This Section identifies potential sources of land contamination during
the operation of the proposed LNG Terminal and associated facilities at
14.2
Legislation
Requirement and Evaluation Criteria
Assessments of land contamination are
guided by the EPD's guidance document Professional Persons Environmental
Consultative Committee Practice Note 3/94 - Contaminated Land Assessment and
Remediation (ProPECC PN 3/94), the Technical Memorandum on Environmental Impact
Assessment Process (EIAOTM), and EPD's 1999 Guidance
Notes for Investigation and Remediation of Contaminated Sites of: Petrol
Filling Stations; Boatyards; and Car Repair/ Dismantling Workshops (Guidance
Notes).
ProPECC PN
3/94
advises that measures for land contamination problems are relatively simple,
mainly relying on good engineering practice, well developed waste management
strategies and established industrial guidelines.
Annex 19 of the EIAOTM: Guidelines for Assessment of Impact on Sites of Cultural Heritage and
Other Impacts, and the 1999 Guidance
Notes, provides guidance on the assessment of potentially contaminated
land, including petrol filling stations, shipyards, car repair/dismantling workshops
and docking facilities.
Discharge of
potentially contaminated surface and groundwater will also be compared against Standards for Effluent Discharged into the
Marine Water of Southern and North Western Water Control Zone prescribed in
the EPD’s Technical
Memorandum on Standards for Effluent Discharged
into Drainage and Sewerage Systems, Inland and Coastal Water issued under
the Water Pollution Control Ordinance
(WPCO).
The following legislation, documents and
guidelines may also cover or have some bearing upon contamination and the
handling, treatment and disposal of contaminated materials in
· Waste Disposal Ordinance (Cap 354);
· Waste Disposal (Chemical Waste) (General) Regulation (Cap 354); and
· Code of Practice on the Packaging, Labeling and Storage
of Chemical Wastes, Environmental Protection Department (1992).
14.3
Potential Sources of Land
Contamination During the Operational Phase
Potential sources of land contamination
during the operation phase of the project were identified as follows:
·
Fuel (diesel) loading/unloading and storage facilities for power
generation, vehicle tanking, emergency fire water pumps, maintenance areas,
workshops, paint shops, washing down facilities, waste and dangerous/hazardous
material stores; and
·
Process water in SCV back up facility.
Potential contaminants include total
petroleum hydrocarbons (TPH), volatile and semi-volatile organic compound (VOCs/SVOCs), heavy metals, other organic hydrocarbons and
inorganic pollutants. It is noted that
accidental spills of LNG are not considered to cause contamination as the LNG
will vaporize quickly leaving behind no contaminating residue. The impacts associated with accidental spills
of LNG are discussed in Section 13 –
Quantitative Risk Assessment of this EIA Report.
As discussed in detail in Annex 13A1, the terminal is designed and
would have operation systems and procedures which will reduce the potential for
accidental spills or leakages, including:
·
The tank design will be full containment, with all tank connections made
through the roof to maximize mechanical strength and integrity.
·
The double wall construction of tanks will comprise an inner wall of low
temperature steel and an outer wall of pre-stressed concrete. The outer concrete wall will include a
reinforced concrete bottom slab and roof and it will contain any leak from the
inner tank
·
Alarm and shutdown devices will be incorporated in the design to ensure
safe tank operation.
·
Fire water systems will be provided to protect the LNG Terminal and
berth.
·
Security will be designed to ensure the safety and integrity of the
facilities.
·
During cargo discharge the vapour pressure in the LNG Carrier cargo
tanks will be maintained by returning vapour from the shore. With this balanced
system, under normal circumstances, no hydrocarbons will be released to the
atmosphere from ship or shore.
·
The carrier and shore Emergency Shut Down (ESD) systems will be
interlinked such that an unusual event on either will automatically activate a
transfer system shutdown (ESD I) and in a severe case will also disconnect the
unloading arms (ESD II). An ESD I test
will be completed before the start of unloading operations. In the event of an ESD II unloading arm
disconnection, LNG spillage would be very small due to the activation of
isolation valve.
·
Appropriate handling procedures for hazardous substances (chemicals,
oils, paints, etc.) will be implemented to reduce potential contamination from
spillages form maintenance areas, workshops and storages.
14.4
Land Contamination
Prevention and Control Measures
In accordance with Clause 3.4.10.1 (ii) of the Study Brief, the following measures are
proposed to reduce the potential for land contamination when the terminal
becomes operational.
·
Fuel, lubricating oil, chemical and chemical waste storage
areas present on the site shall be provided with secondary containment;
·
Individual drainage from lines, pumps, compressors, vessels,
heat exchangers and instruments shall be connected to an on-site Coalescing
Plate Interceptor (CPI) type oil water separator
·
Stationary equipment that could release hydrocarbons and
that are not located in containment areas will be installed on skids containing
drain pans. An open drain system will
collect spillage/leakage/contaminated storm water from these areas and will
connect to the oil water separator;
·
Spill containment and clean up equipment shall be provided
in all areas where oils, chemicals and chemical wastes are handled and stored;
·
Training shall be provided to relevant personnel on
hazardous materials handling and spill control and clean up; and
·
Contaminated materials and dispensed spill control and
clean-up equipment shall be collected and disposed of in accordance with the WDO.
Details of
practices to handle chemical wastes are discussed in Part 2 - Section 7 - Waste
Management, measures to prevent contamination of adjacent water bodies are
discussed in Part 2 - Section 6 - Water
Quality Impacts and the impacts associated with accidental spills of LNG
are discussed in Part 2 - Section 13 - Quantitative Risk Assessment.
14.5.1
Gas Detection,
Alarm, Firefighting and ESD Systems
A centralized
spill, fire and combustible gas alarm and control system will provide input to
an information management system.
Automatic detection devices, manual alarms and audible and visual signalling devices will be strategically located throughout
the terminal. Automatic detection
devices will include flame, fire and heat, smoke, low temperature and
combustible gas detectors. CCTV monitors
will be installed to allow a visual surveillance of critical facilities from
the central control room. An emergency
shutdown system (ESD) will be incorporated in the design of the terminal and
provide the operators with the capability of remotely shutting down the entire
or selective portions of the terminal.
The unloading arms will also be equipped with Powered Emergency Release
Couplers (PERCs).
The PERC maintains containment integrity and prevents damage to the
unloading arms in the event of an emergency as discussed in Part 2 - Section 13 - Quantitative Risk Assessment of this EIA
Report.
With the above
recommended measures in place to prevent, contain and clean-up spills and
leaks, no land contamination or environmental concern would be expected to
arise and no adverse residual impacts are predicted. Accidental spills of LNG are not considered
to cause contamination as the LNG will vaporize quickly leaving behind no
contaminating residue.
14.7
Environmental Monitoring
and Audit
Based upon the
integrated mitigation measures and procedures which will be put in place to
prevent, contain, clean-up and dispose of any spillage, significant
environmental effects are highly unlikely to arise. No specific EM&A measures are therefore
required.
Potential sources of contamination during
the operational phase have been identified for the LNG terminal associated
facilities. Mitigation measures and
controls will be installed to reduce the likelihood of a spill or leak. In the unlikely event of a spill, the
installed mitigation measures and controls are designed to reduce the
environmental impacts associated with land contamination. No land contamination or environmental
concern would be expected to arise.