2.1
The approved EIA
has assumed that ready-mixed concrete in concrete mixer trucks would be
delivered by barges to Telegraph Bay for the construction of Cyberport. The
delivery of concrete by sea or by road would cause environmental and traffic
problems in the peak production period. The production of concrete at an
off-site concrete batching plant would also create environmental problem for
local sensitive receivers. It proposes,
as an alternative, that an on-site concrete batching plant be constructed to
meet the concrete demand on site.
2.2
Estimated quarterly
consumption of concrete quantity required for the current programme of
construction at Cyberport is tabulated in Table 2.1.
Table 2.1 Estimated
Quarterly Consumption of Concrete Quantity
|
Quarter |
Quantity1, m3 |
Average Truck Load per Day2 |
|
2Q2000 |
11,000 |
29 |
|
3Q2000 |
24,630 |
64 |
|
4Q2000 |
39,850 |
104 |
|
1Q2001 |
54,460 |
141 |
|
2Q2001 |
54,460 |
141 |
|
3Q2001 |
71,360 |
185 |
|
4Q2001 |
58,970 |
151 |
|
1Q2002 |
48,285 |
125 |
|
2Q2002 |
48,285 |
125 |
|
3Q2002 |
44,420 |
115 |
|
4Q2002 |
44,420 |
115 |
Quantity is estimated based on 25
production days per month.
Concrete capacity of each mixer truck is
assumed to be 5 m3/Load.
2.3
According to the
concrete consumption in Table 2.1, it is estimated that more than 10 barges
would be required for daily delivery of concrete mixer trucks after the fourth
quarter in year 2000. The maximum barge
traffic would be 26 barges per day in the third quarter of 2001. It is
anticipated this additional barge traffic may have implications on the busy
marine traffic around the Hong Kong waters.
2.4
The short-term
tenancy for the concrete batching plant operated by Ready Mixed Concrete (H.K.)
Limited (RMC), the concrete provider of the site, at Aberdeen may be terminated
very soon. The employment of other batching plant at Ap Lei Chau may also
affect the marine traffic.
It is very likely that the supply of concrete would rely on batching plant not
in the practical vicinity of Telegraph Bay. This would definitely lengthen the
travelling time for barges, with consequential problem on concrete quality.
2.5
The barge traffic
would also create air quality, noise and water quality pollution along the
marine route. Dark smoke from barges is both unsightly and air polluting and
this has been a cause for complaint by residents at Baguio Villas. Barge horn
noise would be unavoidable under misty weather and therefore can be another
cause for complaint. In addition, minor quantities of wastewater may be
discharged from these barges into the water, causing local water pollution.
2.6
The existing jetty vertical seawall is not designed
for berthing of a large number of barges. However, construction of a new jetty
would cause marine water quality impact and programming constraints on the
construction works.
2.7
Other demerits
include the delivery time of concrete by barges. It is very likely that because
of busy marine traffic, concrete may not always be delivered to the site by
barges earlier than, say, 6: 00 p.m., for the concrete to be placed before
7:00pm on each working day. Any delay in the delivery would require concreting
to proceed into the restricted hours and therefore risk the violation of the
Environmental Permit conditions.
2.8
On the other hand,
land transportation of concrete would require a large number of trucks on road
after the 4th quarter of 2000, which would, in turn, cause serious
traffic problem for Victoria Road and generate air quality and noise impacts on
the nearby sensitive receivers
2.9
An on-site
concrete batching plant is therefore desirable from environmental and
operational points of view. Table 2.2 summarizies the benefits between an on
site concrete batching plant and the concrete delivery by barges.
Table 2.2 Comparison
between on site concrete batching plant and concrete delivery by barges
|
|
Concrete Batching off-site |
Concrete Batching Plant on Site |
|
Barge Traffic |
4 to 5 barges
per day for Stage 1 Up to 26 barges
per day for Stage 2 |
2- 3 barges per
day for two days a week |
|
Air Quality
impact |
High, due to
the |
Low, due to the
low number of barges operating and the batching plant is totally enclosed |
|
Noise Impact |
Medium, but
high during misty weather. In case that
land transportation is used, the delivery of concrete will increase the
traffic noise impact on the nearby sensitive receivers. |
Low, due to the
low number of barges operating and the batching plant is totally enclosed. |
|
Water Quality
Impact |
High risk of
polluting the harbour due to barges |
Low risk |
|
Marine Traffic
Impact |
High |
Low |
|
Visual Impact |
Low, as the
earth mound and future buildings will reduce the visual impact |
|
|
Delivery Timing
Control |
Good control on
concrete delivery |
|
|
Potential for
Mitigation |
Mitigation
measures are difficult to implement on barges. |
Easy to
implement. As the concrete batching plant is stationary, the mitigation
measures (such as totally enclose the plant) can easily be applied. |
2.10
It is clear from
Table 2.2 that an on-site concrete batching plant has far better environmental
benefits than an off-site concrete batching plant. In addition, the on-site
concrete batching plant will only supply concrete for the day to day use at
Cyberport only. No concrete will be delivered off site.
In addition, as the concrete batching plant is
constructed on top of a concrete base slab which separates the plant from existing
ground, it is
anticipated that no land
contamination will be resulted during decommissioning of concrete
batching plant.
2.11
RMC has proposed
to install a concrete batching plant with a maximum hourly production of 300 m3
concrete. Location of the proposed batching plant is shown in Figure 2.1.
2.12
The siting of the
concrete batching plant has been carefully examined. The proposed location is
considered the best in terms of environmental and visual impacts while
maintaining the stability of the seawall. In addition, the proposed location is
quite farher awaymost from Baguio
Villa. It is anticipated that the
existing earth mound and the future commercial
buildings would screen the plant at this location from the sensitive
receivers, and hence the potential visual impact can be much reduced. Further
details are given in Chapter 8. For other locations further south along the seawall, the earth mound and the future commercial buildings can only screen a small portion of the proposed concrete batching plant, thisthe advantage of using
earth mound and building advantages to reduce the visual impact may not be guaranteed.
2.13
Furthermore, the
proposed location of the concrete batching plant to the nearest sensitive
receiver is about 280m away, which comply with the Hong Kong Planning and
Standard Guideline (HKPSG).
2.14
In addition, the
proposed plant is very close to the vertical seawalljetty. If
alternative locations are selected, longer converyance system and
more traffic will be required to transfer the cement and aggregates from the
vertical seawall to the concrete batching plant. These may introduce additional
and unnecessary noise and dust nuisance to local sensitive receivers.
2.15
The actual
operation of the plant will be subject to the issuance date of the
Environmental Permit and the S.P. License. The concrete batching plant would
operate until November 2001 when the land lease for the plant expires;
thereafter the need for such a concrete batching plant will be re-visited.
2.16
As the operation
of a concrete batching plant with a total silo capacity exceeding 50 tonnes is
a specified process (S.P.) under the Air Pollution Control Ordinance (APCO),
application for a S.P. license is required in order to conduct the works. As it
takes time for the authority to issue a S.P. license, the intention is to
divide the works into two stages for the operation of the concrete batching
plant. A mobile batching plant of a total cement silo capacity of 45 tonnes
would be employed for temporary production in Stage 1 while a complete batching
plant of a total capacity of 800 tonnes would be operated in Stage 2 (Fig.2.2).
2.17
For the Stage 1
plant, a mobile batching plant Mob 60 with a total silo capacity of 45 tonnes –
one 30 tonnes and one 15 tonnes, would be employed. The mixer capacity is 1.25
m3/batch. The dimension of Stage 1 plant is 23m x 20m x15m. Cement
and aggregates are delivered to the site by barges. Fig.2.3 shows the schematic
diagram for stage 1. Predetermined mixing ratios of cement and aggregates are
set to produce different grades of concrete for application. Appropriate amount
of water is also injected to form the mix.
2.18
Cement is pumped
from the barge to a cement tanker. The cement tanker transfers the cement to
the fully enclosed cement silos. Cement is stored in the silos and properly
weighed for mixing. Dust collectors would be installed at the cement silos and
the concrete mixer. Totally three dust collectors would be employed.
2.19
Aggregates would
be transferred from a barge to a tripper truck through the sea front receiving
hopper. In order to reduce dust emission, water will be sprayed on the barge (Fig.2.4).
The tripper truck then transports the aggregates to the aggregate storage yard
(Fig.2.5). A wheel loader would transfer the aggregates to an
aggregate-receiving hopper (Fig.2.6). Finally, the aggregates are conveyed to a
fully enclosed aggregate storage bin with a total capacity of 30 tonnes by a
belt conveyor. Aggregates are stored in the overhead storage bins and ready for
mixing in the mixer
2.20
For the Stage 2
plant, a fixed batching plant with a total cement silo capacity of 800 tonnes –
two 200 tonnes and four 100 tonnes, would be employed (Fig.2.7). The mobile
batching plant Mob 60 would be used as a standby and will not be operated
concurrently with the Stage 2 plant. The total dimensions of the Stage 2
and Stage 1 plants is 95m x 45m x 24m. The Stage 2 plant is composed of two
identical mixers. Both will be operated at batch mode and the capacity is 3.5 m3/batch
each. Cement and aggregates are also delivered to the site by barges. Similar
operations to the Stage 1 are involved.
2.21
In Stage 2, cement
is directly pumped from the barge to the cement silos. The schematic diagram is
shown in Fig. 2.8. There are totally six cement silos – two are 200 tonnes and
four are 100 tonnes. The two 200 tonnes silos are interconnected while the
other four silos are also connected. Two dust collectors would serve each group
of silos and one dust collector would serve the two mixers. Therefore, totally
five dust collectors would be employed in the Stage 2 plant.
2.22
The operating
hours will be 0700 to 1900 hours on a normal working day. There will be no
operation on Sundays and Public Holidays.
2.23
Aggregates would
be transferred from a barge to the sea front receiving hopper. Afterwards, the
aggregates would be transported to a group of five 200 tonnes aggregate storage
bins by enclosed belt conveyors (Fig.2.9). Moreover, each mixer is equipped
with an overhead storage bin composing of four compartments (Fig. 2.10). Each
compartment can hold 40 tonnes of aggregates.
2.24
Three sets of
generators would be used in the plant - two sets for the batching plant and the
other for maintenance workshop.
2.25
A concrete
recycling machine of capacity 20m3/hr will be installed on-site to
recycle concrete waste (Fig.2.11). In the worst case situation, the recycled
concrete will not exceed 5m3/day.
2.26
Before
decommissioning of the proposed concrete batching plant, remained materials
shall be removed from the facilities before decommissioning of concrete
batching plant. The storage, handling and disposal of unused materials,
chemical waste, construction waste, general refuse shall be conducted with
current waste management practices. In addition, during decommissioning, the
noise and air quality impacts will be much lower than those in the operation
and construction phases.
2.27
Table 2.3 shows
the schedules of the concrete batching plant
Table
2.3 Schedules of Concrete Batching
Plant
|
Description |
Period |
Time |
|
Construction
of Stage 1 |
~ 1
month |
Dec
2001 |
|
Operation
of Stage 1 and Construction of Stage 2 |
~ 3
month |
March
2001 |
|
Operation
of Stage 2 |
~3
month after and onwards |
April
2001 |
2.28
The construction
works during the commencement of Concrete Production and the completion of
Concrete Production (i.e. Dec, 2000 to Dec, 2001) will comprise the following
works:
•
Main Construction
Works for the Telegraph Bay Development
•
Construction and
operation of the Concrete Batching Plant
2.29
The main
construction work includes construction of the Cyberport Phase C1, C2, C3 and
R1, sewage treatment plant, Southern Access Road, Northern Access Road, Road
D1, D2 and L1.
2.30
The working
Programmes for various works are shown in Fig.2.12 and Fig.2.13.