Qatar’s Public Works Authority (Ashghal) is evaluating prequalification entries for the five main packages on the estimated QR10bn ($2.7bn) Inner Doha Resewerage Implementation Strategy (Idris).

Ashghal received prequalification entries from contractors in late May for the projects, three of which will be design and build packages, and the remaining two will be design, build and operate deals.

The first contract is a design and build package to build lateral interceptor sewers, while the second package is a design and build deal to build the main trunk sewer. The third design and build package is for a terminal pump station.

The final design and build package is for the construction of the treated sewage effluent (TSE) return system.

The first design, build and operate package is for the New Doha South sewage treatment works. The other design, build and operate package is for the terminal pump station for the New Doha South sewage treatment works.

The Idris project involves building a series of deep tunnels that will serve the Doha South catchment area over the next 50 years. The scheme will eliminate the need for pumping stations in the Doha South area.

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

Once treated, the effluent will then be transported to any end-user via a TSE return system. Once complete, up to 500,000 cubic metres a day (cm/d) of high-quality TSE will be produced that can be used for irrigation and other purposes.

More than 300 companies attended an industry briefing on the Idris scheme held by Ashghal in January. Completion of the Idris scheme is planned for the end of 2018.

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