Wastewater from the City sewer system flows into the Pretreatment Building where over 5 million gallons per day pass through a screening and grinding device called an "Auger Monster". 

This treatment unit is designed to remove coarse rags, trash and debris. After being screened, the wastewater flows into a "Grit Collector" where the forward velocity is reduced to less than 1 foot per second so that sand, rocks, and gravel will settle out. All materials removed via these pretreatment devices are mechanically washed, separated, and then delivered to the Gallatin County landfill for disposal.