Meant to be used on site in the treatment plant, this pocket-sized guide provides basic operational information about mixing, coagulation, and sedimentation processes in water treatment. It addresses all the basic regulatory, theoretical, operations, inspection, and maintenance issues of these processes, as well as mixing and chemical addition for lime-softening applications. Information on solids produced during the processes is also provided. This field guide is suitable for operators who use mechanical and in-line mixing components with metal salt coagulants to form floc particles.