Pollution and its effects on the environment have emerged as critical areas of research within the past 30 years. The Handbook of Environmental Engineering is a collection of methodologies that study the effects of pollution and waste in their three basic forms: gas, solid, and liquid. In Volume 8, Biological Treatment Processes, tried-and-true solutions comprise a methodology of pollution control. The distinguished panel of authors contributes detailed chapters, which include topics ranging from treatment by land application, activated sludge processes, and submerged aeration to trickling filters, lagoons, rotating biological contactors, sequencing batch reactors, digestions, and composting. Volume 8 and its sister book - Volume 9: Advanced Biological Treatment Processes are designed as both basic biological waste treatment textbooks and reference books for advanced undergraduate and graduate students as well as for designers of waste treatment systems, scientists, and researchers. An indispensable addition to the Humana Press series, Volume 8: Biological Treatment Processes provides an illuminating look at water pollution control and the fascinating evolution of bio-environmental engineering.