Strategic Tunnel Enhancement Programme (STEP) is a huge gravity-driven hydraulic wastewater network tunnel currently being constructed by the Abu Dhabi Sewerage Services Company (ADSSC). The construction activities started in 2009 with the prequalification process commencing earlier in August 2008.
The project, which is scheduled for completion in 2015, is being carried out with an investment of AED 5.7bn ($1.9bn), with CH2M Hill as the program manager.
The current project forms a crucial part of Plan Abu Dhabi 2030, which is a comprehensive plan of developing Abu Dhabi to accommodate the increasing population in the city, which is anticipated to reach three million by 2030.
The project is expected to supply 15 cusec of greywater for irrigation. As of February 2013, 33km of the overall 41km of the tunnel has been tunnelled.
ADSSC currently treats nearly 450,000m³ of wastewater a day. It will be capable of treating 800,000m³ of wastewater when the STEP project is realised