The removal of many heavy metals from industrial wastewater is one of the most important environmental problems to be solved today. The retention of this contaminants by a biofilm supported on granular activated carbon or on natural zeolites is one of the promising technologies for the reduction of this problem, because it is cheap and it removes a broad range of substances, heavy metals and organic compounds. This study aims the development of a system of two mini-columns in series for the removal of chromium (VI) using a biofilm of Arthrobacter viscosus supported on two different materials: granular activated carbon and natural zeolite. The effect of the regeneration of granular activated carbon was also studied. Ministério da Ciência e Tecnologia. Fundação para a Ciência e Tecnologia (FCT) - POCTI/EQU/12017/2000 , SFRH/BD/8646/2002.