After the water passes through the bar screens, it goes into a grit chamber. In the grit chamber, the influent flow of water is slowed so that the sand and gravel fall to the bottom of the chamber. Even after that, it enters the primary clarifier, which slows it even further, allowing the organics to fall to the bottom and the fats an
The water then moves in to an aeration chamber where oxygen is mixed with the water. Microorganisms then consume the material as food which reduces the BODs in the water. Also, they make non settleable solids settleable. Most of the end up in final clarifiers, and they end up in wastewater solids. After that comes chemical systems.
d oils to float to the top. All of this only removes about 50% of the contaminents in the water. The process then moves on to Biological Systems.