Background Decanting lagoons for clay-rich sludge resulting from the washing of granulates can be found on more than 2130 sites in Europe. These lagoons hold large quantities of fine ground mineral sludge which constitutes a significant hazard to surface and underground water (clogging) and to flora and fauna. Its current use for accretion, its storage (gullying, moving sands) and its handling can result in major sources of pollution. This type of hazardous waste is covered by EC Directive 1999/31/EC of 26 April 1999 on the emissions of waste materials. The principal challenge is the industrial transformation of this waste. The ENTEMA project fits into the context of the management of large volumes of waste using an experimental alternative method for recycling clay-rich sludge into expanded clay pellets, with many different applications (light concrete, etc.). Objectives The aim was to carry out a pilot demonstration to validate the transformation of clay-rich sludge from a specific quarry site into expanded clay pellets. The project should have made it possible: to reduce pollution by this type of sludge; to economise on mineral resources, these pellets are currently manufactured using pure clay from clay quarries; to reduce emissions of greenhouse gases (in accordance with the Kyoto protocol) by abandoning the current methods of manufacturing pellets in rotating furnaces, since these installations emit greenhouse gases. Other objectives were to: implement a prototype 250 kW microwave with a capacity of 1.4 t/hr; reduce gas emissions by 75% in comparison with rotating furnaces; optimise the washing process and draw up an environmental guide; reduce lagooning by 80%; improve the mechanical properties of the pellets; reduce lagooning by 25% in 10 years in Europe; stimulate interest among five existing manufacturers; communicate and disseminate the results to 5 professional quarrying groups in Europe (9 000 quarries and 1 500 lagoons), to 30 journals and 10 existing manufacturers. Results This project closed before the end date because of financial issues. So there are no final results to disseminate, even though the implementation process still provides some interesting insights.