This WP will involve developing the hybrid process that combines two processes, the fixation of dissolved pollution on an insoluble adsorbent (activated carbon) and ultrafiltration. Two configurations will be tested: a CRISTAL configuration where the ultrafiltration loop serves as an adsorption reactor and the membrane allows the retention of suspended solids present in the raw water, adsorbent (PAC-powdered activated carbon) having fixed dissolved pollutants, and undesirable germs: cysts, bacteria, viruses. This process makes it possible, for example, to produce drinking water from fresh water with a minimum of residual disinfectant. The main facilities have been in operation for more than 15 years, notably in Lausanne, Switzerland. However, in the context of more complex water such as seawater, the adsorption process is subject to competitive phenomena and if the UF backwash waters can be sent to the beginning of the treatment path, within the framework of this project, this could result in a release of PAC into the treatment path which is not desirable. A second configuration will also be studied with an adsorption reactor (GAC-granular activated carbon) downstream of the membrane process to avoid this dissemination and thus express its adsorption capacity. The UF process will protect the GAC column from suspended solids, bacterial development, etc. This will also limit, should this occur, the release of micropollutants as a result of peak pollution or peak concentrations of adsorbable organic matter. This type of process, in the context of a significant pollutant load, has already made it possible to consider on a semi-industrial scale (AMU) the disinfection of pool water with the retention by membrane of bacteria, viruses and other organic compounds capable of forming chloramines, and activated carbon to treat very small dissolved compounds ( 20nm). While the overall performance of the hybrid process will be studied, the process coupling raises several questions that the project will have to answer: backwash water fate, regeneration of activated carbon, time management of the two processes etc.