Longest Multi Curvature Sewer Tunnel in the Middle East

With the exception growth of population and strategic plans and 2030 Vision to provide capacity to meet the needs of existing and future development in Muharraq Governorate, a BOOT Sewerage Treatment Plant and Conveyance system project was built in Kingdom of Bahrain. The project set out and covers the area of Muharraq, HIDD and Arad, consist of two parts, civil construction of the STP plant, and the other parts, sewer conveyance system. The Sewer conveyance system are constructed in two major section, main collection tunnel – Deep Gravity Sewer (DGS) and lateral connection to replace two major sewage pumping stations and 22 minor across the coverage area – Waste water collection network (WWCN). The WWCN pipeline collects the sewerage and direct it towards the DGS pipeline. The DGS convey the sewerage through gravity tunnel to the treatment plan through an intermediate lifting station (ILS). Concerning the environmental effects, disturbance to the population and neighborhood and impact on the UNESCO protected building (Fort Arad), the DGS route consist of 15.9km of pipeline of DN1000, DN1400 & DN1800 was executed by Micro-tunnelling method. The success of the project contributed the reduction of energy use, reduced risk of odor, traffic disruption during maintenance, sewers backing up and associated sewage flooding. The sewage undergoes treatment process to produce Treated Sewage Effluent (TSE) suitable for re-use in industrial application, irrigation or landscaping. 

47 nos. of shafts are constructed with Secant Pilling method to provide a watertight pit for the microtunnelling activities then later converts to permanent manholes. 

Trenchless installation methods have less impact on the environment and the existing infrastructure than other methods applying open cut trenching. I.CO.P. had undertaken 5.5km of the DN1800 pipeline. Two sets of Herrenknecht AVN1800 were utilized to tunnel the GRP Encased RC Jacking Pipe. The major challenges encountered during the execution of the works are the existing ground conditions (Layered of Anisotropic sequence of rock), high ground water table with influents of sea tidal, long and multiple curvature drives, historical and protected areas and tight construction tolerances. 

I.CO.P claims two major milestone records on the project by executing the longest DN1800 Sea Crossing (892m) and longest DN1800 Multiple Long Curvature Drive (955m with 2 sets of S-curves). Both records are not only valid in the Kingdom of Bahrain but throughout the Middle East Region.