Metropolitan Water District of

          Salt Lake & Sandy

Sedimentation

Once all of these floc particles are formed, they can easily be removed from the water.  This is accomplished in the sedimentation basins.

Sedimentation is the process of allowing particles to sink to the bottom of the basins.  Because the floc particles are heavier than water, they sink.  This causes a layer of sludge to form on the bottom of the basin.  Then, large scrapers are slowly pulled across the bottom of the basin to remove the sludge.

At the end of the sedimentation basins weirs are used to remove only the top few inches of water from the basin. This top layer has the least amount of floc particles because settling has taken place earlier in the process.