Water pollution has increased with urban development and Hong Kong now produces more than two million tonnes of sewage every day. The lack of proper treatment for most of the sewage from the generally older urban areas around Victoria Harbour in the past had resulted in poor water quality there. But in 2002, following the full commissioning of the first stage of the Harbour Area Treatment Scheme (HATS) at the end of 2001, there has been a marked improvement.

    In addition, pollution control at source is now having a positive effect, and river quality is slowly improving. The percentage of rivers in the 'good' and 'excellent' categories increased from 34 per cent in 1986 to 74 per cent in 2002, and the percentage in the 'bad' and 'very bad' categories fell from 45 per cent in 1986 to 13 per cent in 2002.

Sewage Treatment and Disposal

To treat wastewater from the main urban area, sewage collected by the local sewerage network on both sides of Victoria Harbour will be directed to the HATS system for treatment and disposal. The HATS, previously known as the Strategic Sewage Disposal Scheme, is a huge project that is divided into four stages.

    The first stage, which collects sewage from the urban areas of Kowloon, Tsuen Wan, Kwai Tsing, Tseung Kwan O and the north-eastern part of Hong Kong Island for treatment at a sewage treatment plant at Stonecutters Island on the west coast of the Kowloon Peninsula, was brought fully into operation at the end of 2001. In addition to the treatment plant, which some experts considered as one of the most efficient of its kind in the world, the first stage comprises a number of preliminary treatment works at collection nodes, 23.6 kilometres of transfer tunnels up to 150 metres deep, and a tunnelled outfall which disperses the treated effluent into the western anchorage area away from core Victoria Harbour.

    Since commissioning, the system has performed very well. The Stonecutters Island Sewage Treatment Works, which employs a chemical treatment process, has been consistently removing about 70 per cent of the organic pollutants and 80 per cent of the solids from the sewage prior to discharge. Since the first stage actually treats about 70 per cent of the wastewater generated in the harbour catchment, it has thus reduced the total pollution load on the harbour waters by about 50 per cent. The sludge that once flowed into the harbour each day, amounting to about 600 tonnes, is now effectively being removed at the treatment works and sent to Hong Kong's modern landfills for disposal. This has brought about marked improvements in water quality in the harbour. At the eastern end of Victoria Harbour, the levels of sewage bacteria have declined by about 90 per cent, significantly reducing public health risks. Throughout the core harbour area dissolved oxygen has increased by 15 to 20 per cent and ammonia has declined by 30 to 50 per cent, helping to restore water quality to a more natural and ecologically healthier condition.

    The original proposal for the subsequent stages of the scheme envisaged collection of the remainder of the untreated sewage around the harbour (from northern and western parts of Hong Kong Island) using a similar system of deep tunnels, centralised treatment at the works at Stonecutters Island, and eventual discharge of the treated effluent, after disinfection, through a long tunnelled outfall into the deep, oceanic waters to the south of Hong Kong.

    This concept was reviewed in 2000 by a panel of international experts. In their report to the Government, the experts confirmed the use of deep tunnels and centralised treatment as an acceptable and cost-effective way of dealing with sewage. However, in the light of recent developments in sewage treatment technology they recommended that rather than pursuing the long outfall, the Government should consider upgrading the treatment level to a very high standard, and discharging the treated effluent into the harbour on a long-term basis.

    The proposal to adopt a different procedure for the treatment of sewage has raised a number of issues that require further study. The most important of these are whether compact sewage treatment technology developed and applied in temperate climates can treat wastewater effectively under Hong Kong conditions, and whether it is an environmentally sustainable proposition for the relatively congested Victoria Harbour to receive large volumes of effluent, although highly treated, on a long-term basis. At the end of 2001, the Government initiated a series of trials and studies to address these issues. The work is progressing well and the results will be reported around the end of 2003, at which time the community will have an opportunity to debate the findings and express views on the general preference for a way forward. More details are available at the Government's home page.

Sewerage Master Plans

Hong Kong has been divided into 16 areas for which sewerage master plans have been drawn up. These works are being carried out in a phased improvement programme. Construction work under the Chai Wan and Shau Kei Wan sewerage master plan was the first to be completed, in 1997. This was followed by the Tsuen Wan, Kwai Chung and Tsing Yi sewerage master plan in 1998, the Hong Kong Island South sewerage master plan in 2000 and the East Kowloon sewerage master plan in 2001. The Government aims to implement the remaining plans by around 2009.

    To meet needs arising from revised population projections and the Government's development plans, the EPD has been reviewing the sewerage master plans for various areas. Reviews for Central and East Kowloon, Tsing Yi, Tuen Mun, Outlying Islands, Hong Kong Island and North District and Tolo Harbour area are under way. These reviews aim to check the adequacy of the plans and to identify additional sewerage infrastructure to meet future development needs.

    Sewer connections to individual properties are still in progress. Improvements in several parts of Hong Kong Island, Kowloon and the New Territories are well under way. Under the Water Pollution Control (Sewerage) Regulation, the EPD may require house owners to connect their wastewater pipes to new public sewers. In 2002, wastewater from 854 people was directed to public sewers so as to avoid water pollution. Since the regulation came into force at the end of 1995, wastewater from 51 039 people has been connected to public sewers.

Sewage Charges

All water users who discharge their sewage to public sewers pay a basic sewage charge. In addition, 30 trades and industries whose effluent strength exceeds that of domestic sewage also pay a trade effluent surcharge to reflect the additional cost for treating their stronger effluent. These charges aim at recovering partially the operation and maintenance costs of sewage collection, treatment, and disposal facilities. The Government continues to provide funds for capital costs for these facilities from its Capital Works Reserve Fund. The household sewage charge in 2002 was a modest $1.20 per cubic metre of water consumed with an exemption for the first 12 cubic metres consumed in a four-month billing period. As a one-off concession in the 2002–03 financial year, the sewage charge payable by each registered customer during the financial year was reduced by an amount not exceeding $200 and $800 for domestic and non-domestic purposes respectively, whereas the trade effluent surcharge payable was reduced by a flat rate of 30 per cent.

Bathing Beaches

Bathing beaches are an important recreational resource. To protect the health of swimmers, the Government has adopted strict standards for water quality control at bathing beaches. These standards relate to pollution measured as E. coli (the bacteria that can indicate the presence of sewage) and were devised after a thorough study of the health risk facing local bathers. The following table shows how beaches were classified in 2001 and 2002. Beaches in the 'good' and 'fair' categories meet the Government's water quality objective for bathing.

    Since 1998, beach water quality gradings for beaches have been made available weekly during the bathing season through the mass media and the EPD's home page.

Livestock Waste Pollution

Indiscriminate disposal of waste from the livestock industry was formerly one of the main causes of pollution in streams and rivers in the New Territories. Before the livestock waste control scheme began in 1987, a pollution load from livestock waste equivalent to raw sewage from more than 1.6 million people ended up in Hong Kong's rivers and eventually the sea. Since 1988, the Waste Disposal Ordinance has banned livestock-keeping in new towns and environmentally sensitive areas. Where they are allowed, livestock farms must have proper waste treatment systems.

    Under the control scheme, livestock farmers who chose to continue in business applied for a grant and a loan to help pay for pollution-control facilities. Since the start of the scheme in 1987, about $63 million was paid out in capital grants. Farmers who chose to cease business applied for an allowance, and about $883 million has been paid. Livestock waste pollution has been reduced by 97 per cent since the inception of the control scheme.

    The Government has been providing a livestock waste collection service since 1996. A monthly average of about 5 000 tonnes of livestock waste was collected in 2002.