Particle Processes: Common Elements

Many contaminants of interest in water and wastewater are particles, or are made into particles for removal. Typical municipal wastewater treatment plants include both primary and secondary sedimentation, and those with tertiary treatment likely have granular media filtration. Typical drinking water plants using surface water supplies have flocculation, gravity separation (sedimentation or flotation), and granular media filtration processes; increasingly, ultrafiltration or another membrane process is placed in lieu of or in addition to granular media filtration. The production of process water for industrial uses and the pretreatment of industrial wastes prior to discharge to a POTW often include one or more of these particle removal processes. Characteristics of particles that affect their behavior in water and therefore are common to all of the particle treatment processes are considered in this chapter.