Baxter City Council approves filter overhaul after water treatment failures
The resolution represented another episode in the city's ongoing work to deal with a faulty filtration pump cap, which mysteriously started to leak in the back half of 2020 and subsequently failed altogether last month.
With a unanimous vote during its virtual meeting Tuesday, March 2, the Baxter City Council approved $51,400 to replace the city’s water treatment plant filters, as well as provide a framework of temporary pumps and auxiliary components after a problematic filter failed during inspections last month.
These funds may be reimbursed through an insurance plan with the League of Minnesota Cities, which is currently reviewing Baxter’s claim.
The Baxter water treatment plant’s water filters were discussed during the council’s Jan. 20 workshop, when contractors and city staffers warned the council the plant’s second filter cap (which serves as a barrier to contain the plant’s chemical and granular media, but allows water to filter through) was inexplicably failing. Little more than two years into its roughly decade-long life-expectancy, the No. 2 filter cap was found to be leaking media, and the root cause presented a baffling conundrum that stumped staffers from the start.
At the time, city staffers warned action had to be taken by the city by April 1 with regard to all four filter caps in anticipation of exponentially higher water usage after that date. As it turned out, the city didn’t even have that much time.
Staffers noted they were unsure how the other filters — No. 1, No. 3, and No. 4 — could perform, as they are the same product and experience the same usage as No. 2, so they advised a filter overhaul to ensure the system’s long-term viability, with a makeshift dual pumping system to carry the workload in the meantime.
“A dual pumping system (would) give staff flexibility to vary the pumping rate as demand requires over the summer,” said Mark Hallan, an engineer with Widseth. “Maybe you can meet some of your water demands (with the three remaining filters), but there’s no guarantee how those operations will continue here over the next six to nine months.”
The Baxter water treatment facility is somewhat limited because it was designed in the late ‘90s to be a limited usage or temporary amenity, Hallan noted, which has not been reflected in the city’s filtration needs over the intervening decades. During the Jan. 20 workshop, staffers noted the plant has four filter pumps when it probably should have eight to account for the consumption, as well as to address high concentrations of arsenic, ammonia and especially iron in the watershed. To filter out the water properly, it required the current plant complete 300-400 backwashes (or a second cycle of filtration) a year, while an average water treatment facility of a comparable municipality typically requires roughly 150 backwashes per year.
Currently, Hallan noted, BPU notified the city it is capable of pumping 2.2 million gallons daily, so it may mean Baxter will have to be strategic with its water filtration system, possibly alternating between BPU and the Baxter plant during irrigation days or use other potential methods to limit the consumption to no more than 2.2 million gallons per day. The highest daily figure recorded in Baxter through the last four years was 2.3 million gallons, Public Works Director Trevor Walter noted, so going over that benchmark doesn’t represent a common occurrence.
Council member Zach Tabatt asked what a scenario would look like if BPU experienced any significant problems of its own during the next six to nine months.
Walter said the city is capable of doing a partial filtration straight from its source wells.
“The backup is that we can produce water straight out of our wells,” Walter responded. “We don't have any contaminants directly in our wells that we can’t put out there as drinking water, it’s just that you’re gonna see discoloration. … We have the option with the way the water pipe is set up we can run it through the aerators and the detention basin, so we can do a partial treatment and that’s our emergency plan.”
Walter noted this may be subject to some directives from the Minnesota Department of Health in how the city handles phosphates in the water, as well as chlorination and fluoridation, in the meantime. If there was an emergency, while drinkable, the quality of the water will go down, Walter said, which means residents would experience much higher levels of iron and manganese.
City Administrator Brad Chapulis said “not all the pieces of the puzzle are together just yet,” and noted staffers could bring forward recommendations in the future, which could entail water consumption restrictions and irrigation restrictions, but it remains to be seen until the summer months.
Mayor Darrel Olson asked if water parks, pools and similar activities would have an effect on this consumption. Walter said consumption in these situations are relatively consistent over a given 12-month period, while it’s irrigation that causes a substantial spike in June, July and August.