Legislative Council

LC Paper No. CB(1)388/98-99
(These minutes have been
seen by the Administration)

Ref: CB1/PL/EA

LegCo Panel on Environmental Affairs

Minutes of meeting
held on Monday, 5 October 1998, at 8:30 am
in Conference Room A of the Legislative Council Building

Members present :

Hon Christine LOH (Chairman)
Hon HUI Cheung-ching (Deputy Chairman)
Dr Hon Raymond HO Chung-tai, JP
Hon CHAN Wing-chan
Dr Hon LEONG Che-hung, JP
Hon YEUNG Yiu-chung
Hon LAU Kong-wah
Hon Mrs Miriam LAU Kin-yee, JP

Members absent :

Prof Hon NG Ching-fai
Hon Bernard CHAN
Hon Mrs Sophie LEUNG LAU Yau-fun, JP
Hon WONG Yung-kan
Hon CHOY So-yuk
Hon LAW Chi-kwong, JP

Public officers attending :attendingattending
Deputy Secretary for Planning,
Environment and Lands (Environment)

Mr Danny TSUI
Principal Assistant Secretary for Planning,
Environment and Lands (Environment)

Dr Malcolm BROOM
Principal Environmental Protection Officer
(Water Policy and Planning)
Environmental Protection Department

Chief Engineer/Strategic Sewage Disposal Scheme
Drainage Services Department

Mr Peter K K CHAN
Consultant of Montgomery Watson

Professor HUANG Ming-rong
Binhai Wastewater Treatment & Disposal
(HK) Consultants Ltd.
Attendance by invitation :

The University of Hong Kong

Professor Joseph Hun-wei LEE
Redmond Professor of Civil Engineering

The Conservancy Association

Mr Albert LAI
Spokesman on Strategic Sewage
Disposal Scheme

Ms Noel CHAN
Campaign Officer

The Hong Kong Marine Conservation Society

Mr John M K WONG

Friends of The Earth

Mr Plato YIP Kwong-to
Assistant Director

Mr CHENG Luk-ki
Campaign Co-ordinator

Clerk in attendance :

Miss Odelia LEUNG,
Chief Assistant Secretary (1)1

Staff in attendance :

Mrs Mary TANG,
Senior Assistant Secretary (1)2

I Discussion on Phase I of Environmental Impact Assessment (EIA) for Stage II of the Strategic Sewage Disposal Scheme (SSDS)

The Chairman informed that four organisations had accepted the Panel's invitation to attend this meeting to express view on the SSDS.

Meeting with organizations

Department of Civil Engineering, The University of Hong Kong
(LC Paper CB(1)288/98-99(02) tabled at the meeting)

2. At the invitation of the Chairman, Professor Joseph Hun-wei LEE said that the environmental impact of a sea outfall was localised and could be mitigated by careful selection of a discharge location. With well designed sewage outfalls, the discharge of sewage to the sea was not only acceptable but also environmentally preferable to alternative methods of disposal in many cases. Field observations in many parts of the world had confirmed the scientific basis of sea outfall designs. The crux of the issue was what degree of land-based sewage treatment should be provided and where the sewage should be disposed of. In his opinion, the approach adopted in Phase I of the EIA for Stage II of the SSDS was acceptable and the study had followed internationally accepted procedures.

3. On a member's enquiry about the acceptability of the different options, Professor LEE said that the concept of sea outfall design was based on scientific evidence and years of field observations in California, Australia, the United Kingdom and Shanghai. These researches had indicated that the use of sea outfalls could be an environmentally acceptable option under the right conditions. All the four options were environmentally acceptable and had satisfied the basic criteria. As to which option should be selected, Professor LEE stated that costs and environmental benefits were factors to be taken into consideration. He did not object to biological treatment with nutrient removal (BNR) but considered that the matter should be left to the community to decide after a balanced consideration of the costs and benefits of each option.

4. Responding to a member's comments that the speed of oceanic currents varied according to hydrological conditions and that overseas experience in deep sea outfalls might not be relevant to the Hong Kong situation, Professor LEE referred members to the figure on effluent dilution by ocean outfalls which was attached to his submission. He stated that if wastewater was discharged properly at the bottom of the ocean, the pollutants could be efficiently diluted by the turbulent vortices and swirls of ocean currents. The speed of ocean currents to the south of Hong Kong were comparable to that of California. He stressed that the environmental impact of sewage discharge could be mitigated if the discharge location was carefully selected. A combination of factors would affect the hydrography of the outfall location, including water depth, speed of current, prevailing direction of oceanic currents and the difference in density of the receiving waters. These factors would dictate the choice of the outfall location. A state of the art computer model could be used to simulate the actual situation. Of primary importance was that the chosen option should be able to meet the Water Quality Objectives (WQO).

5. On engineering aspects, Professor LEE pointed out that the design of tunnelling outfalls would involve minimal disruption to the community during construction. Overseas experience had confirmed the viability of such a design, which would not be affected by weather conditions. He agreed that different locations would have different geotechnical considerations and detailed geophysical surveys would need to be conducted before the construction of the sea outfalls.

The Conservancy Association (CA)
(LC Paper No. CB(1)288/98-99(03) tabled at the meeting)

6. Mr Albert LAI opined that Hong Kong should take a regional and long term perspective in formulating its sewage disposal policy. CA submitted that given the exceedingly high nutrient levels in Hong Kong waters, BNR should be the minimum treatment process. CA believed that more BNR options, including semi-distributed systems, should be assessed and reviewed in the light of new technological developments and changes in land value. Environmental impact and cost-effectiveness should be the criteria for deciding which BNR option to be selected.

7. Responding to a members' query on the need for BNR, Mr LAI pointed out the worsening trend of rising nutrient levels in Hong Kong waters which were strong indicators that BNR was necessary to avoid possible ecological disasters. He opined that if Hong Kong, being the most affluent city in the Pearl River Delta Region, did not take the lead in adopting BNR in its sewage treatment, no other Guangdong cities could be persuaded to do so. With rapid industrialization in the Pearl River Delta Region, the problem of nutrient levels in the waters of the Region would get worse.

8. Regarding the choice of option, Mr LAI opined that if BNR was considered necessary in the treatment process, then the four shortlisted options by the Consultants, of which only option 4 contained BNR, would be grossly inadequate. He suggested that the Administration should take a fresh look at the matter, including assessing the feasibility of a semi-distributed sewage treatment system.

Friends of the Earth (FOE)
(LC Paper No. CB(1)288/98-99(04) tabled at the meeting)

9. Mr Plato YIP Kwong-to said that he was gravely concerned about the cost effectiveness of a centralised sewage treatment system with long sea outfalls. He called into question the sustainability of the system and stressed the importance of waste recovery.

10. Mr CHENG Luk-ki then highlighted the salient points of FOE's submission. He pointed out that the unacceptable high E Coli, nitrogen and mercury levels in the Hong Kong waters were clear indications that disinfection and higher sewage treatment levels such as BNR were necessary. However, the flexibility to upgrade the treatment level was constrained by the availability of space. He considered that the consultants had averaged out the impact of sewage discharges on the receiving waters over a period of time. Since biological species did not respond to "average" conditions but to their immediate environment, elimination of sensitive species might occur if the impact of sewage discharges significantly deviated from the "average" conditions.

11. Mr CHENG further opined that FOE had doubts over the viability of deep tunnels and the accuracy of the three-dimensional Water Quality and Hydraulic Modelling which had been used as the basis for evaluating water quality for different sewage disposal options. FOE was also concerned about the means for disposal of the large quantities of sludge generated by the treatment process.

The Hong Kong Marine Conservation Society (HKMCS)
(LC Paper No. CB(1)262/98-99(02)b)

12. Mr John M K WONG stated that HKMCS supported the sewage scheme but considered that more water quality modelling studies should be done to ascertain the need for the construction of a long sea outfall. Since the strength of oceanic currents differed depending on the location and given the geographical situation of Hong Kong, the assimilative power of its surrounding waters might not be comparable to that of other countries. He stressed the need for mutual cooperation with the Guangdong authorities in synchronizing the implementation of sewage disposal programmes.

Meeting with the Administration
(LC Paper No. CB(1)262/98-99(03))

13. The Deputy Secretary for Planning, Environment and Lands (DS/PEL) said that the Administration was committed to providing a major programme of sewage treatment and disposal works throughout the territory the purposes of which were -

  1. to protect the health of the community;

  2. to ensure that the community could continue to enjoy the beaches and local waters for recreation;

  3. to conserve the diversity of marine life;

  4. to help restore Hong Kong's attraction to tourists;

  5. to help restore the productivity of local and regional waters for fishing and mariculture; and

  6. to improve the living environment of the city for the benefit of every resident.
14. DS/PEL stated that at the moment Hong Kong was experiencing serious economic and social losses because of the pollution of local waters by inadequately treated sewage. At present, less than half of the sewage produced was given adequate treatment. With the completion of SSDS Stage I in the year 2000, 70% of the sewage in the inner harbour area would be given a high level of treatment. After the completion of the construction of deep sea outfalls under SSDS Stage II, major improvements in local water quality could be achieved by the end of the next decade.

15. According to DS/PEL, the work done so far on the EIA study on SSDS Stage II had indicated that provided that disinfection was added to the system, either Chemically Enhanced Primary Treatment (CEPT), or secondary treatment, or Primary Treatment with BNR, with outfalls located at the East, West or South of Lamma Island could produce environmentally acceptable results. These results had been taken up with the Technical Group set up under the Expert Group on Sewage Disposal which comprised representatives from the National Environmental Protection Agency and officials from Zhuhai and Guangdong. The Technical Group had accepted that the methodology for the EIA study was basically correct and that the Consultants' findings were technically sound.

16. Whilst noting the community's concern about the damages and losses caused by inadequate level of sewage infrastructure, and the potential cost of the SSDS system, particularly the cost of maintenance, DS/PEL stressed that the Administration was committed to providing Hong Kong with a sewage system that was sustainable both economically and environmentally. Ideas and comments on the proposed options were welcome. He referred members to the Administration's paper which set out the pros and cons of the four groups of acceptable options for SSDS Stage II and the projection on costs. The additional recurrent costs for SSDS Stage II works would not arise until the end of the next decade. The extra recurrent cost of proceeding with Stage II works ranged from $500 million under Options 1 and 2 to $1.9 billion under Options 3 and 4. As a rough indication on the future treatment costs, the present unit cost for treating a cubic metre of sewage was 65 cents for primary treatment, $1.17 for CEPT and $1.86 for secondary treatment. The present sewage charge of $1.20 per cubic metre was derived from the total costs against the number of water accounts. On completion of SSDS Stage II, the cost of treatment would be about $1.70 per cubic metre under Option 1 and about $3.60 under Option 4, based on 1998 prices. It would be difficult to translate costs to charges at this stage. As the number of water accounts was expected to increase from just below two million now to slightly over three million by the end of the next decade, the costs would be shared amongst a much larger number of account holders, thereby keeping down the cost for each individual account. Compared to other major cities, Hong Kong's sewage charge was very low, reflecting the low level of treatment provided. Under the system proposed to be developed, sewage charges would remain relatively low, even if one of the more expensive options were to be adopted.

17. On the issue of a centralized versus distributed sewage system, DS/PEL said that a centralised treatment system was more cost effective than a distributed treatment system with multiple discharges. Moreover, it would not be possible to set up a distributed treatment system in the inner harbour area within the next decade, even if LegCo was prepared to support the additional reclamations that would be needed. DS/PEL said that any further delay in putting in place a modern sewage treatment system should not be tolerated. The proposed works were sensible and necessary investments to sustain Hong Kong and would help maintain employment in the present hard times. The future running costs, if shared sensibly, would be relatively small and would be amply repaid by the benefits that would come to the community and to the neighbouring areas in return.

18. The Chairman invited the Administration to comment on the deputations' views. In response, the Principal Environmental Protection Officer (Water Policy and Planning), Environmental Protection Department (PEPO) made the following points -

    Level of nitrogen

    (a) If an option which did not involve BNR was chosen, WQO for nitrogen in Mainland waters could still be met in the area of discharge. There would however be difficulties in meeting WQO for nitrogen in the southern Hong Kong waters - the level of nitrogen would be increased to the order of a few hundredths of a part per million in the water. The ecological effect of that would be impossible to quantify, but it was very unlikely that such would have an ecological meaning.

    (b) It was observed that nitrogen in Hong Kong waters in the dry season was about 0.1 mg per litre and rose to about 0.2 mg per litre in the wet season. It was unlikely that the increase in nitrogen in Hong Kong waters was due to sewage which was discharged in both the wet and dry seasons. The increase was more likely due to the widespread application of fertilisers in the whole of the Pearl River Delta catchment. In solving the problem of nutrient level, there was thus a need to take a much broader approach on the land uses in the Pearl River Delta catchment, rather than focusing on sewage discharge alone.

    (c) The removal of nitrogen from sewage required a long sludge age. The process was lengthy and would inevitably require much space.

    Liaison with the Mainland

    (d) With regard to the need to take a regional approach to dealing with marine water quality issues, the Administration had good links with the environmental authorities on the Mainland, primarily through the Hong Kong-Guangdong Environmental Protection Liaison Group, and would continue to use these to explore the potential for collaborative action on the marine environment.

    Distributed sewage treatment system

    (e) A distributed sewage treatment system with discharges in the harbour would require BNR and much more space to operate. (With the use of a visualiser, PEPO showed an aerial picture of a biological treatment plant in Tokyo to illustrate the extent of space required by such a plant).

    The worst conditions

    (f) When sewage was discharged at the outfall, it diffused and rose until achieving neutral buoyancy at the initial dilution zone which was usually within 50 or 100 metres from the outfall location. Water modelling studies indicated that all the criteria for toxic contaminants were met within or very slightly away from the initial dilution zone. The initial dilution zone was not greatly affected by changes in conditions.

    (g) The water modelling studies also indicated that while there would be a decrease in dissolved oxygen level under options 1 and 3 the decrease would be small and confined to a limited area in the wet season. The relevant criteria for dissolved oxygen, both in the water column and near the sea bed, would be met. Looking at the transient minimum levels in the water column for short periods these were found never to fall below 3 mg/L. Such levels were observed only in very small patches, and for less than 10% of the time over the whole year. The WQO itself allowed for this kind of variation for a limited period. It was therefore considered not a problem for marine life. If the community preferred to take a more prudent approach, consideration could be given to providing a higher level of biological treatment.

    Mathematical models

    (h) The Administration had been using modelling technologies of the Danish Hydraulics Institute which was considered one of the best. A report on the modelling studies would be ready for inspection shortly.

    Waste management

    (i) The projected costs were made on the assumption that the sludge produced would be incinerated. A separate study was currently undertaken by the Environmental Protection Department on the management of sludge produced throughout the territory. The study was expected to be completed in February 1999. A large amount of sludge would be generated regardless of the choice of sewage treatment option and the problem would have to be dealt with separately.
19. PEPO confirmed in response to the Chairman that there would be a back-up system of pumps for the CEPT works. CEPT was basically a physical system, whereas biological treatment was a system that relied on living organisms which would be susceptible to shock loadings. Generally, the operational risk of using a centralised treatment plant with CEPT, with stability conferred by high volume of flow, would pose lesser risk than a distributed system of biological treatment works.

20. Referring to paragraph (c) of the Administration's paper which stated that the new Expert Group on Sewage Disposal was set up in July 1998 and had met once in August 1998, a member queried the adequacy of exchanges between the Hong Kong side and the Mainland side on the detailed arrangements of the EIA study. In response, PEPO pointed out that although the new Expert Group only came into existence in July 1998, the detailed arrangements of the study had been extensively discussed under the Sino-British Joint Liaison Group since 1995. The Mainland experts were involved from the very beginning of the EIA study. These experts were nominated by the Mainland Government and were acting in their official capacity. About four or five meetings had been held to discuss the EIA study. The consultants' reports had been made available to the Mainland experts for comments and discussion. They had agreed on the methodology and approach of the EIA study and had agreed that the consultants' findings were technically sound. At the most recent meeting held in August 1998, Working Paper No. 2 which dealt with the comparison and evaluation of the acceptable options was discussed. Copies of the Paper would shortly be placed in the Advisory Council on the Environment Secretariat, the library of the Environmental Protection Department and other locations where interested parties could make reference to it. Members were assured that there had been continuous discussions with the Mainland counterparts for the past two years and reports had been exchanged in accordance with the items on the agenda.

(Post meeting note: A copy of Working Paper No. 2 was provided by the Administration for deposition in the LegCo Secretariat for members' reference.)

21. Members sought information on geophysical surveys required under each of the four options. DS/PEL advised that these surveys were within the second part of the EIA and would be undertaken after the preferred option had been chosen. A lot of information on the geological conditions of the Lamma Island were in hand but further studies would be required at the detailed design stage. Following this up, members were concerned about the time for conducting detailed geophysical surveys. Without detailed information on the geological conditions in respect of each of the four options, the option chosen might not be feasible from the engineering perspective. Members were worried that extensive engineering problems, similar to those found in SSDS Stage I works, could be encountered. In response, the Chief Engineer/Strategic Sewage Disposal Scheme, Drainage Services Department (CE/SSDS) said that there was in fact successful local example of building deep sea tunnel. The SSDS Stage I interim outfall tunnel, which was a 1.7 km long, 5 m diameter and about 100 m below the western part of the Harbour, had already been completed. The problems associated with the six sewage transfer tunnels of the SSDS Stage I were attributed to the original contractor's refusal to proceed with the works in accordance with the terms of the contracts. The difficulties were not due to adverse geological conditions. The Administration had carried out extensive site investigation beforehand and these had been taken into account in the design of the tunnels. Amongst the six tunnels, water seepage occurred in two of them. Instead of proceeding diligently with the works by limiting the amount of water inflow into the two tunnels, the contractor elected to stop work in all six tunnels. The Administration was finally left with no alternatives but re-entered the sites in December 96 and re-tendered the works. This resulted in significant delay and increase in cost. CE/SSDS added that there were proven engineering means to limit water from entering into the tunnels during construction and these would usually involve grouting work in advance. There were now three new contractors each working actively in two of the six tunnels. All tunnels were in various stages of construction. With the international and local experience, the Administration firmly believed that the tunnels could be completed.

22. As regards the criteria to be used in the selection of option, DS/PEL said that the Administration would make an assessment after all the comments had been received. In the meantime, the Administration would need to ensure that the progress with the EIA study had met the criteria of the academic and technical community and that the assumption on costs was acceptable. Based on the guidance from the community, the Administration would make a decision on the option to be adopted but the final decision would rest the Chief Executive in Council.

23. At the Chairman's instruction, the Clerk read out a joint submission from Professor Hon NG Ching-fai and Hon CHOY So-yuk on their views on the Strategic Sewage Disposal Scheme. (A copy of the submission was circulated to members vide LC Paper No. CB(1)288/98-99(01).)

24. Members considered it necessary to hold a third meeting on 26 October 1998 at 8:30 am to further discuss the recurrent costs of the different options, surveys on geological conditions and the feasibility of other alternative options, in particular the option of a distributed sewage treatment system.

25. Members requested the Administration to provide the following before the meeting -

  1. details on liaison with the Mainland authorities concerning Phase I of EIA for Stage II of SSDS and their response, in particular with regard to the issue of a centralized versus distributed treatment system;

  2. the expected recurrent costs for each of the four options and an estimate on the increase in the amount of sewage charges to be paid by domestic and non-domestic water account holders under each of the four options;

  3. the geophysical surveys in connection with each of the four options, in particular the timing and the procedures for conducting these surveys; and

  4. a coordinated response to the submissions tabled at the meeting.
II Any other business

26. There being no other business, the meeting closed at 10:30 am.

Legislative Council Secretariat
27 October 1998