Sioux Center tours wastewater plant

Bolton & Menk principal engineer Kris Swanson (white hard-hat) showed city officials the basins where wastewater will be held and processed at the site of the new wastewater treatment plant.

SIOUX CENTER—City leaders got a tour Thursday, July 31, of the ongoing construction at the new wastewater treatment plant in the southeast part of town, at the intersection of 20th Street Southeast and 13th Avenue Southeast.

The tour was led by Bolton & Menk principal engineer Kris Swanson. He guided members of the city council and staff, generally following the path and steps taken to process incoming wastewater.

Swanson summarized the work of the plant as creating a massive artificial stomach to “digest” the wastewater they receive.

As Swanson explained on the tour, wastewater arriving at the new plant will first be pumped through a screening process. It will then flow to anoxic basins to be processed without oxygen for nitrogen and phosphorus removal.

Next it will flow into the aeration basins, where oxygen is provided for microorganisms to break down organic compounds. Water then flows to the final clarifiers where solids settle out, then it is sent through ultraviolet (UV) treatment to neutralize any pathogens such as E. coli before the treated water is released.

The wastewater treatment plant project is estimated to cost $25 million when it is completed, according to city manager Scott Wynja. Construction of the new plant began in the fall of 2018.

“All the buildings are up, and now they’re doing finish work inside — electrical, HVAC, plumbing. They’re also doing outside site piping,” said Sioux Center Wastewater Treatment Department Head Zeke Ellis. “Construction is probably more than 60 percent done.”

The new plant was necessary for a couple of reasons, according to Wynja. The first is regulatory.

The DNR had new standards they were going to require the existing plant to meet, but to do so would require extensive upgrades and changes.

The new plant is being built adjacent to Sioux Center’s existing wastewater plant, an aging facility that will not meet new, more stringent DNR standards.

“We have several new processes designed into the new plant which will allow us to meet those standards and release even cleaner water. This plant is designed to serve Sioux Center for a long time,” Ellis said.

“The plant is 40 years old, and with some of the growth of the community, now is probably the time if we’re going to do all these upgrades to consider building a completely new wastewater treatment facility,” Wynja said.

Most of the existing plant is going to be replaced by the new construction, except for a few small segments.

The new plant won’t be fully operational at once. Rather, it will be brought to 100 percent operation in phases. Operations will begin in October, with several phases to be followed before the plant runs at full operation sometime next spring or early summer, according to Wynja.

“You got to work through each phase of it,” Wynja said. “Wastewater is a bit different from even water treatment plant where you flip the switch and you’re treating water. Here, you got to start developing the whole treatment process. It’s a little more detailed in that at the wastewater facility.”

There is room enough at the site so that the plant could be expanded in the future if it is necessary.

“Hopefully, that’d be a ways down the road,” Wynja said.