ABSTRACT
T HE initial stage of treatment in the wastewater treatment process (following collection and influent pumping) is preliminary treatment. Process selection normally is based upon the expected characteristics of the influent flow. Raw influent entering the treatment plant may contain many kinds of materials (trash), and preliminary treatment protects downstream plant equipment by removing these materials, which could cause clogs, jams, or excessive wear in plant machinery. In addition, the removal of various materials at the beginning of the treatment process saves valuable space within the treatment plant.
