Together, they weigh more than the surrounding water and sink to the bottom in a blanket of floc. The water in the basin is slowly stirred, causing the floc particles to collide and stick together. As waster flows up into the basin, the heavier particles on the bottom are scraped to the center and pumped out to be hauled away. After the primary basin process, gravity causes the water to flow from the upflow unit to two secondary clarifiers. The secondary clarifiers allow more time for particles to settle out of the water.
Water flows through filters which contains layers of anthracite coal, sand and gravel.
There are three tertiary treatment filters at the Kirksville purification plant, and a fourth will be completed in the future. After this third stage of cleaning, water is ready for consumption. The clean water is stored in a underground water tank. Once these are full, water is pumped to other ground storage locations or to the City as needed. Kirksville can store almost four million gallons of water in its above ground tank and in the city's four water towers.