If you wish to discharge wastewater into a private wastewater treatment plant, you can be exempted from the requirement to obtain a wastewater discharge permit under certain conditions.

For certain industries and activities (such as the chemical industry, paper production, metal processing, cooling water use), pollutants are to be expected in the wastewater that are not sufficiently purified in a municipal sewage treatment plant. Requirements for this are set out in the sector-specific annexes to the Waste Water Ordinance.

In order to comply with these requirements, special measures and wastewater pre-treatment plants are required to reduce the pollutant load so that the wastewater can then be purified without harm in a public or private wastewater treatment plant.