Two large tunnels at depths of 20 m to 50 m. Value $5.2 billion. October 1998.    Concept is to use link sewers to intercept flows from existing gravity sewers upstream of the existing pumping stations and channel them by gravity through deep tunnels to centralised STWs at the south coast and thence to discharge via deep sea outfalls. With up to 45 m water pressure, tunnels will be driven by EPB or slurry TBM with sealed, bolted, grouted precast concrete segmental lining. Final lining will be cast-in-place concrete with corrosion-resistant membrane.   North tunnel from Changi East to Kranji comprises five contracts. T-01 is for 5.9 km of 6.0 m i.d. tunnel with 5 shafts; T-02 is for 7.7 km of 6.0 m with 7 shafts and an odour control facility (OCF); T-03 for 5.2 km of 6.0 m with 10 shafts, 3 ODFs, and a 250 m lateral connector; T-04 is for 7.2 km of 4.3 m i.d. with 9 shafts, 2 ODFs, and an 800 m lateral connector; T-05 is for 12.5 km of 3.6 m i.d. with 11 shafts and one ODF. Eastern two-thirds of the North tunnel is in Old Alluvium, a competent tunnelling medium. Western one-third in granite.   Spur tunnel T-06 connecting Tanglin and Holland Road areas comprises 9.7 km of 3.3 m i.d. tunnel with 8 shafts. Alignment is in fractured sedimentary rock, dense soil and faulted ground requiring shielded TBM with hard and soft rock capability.   Tendering process complete and award imminent. Visit www.gov.sg/gitis/ for full information about tendering contractors and amounts. October 1999.   Design and construct contract for T-02 Bedok tunnel awarded to Penta-Ocean Construction Co. Ltd value S$75.6 bn plus Y1.3 trillion. Design and construct contract for T-05 Kranji tunnel awarded to jv of Philipp Holzmann/Sembcorp value S$139.5 bn. Visit www.hlzm.de January 2000.   Contract T-04 for the Ang Mo Kio tunnel of the Singapore Deep Tunnel Sewerage System has been awarded to Samsung Corporation of 83 Clemenceau Avenue, #09-01 UE Square, Singapore 239920 in the value of $45 million by the Ministry of the Environment, Sewerage Dept, tel +65 731 9591. Source www.gov.sg/gitis/ March 2000. Remaining contract awards as follows: T-01, Changi tunnel value $47.4 million to jv of WohHup and Shanghai Tunnel Engineering; T-03 Paya Lebar tunnel value $40.5 million to jv of Kumagai Gumi and Sembcorp; T-05 Kranji tunnel value $83 million to jv of Sembcorp and Philipp Holzmann. All contracts include shafts. Contract for T-06 tunnel between Tanglin and Holland Road awaiting award. Visit www.gov.sg/gitis/ for more information. May 2000. T-06 contract for 9.6 km x 3.3 m-diameter section between Tanglin and Holland Road value $60 million awarded to Zueblin Queensway who will use two Herrenknecht TBMs for completion May, 2004. On the other five contracts the shafts are under construction at 1.8 m and 3.0 m diameter for access and 10 m to maximum 16 m for working, with depths of 20 - 50 m. First TBM arrives December, 2000 to start early 2001. T-01 will use Herrenknecht TBM; T-02 NKK TBM; T-03 Mitsubishi TBM; T-04 Mitsubishi TBM; and T-05 two Herrenknecht TBMs. Visit www.herrenknecht.com and look out for www.dtss.gov.sg under construction. Sept 2000.  Braddle Road in Singapore is reported as having been lowered by a few centimetres. The event occurred shortly after the drilling of a probe hole. Contractors are working in the vicinity on contract T03 of the deep sewer scheme. Their TBM was awaiting an unsealed launch from the adjacent shaft, when sand and water entered the chamber. Local correspondents have noted the spatial juxtapositioning of the three events. Visit www.lta.gov.sg 19/01.Invitation to tender, deadline 16th September, 2005 for civil engineering for River Valley Link Sewers Contract 2 of the Deep Tunnel Sewerage System. The tender is for the laying of 3 km of reinforced concrete sewer pipes of 1,800 mm and 2,100 mm diameter by pipejacking/microtunnelling method. The contract, when awarded, will have a period of 30 months. Visit www.gebiz.gov.sg, click on Tender Notice and enter PUB000ETT05000138 as ITT No. or contact Public Utilities Board, Singapore, tel. +65 67319567, fax +65 67319699 or e-mail cheng_lay_beng@pub.gov.sg 35/05.

A joint venture between Black & Veatch and AECOM has been selected by PUB, Singapore’s national water agency, to provide engineering services for Phase 2 of the Deep Tunnel Sewerage System (DTSS).

DTSS Phase 2 will extend DTSS to the western side of Singapore through a 30 km-long South Tunnel, nearly 70 km of link sewers, the Tuas Water Reclamation Plant (WRP) and an estimated 12 km-long deep-sea outfall. The entire DTSS will result in a 50-percent reduction in land taken by used-water infrastructure with three centralized collection and treatment points: Changi WRP in the east; Kranji WRP in the north; and Tuas WRP in the west. A NEWater factory will be integrated with the Tuas WRP and contribute to Singapore’s long-term goal of increasing NEWater production to meet up to 55 percent of its total water demand. For further information click here. Visit http://www.nas.gov.sg/archivesonline/data/pdfdoc/20140610004/media_release_pub_dtss2_signing_ceremony_nea_iwmf.pdf 24/14.

Public Utilities Board (PUB) has appointed Shanghai Tunnel Engineering Co (S) Pte Ltd STEC to design and construct a subsea tunnel (1.6km lenght and 6m internal diameter) along with twin 2200mm and 1200mm diameter water pipelines connecting the Proposed Tuas Water Reclamation Plant (TWRP)/Tuas NEWater Factory to existing network in Jurong Island.  

The TWRP - Tuas Water Reclamation Plant Contract 1 value is EUR81.28 million (SGD116 million). TWRP is a key element of DTSS Phase 2 which advances Singapore's water sustainability. The plant will treat industrial and domestic used water from the western half of Singapore which will be further purified for reuse. With a treatment capacity of 800,000 cubic meters per day, Tuas WRP will be the largest facility of its kind in the world. Construction works are set to begin in July 2021 and are due to be completed in 2024.Visit http://www.stecs.com.sg and https://app.pub.gov.sg/. 26/21.