주요 공학 기술 컨설턴트는 싱가포르의 깊은 터널의 하수 처리 시스템(DTSS)의 2단계를 건설하기 위한 PUB사업에 대한 관리자 결정을 간절히 기다리고 있다.

최종 결정자들 중에는 2013년 10월 24일 까지 관리자에게 서류를 제출한  CH2M Hill, Arup 와 Black & Veatch/AECOM사이의 합작 투자 기업이 있다.

원래 계획에 따르면 DTSS의 2단계 건설은 2014년 7월 1일에 시작되어야 하지만 수 십억 달러의 프로젝트에 착수 할 컨설턴트 결정은 오는 달에 발표될 것으로 보인다.

DTSS의 첫 단계는 27억 달러가 투자된 아시아 최대의 공학 프로젝트다. 이 프로젝트는 1997년에 시작해 2008년 완공됐다.

Major engineering consultancies are eagerly anticipating a tender decision from utility PUB for the construction of the second phase of Singapores Deep Tunnel Sewerage System (DTSS).

CH2M Hill, Arup and a joint venture between Black & Veatch/AECOM were among those shortlisted and which submitted tender documents before the October 24 deadline in 2013.

According to the original schedule, construction on the second phase of Singapores DTSS project should have started on January 1 2014. However, a decision on which consultancy will undertake the multi-billion dollar project is expected to be announced over the coming months.

At a cost of US$2.7 billion, DTSSs first phase was at the time considered one of Asias largest engineering projects.

Covering the north and east of the island, the engineering and construction work for the deep sewer tunnels, the link sewers, Changi water reclamation plant (WRP) and the Changi outfall was broken down into nearly 50 main consultants and contractors and 300 sub-contractors and suppliers. Work started in 1997 and was completed in 2008.

The deep tunnel component included 48km of large diameter sewer tunnels built up to 50m below the ground. A total of eight tunnel boring machines (TBMs) ranging up to 7.2m in diameter were used.

DTSS 1 was constructed with a 100 year design life. A corrosion protection lining was installed to help mitigate the sulphuric acid generated by the high sewage temperatures in Singapore from attacking the lining.

A HDPE primary lining was then used, followed by over 200mm of reinforced concrete for the secondary lining. This was cast against the structural lining of the pre-cast concrete segments.

As well as a shorter, 18km deep tunnel, Phase 2 will also include a new wastewater reclamation plant (WRP) in Tuas.

Singapore is not the only nation undergoing an enormous tunnelling project. Abu Dhabi in the UAE is undergoing a US$1.5 billion Strategic Tunnel Enhancement Programme (STEP). The 40km deep sewer tunnel, up to 80m underground, includes new link sewers and a pumping station.

Meanwhile Qatars Public Works Authority ? Ashghal ? is undergoing the Inner Doha Re-sewerage Implementation Strategy (IDRIS). The 40km long deep trunk sewer programme will include over 70km of lateral inceptor sewers. It will provide a long-term solution to serve the needs of Doha, Al Wakra and Messaieed.

London, too, is undergoing the Thames Tideway project a 25km tunnel running 80m under the River Thames (see WWi article). Eventually the project should help alleviate pressure off of old Victorian sewers that come under strain with storm water during periods of heavy rain. Labelled the super sewer, the project is worth ￡2.8 billion (US$4.6 billion).

Singapore is already ahead of the pack when it comes to water management. All eyes and ears of the industry are awaiting the decision from PUB on DTSS 2 - a project that will eventually put it even further ahead and create infrastructure that will last 100 years.