A review of problems confronted in disposing of sludges from municipal wastewater treatment plants is presented. The quantities and characteristics of these sludges that must be dealt with are enumerated. Waste sludges originating from the activated sludge and tertiary treatment processes together with alum sludges are typically high in moisture and gelatinous in nature and are shown to present the greatest challenge in dewatering. Each of a variety of biological, chemical and physical treatment alternatives is discussed. Recently completed in-house research is noted. This includes the optimization of the aerobic stabilization process, the use of organic polymers and various inorganic additives including iron and sludge incinerator ash on sludge filtration and thickening. (Author)