A plant for treating an aqueous fluid, in particular water, by clarification and adsorption on powdered activated carbon comprising: - a continuously-fed upflow fluidized sludge bed clarifier, said fluidized bed being a fluidized bed of mixed sludge of metal hydroxides and powdered activated carbon, - a static or dynamic mixer upstream of said fluidized sludge bed clarifier, - means for injecting at least one coagulation reagent (21 and 22) such as a metal salt into the static or dynamic mixer, - a supply pipe conveying the aqueous fluid leaving the static or dynamic mixer to the decanter, - means for injecting fresh powdered activated carbon into the aqueous fluid supply pipe, and - a powdered activated carbon recycling system, said decanter comprising three distinct operating zones: - a lower part comprising: - a reaction zone for aqueous fluid, advantageously coagulated beforehand, comprising an inlet system for the aqueous fluid to be treated, advantageously consisting of a distributor in the form of a plurality of dispersion ramps pierced with openings directed toward the bottom of said decanter, as well as the fluidized bed of mixed sludge, - a sludge discharge zone, comprising at least one sludge pit arranged inside the decanter, - an upper part comprising a decantation and recovery zone for the treated aqueous fluid, advantageously by overflow through several spouts or perforated pipes, the concentration of mixed sludge within the fluidized bed in the reactor being at least 1 g/L, said powdered activated carbon representing at least 33% by weight of the mixed sludge and said powdered activated carbon having an average diameter of less than 30 μm, said recycling system advantageously comprising at least one hydrocyclone. - a continuously-fed upflow fluidized sludge bed clarifier, said fluidized bed being a fluidized bed of mixed sludge of metal hydroxides and powdered activated carbon, - a static or dynamic mixer upstream of said fluidized sludge bed clarifier, - means for injecting at least one coagulation reagent (21 and 22) such as a metal salt into the static or dynamic mixer, - a supply pipe conveying the aqueous fluid leaving the static or dynamic mixer to the decanter, - means for injecting fresh powdered activated carbon into the aqueous fluid supply pipe, and - a powdered activated carbon recycling system, said decanter comprising three distinct operating zones: - a lower part comprising: - a reaction zone for aqueous fluid, advantageously coagulated beforehand, comprising an inlet system for the aqueous fluid to be treated, advantageously consisting of a distributor in the form of a plurality of dispersion ramps pierced with openings directed toward the bottom of said decanter, as well as the fluidized bed of mixed sludge, - a sludge discharge zone, comprising at least one sludge pit arranged inside the decanter, - an upper part comprising a decantation and recovery zone for the treated aqueous fluid, advantageously by overflow through several spouts or perforated pipes, - a lower part comprising: - a reaction zone for aqueous fluid, advantageously coagulated beforehand, comprising an inlet system for the aqueous fluid to be treated, advantageously consisting of a distributor in the form of a plurality of dispersion ramps pierced with openings directed toward the bottom of said decanter, as well as the fluidized bed of mixed sludge, - a sludge discharge zone, comprising at least one sludge pit arranged inside the decanter, - an upper part comprising a decantation and recovery zone for the treated aqueous fluid, advantageously by overflow through several spouts or perforated pipes, - a reaction zone for aqueous fluid, advantageously coagulated beforehand, comprising an inlet system for the aqueous fluid to be treated, advantageously consisting of a distributor in the form of a plurality of dispersion ramps pierced with openings directed toward the bottom of said decanter, as well as the fluidized bed of mixed sludge, - a sludge discharge zone, comprising at least one sludge pit arranged inside the decanter, - an upper part comprising a decantation and recovery zone for the treated aqueous fluid, advantageously by overflow through several spouts or perforated pipes,