Who is obliged (and entitled) to build and operate a wastewater system depends on the obligation to dispose of wastewater.
In principle, this lies with the independent cities, the municipalities not belonging to an association and the association municipalities, which must properly dispose of the wastewater produced in their area; in principle, they must construct and operate the necessary facilities and plants for this purpose.
In the case of wastewater disposal from individual properties in outdoor areas or from commercial operations or facilities, the obligation to dispose of wastewater can be transferred to the authorized users or the commercial operation or the operator of the facility at the request of the municipality responsible for wastewater disposal.
In these cases, the new responsible parties may then have to set up their own wastewater facilities in consultation with the local authority responsible for wastewater disposal before discharging into the public sewer system, for which a plant permit under water law is then required.
Which plants do not require a permit is determined by the State Water Act.
If the wastewater system is part of a higher-level system that requires approval in accordance with the Federal Immission Control Act (BImSchG), the water law requirements are also taken into account in the BImSch approval. However, this does not apply if a permit under water law is required, which includes the plant permit under water law.
The documents and plans for the permit application must be prepared by a competent person within the meaning of the State Water Act who is entered in a list maintained by the Rhineland-Palatinate Chamber of Engineers or in a directory maintained there. Registration in a comparable list of another federal state is also valid in Rhineland-Palatinate.
This does not apply to projects of local authorities (with the exception of local municipalities) if the plans and documents have been drawn up by competent members of the administration.
For wastewater treatment plants designed for organically polluted wastewater of 120 kg per day or more biochemical oxygen demand in five days (raw) or for inorganically polluted wastewater of 10 m³ or more wastewater in 2 hours (excluding cooling water), at least a preliminary assessment of the individual case is required to carry out an environmental impact assessment.
