When constructing a factory in the sewerage treatment planning area, is it mandatory to remove the factory wastewater (including harmful substances such as BOD and heavy metals) generated from it to the sewer after establishing a prescribed abatement facility? .　Or is it possible to install the necessary wastewater treatment equipment in the factory, treat it to water quality that conforms to laws and regulations, and then release it to nearby public water bodies?

When constructing a factory in the sewerage treatment planning area, there is an obligation to connect to the public sewerage system in the area where the notification of the sewage treatment zone is notified. At the same time, when discharging wastewater containing substances that exceed the water quality standards stipulated by the Sewerage Law, etc., it is necessary to treat the water quality that meets the standards by abatement facilities, etc., and then discharge it to the public sewerage system.

On the other hand, in areas where the notification of sewage treatment zones has not been notified, there is no obligation to connect to the public sewer. However, when draining wastewater into public water bodies, the Water Pollution Control Law is applied.