A discussion about wastewater treatment took an unexpected festive turn at Tuesday's Post Falls City Council meeting, as utilities manager Craig Borrenpohl used Christmas decorations to explain complex water treatment processes.

The city is adding tertiary treatments during its wastewater facility expansion, which will increase processing capacity from 3.1 million to 5.2 million gallons per day. "We're in startup of these facilities and making sure they're operating to design," Borrenpohl said.

To illustrate how pollutants are removed, Borrenpohl compared the process to cleaning tinsel off a Christmas tree. "That first clump of tinsel is going to come off pretty quickly, but by the time you get to those last little bits, it takes a lot more effort to get the last pieces of tinsel off the tree," he explained.

The analogy resonated with his audience. "I'll never be able to look at tinsel on a tree without thinking of wastewater," Mayor Ron Jacobson quipped after the presentation.

The facility's treatment process begins at the headworks, where trash is removed and water flow is equalized in newly constructed EQ basins. These basins, which Borrenpohl said saved the city millions in design costs, help create consistent downstream flow.

The water then undergoes biological treatment using microbes, passes through secondary clarifiers and receives UV disinfection. The facility currently removes 96% of phosphorous, releasing about 7 pounds during processing.

However, more improvement is needed. "Removal through time-tested processes isn't enough to get us to the 3.19 pounds a day we need to remove additional phosphorous," Borrenpohl said.

The pilot study for these tertiary treatments is expected to meet permit requirements over a 20-year period.

    Post Falls water reclamation facility