This paper determines the sorption capacity of sewage sludge of various organic substances in relation to halogen organic compounds, which are among the main environmental contaminants. The assessment is based on iodine adsorption values and the p-chlorophenol adsorption isotherms. Additionally, the leaching efficiency of p-chlorophenol from sludge into the water solution under the influence of selected physical and chemical factors such as UV radiation, electric discharges and freeze-thaw conditioning has been examined. The results suggest that sewage sludge shows good sorption capacity and that under favourable conditions only a portion of adsorbed p-chlorophenol was leached to the aqueous phase.