ABSTRACT
The two major categories of biological treatment are (1) suspended growth and (2) attached growth processes. The focus of this chapter is aerobic biological treatment using attached growth processes for biochemical oxygen demand (BOD) removal. A combination of suspended and attached growth processes may be used for biological treatment of wastewater. Some of these hybrid processes are discussed at the end of the chapter. Suspended growth processes have been discussed in Chapter 8. Biological processes used for nitrogen and phosphorus removal will be described in detail in Chapter 13.
