The Canteranne wastewater treatment plant, commissioned in 1975 and rehabilitated in 2004, currently treats wastewater from Castelnau de Médoc, Avensan, and part of Moulis-en-Médoc. Due to aging equipment and insufficient capacity, the SIAEPA of Castelnau de Médoc is undertaking a modernization project. This involves renewing the facilities and increasing treatment capacity from 8,000 to 12,000 population equivalents. The project also includes a new discharge system for treated water to the Gironde estuary, in the commune of Soussans.
This public consultation procedure, lasting three months, is a necessary step for obtaining an environmental authorization from the State services. Its purpose is to inform citizens about the project, its stakes, and to gather their observations and proposals before the State makes its decision. The accessible file includes a project presentation, a non-technical summary, environmental impact information, and collected opinions.
Three methods are offered for information and participation: the digital register accessible online for consulting documents and submitting observations (or via email at extension-station-epuration-castelnaudemedoc@mail.registre-numerique.fr), two public meetings organized at the town hall of Castelnau de Médoc (Monday, November 30, 2026, from 4 PM to 6 PM and Friday, February 5, 2027, from 6 PM to 8 PM), and a hearing with the inquiry commissioner at the same town hall on Wednesday, January 13, 2027, from 3 PM to 5 PM, where a paper register will be available.
Following the consultation, the inquiry commissioner will prepare a report with reasoned conclusions. The Prefect of Gironde will then make the final decision regarding the environmental authorization request.
