Harbour Area Treatment Scheme

The Harbour Area Treatment Scheme (HATS) is collecting and treating the sewage on both sides of Victoria Harbour. Here you can learn about why the scheme was implemented, its phases and what the polluter pays principle is doing to help improve the water quality of our world renowned harbour.

The Situation

As the water quality in Victoria Harbour affects many people in Hong Kong, the Government initiated the HATS. The scheme coordinates the overall sewage collection on both sides of the harbour. The scheme came into full operation at the end of 2015.

Map showing the scopes of HATS Stage 1 and Stage 2A

Frequently asked questions about HATS

Stage 1 and its Accomplishments

Stage 1 of HATS treats 75% of the sewage generated from the harbour area. The infrastructure includes a 23.6 kilometre-long system of deep underground tunnels, with the capacity to move up to 1.7 million tones of sewage from Kowloon and the northeastern part of Hong Kong Island to Stonecutters Island. The treatment facility at Stonecutters is one of the largest of its type in the world. With Stage 1 fully commissioned in December 2001, the overall harbour water quality has substantially improved, which means that you can enjoy a cleaner harbour.

More on Stage 1 of HATS

Stage 2A and its Accomplishments

The major works of Stage 2A of HATS comprised construction of 21 kilometres of deep tunnels conveying the remaining 25% of sewage from northern and south-western parts of Hong Kong Islands to Stonecutters Island Sewage Treatment Works for chemically enhanced primary treatment; upgrading eight existing Preliminary Treatment Works (PTWs) in northern and south-western parts of Hong Kong Island; and upgrading the treatment capacity of Stonecutters Island Sewage Treatment Works and construction of disinfection facilities. After the full commissioning of Stage 2A at the end of 2015, all sewage from both sides of Victoria Harbour are conveyed to Stonecutters Island Sewage Treatment Works for treatment, disinfection and discharge into the western approaches of the harbour, the water quality across the harbour is overall enhanced.

Sludge treatment facility at Stonecutters Island Sewage Treatment Works

General information on Stage 2A of HATSMore details on Stage 2A of HATS

Stage 2B

The Government has completed a review of the implementation of HATS Stage 2B (the Review) which is to provide for an underground biological treatment facility adjacent to the existing SCISTW.  The Review reveals that HATS Stage 2A has already provided adequate capacity to handle the projected sewage flow and the bulk of Victoria Harbour is compliance with the Water Quality Objectives (WQOs) upon its commissioning.  The Review thus concludes that in terms of WQOs compliance, the implementation of HATS Stage 2B at this stage is not critical.  Meanwhile, the implementation of HATS Stage 2B will be kept under review taking into account the water quality situation and the latest technological development in biological treatment.

The Polluter Pays Principle

HATS and other sewerage facilities require a significant amount of resources for daily operation in order to sustain our efforts for protecting the marine environment. In accordance with the polluter pays principle, those who create waste have a responsibility for helping to pay to clean it up. We have been applying this principle in the provision of sewage services through implementation of the Sewage Services Charging Scheme, under which we currently recover only part of the operating cost through collection of sewage charge and trade effluent surcharge. The deficits are subsidised by the Government.

More on the polluter pays principleMore on sewage treatment and charges
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Last review date: April 2022