Written by two of the field's foremost researchers, this comprehensive learning resource presents the biological principles that underlie modern microgbiological treatment technologies designed to improve environmental quality. The first half is focused on the principles, the tools for describing the stoichiometry and energetics of microbial reactions, and for the proper application of kinetics. The second half features applications--with many example problems--to take readers through the procedures to understand how microbial systems work and to design a treatment process.