Abu Dhabi Sewerage Services Company (ADSSC) is inviting bids for two further contracts to build sewerage networks as part of an AED2bn ($544m) infrastructure programme.

Under the wider project, called the asset enhancement scheme, the state-run utility is asking contractors to build a total of 137 kilometres of gravity sewers, which will enable ADSSC to axe 36 pumping stations.

The two new tenders are for Abu Dhabi Island and northeast region of the Abu Dhabi mainland.

“The asset enhancement programme is an investment driven primarily by anticipated demand on the system as a whole,” says Shahzad Orakzai, manager of the programme management department at ADSSC.

The winner of the contract for the northeast region will build 26.7km of sewers with capacity to serve a population of 1.6 million.

The contractor will also be required to remove six pumping stations from service and build a temporary replacement. The bid deadline is 8 December.

Under the contract covering Abu Dhabi Island, the contractor will remove two pumping stations from service and build another temporary facility.

The contractor will also build 12km of sewers with capacity to serve 1.3 million people. Bids are due in mid December.

ADSSC has put a third tender for Mafraq and Bani Yas on hold while it waits for approval from Abu Dhabi’s Urban Planning Council. It has already selected a preferred bidder for a fourth contract, for the Al-Ain region.

It is now waiting for approval from the emirate’s Executive Council before it can make an award. The winning bidder will build 69 kilometres of sewers and decommission 11 pumping stations. The new system will have capacity to serve 707,000 people. Combined, the four contracts will add 137km of sewers, enough capacity to serve a population of 3.9 million.