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Advisory Council on the Environment

Environmental Impact Assessment Ordinance (Cap. 499)


(ACE-EIA Paper 5/2002)
For advice

 

Environmental Impact Assessment
Decommissioning of Cheoy Lee Shipyard at Penny's Bay

Purpose

This paper presents the key findings and recommendations of the Environmental Impact Assessment (EIA) Report for the Decommissioning of Cheoy Lee Shipyard at Penny's Bay submitted under section 6(2) of the Environmental Impact Assessment Ordinance (EIAO). The Civil Engineering Department (CED) and their consultants will make a presentation. Comments from the public and ACE will be taken into account by the Director of Environmental Protection when he makes his decision on the approval of EIA report under the EIAO.

Advice Sought

2. Members' views are sought on the findings and recommendations of the EIA report.

Need for the Project

3. The Cheoy Lee Shipyard (CLS) is about 19 ha in size and located on the north and eastern shores of Penny's Bay, Lantau (see Figure 1.1). The CLS is to be decommissioned and the area to be cleared up will be used for the construction of infrastructure associated with the theme park development, including the Penny's Bay Section of the Chok Ko Wan Link Road, Road P2, and etc.

Description of the Project

4. The Project is a Designated Project under Item 17, Part II of Schedule 2, the EIAO, (i.e. decommissioning of "a facility for ship building or repairing more than 1 ha in size or with a lifting capacity in excess of 20 000 tonnes"). Based on the recommendations of the EIA, a treatment plant for dioxin-contaminated soil is proposed at To Kau Wan, North Lantau. The treatment plant is also a Designated Project under Item G.4, Part I of Schedule 2, the EIAO (i.e. construction and operation of "a waste disposal facility, or waste disposal activity for refuse or chemical, industrial or special wastes").

5. The EIA study brief for the project was issued to CED on 9 November 2000. An application for the approval of the EIA report was submitted by CED on 14 December 2001. On 9 February 2002, the Director of Environmental Protection advised CED under Section 6(3)(a) and Section 6(4) of the EIA Ordinance that the EIA report is suitable for public inspection.

6. The CLS is located on the north and eastern shores of Penny's Bay, Lantau. The shipyard operation started in 1964. The CLS ceased its operation in April 2001. The past businesses in the CLS included boat manufacture, repair and maintenance. The key works of the CLS decommissioning project include demolition of the existing structures within the CLS, decontamination works, slope improving works behind the CLS and the implementation of mitigation measures.

Specific Environmental Aspects to Highlight

7. The major environmental issues identified for the Project are: land contamination, air quality, water quality and ecology.

Land Contamination

Soil Contamination

8. Based on the results of the land contamination assessment, soil contaminated with metals, total petroleum hydrocarbons (TPH), semi-volatile organic compounds (SVOCs) and dioxins was found. The estimated volumes of contaminated soil, recommended remediation methods and treatment locations are summarized in Table 1.

Table 1: Estimated Volumes of Contaminated Soil, Remediation Methods and Treatment Locations

Soil Contaminants Recommended Remediation Methods Treatment Locations Quantities (m3)
Metals only Cement Solidification CLS 48,000
TPH/SVOCs Biopiling To Kau Wan 700
Metals and TPH/SVOCs Biopiling followed by Cement Solidification To Kau Wan 8,300
Dioxins and metals/ TPH/SVOCs Thermal Desorption* followed by Cement Solidification To Kau Wan 30,000
    Total = 87,000

Note: * Oily residues from thermal desorption will further be incinerated at the Chemical Waste Treatment Facility at Tsing Yi.


Consideration of Sites for Decontamination

9. An area of about 5 ha. and a period of about 3.75 years are required for the treatment of contaminated materials. The EIA recommended that decontamination of metal-contaminated soil would be conducted at the CLS site whereas other contaminated soil would require off-site treatment to meet the project requirements and the tight project programme. A site search exercise was conducted. The To Kau Wan (TKW) site in North Lantau is selected for the off-site treatment to meet the various selection criteria including land availability, sufficient site area, adequate access (by a restricted temporary road), proximity to Penny's Bay and relatively remote location with no adverse environmental impacts.

Consideration of Alternative Remediation Methods

10. A comparison of various options for decontamination works, and the key justifications for selecting the remediation methods for different types of contaminated soil are summarized in Table 2.

Table 2: Key Justifications for Recommended Remediation Methods

Soil Contaminant(s) Remediation Methods Key Justifications
Metals Cement solidification
  • Well developed technology
  • Higher certainty of success
  • Simplicity in process (for limited quantity)
  • Solidified soil is acceptable to be reused as backfill
TPH/SVOCs Biopiling
  • Much faster than in situ treatment
  • Higher certainty of success
  • Simple operation
  • With operation experience in Hong Kong
Dioxins Thermal desorption (followed by incineration of oily residue)
  • In line with international practice for treating organic contaminants in soil including VOCs, PAHs, PCBs, pesticides and dioxins
  • Permanent remedial solution to destroy dioxins to meet the clean-up target
  • Higher implementability in terms of final waste handling and disposal (treated soil suitable for public filling, relative small amount of oily residue that requires further treatment by incineration)

11. Treatability tests for biopile, cement solidification and thermal desorption will be conducted to determine the operating parameters and treatment efficiencies. The contaminated soil will be cleaned up and suitable for public filling.

Air Quality

12. Air quality modelling results for dust and dioxins during excavation indicated that the impacts would be low and would meet the criteria. To reduce the impacts, the top layer of soil shall be sprayed with fine mist of water immediately before the excavation and inactive excavated area shall be covered by impermeable sheeting.

13. Air emissions from remediation processes will be controlled by the following mitigation measures, and the emissions have been modelled and assessed in the EIA to be within the respective criteria:

  1. The design of thermal desorption plant is of enclosed type. The dioxin emissions shall be limited to 0.1 ng/m3 and Total Organic Compounds (TOC) emission limited to 20 mg/m3.
     
  2. TOC emission from the biopile shall be limited to 20 mg/m3, with maximum flow rate of 56 m3/min. Back-up carbon absorber shall be installed for the biopile to ensure that the TOC criterion is satisfied. The biopiles shall be covered by impermeable sheeting to avoid emission of VOCs.
     
  3. Temporary stockpiles for cement solidification shall be covered. Handling and mixing of cement shall follow the Air Pollution Control (Construction Dust) Regulation. Mixing process at TKW will be conducted in an enclosed area to minimise dust emission.
14. According to the EIA report, the health risk associated with the operation of the treatment facilities has been assessed to be in compliance with international criteria.

Water Quality

15. The key water quality concerns of the project are contaminated runoff, the discharge of contaminated water (e.g. from wheel wash and equipment decontamination) and potential groundwater contamination. Catchpits and perimeter channels will be constructed in advance of site formation works and earthworks. Excavated contaminated soil will be stored and treated in bunded areas and will be covered. Purposely-built wastewater treatment units are recommended to treat potentially contaminated water. No adverse water quality impacts (including those on the planned Water Recreation Centre) would be caused by the CLS decommissioning project.

Ecology

16. The slope improvement works would affect Rice Fish habitats at Mong Tung Hang Stream (MTHS) and several restricted/protected plant species. To compensate for the impacts on restricted/protected plant species, transplanting of affected individuals to the identified receptor sites in the Tai Tam Country Park is recommended. The recreation of a suitable habitat for the Rice Fish at upper location of the MTHS is recommended. No adverse residual ecological impact is anticipated.

Environmental Monitoring and Audit (EM&A)

17. A framework for EM&A programme is proposed in the EM&A Manual. An Independent Environmental Checker will be employed to audit the EM&A programme including demolition, remediation and other requirements. An Environmental Project Office (ENPO) has been set up to oversee the cumulative environmental impacts arising from the developments in Penny's Bay and the adjoining areas including the CLS decommissioning project.

Comments received so far from the Public during the Public Inspection Period

18. CED is to make the EIA report, the EM&A Manual and the Executive Summary available for the public to comment under the EIAO. Members will be briefed on any comments received from the public at the meeting.

Environmental Assessment and Noise Division
Environmental Protection Department
February 2002



 

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