The ability of granular activated carbon (GAC) and bone char to be regenerated by bacteriological activity has been investigated using an azo-dye adsorbate. The azo dye/granular activated carbon system proved difficult to regenerate due to poor dye desorption. However, the non-activated bone char/azo dye system was successfully regenerated using a consortia of bacteria. Although azo dyes are relatively resistant to degradation, the consortia of bacteria including Flavobacterium sp. was able to break the azo bond and degrade the dye. These results support the hypothesis of adsorbent regeneration occurring by the desorption of sorbate from the pore structure to the biomass in the macropores of the adsorbent. Scanning electron microscopic (SEM) investigations have shown that bacteria successfully colonize the macropore structure of GAC and bone char adsorbents.