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 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.

Abu Dhabi Sewerage Services Company planned to discharge the generated sewerage from Reem Island to the STEP Tunnel located in the Island Abu Dhabi, through Trunk Sewer Link and a pumping station.
KN Intl. was awarded by the Abu Dhabi Sewerage Services Company (ADSSC) to plan, design and supervised the construction of the link sewer project. Construction works involve excavation using tunnel boring machines and casing of the tunnel with precast concrete sections. The hydraulic tunnel and the access shafts are being lined with a special membrane to protect the concrete sections. The tunnel is designed to last for about 100 years.