PURPOSE: The foul water can be processed continuously. The foul water can be processed without the breakthrough of the residual contamination circle. Provided is the processing method of the city sewage containing the volatile organic compound or the other pollution source or the foul water including the industry wastewater. CONSTITUTION: A wastewater treatment method. With the supply of the processing object city sewage containing the volatile organic compound or the other pollution source or the foul water including the industry wastewater(7). The swing of substitution to the activated optical catalyst of the supply of the media required for the deactivated optical catalyst regeneration or the deactivated optical catalyst(6). The step that at the same time operates is included alternately in other words among two or more UVs or visible ray / optical catalyst reaction processes.
