Isanti council approves static mixer for water treatment plant in 4-1 vote

The Isanti City Council on July 16 approved a resolution to install a static mixer at the citys water treatment plant to improve chemical blending and reduce manual adjustments during high summer demand. The council voted 4-1 to authorize purchase and installation, with the device quoted at $24,000 and the lowest installation quote producing a total cost of $35,001.75.

Public Works staff explained that when all four filters must run to meet summer demand the plant has seen inconsistent chemical levels and increased "babysitting" of two filters. "This would allow the chemicals to be mixed or blended a lot better before they go into each filter, which is gonna give us better results," the Public Works representative said. Staff and the administrator noted the purchase is unbudgeted but justified to preserve filter life; the expense will be paid from Fund 500.

Councilors probed the installation costs and timing. One council member questioned why contractor labor is necessary for what appears to be a bolted inline installation and noted the quoted $11,000 initiation/install cost; staff replied that the unit weighs roughly 400 pounds, must be installed in a single operation during winter conditions, and adds risk if attempted by city crews. The administrator said the city does not anticipate other major plant projects before 2028 that could be combined with this work and that the underdrain evaluation is scheduled for 2028.

The lone dissenting vote reflected concern about the upfront contractor cost given that some project components appear mechanical or plumbing-related. Supporters emphasized public-safety risk in delaying work that improves chemical dosing consistency and the potential operational savings from extended filter life.

The council directed staff to proceed with procurement and scheduling; staff said the installation will be scheduled for a time that minimizes service risk and will use the lowest qualified bid.