Abstract Polluted surface water was remediated in a bioreactor using biofilms on filamentous bamboo in batch and continuous flow modes. The CODcr (Chemical Oxygen Demand, using K2Cr2O7 as oxidizer) removal rate of the enhanced systems increased more than 13% relative to a controlled system. In the batch reactor with 4-h cycles, the CODcr was mainly removed by the biofilm on the filamentous bamboo. The removal rate of the CODMn (permanganate index), NH4+–N (ammonia nitrogen), turbidity, and total bacteria were 11.2–74.3%, 2.2–56.1%, 20–100%, and more than 88.6% in a continuous flow biofilm reactor with a 3.5h retention time. The biofilms contained diverse organisms including protozoa and metazoa.