The territory’s Drainage Services Department has signed a 248 million Hong Kong dollar (HKD) ($32m) consultancy agreement with engineering design firm AECOM Asia Company for the relocation of the Sha Tin sewage treatment works to underground caverns.
Investigation and design works for the proposed project are scheduled for completion in phases from 2017 with the completion of construction expected in 2022. The estimated cost of the investigation and design stage is nearly HKD 638m ($82m).
Director of drainage services Daniel Chung said the relocation project would release the existing 28-hectare Sha Tin site for housing and other uses “that can improve livelihoods”.
Chung said the scheme was “an innovative project that makes effective use of underground space for sustainable development and enhances the environment for the community's benefit”.
The scope of the consultancy agreement covers preliminary and detailed designs, detailed impact assessments, site investigations, public information activities, tendering and supervision of future construction work.
The existing Sha Tin facility, which has a design capacity of 340,000 cubic metres per day, lies at the mouth of the Shing Mun river and is the largest secondary sewage treatment works in Hong Kong.
According to project study documents (2-page / 160 KB PDF), “land is a scarce resource in Hong Kong and there is a pressing need to optimise the supply of land for various uses by sustainable and innovative approaches to support social and economic development”.
The study said: “One practicable approach is rock cavern development”. There have already been successful examples in Hong Kong of relocating service facilities to caverns, including the Stanley sewage treatment works that was completed in 1995. In 2009, the relocation of above-ground saltwater reservoirs to caverns released the site that is now home to the University of Hong Kong’s Centennial Campus.
“These projects have demonstrated that rock caverns are valuable resources, while providing added environmental, safety and security benefits for many applications,” the study said.