in the reported program, a study of the adsorption of an acid dye (ab-80) and of a basic dye (br-22) has been carried out on charred woollen fibres, with a view to using that industrial waste material in the treatment of liquid effluents. the authors have first studied the dye diffusion; the diffusion of ab-80 appeared much slower than that of br-22, due to the steric cumbersomeness of the ab-80 molecule. as a result, the temperature effect on the diffusion, owing to its influence on the dye aggregation, was clearly more pronounced for ab-80 than for br-22; that fact was confirmed by the determination of adsorption isotherms at different temperatures under favourable conditions, the curves indicated satisfactory adsorption values; as they were either of type h (ab-80) or l (br-22), they also indicated the efficiency of the aforesaid fibres in the treatment of slightly-concentrated effluents. results obtained in the treatment of an industrial effluent in a stirred reactor are presented. 41 refs. in french