The environmental impacts associated with the
construction and operation of the Project are summarised in the following
sections.
3.1.1
Construction Phase
Dust from excavation, site formation and
construction activities is the only key air quality concern during the
construction of the Project. Owing
to the small scale of the civil construction requirement and the distance from
the Air Sensitive Receivers (ASRs), no adverse dust impact is anticipated. In addition, only a limited number of
diesel-powered equipment will be operated on site, and therefore impact from
construction equipment is expected to be minimal. With the implementation of the dust control measures
stipulated in the Air Pollution Control
(Construction Dust) Regulation, no adverse air quality impact is envisaged
from the construction of the Project.
3.1.2
Operational Phase
The
operation will significantly reduce SO2 and NOx emissions. Further reduction in particulate emissions is also
anticipated as a result of the LS FGD operation.
The following reduction efficiencies
are used as the basic assumptions for the operational air quality assessment:
·
SO2
emission reduction by up to 90%; and
·
NOx
emission reduction by up to 80%.
A comparative air quality assessment was
conducted for CPB by scale model testing performed in a Boundary Layer Wind
Tunnel to simulate the behaviour of the exhaust plume before and after
installation of the proposed emission control equipment.
The modelled percentage
reductions in SO2, NOx and particulates concentrations at the 36 ASR locations
after implementation of the retrofit programme are similar in magnitude to the
proposed emission reductions at source.
The comparative study demonstrated that all the identified ASRs will
have an improvement in air quality after the retrofit.
3.2.1
Construction Phase
The construction noise assessment conducted
for the Project indicates that the predicted noise levels at the noise
sensitive receivers (NSRs) are expected to range from 43 to 51 dB(A) and are therefore
well within the noise criteria.
This is due mainly to the considerable separation distance and the
screening offered by the topography and the existing buildings. In view of the assessment results, the
noise generated during the construction phase is not expected to cause any
adverse impact and mitigation measures will not be required.
3.2.2
Operational Phase
The noise levels at the identified NSRs (Sha
Po Kong village and the planned holiday camp at Siu Lang Shui) from the
operation of the Project have been predicted based on the specified maximum
sound pressure levels (SPL) for the new equipment to be installed at CPB. The results indicate that the identified
NSRs will be subject to noise levels which comply with both the stipulated
daytime and night-time noise criteria.
The suppliers of the new equipment should
guarantee the specified SPL by providing a certificate of measurement and
verify the SPL during testing and commissioning in accordance with
international standard procedures.
If necessary, the suppliers should apply attenuation measures to achieve
the guaranteed noise levels during the detailed design stage. With the noise specifications in place,
further mitigation measures will not be required during the operational phase
of the Project.
3.3.1
Construction
Phase
Water quality modelling has been performed to assess the construction
phase impacts, with the assumption that no mitigation measures are adopted. The findings indicated that for both the
dry and wet seasons, no exceedances of the Water Quality Objectives (WQO) and
the evaluation criteria are predicted to occur during the dredging
operations. The impact assessment
has also shown that other land-based construction works, if properly controlled,
are not expected to cause any adverse impacts to the
surrounding waters and the sensitive receivers.
3.3.2
Operational
Phase
No effluent is anticipated to arise from the operation of the NOx
control system and hence water quality impacts are not expected.
In the LS FGD process, the gypsum slurry from the absorber unit is
treated, resulting in dewatered gypsum and a small quantity of liquid
effluent. The resulting effluent
may have a small chemical oxygen demand and/or reduced dissolved oxygen
concentrations. The effluent will
be treated to comply with the discharge standards stipulated in the Technical Memorandum on Standards for
Effluents Discharged Into Drainage And Sewerage Systems, Inland And Coastal
Waters issued under the Water
Pollution Control Ordinance. It
is then added to the cooling water flows and discharged via the existing CPB sub-marine
cooling water outfall, resulting in a small increase (about 0.02%) in the total
flows from the outfall. The treated
FGD effluent would not be expected to have any adverse effect on the temperature of the cooling water or on
the quantities of residual chlorine in the discharge.
The high degree of mixing inherent in the coastal margin or coastal zone
will result in rapid dilution of the effluent to very low concentrations and no
exceedance of the WQO or evaluation criteria for dissolved oxygen (DO),
dissolved metals, temperature, suspended solids (SS), salinity and sulphate is
expected. As a result, further mitigation
measures are considered unnecessary.
3.4.1
Construction
Phase
The key potential impacts during the
construction phase are related to the management of dredged sediments,
demolition materials, excavated materials and construction waste. With the implementation of the
mitigation measures recommended, no adverse environmental
impacts arising from storage, handling, collection, transport and disposal of
wastes are expected.
3.4.2
Operational
Phase
About 240,000 tonnes of commercial grade gypsum will be generated each
year from the FGD process and can be commercially recycled in the Pearl River Delta
and
With the implementation of the recommended mitigation measures, no
unacceptable environmental impacts associated with the storage, handling,
collection, transport and disposal of a small quantity of industrial waste and
general refuse arising from the operation of the Project are expected.
A number
of existing facilities at CPB, including the FODT, the DG Store, the IPRS, the
LPG compound and the CO2 tanks, are required to be demolished to
accommodate the proposed emissions control equipment. A land contamination assessment was
carried out at these areas following the methodology and procedures described in
the Contamination Assessment Plan (CAP) which had been approved by the EPD. The land contamination assessment
included soil and groundwater sampling, laboratory analyses for target
parameters, preparation of a Contamination Assessment Report (CAR) and
preparation of a Remediation Action Plan (RAP).
With the
implementation of the remedial measures in the RAP, the hazard and
environmental impacts associated with the potential land contamination and the handling
and treatment of the contaminated soil and groundwater are considered very low.
The land-based construction works and operation of the
Project will be conducted entirely within the existing industrial site of the CPPS
and therefore no impact to terrestrial ecology is envisaged.
The literature review of the existing marine ecological resources in the
Study Area identified two key sensitive receivers, namely the Sha Chau and
The predicted changes to water quality attributable to the construction
and operational activities are not expected to cause exceedances of the WQOs,
and therefore no impacts to the marine ecological resources or marine mammals
are anticipated.
Mitigation measures designed to minimise impacts to the population of
Indo-Pacific Humpback Dolphins that use the area include restrictions on vessel
speed and adopting the local construction practice of using bubble curtains/jackets during percussive piling work for the
construction of the additional berthing facility. Other mitigation measures designed to
mitigate impacts to water quality to acceptable levels (i.e., compliance with
WQOs) are also expected to mitigate impacts to marine ecological resources.
3.7
Landscape and Visual
Considerations
It has been confirmed that the height of the proposed structures
associated with the Project will not exceed the existing maximum building
height of +83 mPD and no additional chimney will be erected in the
Project. In accordance with the
requirements of the EIA Study Brief for the Project, detailed landscape and
visual impact assessment is not required for this EIA Study.
As all the new structures and emissions
control equipment of the Project will be located within the existing industrial
setting of CPPS, it is not expected to result in any negative impact on the surrounding landscape. With the adoption of a colour scheme that
complements the industrial surroundings of the existing CPPS, the Project is also
expected to have a very low visibility.