Qatar’s Public Works Authority (Ashghal) has invited companies to submit prequalification entries for two major sewerage schemes.

Contractors have until 28 February to submit prequalification documents for the design and build (DB) contracts for the Al-Shamal sewage treatment works and the expansion of the Doha Industrial area sewage treatment facility.

For the Al-Shamal treatment project, the work will involved design, building, operation and maintenance of a new central sewage treatment plant to serve the Al-Shamal township and the neighbouring areas. The new treatment facility will replace the existing package treatment plant on the same site. The capacity of the new treatment centre will be 7,500 cubic metres a day (cm/d) average flow, with the ability to treat an instantaneous peak flow of 234 litres a second (l/s).

The contract will also include the design, construction, operation and maintenance of a septage tanker reception station, treated sewage effluent (TSE) pumping station and a TSE tanker filling station together with the designs of both foul sewage and TSE long-distance transfer pipelines. The contract for the Al-Shamal scheme is expected to be tendered in June, with a contract award scheduled for January 2014.

For the Doha Industrial Area sewage treatment facility, work will involve designing, building and commissioning of the phase 2b expansion.  The expansion will increase the capacity of the facility by 24,000 cm/d average flow with a capability to treat an instantaneous peak flow of 834 l/s. The contract will also involve the design, construction and commissioning of a TSE disposal unit through ground injection. The work will take 24 months to complete, and tenders are expected to be issued in June this year, with a selection of the winning contractor scheduled for January 2014.

The contracts are the latest of several major schemes that Doha is planning to expand the country’s sewage treatment capabilities.  

In January, Ashghal invited local and international contractors, and consultants to attend a briefing on the Inner Doha Resewerage Implementation Strategy (Idris).

The estimated QR20bn ($5.5bn) 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 sewerage treatment plant, 92km of treated sewage effluent return facilities and the decommissioning 37 existing pump stations.

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.