City considering treatment of septic waste

Kalispell's city government is cool to the idea of accepting and processing septic waste from rural Flathead County.

But the City Council has not ruled it out yet.

The city's public works staff and consultants recommended waiting three to five years to sort out how federal requirements will pan out on nitrogen and phosphorus discharges from Kalispell's sewage treatment plant - which would affect whether the city could accept septic waste from the county.

The county government has approached the city treatment plant about accepting rural septic waste to reroute the material from being applied as fertilizer on agricultural land.

That practice sometimes prompts protests from neighbors, Flathead County-City Health Department Director Joe Russell said. Sometimes, the wastes are not applied properly to the land.

Glacier Gold in Olney does not have the capacity to accept any more septic waste, Russell said.

"I'd like for us to keep our minds open. Some time in the future, there may be a case for this," council member Duane Larson said.

Flathead County has not yet formally asked Kalispell to accept septic waste, but it has sent out some informal feelers.

The city staff put the price tag at $4.2 million up front with an estimated $195,000 to $245,000 increase in annual operating costs at the city sewage-treatment plant.

"In order for this to work, the county has to take the financial risks away," Interim City Manager Myrt Webb said.

The city Public Works Department estimated that building a facility to receive septic waste would cost $1.2 million. Another $3 million would be needed for the plant to deal with the increased concentrations of organic material and nutrients in the waste.

The department also calculated that dealing with the nutrient-heavy waste would cost the plant an extra $195,000-$245,000 a year.

Russell speculated that the county might consider paying septic-waste-acceptance rates to the city that are based on the concentrations of nutrients in the material.

The state estimated that private companies collected and applied about 2.55 million gallons of Flathead County septic waste in 2007. This volume is expected to grow to about 3.32 million gallons annually by 2025.

The 2.55-million-gallon annual figure equals about 0.25 percent of the Kalispell plant's treatment capacity.

But the nutrient-laden septic waste is from 50 to 80 times more concentrated than the city's sewage, the city staff and consultants said.

An analogy would be that accepting the rural septic wastes would equate to the city adding 3,500 people to its sewage plant's current responsibility for 20,000 Kalispell residents.

The city plant is expected to finish an expansion in spring 2009 that would increase its treatment capacity from 3.1 millions a day to 5.5 million gallons a day. The plant already operates close to the 3.1-million-gallon-a-day level.

The 3.1-million-gallon figure is just enough to serve Kalispell and Evergreen.

The 5.5-million-gallon figure would be capable of serving Kalispell's predicted 2015 population of 23,600 plus Evergreen, which is growing more slowly. Schematics are already on file to expand the Kalispell's plant's capacity beyond 5.5 million gallons a day.

Meanwhile, the city - along with every other sewage-treatment facility in the state - is under heavy federal pressure to decrease the amount of nutrients in its discharged water to head off organic-pollution problems in nearby bodies of water.

For Kalispell, that means Ashley Creek, the Flathead River and Flathead Lake.

Right now, Kalispell's plant is legally allowed to discharge 25.8 pounds of phosphorus and 286 pounds of nitrogen a day into Ashley Creek.

In three to five years, those federal legal limits are expected to shrink to 19.4 pounds of phosphorus and 214.5 pounds of nitrogen a day.

A major wrinkle is that those figures are absolute numbers.

That means as the volumes of wastewater increase in going through Kalispell's sewage plant, the concentrations of nitrogen and phosphorus in the discharged fluids will have to significantly shrink for the city to keep pace with the absolute limits put on its discharges.

Reporter John Stang may be reached at 758-4429 or by e-mail at jstang@dailyinterlake.com