Construction going smoothly for new wastewater plant

Editor | July 28, 2020 2:16 PM

Progress on the City of Whitefish’s new wastewater treatment plant is humming along.

Construction of the new plant began this winter and the project is currently on schedule. The total project cost, including engineering, design and contingency, is $24.8 million.

The new wastewater plant, constructed adjacent to the current plant on the south end of town, has been designed to more stringent state standards for treatment and to serve the city up to a population of 20,000.

The city purchased equipment from Aqua-Aerobic Systems, Inc. for the AquaNereda system. The type of wastewater treatment plant is a sequencing batch reactor, which is a type of activated sludge plant with multiple unit processes contained within the same concrete basin.

Public Works Director Craig Workman said the technology in the new plant has been used widely in Europe, but Whitefish will be one of two cities to implement the type of plant here. The time of the treatment process from when the wastewater enters the plant, is treated and then clean water is discharged into the Whitefish River will be reduced significantly.

“What is currently a 30-day process will become a six-day process,” he said. “In a this type of treatment the different processes are all happening at once instead of individually so it it’s able to occur more quickly.”

The city’s current wastewater treatment system also slows down in winter because of lower temperatures, but the new system is expected to work much better during the winter. The new system will come with another added benefit of being easier on the nose — the current plant has for years gotten complaints from neighbors.

The new plant, while costing between $4 million and $5 million more than other types of plants, comes with less energy use, Workman notes.

“The energy savings from the new plant should pay back that extra cost in less than 10 years,” he said.

The new plant will include three treatment basins, but is being constructed so a fourth basin can be added later as the need arises.

“There’s plenty of room for expansion,” Workman said.

Swank Enterprises is the contractor on the project.

The project got a head start with a mild winter. One issue arose, however, due to unexpected soil conditions on the site. Changes had to be made to the foundation plan at an additional cost of about $300,000.

Vertical construction is now well underway at the plant with the floor as well as several of the 25 foot tall reactor walls having been constructed for the treatment basins.

The system that will discharged the treated water into the river has been installed in compliance with the permits issued by Montana Fish, Wildlife, and Parks and the U.S. Army Corps of Engineers.

A new 1,600 feet of non-potable water line has been installed at the site.

“This new non-potable line is one of the ways we will be recycling treated wastewater at the plant and will eliminate the use of more than 4 million gallons of potable water per month,” Workman said.

A retaining wall has also been constructed along the Rocksund trail of the city’s river pathway and the path has been restored.

Construction on the project is expected to be completed in summer 2021.