The Public Works Authority’s (Ashghal) QR10bn ($5.5bn) Inner Doha Resewerage Implementation Strategy (Idris) is one of the largest infrastructure projects planned in Qatar.

The project’s deep tunnels will use gravity to transport effluent, eliminating the need for pumping stations

The scheme aims to meet southern Doha’s sewerage requirements for the next 50 years by taking effluent away using sewers that connect to large-diameter tunnels.

The project’s deep tunnels will use gravity to transport the sewage, eliminating the need for pumping stations that would take up valuable real estate space in downtown Doha.

The construction work involves building 76 kilometres of lateral interceptor sewers, 33km of trunk sewer, a terminal pumping station, the New Doha South wastewater treatment plant, 92km of treated sewage effluent return facilities, and the decommissioning of 37 existing pump stations.

Ashghal plans to split the project into six packages, some of which will be divided further into individual contracts.

• Package 1: three design and build contracts for the lateral interceptor sewers
• Package 2: three design and build contracts for the main trunk sewer
• Package 3: a design-build-operate contract for the terminal pumping station
• Package 4: a design-build-operate contract for the New Doha South sewage treatment plant
• Package 5: three design and build contracts for the treated sewerage effluent return systems
• Package 6: two contracts for the decommissioning of the pumping stations

The first contracts on the resewerage programme are expected to be tendered this year and construction work on the project is due to get under way in mid-2014. Completion is planned for the end of 2018.

Ashghal held briefing sessions with several hundred interested local and international contractors, and consultants on Idris on 23 January in Doha.

Ashghal appointed the US’ CH2M Hill in late 2011 to manage the scheme. The company has worked on the concept and preliminary designs, and will also manage the design and construction consultants.