Jeff Bodenhofer

Maquoketa is extending trails, improving downtown facades, and preparing to reconstruct Platt Street.

But on the horizon is a less glamorous project no one will see but everyone will have a part in.

It’s a yet-to-be-determined solution to a Midwest problem. And it comes with an uncertain price tag of up to $2.5 million, according to unofficial estimates by Alliance Water Resources Manager Jeff Bodenhofer and City Manager Gerald Smith.

The problem is elevated levels of nitrogen, phosphorus and other nutrients being discharged into groundwater and killing fish and aquatic organisms in the Gulf of Mexico. 

As a result, the Environmental Protection Agency is enforcing stricter standards for nutrient removal in wastewater discharged from cities, including Maquoketa.

The nitrogen and phosphorus being discharged by Alliance is a bit more than those standards allow, and the city must correct the issue. The source of the issue has yet to be determined, but a solution could cost up to $2.5 million, Smith said.

However, the health of Maquoketa residents is not being affected, Bodenhofer said.

“We’re elevated, and we have to come into compliance,” Bodenhofer explained. “But it’s not like, ‘Oh, boy, we’re pouring harmful chemicals into the river.’

“It’s not affecting our drinking water,” he emphasized. “Our aquifer (water source) is more than 3,000 feet down under bedrock. It’s protected.”

The eutrophication problem

The problem is eutrophication. In this case, nutrients — typically nitrogen and phosphorus — flow from various Midwestern water sources into the Mississippi River. That excessive amount of nutrients eventually collects in the Gulf of Mexico and contributes to what scientists call the “hypoxic” or “dead” zone. The nutrients act as fertilizer, causing bacteria to grow, depleting the oxygen supply in the water and thereby killing fish and other aquatic organisms. 

The EPA released a 2015 report that detailed the “hypoxic zone” and set standards to try to mitigate, if not reverse, the damage that was already done in the Gulf region.

“It’s a cumulative effect,” Bodenhofer said. He explained that a wastewater treatment plant such as Maquoketa might exceed limits by a fractional amount. However, if everyone exceeds those limits, it becomes a problem. As a result, Iowa devised its own Nutrient Reduction Strategy plan, requiring wastewater treatment plants to reduce nitrogen discharge by 66 percent and phosphorus discharge by 75 percent.

Bodenhofer explained that all wastewater facilities that discharge more than 1 million gallons of treated wastewater per day had to complete a study testing the nitrogen and phosphorus levels flowing into and out of their treatment plants, including Maquoketa’s plant. Maquoketa discharges about 650,000 gallons of treated wastewater per day but has the capacity to discharge about 1.4 million gallons, he said.

Instead of paying an outside company to complete the testing, Alliance offered to do it for free, thereby saving the city at least $45,000 for tests Alliance was already doing, Bodenhofer said.

The study had to be submitted to the Iowa Department of Natural Resources by March 1, 2017, and include a date by which necessary changes would be made.

That date is Dec. 31, 2023.

The next steps

The city’s next step, according to Bodenhofer, is to hire an engineer to examine the test results, determine the source of the elevated numbers, and devise a solution to remedy it.

Because the exact cause is still unknown, so is the solution and the cost to fix it.

“It could be anything from a chemical addition in the treatment process to building an addition to the plant or changing our sludge process,” Bodenhofer explained.

Adding a chemical would be less expensive, while building an addition would cost more, he said.

Possible “vague” estimates were $1.2 million from a study done before 2017, Bodenhofer said. Smith advised Maquoketa City Council that the solution could cost up to $2.5 million.