Dubai Municipality has raised the budget for its planned deep tunnel sewer network to AED30bn ($8.2bn).

Hussain Nasser Lootah, director general of Dubai Municipality, has revealed that the project is planned to be developed between 2019 and 2025, and will have an estimated cost of AED30bn. The Municipality had previously stated the planned budget was AED12.5bn.

The increase in budget may be a reason behind the municipality’s decision to prepare plans to develop the deep tunnel scheme under a public-private partnership (PPP) model. MEED reported in June that Dubai had appointed Netherlands-based KPMG to advise the municipality and assist with preparation for developing the project under a PPP model. The project had originally been planned to be developed through conventional EPC packages.

The Dubai Strategic Sewerage Tunnels project will contain two main tunnels with a total length of 75km. The Bur Dubai deep tunnel will have a total length of 50km and the Deira tunnel with have a total length of 25km. The tunnels will be supported by about 140km of link sewers and two major pump stations. The tunnels will reach depths of up to 90m below ground level.

The deep tunnel sewerage network and 2 major pump station will replace 11 major pump stations and more than 100 other pump stations that currently serve Dubai’s wastewater network.

In May 2016, the municipality awarded US-based Parsons a consultancy contract for the tunnels project, which will have a total length of 75km. The firm was awarded the contract to provide a number of consultancy services for the duration of the project, including feasibility studies, preliminary design, tender preparation and support. The consultant was also due to provide programme management of the detailed design and construction phases and supervision of the construction of the primary tunnels.