Officials who oversee the Kalispell Wastewater Treatment Facility are weighing different options for how the plant can best serve the area’s growing population as the facility’s discharge permit — granted through the Montana Department of Environmental Quality — nears its expiration date.

The topic was discussed at the Flathead Basin Commission meeting on Wednesday as conservation leaders, city and county officials and others gathered to discuss challenges related to the management of stormwater and wastewater in the valley.

In August 2015 the state authorized the Kalispell wastewater facility to discharge much of its treated wastewater into the nearby Ashley Creek. That permit is slated to end on July 31 of this year, but officials say several obstacles have become more evident as officials work toward reapplying for a new five-year permit.

According to Kalispell Public Works Director Susie Turner, discharge limits set forth by the state are gradually becoming more stringent. These tightened regulations come as Kalispell and the greater Flathead Valley continue to see steep spikes in population growth.

Dean Sirucek , a Flathead County Planning Board member who is also a member of the Flathead Basin Commission, said at Wednesday’s meeting new subdivision proposals are coming before the board on a monthly basis. And with those proposals come their associated septic systems.

“Servicing this growing population will be a challenge in the future and if we can’t treat it here at the facility, it will just go out into septic fields. We are looking at different ways to meet that growth while also protecting our water resources,” Turner said.

One method Turner and others are considering, which was recently submitted in writing to DEQ as an attachment to the city’s permit reapplication, is nutrient trading.

Pending approval from both the state and city, this means Kalispell could obtain a “nutrient standards variance,” which means state law would allow the facility to continue discharging in compliance with the terms of that variance for a defined period of time without significant or costly upgrades.

The “trading” in this case means the facility would take on new septic systems in the greater Kalispell area, including industrial and residential systems, in exchange for credits. The city could then use those credits to meet regulatory obligations, such as meeting those stringent discharge requirements.

To develop the trading plan, DEQ would first determine the amount of credit that could be applied to the city’s effluent limits, or the amount of additional effluent that could be discharged upon taking on additional septic systems.

But in other cities where similar nutrient trading programs have been approved, the credits don’t come out to a one-to-one ratio. In Missoula for example, for every 13.9 pounds of nitrogen discharged by their treatment facility, only one pound of credit is applied to the load limits in the city’s permit.

“That’s the cost benefit. Is it really worth bringing on 30 septic systems in exchange for only several pounds of credit?” Turner asked. “At this point everything is still in the beginning stages and we aren’t even sure much credit can be added to our treatment discharge permit. But these are all things we will be considering heavily.”

AS FAR as which septic systems the treatment facility could take on, officials have identified groupings of existing septic permits that could possibly be hooked up to the city system.

They have so far identified over 1,600 septic systems, primarily residential. Of those, about 700 fall within the Ashley Creek drainage system, which Turner said would be some of the easiest and most convenient systems to hook up to the facility in the future. But other groupings fall within the Whitefish River, Stillwater River and Flathead River drainage basins.

“If we were to bring on other septic systems, there isn’t a reason why we shouldn’t consider the entire Flathead Lake watershed in that,” Turner said. “So those in the Ashley Creek drainage area would be more easily attainable, but these others are possibilities, too.”

But bringing on residential systems is no easy task, as the process can be costly and requires approval from homeowners. Even if nutrient trading is approved and all parties wish to move forward with the program, finding an audience that is willing to connect to the system will be a challenge.

“Septic falls into the category of one of those issues that people tend not to care about as much because they don’t see it,” said Aaron Losing, manager of the treatment facility. “We will need others to be interested.”

While nutrient trading is one possibility for meeting the city’s future wastewater discharge needs, Turner noted other routes are being considered. Those include expanding discharge points to include other outlets such as the Flathead River, assuming such measures are approved by the state and city, or irrigating the effluent to agricultural lands where it could be utilized.

Losing and Turner say most likely a mix of different methods eventually will have to come into play in order for the city to manage its growing wastewater needs well into the future.

“Our mission to protect Flathead Lake and water resources hasn’t ever changed,” Losing said. “We all use these resources.”

Reporter Kianna Gardner can be reached at 758-4407 or kgardner@dailyinterlake.com