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Order Received for Deep Tunnel Sewerage System
Phase 2 Project Contract T-08 in Singapore

September 14, 2017

Penta-Ocean Construction Co., Ltd. (President Takuzo Shimizu) has jointly received the contract for the project of the Deep Tunnel Sewerage System (DTSS) Phase 2 T-08 by PUB, Singapore’s national water agency, with its joint venture partner Koh Brothers Building & Civil Engineering Contractor (Pte.) Ltd. The total contract amount is approximately converted into JPY42.3 billion, of which Penta-Ocean has a share of JPY27.5 billion (65%). The construction period is 70 months and scheduled for completion in June 2023. This is the third contract where Penta-Ocean had been successfully awarded by PUB following the DTSS Phase 1 T-02 in 2000, and the water supply tunnel named NIPE-C4 in 2011.

DTSS Project includes construction of deep tunnel sewers to convey used water by gravity to centralised water reclamation plants located at the coastal areas. The used water is then treated and further purified into ultra-clean, high-grade reclaimed water called “NEWater”, or discharged to the sea through the outfalls.

The awarded contract T-08 is the segment of the tunnel construction including undersea parts (total length 3.5km), connecting to the water reclamation plants to be newly constructed in Tuas Basin. The tunnel with a length of approximately 9.9km will be built by means of 4 tunnel boring machines.

The DTSS Phase 1 contract T-02 was a significant milestone project marking our company’s first venture in overseas tunneling and successful completion of deep and long stretch tunnel. Subsequently, we have continued the development of a shield tunneling project. In addition to the previous achievement, getting high technical evaluation points led to this time’s order. In Singapore, we will achieve a total of 38.9km of shield tunneling and 20 tunnel boring machines including this award.

Since entering Singapore market in 1964, the Company has been participating in several large-scale projects going forward. Major infrastructure projects such as ports, harbours, subways, and expressways have been planned in this country. Based on wealth of experiences and capable human resources, we will continuously contribute to the growth of Singapore, considering the country as the most important base in our overseas business operations.

Site location

Site location

Construction outline

Project Name

Design and Construction of Sewer Tunnels for the Deep Tunnel Sewerage System Phase-2 Project Contract T-08


PUB, Singapore’s national water agency


Penta-Ocean Construction Co., Ltd. and Koh Brothers Building & Civil Engineering Contractor (Pte.) Ltd. Joint Venture

Contract Amount

Approximately JPY42.3 billion (SGD520 million)

Site Location

Jurong/Tuas District, Singapore

Construction Period

70 months (from September 2017 to June 2023)


Land Civil, Tunneling Work
[Tunnel Part]
·Construction Method: Slurry Type Tunnel Boring Machine
·Number of Shield Machines: 4nos
Internal Diameter 6.0m×2,949m
Internal Diameter 4.0m×2,762m
Internal Diameter 3.3m×2,931m
Internal Diameter 3.3m×1,307m
*Undersea Part: Total Length 3,480m [Shaft Part]
·Number of Shaft Locations: 9nos
·Depth of Shafts: 45m to 58m
·Secondary Lining, Live Sewer Connection and Odour Control Facilities etc.