Victoria Harbour's water quality is set to improve when the second stage of the Harbour Area Treatment Scheme reaches its halfway mark next year.
Hong Kong's famous landmark should see 90 per cent of the current Ecoli eliminated from discharged sewage.
During this stage of the project, the Drainage Services Department will upgrade the 10-hectare sewage treatment works on Stonecutters Island in West Kowloon by building the world's largest underground pumping station.
There will be eight pumps and each pump can process sewage equal to one standard swimming pool in 10 minutes.
A tunnel will connect it to the existing works to allow the diversion of the waste.
A new conveyance system will take the waste from eight preliminary treatment works on the north and south of Hong Kong Island to the upgraded Stonecutters Island works for sedimentation and disinfection via an underwater tunnel.
"We will see a cleaner Victoria Harbour, which will provide a better living environment for the marine ecosystem," said Henry Chau Kwok-ming, the department's chief engineer for the scheme.
Chau added that the level of oxygen in the sea water in the harbour would increase by 5 per cent, as more organic waste from the sewage was removed.
This gain is on top of the 10 per cent increase already achieved by the first stage of the scheme.
"The water quality [of the Victoria Harbour] is expected to improve, as 90 per cent of the Ecoli will be eliminated from the point of sewage discharged, after the expansion of the disinfection facility [on Stonecutters Island]," said a spokesman for the department.
The first half of the second stage of the scheme is expected to be completed in late 2014, and has cost HK$17 billion.
When finished, the Stonecutters Island sewage works will treat up to 2,450,000 square metres of sewage per day.
The scheme, which was commissioned in 2001, has already treated 75 per cent of the sewage generated from the harbour area using a chemically enhanced primary treatment process to remove solids and organic matter.
There are also plans for new biological treatment facilities on the island.