A review of problems confronted in disposing sludges from water purification and municipal wastewater treatment plants is presented. The quantities and characteristics of these sludges that must be dealt with are enumerated. Each of a variety of biological, chemical and physical treatment alternatives is discussed. This includes the optimization of the aerobic stabilization process, the use of organic polymers and various inorganic additives including iron and aluminum salts, and sludge incinerator ash on sludge filtration and thickening. Pasteurization is also discussed. Land spreading, strip mine reclamation, landfill, ocean disposal, and pipeline transport are discussed. The present economics of some processes are noted. (Author)