On the total of 21 hectares of landfill site in the Mertesdorf waste management and recycling center, 2 already filled landfill sections are to be closed and sealed with a DK II surface sealing system.

Surface engineering section 1 (OBA1) covers around 44,000 m 2 and surface engineering section 2 (OBA 2) is about 78,000 m 2 . Both construction phases will be carried out in parallel. The construction phases are spatially approx. 400 m apart. In accordance with the federal quality standard, the external testing services (mineral and polymer) must be provided for both construction phases.

As part of the measure to shut down the two construction phases at the Mertesdorf landfill, third-party inspection services in accordance with the Landfill Ordinance are required. The associated construction measures include the production of the surface sealing of class II according to DepV. The surface sealing system consists of the following components (from bottom to top):

- Gas-permeable base and leveling layer

- Geosynthetic clay liner

- plastic waterproofing membrane

- Plastic drainage element in OBA 1 / mineral drainage layer in OBA 2

- Recultivation soil

The construction work also includes the creation of the surface drainage system, the connection of the active gas collection system, the preparation of the passive degassing and the creation of the path system.

The performance of the external inspection includes the implementation of the prescribed quality controls in accordance with the Federal Quality Standard (BQS) and the quality management plan based on it with regard to all construction services and components that are in direct contact with or in the area of influence of the surface sealing system.