Hong Kong harbour area treatment

Year:2001: stage 1, 2015: stage 2

Duration:Stage 1: 7 years, Stage 2: 6 years

Cost:HK$25.8bn (about £2.5bn)

Country: Victoria Harbour, Hong Kong

What did this project achieve?

In Hong Kong’s Victoria Harbour get rid of the sewerage, bad smells and disease

The harbour area treatment scheme (HATS) is a major sewage treatment project designed to clean up Victoria harbour in Hong Kong.

HATS serves up to 5 million people living near the harbour and run by the city-state’s drainage services department.

The scheme aims to treat sewage before it’s discharged into Victoria harbour – improving the quality of water for residents as well as marine wildlife.

Stage 1 of HATS was completed in 2001. It saw the construction of a 23.6km tunnel to transfer sewage from Kowloon – the most densely-populated area of Hong Kong – to a treatment works at nearby Stonecutters’ Island.

This first stage of the project treats about 75% of sewage pumped into the harbour.

Stage 2 of the scheme – dealing with waste from the northern and south-western parts of Hong Kong - was completed in 2015. The project included an upgrade of the Stonecutters’ Island treatment works.

The improvements HATS has made to water quality in the harbour has led to the reinstatement of Hong Kong’s annual cross-harbour swimming race.

The sporting event had been banned for 33 years amid fears swimmers could pick up diseases from polluted waters.

Difference the sewerage treatment has made

The HATS scheme has improved the quality of the water in Victoria harbour. It’s made both the harbour and Hong Kong’s beaches safe for swimming.

The harbour and nearby areas have been redeveloped as part of the scheme – creating a more pleasant environment for Hong Kong locals and increasing tourist income for the area.

The Victoria harbour front has stopped smelling of sewage.

How the work was done

The 2 stages of the HATS scheme involved the construction of 44km of deep level sewage tunnels and the expansion and upgrade of the Stonecutters’ Island sewage treatment works.

Stage 1 of the scheme started in 1994 and saw engineers construct 23.6km of segmental lined tunnels 130m below sea level.

The new tunnels were designed to carry sewage from Kowloon to the treatment plant on Stonecutters’ Island – set to be upgraded in stage 2 of the works. Waste had previously been pumped directly into the harbour.

The project team also upgraded 7 existing preliminary treatment facilities on the island as part of stage 1.

Overhauling the Stonecutters’ Island treatment works was a large part of stage 2 of the scheme.

The HATS project team constructed a new underground pumping station for the Stonecutters’ Island plant. Engineers also built new disinfection facilities and installed a state-of-the-art computer system for the scheme.

The upgrade to the treatment works aimed to increase the daily capacity of the plant from 1.6m metres³ a day to 2.8m³ a day.

"​‌

A quiet revolution is taking place in Victoria Harbour as nature starts to reclaim the waters.

Ian Brownlee, planning consultant

South China Morning Post, November 2015

Fascinating facts

HATS has reduced the amount of E coli in water near Stonecutters’ Island by 99%. Other pollutants in the harbour have dropped by around 75%.

E coli bacteria can cause diarrhoea, respiratory problems and pneumonia - among other illnesses.

Cleaner waters in Victoria harbour have led to the return of coral to the bay. Most types of coral can’t survive in polluted water.

People who made it happen

  • Client: Drainage services department, Hong Kong
  • Consulting engineers: Ove Arup and Partners (Hong Kong)
  • Construction engineers: Gammon Construction Ltd, Leighton LNS Joint Venture

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