This study investigated the treatment of wastewater by adsorption process through fixed-bed column using recycled garden waste. A new adsorbent was manufactured from agricultural waste using zinc chloride (ZnCl2) as activated agent at 700°C for 1 h. The porosity characterization of the prepared activated carbon was investigated by the Branuller-Emmett and Teller (BET) test. Three models, namely Yoon-Nelson, Thomas and Adam-Bohart were applied to represent the breakthrough curves of hexavalent chromium (Cr-VI) removals. The fixed-bed column study was conducted at different wastewater flow rates (6, 9 and 12 mL/min) and different bed depths (3, 5 and 7 cm). The removal efficiencies of Cr(VI) were increased from 42% to 95% with increase of activated carbon bed depth from 3 cm to 7 cm.