This Section identifies potential sources of land contamination during
the operation of the proposed LNG Terminal and associated facilities at Black
Point and assesses potential environmental impacts. Recommendations have been made for
operational practices, control measures and waste management for prevention of
site contamination.
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 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 3.7.10.1 (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 3 - Section 7 – Waste
Management, measures to prevent contamination of adjacent water bodies are
discussed in Part 3 - Section 6 – Water Quality Impacts and
the impacts associated with accidental spills of LNG are discussed in Part 3 -
Section 13 - Quantitative Risk
Assessment.
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 3 - 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.