ABSTRACT
Activated sludge is by far the most widely used secondary biological treatment process for treating wastewater at many major POTWs. This chapter provides process descriptions for three activated sludge processes: with diffused aeration using air, using high purity oxygen and mechanical aeration. The three phenomena that dictate fate of VOCs in biological treatment systems are also discussed: volatization and stripping, sorption (absorption and adsorption) and biodegradation. A comparison of the three VOC fate models most commonly used to treat these phenomena — WATER8, TOXCHEM+ and BASTE — is then presented.
