The handling and processing of excess biomass produced in wastewater treatment plants is an important aspect of wastewaster treatment. Current approaches to sludge treatment include the wet destruction of the biosolids. This approach does not require preceding dewatering operations and enhances biodegradability of the sludge particles. However, high costs, corrosion problems and restricted knowledge still prevent wet sludge disintegration from realising its understanding of potential as an industrial process. This paper reviews the current state of the art and compares several wet sludge disintegration techniques, including mechanical, chemical, thermochemical, biological and oxidative treatments.