City hears plan for updates at wastewater plant

Photo by Deb Gau Kelly Yahnke, of engineering firm Bolton & Menk, presented a the Marshall City Council with a facilities plan for the city wastewater treatment plant.

MARSHALL — Wastewater treatment isn’t a new topic of discussion for the city of Marshall. Parts of the city’s existing wastewater plant are more than 20 years old, and replacing them is a need city staff know is coming.

After Tuesday’s meeting of the Marshall City Council, however, the city will have a game plan on how to move forward.

Part of the agenda Tuesday was a public hearing on a facilities plan for the wastewater plant. After hearing more about it from Kelly Yahnke, of engineering firm Bolton & Menk, council members voted to approve the plan.

There were a few different reasons for the city to adopt a wastewater facilities plan, Yahnke said. One was that the facilities are aging, and will need to be updated or replaced in the future. Other reasons for the facilities study include changing standards for the amount of pollutants allowed in water discharged into the Redwood River from the wastewater plant.

Marshall has a permit issued by the Minnesota Pollution Control Agency, which defines how much of pollutants the wastewater facility can discharge. That permit is scheduled to be reviewed in 2019. In his presentation, Yahnke said, it’s also expected that the city will someday receive a limit on the amount of total nitrogen permitted in its discharged wastewater.

The facilities plan studied possibilities for removing nitrogen and phosphorus from city wastewater, and capacity and maintenance needs for the wastewater plant.

Yahnke said the facilities plan proposed two major phases of work to address all those concerns. The first phase would “Basically just upgrade the facility,” Yahnke said. Several aging parts of the plant would be replaced, and systems used for turning waste into fertilizer safe for application on farm fields would be expanded. This would allow the plant to cope with future population and industrial growth, the plan said.

Projected capital costs for Phase 1 of the plan, including contingencies and engineering costs, are about $9.47 million, Yahnke said.

The second phase of the facilities plan would kick in if the city is given a limit for total nitrogen in its wastewater. The plan includes two different systems that could be used to cut down on the amount of nitrogen in the water. Projected costs for the two systems would be about $8.18 million or $17.56 million, depending on which of the two options the city pursues.

The facilities report investigated a few different possibilities for financing updates to the wastewater plant. Options included state and federal grants, and loans.

Yahnke recommended Marshall move ahead with Phase 1 of the plan — the facility and equipment updates. If the city is able to receive grant funding for water infrastructure, it could then consider moving forward with a nitrogen removal system.

After the public hearing, council members voted to adopt the proposed wastewater facilities plan, and submit the plan to the MPCA for review and approval.