In order to evaluate the effect of preozonation on GAC adsorbability and biodegradability and to discuss the performance of BAC, three kinds of batch experiments have been conducted, using humic acid as the test substance. Conclusively, it is recognized that preozonation evidently improves the biodegradability of humic acid, but the equilibrium adsorption constant k, is not changed. However, the adsorption rate is greatly improved. Based on these results and continuous experiments, the characteristics of the removal mechanism of organics by a BAC filter and a GAC filter are compared.