ABSTRACT
P RELIMINARY treatment may include several processes, each designed to remove specific materials. Selection of what processes are included in pretreatment depends on the collection system (e.g., combined sewer systems, which collect stormwater, bring more grit into the influent than do sanitary sewers), and upon the nature or make-up of the wastewater in the community. Moreover, the balance between residential wastewater contents and industrial wastewater contents, and the individual industries that add wastes to the system will be determining factors in process selection for a treatment system.
