HATS Stage 1 provides treatment to 75% of sewage from both sides of Victoria Harbour. With the full commissioning of Stage 1 in end 2001, about 600 tonnes of sewage sludge are prevented from entering Victoria Harbour every day and the water quality of Victoria Habour has improved significantly.
HATS Stage 2A provides treatment to the remaining 25% of sewage from the northern and southwestern parts of Hong Kong Island. In addition, a disinfection facility is installed to further improve the quality of the harbour waters. The implementation of HATS Stage 2A leads to significant improvement in the harbour water quality. The provision of disinfection under Stage 2A removes over 99% of the E. coli from the sewage, making it possible to re-open the Tsuen Wan beaches.
An average increase of ABOUT 13% of dissolved oxygen (vital for marine life) in the harbour waters, bringing obvious benefi ts to marine ecology.
Treat all the sewage discharging to the harbour
Maintain a healthy marine environment whilst meeting future development needs
The levels of key pollutants in the harbour waters have generally decreased:Ammonia nitrogen (toxic to marine life) has declined by 40%;Total inorganic nitrogen (nutrients, which in rich supply can increase the likelihood of red tides) has reduced by 16%;The overall E. coli level (an indicator of disease-causing micro-organisms) has reduced by some 90%
See more species of marine life
Remove the sight of sewage plumes
Resume cross harbour race
Re-open the tsuen wan beaches
Prospects: To facilitate the sustainable development of the harbour area in the long term, HATS Stage 2B will be constructed near to SCISTW and will provide biological treatment to all the effluent, thus improving water quality further. The time table for the implementation of HATS Stage 2B will be subjected to review, taking into account the increase in population and water quality trends.