Filtration membrane cleaning comprises emptying concentrate compartment and back-washing from permeate compartment with gas or liquid pulses

Cleaning hollow fiber liquid filtration membranes in a housing between concentrate and permeate compartments comprises emptying the concentrate compartment of liquid and materials in suspension and back-washing the membranes by passing a liquid, e.g. filtered water through them from the permeate compartment into the concentrate compartment, unsticking and removing impurities deposited on the membranes. Cleaning hollow fiber liquid filtration membranes (M) in a housing between concentrate and permeate compartments comprises emptying the concentrate compartment of liquid and materials in suspension and back-washing the membranes by passing a liquid such as filtered water through them from the permeate compartment into the concentrate compartment, unsticking and removing impurities deposited on the membranes. The back-washing is assisted by pulses of the liquid and/or a gas, especially air, the pulses lasting for between 2 and 60 seconds and used at a rate of between 1 and 10 during a back-washing phase. The back-washing liquid can contain an additive such as a disinfectant or oxidation agent, or an acid or base chemical compound. Procédé de nettoyage de membranes de filtration en fibres creuses à peau interne, comprenant les étapes consistant à : vider le compartiment concentrat pour évacuer le liquide à filtrer qu'il contient et les matières en suspension, puis effectuer un rétro-lavage par passage de liquide du compartiment perméat vers le compartiment concentrat au travers des membranes pour décoller et évacuer les impuretés déposées sur celles-ci tout en faisant circuler un gaz dans le concentrat. Des pulsations du gaz et/ou du liquide de rétro-lavage sont provoquées par des moyens de commande (5, 5a ; 7, 7a) pendant au moins une phase du rétro-lavage.