Baxter City Council considers biological water treatment methodology

Implementing microbial filtration may cost a fraction of renovating the current facility or building a new one, all the while slashing operational costs by $44,000 - $85,000 per year.

Biological Filtration Diagram.JPG

BAXTER — The Baxter City Council spent a lengthy workshop Tuesday, Feb. 18, discussing the potential for microbes in the Baxter Water Treatment Facility — not bad bugs in a petri dish, mind you, but positive microbes capable of cleaning up drinking water and slashing costs.

WSB Graduate Engineer Ursinio Puga updated the council on the results of a 2019 study into the effectiveness of biological filtration, essentially microbial activity, for the removal of iron, manganese and ammonia from the raw water at the Baxter Water Treatment Plant.

Puga noted the study indicated the city was up to standards for clean water, with a capacity of filtering 3.6 million gallons per year at the plant. The city is capable of pumping and treating roughly 2,000 gallons per minute, and can store up to 2.8 million gallons at any given time.

While it’s not an imminent situation that needs to be addressed — Puga said the city of Baxter will likely need to revamp the treatment facility in the next 20 years, probably after 2030 — he noted to meet growing capacity it may be wise to implement a methodology that combines a smaller saturation of chemical disinfectants (particularly chlorine) alongside natural microbial filtration.

Utilizing microbial activity could increase capacity by 30% to 40%, Puga said, without requiring new filters. At the same time, Puga said, a reduction in chlorine by 90% would engender a reduction in chemical byproducts in the facility by 80% and potentially smaller costs to maintain equipment harmed by chlorine.


Installing and outfitting equipment on site — such as discontinuing chlorine apparatuses, adding tanks, barriers and oxygen monitoring systems, for example — would come to $701,000, without interrupting water treatment as an addition or new facility would require.

Public Works Director Trevor Walter observed that converting over to a biological treatment plant would enable the city to provide high quality water filtration at cheaper operational costs without the need to renovate and re-equip the existing the current plant’s facility in a substantial, costly manner.

“The Utilities Commission, I can say, was very excited after they read through this,” Walter said of the study and its recommendation for a biologically-based treatment method. “It's probably a very, very cost effective option for us to meet our needs probably for the next 20 years. Very cost effective, and the payback is less than seven years.”

Puga noted a new facility or sizable expansion to meet growing needs could cost anywhere between $5 to $10 million. Currently, the city spends just north of $131,000 annually, while a biologically-based system could save Baxter $44,000 to $85,000 a year.

“If the city were to go biological,” Puga said, “essentially, the city's looking at anywhere between $1,250,000 to $2,350,000 in operational savings for the next 20 years. … So, operational savings minus capital investment, is predicted to be anywhere between half a million to $1.6 million over the next 20 years.”

While over 800 cities across the country now utilize this methodology, it’s worth examining if microbial filtering can work in Baxter and is a good investment as a presented by WSB, said City Administrator Brad Chapulis, which may entail further examination of the issue.

“From a staff standpoint, you want to trust, but verify,” Chapulis said. “Get verification that the numbers that are in the study are accurate, are within the range of accuracy, to make sure that when you make a determination to go work, or don't go, that you have as much data as possible to make an important decision.”

GABRIEL LAGARDE may be reached at or 218-855-5859. Follow at .


Baxter City Council members Mayor Darrel Olson (left) talks with council member Mark Cross during a break in the workshop Tuesday, Feb. 18, during which biological water treatment methods and infrastructure projects were discussed at length. Gabriel Lagarde / Brainerd Dispatch

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