The contract covers the construction of a 15.6 kilometre tunnel with a diameter of 5 metres, from the Musafah area to Mafraq (MEED 15:1:09).

This segment is the middle section of a 42-km-long tunnel running from an existing pumping station on Abu Dhabi island to the Mafraq wastewater treatment plant and on to another plant at Al-Wathba.

Companies are also being prequalifed for four other packages on the project, covering the link sewers and a pumping station.

The estimated cost of the deep-sewer tunnel project is AED2bn ($545m).

The project is part of sewerage firm’s AED4bn Strategic Tunnel Enhancement Programme.