The project consists of the construction of an anaerobic digestion unit with a total capacity of 2,200 m3 located on the site of the Verdié wastewater treatment plant in Montauban (82), intended to produce biogas from the by-products of urban and industrial wastewater treatment (sludge, grease and waste materials). It provides for the establishment of a unit for the methanisation of sludge and grease produced by the treatment plant (STEP) but also by other STEPs in the department, with a biogas purification unit allowing the reinjection of biomethane into the Gaz Réseau Distribution France (GRDF) network and the establishment of a reception unit for external methanogenic materials: sewage sludge, sewage and catering grease. This project is carried out by the company SAUR through the dedicated company GEM (GESTION POUR L'ENVIRONNEMENT DE MONTAUBAN). It is part of the concession contract, the public sewerage and urban rainwater management services of the Greater Montauban Agglomeration Community. It is accompanied by work not presented in this dossier allowing the extension of the hydraulic and organic capacity of the Verdié treatment plant. The provisional period of execution of the operation runs from 04/08/2022 to 31/12/2025.