The Chlorine Contact Chamber provides the detention time necessary to ensure a chlorine solution has time to react with the plant effluent before it is discharged into the East Gallatin River. This chemical reaction disinfects the plant effluent. As the flow enters this tank it follows a serpentine channel configuration to provide more than 80 minutes reaction time.

All residual chlorine is neutralized with sulfur dioxide before the final treated water leaves the plant. A flash mixer at the end of the chlorine contact tank ensures that the sulfur dioxide comes in contact with the chlorine before it is discharged.

This is the plant effluent as it flows over the weir at the end of the Chlorine Contact Chamber. Compare this quality of water with that flowing out of the Grit Collector  at the head of the Plant.