The carbonised solid residue of olive mill products, called J-carbon (0.6-0.7 mm), was compared with Sigma activated carbon (powder) and Chemviron activated carbon (0.6-0.7 mm) in treatment of the effluent of Flexsys＇ wastewater. The removal of NH3, TOC as non-specific organics, and six specific leading organic pollutants from Flexsys＇ wastewater effluent were examined. All three different carbon sources have almost similar behaviour in removing the above pollutants; the removal efficiencies were as follows : Sigma carbon : benzothiazole, 1,2-dihydro-2,2,4-trimethylquinoline, N-dimorpholinyl ketone, methylsulphyl benzothiazole and methyl-2-benzothiazole sulphone 100% > TOC 94% > NH3 82% > tetrachloroethene 50%. Chemviron carbon : benzothiazole, 1,2-dihydro-2,2,4-trimethylquinoline, N-dimorpholinyl ketone, methylsulphyl benzothiazole and methyl-2-benzothiazole sulphone 100% > NH3 87% > TOC 40% > tetrachloroethene 31%. J-carbon : benzothiazole, methylsulphyl benzothiazole and methyl-2-benzothiazole sulphone 100% > NH(3)78% > 1,2-dihydro-2,2,4-trimethylquinoline 70% > tetrachloroethene 58% > N-dimorpholinyl ketone 50% > TOC 37%.