• Capabilities: Engineering, Geotechnical Engineering
  • Sectors: Water, Contractors

Harbor Area Treatment Scheme

Hong Kong - A 170 meter deep undersea trunk sewer tunnel system for collecting and transferring the primary treated sewage away from the urban areas.

170m

undersea trunk sewer tunnel system

100%

sewage bacteria removed

As a major tunnel part of the Harbor Area Treatment Scheme Stage 2A project, this contract involved the construction of a 12 km long trunk sewer tunnel system at up to 170 meter depth below sea level along the northern coast of Hong Kong Island and across the Victoria Harbor.

Arcadis was appointed to design the permanent lining of the shafts and the tunnels as well as provide support for the tunnels constructed by the drill-and-blast method. Due to all tunnels and shafts in rock, including their intersections, are required to be built from unreinforced concrete, this has created a greater challenge for the tunnel section along the coast of the Hong Kong Island.

Arcadis developed a design methodology using 2D and 3D numerical modelling and considered the stress level within the tunnel lining, instead of bending moment and shear in conventional design methodology. Through this innovative design approach, we enabled our client to win the construction contract and deliver it successfully.  Our blasting assessment also ensured safety of the public and the construction personnel during construction period.

Outcomes we delivered:
  • Maintained a healthy marine environment by removing 100% of the sewage bacteria from the sewage
  • Enhanced primary treatment capability of Stonecutters Island Sewage Treatment Works up to about 2.45 million cubic metres per day.


Outcomes

170m

undersea trunk sewer tunnel system

100%

sewage bacteria removed

2.45 million

cubic metres of sewage treated daily

Questions about this project

Tony Chen

Technical Director - Tunnels & Geotechnics +852 2911 2720 Ask me a question