Adsorption of phosphorus (P as phosphates) in saturated slag media (dust and cake) columns was studied to assess the slag media's capability in removing P from wastewater. Prior to the experiments, slag media were completely washed to rinse off the soluble metal ions which are generally responsible for forming insoluble precipitates. Experimental data revealed that the adsorption capacities of washed slag media are still much higher than that of a sandy roam soil. Two dynamic models were tested for simulating the adsorption behavior of phosphorus in columns packed with slag media. The model employing the intraparticle transport through surface diffusion is successful, while a simplified model based on the linear driving force approximation (LDFA) could not predict the column behavior properly at low concentrations, particularly on the cake slag. (C) 1997 Elsevier Science B.V.