K. Wah Materials Limited
Environmental Impact Assessment Study
for Cement Silos Addition Work in Tai Po Depot
Executive Summary
5 Summary of potential impacts
5.1 Air
Quality Impacts
5.1.1 Construction
Phase
5.1.2 Operational
Phase
5.2 Noise
Impact
5.2.1 Construction
Noise
5.2.2 Operational
Noise
5.3 Water
Quality Impact
5.3.1 Construction
Phase
5.3.2 Operational Phase
5.4 Visual
impact
6 summary of MITIGATION MEASURES
7 Environmental Monitoring and Audit
(EM&A)
TABLES
Table 1 Summary of Major Mitigation Measures
FIGURES
Figure
2 Photomontage of the Cement Depot
with Mitigation Measures
This
executive summary outlines the findings and recommendations of the
Environmental Impact Assessment (EIA) Study for the proposed expansion of
cement depot in Tai Po. The executive summary is structured as follows:
l
Project Background
l
Project Description
l
Scope of the Study
l
Potential Environmental Impacts and Mitigation Measures
l
Summary of Environmental Outcomes
l
Environmental Monitoring and Audit Requirements
l
Conclusions
The
existing Tai Po cement depot is operated by K. Wah Materials Ltd. (hereafter
refer to as the Project Proponent). It covers approximately 5,900 m2
and consists of 6 cement silos with a total capacity of 8,500 MT (Fig.1a).
Cement is delivered to the depot through cement barges. Existing cement silo
capacity is not capable of storing all the cement from one single shipment
load. Current practice is to unload the cement from the silos by cement tanker
for immediately delivery to clients, thus free up the silos for further
storage. As a result, the barge is required to berth alongside the shore for a
longer period and uploading of cement can only be operated in batch mode.
In order to reduce potential nuisance of the barge
operation, the best way is to increase the depot storage capacity. The Project
Proponent plans to construct three additional cement silos of total capacity at
7,500 MT. With the three additional silos, the total capacity of the depot will
be increased to 16,000MT.
As the depot capacity involving cement works will be greater
than 10,000MT, it is thus classified as a Designated Project under item K.5 of
Part I of Schedule 2 of the Environmental Impact Assessment Ordinance (EIAO)
(Cap. 499). An Environmental Permit is
therefore required for the construction and operation of the cement depot. The
Project Proponent has commissioned Ove Arup & Partners Hong Kong Ltd (Arup)
to provide the environmental consultancy services for this application. A study
brief (ESB-084/2001) was issued by EPD on 30 October 2001 outlining the
requirements of the EIA Study and an EIA report has been prepared accordingly.
Due to the limited capacity of existing silos, 3
additional silos of total capacity at 7,500MT are proposed to be
constructed within the existing cement depot (Fig. 1b). Each silo will be
fitted with a dust collector and connected to the existing loading points for unloading
to the cement
tankers. Therefore, there will be no increase in the number of cement tanker
loading points.
Additional cement silos are purely for storage purpose
only. It shorthens the duration for cement unloading from the ocean going
vessel and cement uploading from the barge. Moreover, it allows more efficient
planning of cement tanker delivery. Therefore, the duration of any noise
nuisance and marine traffic impact from the barge and vessel operations will be
greatly reduced.
The construction of the additional cement silos will
consist of three stages, including ground excavation, setting of foundation and
the silo erection works. The tentative construction programme for
the addition of 3 silos will start from February 2003 to November 2003 and
their operation will start immediately afterwards.
The EIA study has addressed the likely potential
noise, dust, water quality, waste management and visual impacts of the project
during construction and operational phases of the cement works, with and
without mitigation measures. As the proposed project site is within the existing
industrial premises, there will not be any impacts on local ecology,
landscaping, site of cultural importance or listed buildings.
An EIA report has been
prepared to provide information on the nature of environmental impacts likely
to arise from the construction and operation of the proposed expansion of the
existing cement depot. The EIA has also assessed the acceptability of the
identified environmental impacts on representative sensitive receivers
following the implementation of the proposed mitigation measures.
The assessment
methodologies adopted for the study follow the guidelines as outlined in the
Technical Memorandum on EIAO Process. Quantitative assessments have been
carried out with the use of computer models and standard theoretical
principles, which are accepted by EPD.
K.Wah Concrete Ltd. agreed that the West Wing
Concrete Batching Plant will not be operated during the construction period. Other than watering the ground by an automated watering
system at an interval of every 30 minutes, those measures specified under the
Air Pollution Control Regulation (Construction Dust) for dust control have to
be strictly followed. The predicted cumulative 1-hr and 24-hr TSP concentrations
at all the air sensitive receivers will comply with the Air Quality Objectives.
Other than
watering the ground by an automated watering system at an interval of every 30
minutes, those measures specified under the Guidance Note on the Best Practicable
Means Requirement for Cement Works (Cement Depot) BPM 3/1 have to be strictly
followed. The predicted 24-hr TSP and
24-hr RSP at all sensitive receivers will comply with the AQO limits.
A revised licence for the
Specified Process (cement works) for the operator of the cement works will be
required. The licensing conditions should be strictly followed to ensure that
there is no environmental impact on the nearby sensitive receivers.
5.2
Noise Impact
Taking into account the noise
level generated from the operation of the existing cement works and the
adjacent concrete batching plant, the predicted cumulative noise levels of the
construction of the project at the noise sensitive receivers of Casa Marina
III, will exceed the respective construction noise limits for the “Do-nothing”
scenario. A combination of mitigation measures have been evaluated to reduce
the identified impacts, including:
l
the use of silenced Powered Mechanical Equipment for excavation;
l
the use of portable barriers for Drilling Rig; and
l
the implementation of good site practices.
With the implementation of
the recommended mitigation measures, the predicted noise levels during the
construction of the proposed expansion of the cement depot at the nearby
domestic premises will comply with the daytime construction noise criterion.
Three types of operational
noise source are identified in the EIA report, including:
·
Off-site noise from the ocean-going vessel;
·
On-site cement works and the associated facilities; and
·
Off-site traffic noise.
Off-site Ocean Going
Vessel
There is no
nighttime work (0700 – 2300) for the ocean going vessel. The predicted noise
impacts generated from ocean going vessel at the sensitive receivers along the
coast of Ma On Shan and Planned whitehead development will comply with both the
day and evening time noise criteria provided that the vessel is anchored at a
proper location as determined in the EIA report.
On-site Cement Work and
the Associated Facilities
The predicted cumulative
noise impacts generated by on-site activities on Casa Marina III will be higher
than the operation noise limits. A combination of mitigation measures has been
evaluated to reduce the identified impacts and they are summarized in Table 1.
l
Adopt screw conveyor barge instead of pumping barge
l
Erect acoustic barriers for the Cement Unloading Bay
l
Restrict the operation time of the cement
depot from 0700 to 2300
With the implementation of
the suggested mitigation measures, the predicted noise impacts generated from
the cement depot operation on the sensitive receivers (incl. Casa Marina III)
will be insignificant (<1dB(A)).
Off-site Traffic Noise
Noise generated from off
site activities is mainly from the vehicular traffic flow. It is predicted that
the overall traffic noise at Casa Marina III will exceed the noise limit in
2018. However, the major contribution of the traffic noise level is from the
vehicles on existing road. Noise impact from the cement tankers will be
insignificant (< 1dB(A)). Mitigation measures on the cement tankers are
therefore not necessary.
During the excavation works, soil surfaces would be exposed and suspended
particles will be present in the surface runoff. As the construction site is
located near Tolo Harbour, the coastal waters could be potentially impacted by
sediment laden and polluted runoff if the construction runoff is not properly
controlled. Pollution sources will include the excavated material with rain
wash and wash water from dust suppression sprays. Uncontrolled discharge of
debris and rubbish, such as packaging and used construction materials, could
result in floating refuse affecting the aesthetic quality of the coastal
waters.
Mitigation measures will be implemented to control
construction site runoff, and to minimise the chances of introducing sediment
and other pollutants into the nearby coastal waters. Good practices outlined in ProPECC PN 1/94 “Construction Site Drainage”
shall be followed.
Domestic
sewage would be generated from the site workforce during the construction
phase. Properly maintained portable
chemical toilets are adopted on-site. No water quality impact is anticipated.
During operational phase, there
is no effluent discharge to the adjacent water body and adverse water quality
impact is therefore not anticipated. The surface run-off will be collected by on-site
drainage channel and re-used after treatment by sedimentation. Regular
environmental audit shall be conducted to check the environmental performance
of daily operation to ensure that no effluents will be discharged into Tolo
Harbour.
The positioning of additional silos in adjacency of
the existing silos is considered the best location within the site boundary. By
making use of the screening effect of existing silos, the proposed location
helps to reduce the visual impact.
Slight
or moderate adverse visual impact will be induced by the project at all
sensitive receivers. Mitigation measures on the design details of the silos are
recommended to reduce the visual impact on these receivers. In order to increase the compatibility with
the existing environment, the height and shape of the additional silos will be similar to that of the existing silos. The barrier under the
silos will be painted deep green, while the surface of the silo is left in
non-reflective grey white colour. Fig.2c shows the photomontage for this option.
With these mitigation measures, visual impact will be reduced
to slight and negligible at all locations.
The overall evaluation of visual
impact is acceptable with mitigation measures.
5.5
Waste Management
Waste to be
generated during the construction phase of the proposed development will
comprise excavated material, construction material and general refuse. The volume of excavated material is
estimated to be approximately 1000m3. Due to the inert nature of the
excavated material, the material can be considered for re-use on site or dispose of at public filling area.
During the operational phase, all cement is expected to be delivered to
the clients through the cement tankers on the same day as barge uploading. In
addition, maintenance of the tankers is not allowed in the Depot. There is also
no diesel fuel stored in the Depot.
Good waste management practices including avoiding, minimizing, reusing
and recycling will be adopted to reduce waste generation during construction
phase. Scrap metals or abandoned
equipment will be recycled if practical.
General refuse generated from the construction and operation of the
project will be collected from lidded bins and delivered to a central
collection point where they will be stored in containers to prevent, windblown
litter, vermin, water pollution and visual impact.
The proposed project site is within the existing cement
depot. There will not be any impacts on local ecology, landscaping, site of
cultural importance or listed buildings.
The major mitigation measures during the construction
and operational phases are summarized in Table 1.
Table 1: Summary of major mitigation
measures
|
Environmental Issues |
Mitigation Measures |
|
|
Air Quality |
Construction (Dust) |
·
Complied with the Air Pollution Control Regulation
(Construction Dust) |
|
Operation (Fugitive Dust Emission) |
·
Complied with the Guidance Note on the Best
Practicable Means for Cement Works (Cement Depot) ·
Application with the new licence for Specified Process
(Cement Works) and observed for the licence conditions |
|
|
Noise |
Construction |
·
Use of Quiet Plant ·
Use of Portable Noise Barrier ·
Good Site Practices |
|
Operation |
·
Adopt screw conveyor barge ·
Erection
of barriers and enclosures ·
Restriction
the operation hour of cement depot and ocean vessel |
|
|
Water Quality |
Construction (Surface run-off) |
·
Complied with ProPECC PN 1/94 “Construction Site
Drainage” |
|
Operation |
Not required |
|
|
Visual Impact |
Construction |
·
Adoption of Hoarding |
|
Operation
(Visual intrusion) |
·
Adopt similar height and shape as the existing silos
for additional silos ·
Make use the screening effect of existing silos ·
Paint the barrier under the silos with deep green colour |
|
|
Waste Management |
Construction |
·
Good storage, collection and transport
practices of Waste ·
Waste dispose at appropriate disposal
areas |
|
Operation |
Not
required |
|
Due
to the small number of Power Mechanical Equipment and small size of the
construction site, it is considered that environmental monitoring and auditing are not required provided that all the
proposed mitigation measures listed in the EIA report are implemented.
The
EIA study has assessed the potential environmental impacts on air quality,
noise, water quality, visual impacts and waste management aspects. Mitigation
measures, where required, will be implemented during construction and
operational phases for compliance with the environmental standards. No
unacceptable residual impacts are expected.