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Advisory Council on the Environment

Report of the 68th and 69th Environmental Impact Assessment Subcommittee Meetings

(ACE Paper 10/2002)
For advice

INTRODUCTION

At its meetings on 4 March and 18 March 2002, the Subcommittee considered the following EIA reports-
 

  1. EIA report on Yau Tong Bay Development- Reclamation of Yau Tong Bay;
     
  2. EIA report on Yau Tong Bay Development-Engineering Feasibility Study for the Comprehensive Development at Yau Tong Bay; and
     
  3. EIA report on Decommissioning of Cheoy Lee Shipyard at Penny's Bay.

ADVICE SOUGHT

2. Members are requested to advise whether the three EIA reports should be endorsed.

VIEWS OF THE SUBCOMMITTEE

EIA report on Yau Tong Bay Development - Reclamation of Yau Tong Bay
(ACE-EIA Paper 3/2002)
EIA report on Yau Tong Bay Development - Yau Tong Bay Development-Engineering Feasibility Study for the Comprehensive Development at Yau Tong Bay
(ACE-EIA Paper 4/2002)

Need for the projects

3. The Yau Tong Bay Development project will produce about 13,900 residential units to provide accommodation for about 39,000 people. The Engineering Feasibility Study aims to formulate the optimum plan for the development of the site after reclaiming Yau Tong Bay.

4. The Yau Tong Bay Reclamation project plans to resume the existing marine lots and reclaim land to develop the future Comprehensive Development Area (CDA) in Yau Tong.

5. The two EIA reports are submitted together so that the overall cumulative environmental impacts on various phases of the development can be presented and addressed in a holistic manner.

Description of the projects

6. At present, a wide variety of activities are undertaken at the Yau Tong Bay marine lots, including shipyards, timber yards, concrete batching and industrial building. The Engineering Feasibility Study identifies two designated projects, i.e. the reclamation works at Yau Tong Bay and the decommissioning of shipyard and repairing facilities at the marine lots.

7. The extent of Yau Tong Bay reclamation would be dictated by the ultimate alignment adopted for the proposed Western Coast Road (WCR). If the WCR runs along the existing coastline to link Tseung Kwan O to South East Kowloon, the Study will assume a "full reclamation" scenario with a total project area of 28.5 ha of which 18 ha will be reclaimed land. If the WCR links Tseung Kwan O to South East Kowloon via an inland tunnel, the Study will assume a "minimum reclamation" scenario with a total project area of 21.5 ha of which reclaimed land will be reduced to 12 ha.

Views and recommendations of EIA Subcommittee

8. Members' concerns on the two projects are mainly on the problems of the interface of industrial and residential buildings; the harmful effects of past businesses operating in the dissenting lots; whether the projects would have any adverse impact on the opportunity of fishing activates in Yau Tong Bay; whether there would be sufficient capacity to collect and treat wastewater generated by the projects during construction stage, and also household sewage from residents of the development upon completion; the treatment of hazardous materials such as asbestos; the treatment and disposal of highly contaminated materials such as polychlorinated biphenyls and mercury, and the visual and landscape impacts arising from the project.

Interface of industrial and residential buildings

9. To ensure proper implementation of mitigation measures to address the interface problems of industrial and residential buildings, the project proponent indicated that the measures could be included as conditions of the Environmental Permit. As for the single aspect buildings, the project proponent explained that since the area was zoned as CDA, any development within a CDA would require the further submission of a Master Layout Plan to be approved by the Town Planning Board. The single aspect building design and the proposed mitigation measures could be imposed as conditions of the approval given the Town Planning Board. Furthermore, such comprehensive development projects would go through land exchange programme. A clause could be included in future Government lease that the proposed design of the single aspect buildings and other mitigation measures should be to the satisfaction of EPD.

10. Regarding the buffer between the dissenting lots and the adjacent buildings, the project proponent pointed out that the buffer area would be at least 60 metres in width. On air emissions from the dissenting lots, the project proponent explained that, according to their investigation, those industries currently operating in the three dissenting lots would not cause any adverse air quality impacts to sensitive receivers in the area. EPD staff also confirmed that new industries involving "specified process" would require the approval of EPD before they could operate in the dissenting lots. In fact, it was quite unlikely that establishments involving specified process would operate in the type of industrial building that might still occupy one of the dissenting lots.

11. One Member expressed concern about hazardous materials stored in the dissenting lots. The project proponent clarified that the materials stored were mostly timber and building materials such as bricks and sand. Another Member pointed out that timbers were usually treated by boric acid which, if washed down the drainage, would have adverse impact on the environment. The project proponent explained that the timber used for shipbuilding purpose would have to undergo various treatments on land, not in water, including a long period of exposure under the sun. During the process, even if the timbers had been treated by boric acid, the effect would have been eliminated.

Impact on fisheries

12. A Member had doubts about the proposed land use at Yau Tong Bay area and enquired whether the natural environment could be better preserved. He also expressed concern whether the household sewage from Yau Tong Bay would affect fishing ground in nearby waters. The project proponent explained that with shipyards operating in the area, the seabed of Yau Tong Bay was highly contaminated for any fishing activities. Though rigorous measures would be implemented to deal with the contaminated sediments, the use of Yau Tong Bay for recreational purpose would not be appropriate unless huge resources would be invested which in turn would be beyond economic viability.

Household wastewater

13. A Member doubted whether there would be sufficient capacity to handle wastewater generated during the construction stage and household sewage collected upon the completion of the development project. The project proponent clarified that household sewage in Yau Tong Bay area would be collected and directed to the Kwun Tong Preliminary Treatment Works (KTPTW) for initial screening and then transferred to the Stonecutters Island for treatment.

14. The spare capacity of the KTPWT might be taken up by development which would have population in-take after 2011. If KTPWT was overloaded after 2011, a contingency measure in the form of an underground temporary sewage retention tank would be provided during the first phase of Yau Tong Bay development around 2008. In the meantime, the KTPWT was planned for upgrading to ensure that the total sewage flow within the catchments could be handled by 2016. The project proponent confirmed that the wastewater generated during the construction stage and household sewage from residents upon completion of the development would be properly collected and treated before disposal.

Asbestos

15. The project proponent clarified that all asbestos contained materials would be handled in strict accordance with the Air Pollution Control Ordinance and related codes of practice on asbestos. All asbestos removal and disposal work had to be carried out by registered contractors.

Disposal of polychlorinated biphenyls and mercury

16. A Member pointed out that polychlorinated biphenyls (PCB) and mercury were highly toxic materials and required special disposal arrangements in overseas countries. He wondered why the EIA report just recommended disposal in landfills and queried whether that would conform to international practice. The project proponent clarified that PCB and mercury-containing materials would be stabilized, subject to a leachate test and would be put inside steel drum with geosynthetic lining before disposal in landfills. EPD staff confirmed that the proposed measures would be suitable in dealing with PCB and mercury-containing materials of low concentration and small quantity. Contaminated materials that would be back-filled on-site as clean soil would be subject to more stringent full solidification test.

17. EPD staff further clarified that the project proponent and consultants, based on site investigations and laboratory analysis conducted at the marine lots, had produced and reported estimates on the nature and quantity of contaminants and recommended remediation measures. They could be required, under the environmental permit, to conduct more detailed site investigations, implement environmental monitoring and auditing work, collect and analyse samples of clean-up soil, and produce regular report to EPD to ensure that the site would be cleaned up. EPD could also require the proponent to fund the collection and analysis of soil samples separately and independently by an accredited laboratory to verify the work of the project proponent to ensure that the site was properly cleaned up to acceptable standard.

Visual and landscape impacts

18. Since the Yau Tong Bay development was situated at the sea front, a Member expressed concerns about the visual and landscape impacts arising from the project. The project proponent informed the meeting that the layout plan of the project was not yet fixed. Since the area was zoned as CDA, the final layout would be considered by the Town Planning Board. The proponent would pay special attention to the visual and landscape impacts of the project.

Conclusion

19. The Subcommittee agreed to endorse the EIA report with the following proposed conditions-
 

  1. the decontamination measures to address land contamination should be subject to the approval of EPD; and
     
  2. the proposed measures in the EIA report to mitigate the interface of industrial and residential buildings should be adopted if at the time of development there are still polluting industries in the dissenting lots.

20. The Subcommittee also concluded that though not related to the EIA report in question, it was the general view of the Subcommittee that the "minimum reclamation" scenario should be adopted for Yau Tong Bay reclamation.

EIA report on the Decommissioning of Cheoy Lee Shipyard at Penny's Bay
(ACE-EIA Paper 5/2002)

21. The Cheoy Lee Shipyard (CLS), located on the north and eastern shores of Penny's Bay, Lantau, is about 19 ha in size. It has to be decommissioned and cleaned up for the construction of infrastructure associated with the theme park development.

22. The major works of the project include demolition of the existing structures, decontamination works, slope improving works behind the CLS and the implementation of mitigation measures. Base on the recommendations of the EIA report, a treatment plant for dioxin-contaminated soil is proposed at To Kau Wan.

Views and recommendations of EIA Subcommittee

23. Members' concerns on the project are mainly the selection of thermal desorption as against other alternative technologies for treatment of dioxin-contaminated soil; the viability of direct incineration of dioxin-contaminated soil at the Chemical Waste Treatment Centre (CWTC) at Tsing Yi; the feasibility of adopting the in-situ capping and biodegradation methods; details of the thermal desorption method and whether there was any successful examples in overseas countries in using that technology for treatment of dioxin contaminants; the use of chemical de-chlorination or incineration for residue treatment; treatability test on chemical de-chlorination; cost effectiveness of the technologies considered; on-site versus off site thermal desorption; site selection; risks of transporting dioxin-contaminated soil; safety measures of the treatment plant at To Kau Wan (TKW); risk assessment of the treatment plant at TKW; the risks of parallel operation of the treatment plant at TKW and the theme park; decommissioning of the TKW treatment plant; and Rice Fish at Mong Tung Hang Stream (MTHS).

Declaration of interest

24. At the 69th meeting, Mr. Lin Chaan-ming declared interest as the Hong Kong Productivity Council had agreed to provide technical support to a company which might take part in the decontamination exercise but no advice had been given to that company yet. The Chairman ruled that Mr. Lin should abstain from voting if voting was necessary.

Thermal desorption followed by incineration versus other alternative technologies

25. In response to Members' concern on the selection of a suitable technology for the treatment of dioxin-contaminated soil, the project proponent confirmed that they had made a comparison of all known feasible technologies, or combination of technologies, available in overseas countries, including thermal desorption followed by base catalyzed de-chlorination and other technologies practised in the United States and Australia, and also those available locally, including the CWTC at Tsing Yi.

In-situ capping

26. On the viability of the in-situ capping method, the project proponent pointed out that the method was effective in preventing direct human exposure to the contaminants but would not reduce their toxicity. A long-term environmental risk would remain on site and affect the future land use. The project proponent emphasized that they should not leave the problem to future generations.

Direct incineration of dioxin-contaminated soil

27. The project proponent explained that direct incineration was effective in removing organic pollutants including dioxin. Direct incineration could either be done in the CWTC at Tsing Yi or a purpose-built incinerator. However, the process of direct incineration was very expensive in cost and would produce more greenhouse gases. A detailed cost comparison of known feasible technologies is given in paragraph 34 below.

The Chemical Waste Treatment Centre at TsingYi

28. The CWTC at Tsing Yi, though basically effective in treating dioxin-contaminated soil, had a number of constraints. First of all, it was not designed for treatment of solid waste. Without any modification, it would take about 90 years to incinerate 30,000 m3 of dioxin-contaminated soil. If minor modification was made to the kiln, the daily capacity in treating solid waste would be increased and the time taken would be shortened to about 18 years. The implications of those two scenarios were that the contaminated soil had to be stored in another site.

29. Major modification to the kiln and other handling facilities would require two to three years' time. But even with major modification, it would still take about 3.5 years to incinerate the soil. Due to the high energy cost, the cost for CWTC to incinerate the soil directly would amount to about $460 million which was higher than the cost of the thermal desorption plus residue treatment by means of incineration at CWTC (about $350 million) recommended in the EIA report. Another constraint was the impact of transporting large volume of contaminated soil to CWTC. Direct incineration of the contaminated soil at CWTC was therefore not recommended in the light of the constraints in time, storage and transportation.

Bio degradation

30. According to the project proponent, bio-degradation was a possible method in treating organic pollutants but it was not suitable for dioxin because of the low biodegradation rate. There was no record of successful field application in treating large quantity of dioxin-contaminated soil. The technology was not matured enough for implementation.

Thermal desorption

31. One Member pointed out that of the 13 technologies mentioned in the EIA report, only two had actually dealt with dioxin as a principal contaminant. Those establishments were still in operation without any proof of successful decommissioning. The project proponent clarified that there were 170 decontamination projects in the past 15 years using thermal desorption, of which 20 had dealt with dioxin contaminants. The project in Australia (i.e. the site for the Sydney Olympic Games) had been successfully implemented and the treatment plant decommissioned. Another example was the Coleman-Evans plant run by the United States environmental protection authorities which had very stringent environmental requirements. The Coleman-Evans plant which dealt with larger quantity of contaminated soil and soil conditions more challenging than those at CLS had already passed the Proof of Performance Test.

The use of chemical de-chlorination or incineration for residue treatment

32. The project proponent advised the Subcommittee that after the thermal desorption process, the dioxin condensate would require further treatment either by chemical de-chlorination or incineration. A Member enquired about the pros and cons of those two processes. The project proponent pointed out that the destruction efficiency of chemical dechlorination was much lower than that of incineration and would generate five times more oily residues. Further treatment of the oily residue generated from chemical de-chlorination was required, resulting in double handling and more environmental impacts. In fact, the only waste oil recycling plant in Hong Kong was not licensed to accept dioxin-containing oil for recycling. On the other hand, incineration of the dioxin condensate was well proven and would meet emission standards.

Treatability test on chemical de-chlorination

33. A Member wondered why a treatability test on chemical de-chlorination was not conducted. The project proponent explained that the purpose of the treatability test was not to test the viability of the technology. Rather, it was to test the characteristics of the treatment process in detail and to ascertain whether procedural adjustment was necessary. The conduct of a treatability test on chemical de-chlorination would require the setting up of a thermal desorption plant to produce sufficiently large samples of dioxin condensate. Considering the implications of that process and the fact that the CWTC at Tsing Yi could incinerate dioxin condensate, a treatability test on chemical de-chlorination was considered neither necessary nor practicable.

Cost effectiveness of the technologies

34. The cost comparison of the alternative technologies is as follows-
 

    $ Million
In-situ capping   100
Direct incineration by a new incinerator   425
Direct incineration at CWTC   610
Thermal desorption plus incineration   350
Thermal desorption plus chemical dechlorination plus incineration   420

On-sit versus off-site thermal desorption

35. On the issue of on-site versus off-site thermal desorption, the project proponent explained that if the process was conducted on-site at CLS, the site preparation work, the setting up of the treatment plant, the thermal desorption process and the eventual decommissioning would take three to four years' time. It would have a series of knock-on effects on other infrastructure works and would delay the theme park project. The removal of that time-consuming process to another site would facilitate other works at CLS to proceed concurrently.

Site selection

36. The project proponent informed Members that they had considered a total of four sites, i.e. Area 6B of Penny's Bay, Tai Chuen, Siu Ho Wan area and TKW. Area 6B of Penny's Bay, with reclamation work still in process and at land transportation distance of 2.9 km from CLS, was not big enough for the thermal desorption process and other related facilities. Tai Chuen, with marine access only and at sea transportation distance of 12.6 km from CLS, was also small in area and considered not suitable because of its closeness to the Ma Wan Fish Culture Zone. Siu Ho Wan area, at 7.5 km land transportation distance from CLS, was excluded from consideration because it had been reserved for other project and that it was close to the North Lantau Highway and the Siu Ho Wan Water Treatment Works. TKW was 6.1 hectares in area, readily available for four years, with both land and marine access and at a land transportation distance of 3.6 km from CLS and non-environmentally sensitive, was considered the most suitable site among the four.

Transportation risk

37. A Member expressed concern about the risks of treating dioxin-contaminated soil at TKW, having regard to the location of the site in a coastal environment and the proximity to a highway during transportation. Any leakage or migration of the contaminants through air or tidal flow and eventually entering the food chain would be highly dangerous.

38. The project proponent clarified that the treatment of metal- contaminated soil would be done on-site except for organic and dioxin-contaminated soil. A licensed waste collection fleet would put the dioxin-contaminated soil in roll-off trucks with sealable top and transported the soil to TKW under speed limit control and the escort of two other vehicles. The transportation route from CLS to TKW would not trespass any public express roads or highways. Instead, only dedicated roads and local roads would be used.

39. The transportation of dioxin condensate from TKW to CWTC would have low inherent risks given the non-volatile, insoluble and low inflammability nature of the contaminants and the adoption of the same safety precautions mentioned above. The risk assessment of the transportation of both dioxin-contaminated soil and dioxin condensate indicated minimal risk in both spillage and explosion.

Safety measures of the treatment plant at To Kau Wan

40. A Member expressed serious concern about the safety measures of the treatment plant at TKW. The project proponent pointed out that the site at TKW would be paved with concrete to prevent leaching to the underneath soil and the thermal desorption system would be bunded to provide an enclosed environment. Dioxin particles were insoluble in water and would not be carried away easily in storm or rainwater run-off. Furthermore, there would be effective wastewater treatment system at the treatment plant to control any run-off from site. The standard to be adopted would be non-detectable amount of dioxin. Regarding air emission, according to a modeling conducted by the project proponent using very conservative assumptions, the result was that the emission at the receptor was 300 times lower than the required standard. In unlikely event of air emission, there would be an activated carbon system as a back up. The overall water and air impacts arising from the project would be very minimal and within acceptable standards.

Risk assessment of the treatment plant at To Kau Wan

41. On the risk assessment of the treatment plant at TKW, the project proponent pointed out that dioxin contaminants had low volatile organic compounds level. Since there would not be storage of fuel on site, explosion risk, if any, would be fairly low. There would also be regular monitoring of dioxin emission and more frequent monitoring of dioxin-indicative surrogate gases. In case of high emission, the feed system would be automatically shut-off. Other safety measures included explosion relief valves and redundant temperature control system. During the detailed design stage, the contractor would be required to conduct a detailed process safety analysis prior to start up of the system and the workers would be fully trained to follow safety procedures.

Parallel operation of the treatment plant and the theme park

42. A Member expressed concern that the treatment plant at TKW and the theme park might operate in parallel for a period of time. The project proponent pointed out that the decommissioning of the treatment plant at TKW in 2006 represented the worst-case scenario. The treatment plant could most likely be decommissioned earlier. The treatment process and the decommissioning of the plant would comply with all environmental legislation and requirements and would have no effect on the activities at the theme park, even if they last beyond the opening of the theme park.

The decommissioning of the To Kau Wan treatment plant

43. Some Members expressed concern that the decommissioning of the thermal desorption plant was not a designated project under the EIA Ordinance. The project proponent pointed out that the decommissioning of the plant was part of the current project and details were included in the EIA report. There were ample experiences in the decommissioning of thermal desorption plants and the decommissioning process of the plant at TKW would have reference to those experiences.

Rice Fish

44. Some Members enquired about the disappearance of Rice Fish from MTHS. The project proponent pointed out that Rice Fish was last recorded in the MTHS in February 1999. As Rice Fish was generally found in standing water-bodies or slow flowing streams, its occurrence in a fast flowing stream such as MTHS was unusual. The four field investigations at MTHS under the current EIA could not find any Rich Fish. The cause of disappearance of the fish could not be ascertained but could be due to natural decline of an unstable population. Though no Rice Fish was detected in field surveys, the project proponent acknowledged the possibility that Rice Fish might still occur in MTHS and recommended that at least two more surveys would be conducted prior to the commencement of slope works. Furthermore, the project proponent indicated that they would re-create suitable habitats in MTHS and source a Rice Fish population from other areas in Hong Kong and introduce it to the re-created habitat if no Rice Fish was found in future investigations.

Conclusion

45. After discussion, the Subcommittee ruled out the methods of in-situ capping and direct incineration of dioxin-contaminated soil in view of the long-term environmental risk of dioxin-contaminated soil of the former approach and the high cost and the prolonged time required of the latter technology. Other technologies such as biodegradation and chemical de-chlorination were either not matured enough to deal with large quantity of dioxin-contaminated soil or not practicable in Hong Kong. After further discussion, the Subcommittee agreed that among all technologies considered, thermal desorption plus residue treatment by means of incineration at Tsing Yi CWTC would be an effective technology with proven record in dealing with dioxin contaminants and would not cause insurmountable environmental problems. The Subcommittee also agreed that the TKW site was the most suitable site among those considered by the project proponent. The subcommittee considered the TKW treatment plant acceptable, given the non-volatile, insoluble nature and low concentration of the pollutants, and the safety and precautionary measures proposed by the project proponent.

46. Mrs. Mei Ng objected to the EIA report on the following grounds-
 

  1. she was not convinced of the information provided in the EIA report as certain information was provided without verification;
     
  2. the comparison of the alternative technologies was not done on equal basis given that a treatability test on chemical de-chlorination was not conducted and the treatability test on thermal desorption was not yet completed;
     
  3. transportation risks of dioxin-contaminated soil and possible cross contamination; and
     
  4. the lack of land validation at TKW and the decommissioning of the treatment plant.

47. After detailed discussion, the Subcommittee concluded that the Subcommittee would recommend the EIA report for endorsement by the Council with the following proposed conditions-
 

  1. the treatability test on thermal desorption should be completed before the commencement of the thermal desorption process;
     
  2. there should be a clear method statement on various stages of work of the project including soil excavation, transportation of dioxin-contaminated soil and dioxin condensate and the handling methods in case of accidents. The method statements should be considered and accepted by the Environmental Protection Department before soil excavation could commence and that the Environmental Monitoring and Auditing Manual should be based on those method statements;
     
  3. the project proponent should set up a proper environment management system for the entire decommissioning project;
     
  4. the project proponent should implement all safety and precautionary measures included in the EIA report; and
     
  5. the monitoring of Rice Fish at the re-created habitat in MTHS should be extended from one year to three years.

EIA Subcommittee Secretariat
March 2002

 

 

 

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