latest technology would cost up to $176 million. A new engineering study shows the Water Works likely will not have to build a

Related: Iowa Supreme Court may decide fate of Water Works lawsuit

Stowe explains, “Our consultants have recommended several strategies that don’t involve completely replacing our current nitrate removal facility, but rather improving it. If we can get by with repairing and upgrading, we view that as a better alternative than building new. It is essential that we improve and upgrade our current facility and technology so we can continue to deliver safe, quality drinking water to our 500,000-plus customers in the Des Moines metro area and central Iowa.”

IPCW once again asks Water Works to drop lawsuitIn response to the Water Works announcement, the Iowa Partnership for Clean Water (IPCW) issued a press release. IPCW once again strongly urges the utility to pursue alternatives “to its costly and divisive lawsuit.”

IPCW notes the Water Works is now considering a five-year improvement plan, which totals $241 million. And the Water Works says $70 million of this is for nitrate removal measures. But a Black & Veatch engineering study available on the Water Works website says replacement cost of the Water Works nitrate removal facility is about $9.2 million. Both figures are notably lower than the original $180 million estimated by the utility when it announced the lawsuit a year ago.

Des Moines Water Works also has changed its stated reasons for pursuing a lawsuit several times since it was filed in 2015, says IPCW. On different occasions, Water Works leaders have attributed the lawsuit to a sound business decision, a commitment to the environment and water quality, protection for Des Moines Water Works ratepayers, and more. The Water Works 10% rate hike, which will take effect later this spring, was originally attributed to decreased consumption and general operations and maintenance costs, not new nitrate-removal equipment, although the two are highly intertwined in recent media coverage.

Water Works asked to support Nutrient Reduction StrategyIPCW applauds DMWW’s recent action that will decrease by half the amount of nitrates the utility puts back into the river after treatment: “This type of effort is a step in the right direction. If the ultimate goal of the lawsuit is to truly increase water quality and ensure a safe drinking water supply, DMWW should acknowledge the progress being made and support efforts to enhance the science-based Nutrient Reduction Strategy.”

“Leaders at the Water Works have struggled to explain a clear vision for infrastructure improvements that best serve the public,” says Des Moines City Councilwoman and IPCW board member Christine Hensley. “Instead, they pursue costly litigation that has created a divide among rural and urban communities, where there should be collaboration to address water quality issues. I’m very interested in the prospect of a regional water treatment facility that would better represent the interest of all DMWW customers and bring balance to the decision-making process for infrastructure updates and policy initiatives.”

Lawsuit seen as stifling progress on water quality“I’ve said it before: Bill Stowe needs to get his story straight,” says Plymouth County Supervisor and IPCW board member Don Kass, a farmer. “I understand that infrastructure needs are costly and are crucial to maintaining safe drinking water. That is a core initiative of any public water utility and should be taken seriously.”

Kass adds, “Unfortunately, infrastructure enhancements at Des Moines Water Works are long overdue. However, addressing existing infrastructure needs under the guise of water quality and nutrient reduction is simply misleading to the ratepayers and the public at large. Iowa farmers are making steady progress on nutrient reduction and understand the importance of conservation, but progress is being stifled by this looming litigation.”

About Iowa Partnership for Clean Water: IPCW is a 501c4 organization dedicated to broadening the understanding of agriculture, as it pertains to clean water and conservation initiatives within Iowa, says Kass. “IPCW brings together active voices within Iowa to promote the environmentally responsible practices that Iowa farmers employ to ensure the health and safety of all Iowa citizens.”