After the Coagulation, Flocculation, and Sedimentation processes are complete, the
Filtration process is essential in further reducing the concentration of unsettled particles in
the water. Filtration is the process of passing water through filter media for the
purpose of removing undesirable constituents. The Chalk Bluff and Glendale facilities utilize rapid sand
filters consisting of sand and anthracite coal to complete this task. The
filters are capable of reducing turbidity levels to below TMWAs in
house standard of no more than 0.1 NTUs*. The filters are very effective, but
as a filter begins to clog up and no longer filters efficiently, it is necessary
to remove that filter from service and backwash it. An automated backwashing system is used
at Chalk Bluff and Glendale to successfully clean and ready a filter for
further efficient and effective filtration. Turbidity removal is extremely important because particles in
the water can interfere with the disinfection process.
