ENG-2015 — Page 301

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The Environment

transports it through a network of deep tunnels to Stonecutters Island for treatment. Stage 2A involves extending the deep tunnel system to take the untreated sewage from the remaining parts of Hong Kong Island to the Stonecutters Island Sewage Treatment Works (SCISTW), which will be expanded to provide centralised chemical treatment to sewage from the entire catchment under the scheme. Stage 2A works began in 2009 and the project was commissioned in December 2015. Since then, sewage from both sides of Victoria Harbour has been intercepted and diverted to the Stonecutters Island plant for centralised treatment and disinfection before discharge. The government will commission a consultancy study on further enhancing the quality of the harbour's waters in early 2016.

Since 1991, the government has spent a further $28 billion on other sewerage schemes and will spend another $14 billion on schemes over the next five years, including sewerage for rural villages. The Water Pollution Control (Sewerage) Regulation empowers the EPD to direct house owners to connect their waste water pipes to new public sewers. Since the regulation came into force in 1995, more than 9,000 village houses have been connected to the public sewers.

Sewage disposal facilities in rural areas

Improvements continue to be made to sewage disposal facilities in rural areas. In 2015, the government drew up plans to invest further in projects providing public sewers to convey domestic discharges from villages in rural and other un-sewered areas to treatment works. Loan and grant schemes for eligible households to connect houses to public sewers are available.

Sewage Charges

All water users who discharge their sewage into public sewers pay a basic sewage charge in accordance with the Sewage Services Ordinance. Also, 27 trades and industries whose effluent strength exceeds that of domestic sewage pay a trade effluent surcharge reflecting the additional cost of treating their stronger effluent. These charges are used to recover the operation and maintenance costs of sewage collection, treatment and disposal facilities, while the government provides funds for construction.

In support of the polluter-pays principle, in 2007 the government initiated a gradual increase in the sewage charges for handling domestic waste water over 10 years. The average bill for domestic accounts will rise from the 2007 level of $11 per month to $27 per month eventually.

Water Quality

Water pollution, if left unchecked, tends to increase with urban development and population growth. The lack of proper treatment for most of the sewage from older urban areas around the harbour resulted in poor water quality, but since Stage 1 of the harbour scheme went into operation in 2001, there has been a marked improvement. The dissolved oxygen level in the water has increased, while pollutants such as ammonia and faecal bacteria have decreased. With the commissioning of Stage 2A in 2015, sewage around the harbour is collected for centralised treatment, resulting in further improvement in water quality.

Pollution control at source has yielded positive results and river quality has also improved. The percentage of rivers monitored in the 'good' and 'excellent' categories increased from 34 per

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