Abu Dhabi Sewerage Services Company (ADSSC) has appointed UK-based consultant Mott MacDonald to provide contract administration and site overview services for the estimated AED2bn ($572m) contract to build a pumping station on its Strategic Tunnels Enhancement Programme (Step).

When completed, the pumping station will be more than 100 metres deep and about 40 metres in diameter and will have an ultimate peak pumping capacity of approximately 3.3 million cubic metres a day (cm/d).

Brazil’s Odebrecht was awarded the contract to build the pumping station at the end of 2011.

The contract is a crucial part of the Step scheme, which will overhaul Abu Dhabi’s sewerage system with a network of deep gravity sewers and tunnels.

Construction has already started on the scheme’s three tunnel packages that were awarded by Adssc in 2009 and 2010.

Italy’s Impregilo is working on the AED785m second tunnel contract for Step. It involves the construction of a 10-kilometre-long tunnel between Mafraq and Al-Wathba.

Impregilo is also working on the AED891m contract to build the middle section of the 40km-long tunnel from Mussafah to Mafraq.

South Korea’s Samsung C&T is working on the third estimated AED1.1bn tunnel contract, which involves digging a 16.1km, four-metre-diameter tunnel from Abu Dhabi island to the Mussafah area.

US-based CH2M Hill is the programme manager for the overall Step scheme.

The project is due for completion in 2015.