State utility Abu Dhabi Sewerage Services Company (ADSSC) has issued a tender to build deep-gravity sewers in the Mafraq and Bani Yas areas of the emirate.

The company has invited 10 contractors to bid for the project, which is part of its AED2bn ($544m) asset enhancement scheme.

Under the contract, the winning bidder will build 29.6 kilometres of deep-gravity sewers and take 17 pumping stations out of service.

The deadline for bids is 23 December.

ADSSC is also seeking bids for two other contracts as part of the asset enhancement scheme. The first covers the northeast part of Abu Dhabi mainland and involves the construction of 40.7km of deep-gravity sewers and the removal of 10 pumping stations. The deadline for bids is 8 December.

A third contract covers the construction of 12km of deep-gravity sewers and the decommissioning of two pumping stations on Abu Dhabi Island. Bids are due on 23 December.

The asset enhancement scheme also extends to Al-Ain in the east of Abu Dhabi emirate.

ADSSC is evaluating bids for two contracts in the area. The winner of the first contract will build 33.8km of deep-gravity sewers and remove three pumping stations in Al-Ain between Zakher and Al-Hama. The winner of the second job will build 35.4km of sewers and remove six pumping stations in Al-Ain.