For information

Legislative Council
Panel on Environmental Affairs
Panel on Planning, Lands & Works

Strategic Sewage Disposal Scheme
Environmental Impact Assessment


Members were consulted on the outcome of the first phase of the Strategic Sewage Disposal Scheme Environmental Impact Assessment (SSDS EIA) study on 11 September, 5 October and 26 October 1998. At the two meetings in October, academics and environmental groups were also invited by the Panel to give their expert views on the consultants' findings and recommendations.

ExCo's Decision

2. On 5 January 1999, the Chief-Executive-in-Council directed that the second phase of the EIA Study for the treatment system and oceanic outfall to be built under the SSDS should assume that chemical treatment would be used, enhanced by disinfection, and that the outfall would be in the East Lamma Channel. The Chief Executive-in-Council also directed that land should be reserved at the quarry on Lamma Island, pending consideration of upgrading the level of treatment, and that Hong Kong officials should continue to liaise with the Mainland Authorities through the Expert Group on Sewage Disposal to consider what further work might be necessary to plan for the possible longer term development of Hong Kong's sewage treatment system. A brief on ExCo's decisions has been sent to members for information.

3. The decisions had been made on the basis that :

  1. upgrading the existing treatment system with disinfection and building an outfall to the East of Lamma would be the fastest way to address the severe water quality problem in the inner harbour area in an environmentally acceptable manner;

  2. it would not involve any abortive expenditure if further studies either locally or with the Mainland Authorities indicated a need to increase the level of treatment or plan additional outfalls; and

  3. reserving the land on Lamma Island would preserve the necessary flexibility to upgrade the system should this be necessary.

4. In reaching these decisions, ExCo had considered :

  1. the options identified during the first phase of the EIA study;

  2. the state of sea water quality in the inner harbour and surrounding waters, and the urgency of measures to address pollution problems;

  3. progress of Stage I works for providing treatment to sewage from the main urban area; and

  4. views presented by the Advisory Council on the Environment (ACE) and from academics, environmental groups, professional bodies and individual legislators during hearings arranged by this Panel.

5. All the options which had been considered, ranging from chemical treatment with disinfection to biological nutrient removal and disinfection , with a discharge either east,west or south-east of Lamma Island, are environmentally acceptable. Chemical treatment plus disinfection with a discharge east of Lamma Island is the most cost-effective system that will meet the environmental criteria. It is also the option which can be completed in the shortest possible time. Given the severe state of water quality in the inner harbour, this was a key consideration. This option also provides full flexibility for future modifications, if required. ExCo has directed that land be reserved at the quarry on Lamma Island for that purpose.


6. The choice of option to study under the second phase of the EIA was made after lengthy and intensive study and consultations, both in Hong Kong and with counterparts in the Mainland. This Panel, the Advisory Council on the Environment, environmental groups, tertiary institutions and various professional bodies were briefed on the outcome of the first phase of the EIA in September and October 1998.

7. An Expert Group on Sewage Disposal and a Technical Group were formed in July 1998 between Hong Kong and the Mainland to take forward the discussions on SSDS. They had each met twice to consider the consultants' findings. At the second Expert Group Meeting, while agreeing that the findings of the first phase of the EIA study were technically sound and that the four options identified were acceptable, the Mainland side expressed a preference for the discharge to be within Hong Kong waters, away from the sensitive receivers in the Mainland waters. It was agreed that the selected option should not be seen necessarily as the final arrangement due to uncertainties such as the future socio-economic development of the region. Should the need arise, the selected option may need to be further improved, for example, by upgrading the treatment level or constructing a longer outfall. In this respect, the Technical Group has already started discussion to draw up a study programme to address the need and options for the possible long-term development of Hong Kong's sewage treatment system.

Next Steps

8. The decision that has been made is to proceed with the second (final) phase of the EIA study on the assumption that chemical treatment plus disinfection with a discharge east of Lamma Island will be adopted.

9. In the final phase of the EIA study, the consultants will :

  1. carry out the schematic design for the selected option which includes the preliminary site layout, general arrangement of the process units, outfall alignment and diffuser design;

  2. carry out the site specific EIA study for the construction and operational phases;

  3. formulate effective measures to mitigate any significant impact identified during the site specific detailed EIA; and

  4. formulate an environmental management plan and make recommendations on the requirements for an effective environmental monitoring and audit programme.

10. The whole SSDS EIA study is expected to be completed by mid 1999.

Planning, Environment and Lands Bureau
January 1999