Grit Chamber

After passing through the bar screen, the influent enters the grit chamber.  Here, the wastewater passes into a wide basin, which slows the wastewater's velocity.  The slower flow causes grit to settle out.  Grit is the heaviest material in wastewater and includes substances such as sand, coffee grounds, eggshells, gravel, and cinders.  Grit cannot be broken down by biological processes, so it is hauled to a landfill.