Environmental Impact Assessment Ordinance (Cap.499)
(ACE-EIA Paper 16/2001)
Environmental Impact Assessment
Demolition of Kwai Chung Incineration Plant
This paper presents the key findings and recommendations of the Environmental Impact Assessment (EIA) Report for the Demolition of Kwai Chung Incineration Plant (KCIP) 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.
2. Members' views are sought on the findings and recommendations of the EIA report.
Need for the Project
3. The Kwai Chung Incineration Plant was put into service as a municipal solid waste incinerator in 1978. The phasing out of the Kwai Chung Incinerator, which ceased operation in May 1997, fulfils the Government policy set out in the "White Paper: Pollution in Hong Kong - A Time to act (1989)" with significant environmental gains. If the demolition were not to proceed, the premises will progressively dilapidate and fall into disrepair, potentially causing problems to the surrounding environment and the general public and therefore demolition is required. The demolition will release the site for future beneficial use.
Description of the Project
4. The project is a Designated Project under Schedule 2, Part II of the EIAO, "Decommissioning Projects", Item 3 "a municipal incinerator". The study brief was issued on 21 December 1998. An application for the approval of the EIA was submitted on 15 September 2001. On 13 November 2001, the Director of Environmental Protection advised CED under Section 6(3)(a) and Section 6(4) of the EIA Ordinance that the EIA report was suitable for public inspection.
5. The KCIP is located at Kwai Yue Road, Kwai Chung, facing the Rambler Channel, Tsing Yi South Bridge and Route 3, and has a site area of about 14,000 m2. It is adjacent to the existing Kwai Chung Preliminary Sewage Treatment Works, the existing public cargo working area, the former Gin Drinkers Bay Landfill (Kwai Chung Park) and a future public fill barging point. The nearest residential use is more than 500 m away (see Figure 1).
6. The project is to demolish all the buildings including a 150 m high chimney, and to clear the land within KCIP. Areas of contaminated land will be decontaminated as appropriate.
Specific Environmental Aspects to Highlight
(a) Alternative Methods of Demolition
7. Different alternative methods for demolition have been considered. A proposal for explosive demolition of the chimney was dropped due to concerns on asbestos containing materials, potential hazard from landfill gas and risk to the nearby facilities and the road users on the Tsing Yi South Bridge and Route 3. Conventional top down demolition methods using mechanical equipment will be adopted.
(b) Contaminated Land
8. Portions of the site were found to be contaminated mainly with heavy metals and petroleum hydrocarbons, and small amount of polynuclear aromatic hydrocarbons are present in some localised areas. Figure 2 summarises the main findings of the contamination assessment. The 'Dutch' criteria was adopted for contamination assessment and subsequent remediation. The site will be treated to a standard that is suitable for residential use. The estimated quantities of contaminated soil are: heavy metals (1750 m3), total petroleum hydrocarbons (TPH) and polynuclear aromatic hydrocarbons (PAH) (total 450 m3). Additional confirmatory testings for contaminated soil will be carried out during the site remediation works.
9. Soil contaminated with heavy metals will be chemically treated by mixing with cement and subject to Toxicity Characteristic Leachate Procedures (TCLP) test, and would be re-used on site. All TPH and PAH will be landfilled.
(c) Dioxins and Furans
10. Small amounts of dioxins and furans contaminated ash were found deposited on the floors and walls of some structures. The United States Environmental Protection Agency (USEPA) criteria of 1 part per billion toxicity equivalent (1 ppb TEQ) for residential use were used for the contamination assessment. About 20 m 3 of ash was found to be contaminated with dioxins and furans. Dioxins and furans ash will be treated by mixing with cement and subject to TCLP test of 1 ppb TEQ. Pilot tests for the treated dioxins contaminated ash will be carried out before the site remediation works. Treated ash will be placed into polythene lined steel drums and then disposed of to a government landfill.
11. There are asbestos containing materials (ACM) found on the site in the chimney, the base of the chimney, the main building offices and the main building. When the Kwai Chung Incineration Plant ceased operation in 1997, bulk asbestos removals from the plant were undertaken for the base of chimney, main building offices and office block prior to the removal of main plant and machinery in about 1997/98. The remaining ACM to be removed is from the chimney and main building. An asbestos consultant will be employed by the proponent to supervise the contractor to ensure that ACM is removed in line with the requirements of the Air Pollution Control Ordinance.
(e) Landfill Gas Hazard
12. The site is near the decommissioned Gin Drinker's Bay Landfill, and therefore an assessment was carried out for landfill gas hazard. The conclusion indicates that the risk of gas hazard during demolition works is 'medium' for demolition and 'high' for site investigations. Precautionary measures are recommended, to include training, no smoking to be allowed on site, use of mechanical ventilation and spark arrestors for electrical equipment for underground works, provision of breathing apparatus and monitoring of landfill gases.
(f) Waste Management Plan
13. A Waste Management Plan will be required for all stages of the demolition and soil remediation works. The Plan will include details on the types, quantities, disposal methods, timings and locations for disposal of wastes, responsibilities for implementation and possible recycling and reuse of materials.
(g) Other Impacts related to the demolition
14. Short term construction dust is expected to comply with the requirements under the Air Pollution Control Ordinance. Construction noise will comply with requirements under the Technical Memorandum of the EIAO and Noise Control Ordinance as the nearest noise sensitive receivers are over 500 m away. Site run-off and drainage impacts would be prevented or minimised by implementing the measures recommended in the EIA, such as the use of sediment traps, temporary channels, temporary diversion and oil interception facilities.
Environmental Monitoring and Audit (EM&A)
15. A framework for EM&A has been put forward in the EM&A Manual. An Independent Checker (Environment) will be employed to audit the EM&A programme including demolition, remediation and other legislative requirements.
Comments received so far from the Public during the Public Inspection Period
16. CED would make the EIA report, EM&A Manual and Executive Summary available for public comment under the EIAO on 20 November 2001. Members will be briefed on any comments received from the public at the meeting.
Environmental Assessment and Noise Division
Environmental Protection Department