Recently, the sewage treatment works have been received industrial wastes. Therefore, sewage has contained the substances of phenols, cyanides, strong acids, strong alkalis, heavy metals and others. It is important to examine the effects of these substances on biological treatment. This paper reports the effect of the toxic substance by means of the trickling filter process. It includes the effect of the toxic substance on the removal efficiency and the accumulation of copper in the slime. The copper was chosen as the toxic substance.
