Physical Processes

This chapter provides a theoretical background on the mathematical models for the physical processes, excluding the fluid flow itself. It introduces the fundamental physical transport processes, which include the generic transport equation and the special case of heat transfer. Excessive thermal discharge into rivers and streams from wastewater treatment plants is an important environmental stressor that needs to be monitored. Thermal radiation transmits energy through electromagnetic waves. Thermal radiation is often of secondary importance when compared with convection and conduction in water and wastewater treatment processes. The chapter also presents treatments related to physical processes, specifically the transport of particulate matter. One major impurity in water and wastewater is particulate matter suspended in influent. Hydraulics consists of the application of theories of fluid mechanics to practical problems in water resources. Sometimes hydraulics and fluid mechanics are used interchangeably.