This Section
assesses the potential noise impacts associated with the construction and
operation of the proposed biodiesel plant at Tseung
Kwan O Industrial Estate (the Project).
The principal legislation relating to the
control of construction noise is the Environmental
Impact Assessment Ordinance (EIAO)
(Cap. 499). The Technical
Memorandum on Environmental Impact Assessment Process (EIAO-TM), issued under the EIAO,
provides guidelines and noise criteria for evaluating the noise impacts.
The Noise
Control Ordinance (Cap. 400) (NCO) also provides means to assess
construction noise impacts. Various
Technical Memoranda (TMs), which stipulate control
approaches and criteria, have been issued under the NCO. The following TMs
are applicable to the control of noise impacts from construction activities:
·
Technical Memorandum on Noise from
Construction Work other than Percussive Piling (GW-TM); and
·
Technical Memorandum on Noise from
Construction Work in Designated Areas (DA-TM).
Under the EIAO, potential noise impact arising from general construction
works during normal working hours (ie 07:00 to 19:00
hrs on any day not being a Sunday or public holiday) is to be assessed in
accordance with the noise criteria specified in the EIAO-TM. The EIAO-TM noise standards are presented in
Table 5.2a.
Table 5.2a EIAO-TM
Day-time Construction Noise Standards (Leq,
30 min dB(A))
|
Use |
Noise Standard (dB(A)) |
|
Domestic Premises |
75 |
|
Educational Institutions (normal periods) Educational Institutions (during examination periods) |
70 65 |
|
Notes: (1) The above standards apply to building
uses which rely on opened windows for ventilation. (2) The above standards shall be viewed as
the maximum permissible noise levels assessed at 1m from the external façade. |
|
When undertaking an assessment for a
Construction Noise Permit (CNP) application for the use of Powered Mechanical
Equipment (PME) during restricted hours, the Noise Control Authority will
compare Acceptable Noise Levels (ANLs), as
promulgated in GW-TM, and Noise Levels (CNLs)
(ie after accounting for factors such as barrier
effects and reflections) associated with the proposed PME operations. The ANLs are
related to the noise sensitivity of the area in question and different Area
Sensitivity Ratings (ie A, B or C (see Table 5.2b)) have been established
to reflect the background characteristics of different areas. The appropriate Area Sensitivity Ratings
for the Noise Sensitive Receiver (NSR) is determined with reference to Table
5.2b.
Table 5.2b Area
Sensitivity Ratings
|
Types of Area Containing NSR |
Degree to which NSR is affected by
Influencing Factor (IF) |
||
|
|
Not Affected |
Indirectly
Affected |
Directly
Affected |
|
Rural area, including |
A |
B |
B |
|
Low density residential area consisting of low-rise or isolated
high-rise developments |
A |
B |
C |
|
Urban area |
B |
C |
C |
|
Area other than those
above |
B |
B |
C |
|
Notes: The following definitions apply: (a) " (b) "directly
affected" means that the NSR is at such a location that noise generated
by the IF is readily noticeable at the NSR and is a dominant feature of the
noise climate of the NSR; (c) "indirectly
affected" means that the NSR is at such a location that noise generated
by the IF, whilst noticeable at the NSR, is not a dominant feature of the
noise climate of the NSR; (d) "not
affected" means that the NSR is at such a location that noise generated
by the IF is not noticeable at the NSR; and (e) "urban area" means an area of high density, diverse
development including a mixture of such elements as industrial activities,
major trade or commercial activities and residential premises. |
|||
The relevant ANLs
for each area sensitivity rating are shown in Table 5.2c.
Table 5.2c Acceptable Noise
Levels for General Construction Works (ANL, Leq,
5 min dB(A)) (GW-TM)
|
Time period |
Area Sensitivity Rating (dB(A)) |
||
|
|
A |
B |
C |
|
All days during the evening (ie 19:00-23:00 hrs) and general holidays (including
Sundays) during the day and evening (ie 07:00-23:00
hrs) |
60 |
65 |
70 |
|
All days during the night-time (ie 23:00-07:00 hrs) |
45 |
50 |
55 |
The Noise Control Authority will consider
a well-justified CNP application, for construction works within restricted
hours as guided by the relevant Technical Memorandum issued under the NCO. The Noise Control Authority will take
into account adjoining land uses and any previous complaints against
construction activities at the site before making a decision. Nothing in this EIA Report shall
bind the Noise Control Authority in making its decision. The Noise Control Authority may include
any conditions in a CNP that it considers appropriate. Failure to comply with any such
conditions may lead to cancellation of the CNP and prosecution action under the
NCO.
Percussive
piling is prohibited between 19:00 and 07:00 hrs on any weekday not being a
general holiday and at any time on Sunday or general holiday. A CNP is required for carrying out
percussive piling between 07:00 and 19:00 hrs on any day not being a general
holiday. The Technical Memorandum on Noise from Percussive Piling (PP-TM) issued under the NCO sets out the requirements for
working and determination of the permitted hours of operations. The ANLs for
percussive piling for different type of NSRs are
shown in Table 5.2d.
Table 5.2d Acceptable
Noise Levels for Percussive Piling
|
NSR Window Type or Means
of Ventilation |
Acceptable Noise Levels
(dB(A)) |
|
NSR (or part of NSR) with no windows or other
openings |
100 |
|
NSR with central air conditioning system |
90 |
|
NSR with windows or other openings but without
central air conditioning system |
85 |
|
Note: (a)
A
10 dB(A) should be subtracted from the ANLs shown
above for NSRs which are hospitals, medical
clinics, educational institutes, courts of law or other NSRs
which are considered by the Authority to be particularly sensitive to noise. |
|
The CNP may contain permitted hours of
operation as a condition with reference to the predicted noise levels at the NSRs.
The EIAO-TM
and Technical Memorandum on Noise From Places Other
than Domestic Premises, Public Places or Construction Sites (IND-TM)
specifies the applicable ANLs for the operation of
the Project. The ANLs are dependent on the ASR and the time of the day and
are presented in Table 5.2e.
Table 5.2e ANLs to be used as Fixed Plant Noise Criteria
|
Time
Period |
Leq 30min
(dB(A)) |
||
|
|
ASR “A” |
ASR “B” |
ASR “C” |
|
Day-time (ie
07:00-19:00 hrs) |
60 |
65 |
70 |
|
Evening (ie
19:00-23:00 hrs) |
60 |
65 |
70 |
|
Night-time (ie
23:00-07:00 hrs) |
50 |
55 |
60 |
Fixed plant noise is controlled under Section 13 of the NCO and
the predictions will be undertaken in accordance with the IND-TM. The noise criteria for planning and
design of Designated Projects are set out in the EIAO-TM as follows:
·
the noise level at the facade of the nearest NSR is at
least 5 dB(A) lower than the appropriate ANL (as shown in Table 5.2d) as
specified in the IND-TM; or,
·
the prevailing
background noise level (for quiet areas with a noise level 5 dB(A) below the
appropriate ANL).
The noise criteria stipulated in the IND-TM are also dependent on
the ASR of the NSR, as shown in Table 5.2e. For this assessment, the ASR assumed for the NSR and
the associated ANL are discussed in Section
5.3.2.
In any event, the ASR assumed in this EIA Report is for indicative assessment
only. It should be noted that fixed
noise sources are controlled under Section 13 of the NCO. At the time of
investigation, the Noise Control Authority shall determine noise impact from
concerned fixed noise sources on the basis of prevailing legislation and
practices being in force, and taking account of contemporary conditions /
situations of adjoining land uses.
Nothing in this EIA Report
shall bind the Noise Control Authority in the context of law enforcement
against any fixed noise source being assessed.
The Project Site is located in the western
part of the Tseung Kwan O Industrial Estate. The nearest existing high-rise
residential developments are located at more than 2.6km and 2.4km away in the
Eastern District of Hong Kong Island and Tseung Kwan
O (TKO), respectively. Background
noise levels are typical of a general rural environment and there are limited
numbers of vehicles or industrial plant items operating during evening and
night-time periods. The major
existing noise sources were identified as the general noise from the Tseung Kwan O Industrial
Estate and the traffic noise
in the vicinity.
In accordance with the requirements given
in Section 3.4.3.2 of the EIA Study Brief, the Study Area for the noise impact
assessment covered a distance of 300m from the boundary of the Project
Site. The Study Area was extended
to include NSRs at distances over 300m from the
Project as the proposed biodiesel plant will be operated during night-time
period. The area considered in the
assessment is shown in Figure 5.3a.
Existing NSRs
that would potentially affected by the Project are identified as the Island
Resort at Siu Sai Wan which
is located at more than 2.5km to the south-west of the Project Site boundary,
and Oscar By the Sea in Tseung Kwan O which is
located at more than 2.2km to the north of the Project Site. Other existing NSRs,
including residential developments and schools, are located at a further
distance away to the north. Planned
residential developments and schools in TKO Area 85 and Area 86 are located at
more than 800m to the north of the Project Site boundary. The locations of the identified
representative NSRs and photographs showing the
existing representative NSRs are presented in Figures 5.3b and 5.3c. The locations of the identified
representative planned NSRs for assessment are
presented in Figure 5.3d.
As the NSRs are located in an isolated
high-rise development area and are indirectly affected by
The identified
representative NSRs selected for assessment and the separation
distances between the representative
NSRs and the Project Site are listed in Table 5.3a.
Table 5.3a Representative
Noise Sensitive Receivers Selected for Assessment
|
NSR |
Location |
Use |
No. of Floors |
Distance to the Project Site (km)
(Approx.) |
|
IR1 |
Island Resort |
Residential |
50 - 51 |
2.5 |
|
A86R1(a) |
Planned Residential Development in Area 86 (The |
Residential |
40 – 50 |
0.8 |
|
A86S1(b) |
Planned School in Area 86 |
Institution |
7 - 8 |
0.9 |
|
CSS1(c) |
|
Institution |
4 - 6 |
2.3 |
|
Notes: (a)
The first phase of the (b)
Planned NSR A86S1 was selected for operational
noise impact assessment only as it is expected that the operation of the
school will not be prior to the completion of the construction of the
proposed biodiesel plant. (c)
Existing NSR CSS1 was selected for construction
noise impact assessment only as the assessment point for NSR A86S1 is located
closer to the proposed biodiesel plant than CSS1 for the operational noise
impact assessment. |
||||
The major activities associated with the
construction phase will involve the use of PME and they are summarised as
follows:
·
Foundation
work for Jetty and Buildings – piling, excavation, transportation of materials and
the use of generators and cranes; and
·
Building
and civil works – the use of excavators, cranes, concrete lorry
mixers, rollers, lorries and generators.
The
construction noise assessment was undertaken based on the proposed construction works programme (see Figure 3.2f)
and plant inventory presented in Annex B1. The plant inventory was reviewed by the
Design Engineer and was confirmed to be suitable for completing the proposed
biodiesel plant within the scheduled timeframe.
The construction of the building
foundation will require percussive piling.
However, it will be controlled under the NCO and therefore is not included in this assessment.
The normal
working hours of the Contractor will be between 07:00 and 19:00 hrs from Monday
to Saturday (except public holidays).
A CNP will be applied if percussive piling to be conducted between 07:00
and 19:00 hrs on any day other than public holidays. Construction activities during
restricted hours are not expected.
Should evening and night works between 19:00 and 07:00 hrs of the next
day or on public holidays (including Sundays) be required, the Contractor will
submit a CNP application which will be assessed by the Noise Control
Authority. No percussive piling
will be conducted during the restricted hours and on public holidays.
Fixed Plant Operation
Noise
associated with the operational phase of the proposed biodiesel plant will
arise from the tank farm, fat preparation plant, steam boiler room, process
building, wastewater treatment plant, jetty and the loading/unloading
area. The layout plan of the
proposed biodiesel plant is shown in Figure 3.2c. The dominant noise sources are mainly
from the machinery including the following equipment:
·
Various kinds of pumps and agitators;
·
Cooling tower at roof top of the fat preparation plant;
·
Steam boiler plant and thermal fluid heater;
·
Compressor, dewatering plant and blower;
·
Gantry and barge at the jetty; and
·
Loading/unloading of feedstock and products to and
from the road tankers.
Appropriate sound power levels (SWL) of
the compressor, barge and gantry were made reference to GW-TM. The Project
Proponent and Design Engineer have confirmed that water cooling tower and
air-cooled chiller will be used for the Fat
Preparation Plant and site office, respectively. The water cooling tower to be used will
have motor power of 30kW, ie equivalent to 40
horsepower (hp). Reference was made
to the Good Practices on Ventilation
System Noise Control to determine the SWL of water cooling tower with 40
hp. The noise levels for other equipment have
made reference to the specifications provided by the suppliers and the results
of field measurement conducted at overseas biodiesel plants. To minimise the noise impact to the
environment, most of the noise sources will be housed within individual
enclosures. All outdoor pumps will
be provided with complete noise enclosures with no opening facing the LO
The specification of the Project will
require that all the pumps in the Project and other equipment in the tank farm,
steam boiler room, process building and wastewater treatment plant will have a
maximum allowable measured free-field SPL of 85 dB(A)
at 1 m from each noise source, with no tonality, impulsiveness and
intermittency characteristics, and the water cooling tower and air-cooled chiller
will have a maximum allowable SWL of 102 dB(A). Pumps, water cooling tower and air-cooled chiller
with such specifications are widely available in the market and have been
widely adopted in other biodiesel plants over the world (see Annex B2). The Project Proponent and Design
Engineer have confirmed that the fixed plants and equipment stated in the EIA Report will have sufficient capacity
and output power for carrying out the intended operation.
The suppliers of pumps
should guarantee the specified SPL (ie 85 dB(A)) and
the equipment should be free of the characteristics of tonality, impulsiveness
and intermittency, by providing a certificate of measurement and verify the SPL
during testing and commissioning in accordance with international standard
procedures. With such guarantee
included in procurement contract, the noise emission from the equipment should
comply with the tender specification.
If necessary, the suppliers should apply attenuation measures to achieve
the guaranteed noise levels determined during the detailed design stage. The process engineers have also
confirmed that the proposed equipment is available in the market.
The operation of the proposed biodiesel
plant will result in a small increase in traffic to the existing TKO Industrial
Estate. As per Table 3.2b, the truck trips that will be generated by the Project
will be about 186 truck trips per day (including both the number of trucks
going in and out of the plant). This truck trip generation is considered
insignificant compared with the background traffic on
The construction noise impact assessment
was undertaken in accordance with the procedures outlined in the GW-TM, which is issued under the NCO and the EIAO-TM. The assessment
methodology is summarised as follows:
·
Locate
representative NSRs that may be affected by the
Project;
·
Determine
the types of plant to be used for corresponding activities, based on the agreed
plant inventory;
·
Assign
sound power levels (SWLs) to the PME proposed based
on the GW-TM and list of SWLs of other
commonly used PME ([2]);
·
Calculate
the correction factors based on the distance between the NSRs
and the notional noise source position of the work sites;
·
Apply
corrections in the calculations, such as potential screening effects and
acoustic reflection, if any; and
·
Predict
the construction noise levels at NSRs in the absence
of any mitigation measures.
The total SWL associated with each
construction activity was established based on an assumed plant inventory. The
notional source position was established in accordance with the procedures
stated in the GW-TM. The
potential noise impacts at NSRs were subsequently
evaluated by comparing the predicted noise levels with the EIAO-TM day-time construction noise limits (Leq,
30min dB(A)), as outlined in Section 5.2.1.
Fixed
Plant Operation
Noise impact assessment due to on-site
operation of the Project was undertaken based on standard acoustic principles
as per the requirements of the EIAO-TM. The methodology for
the fixed plant noise assessment is presented below:
·
Identify
types of equipment and the number of equipment;
·
Make
reference to the GW-TM and Good Practices on Ventilation System Noise
Control for the SWL of equipment, if available, or employ maximum SPL for
the major noise sources that will be specified in the tender specification;
·
Identify
representative NSRs as defined by the EIAO-TM based on existing and committed landuses in the Study Area that may be affected by the
Project;
·
Calculate
the distance attenuation to the NSRs from the noise
sources; and
·
Present the results in terms of Leq
(30min) dB(A).
The noise
impact due to the operation of the proposed biodiesel plant was assessed and
compared with the noise criteria as outlined in Section 5.2.2.
With
the large separation distance between the representative NSRs
and the Project Site, the predicted construction noise levels at the identified
representative NSRs are well within the stipulated
construction noise criteria. The
representative NSRs will not be adversely affected by
the construction of the Project. A
summary of the predicted construction noise levels is presented in Table
5.6a. Details of the noise
calculations are presented in Annex B3.
Table 5.6a Predicted
Construction Noise Levels at Representative NSRs
|
NSR |
Description |
Approx. Horizontal Distance to Notional
Source Position(a) (km) |
Predicted Construction Noise Levels(b),
Leq, 30 min dB(A) |
|
A86R1 |
Planned Residential Development in Area
86 (The |
0.82 |
58 - 64 |
|
CSS1 |
|
2.38 |
48 – 55 |
|
IR1 |
Island Resort |
2.60 |
48 – 54 |
|
Notes: (a) According
to the GW-TM, notional source position refers to the position mid-way between
the approximate geographical centre of the construction site and its boundary
nearest to the NSR. (b) All
predicted noise levels were corrected with 3dB(A)
for façade reflection. (c) Assessment
criteria for construction noise impact are 75 dB(A)
for domestic premises, 70dB(A) for educational institution and 65dB(A) during
examination periods). |
|||
The noise levels
due to the operation of the proposed biodiesel plant at the representative NSRs
were predicted and are
summarised in Table 5.6b.
The predicted noise levels are well within the stipulated day-time and
night-time (ANL-5) noise criteria.
Details of the noise calculations are presented in Annex B4.
Table 5.6b Predicted
Operational Noise Levels at Representative NSRs
|
NSR |
Description |
Predicted Facade Noise
Level(a), Leq, 30 min dB(A) |
|
|
Day-time (07:00 – 23:00hrs) |
Night-time (23:00 – 07:00hrs) |
||
|
A86R1 |
Planned
Residential Development in Area 86 (The |
49 |
47 |
|
A86S1 |
Planned
School in Area 86 |
48 |
46 |
|
IR1 |
Island
Resort |
40 |
38 |
|
Notes: (a) All predicted noise levels were
corrected with 3dB(A) for façade reflection. (b) According to EIAO-TM,
day-time and night-time (ANL-5) noise criteria are 60 dB(A)
and 50
dB(A), respectively. |
|||
Except for the water cooling tower and air-cooled chiller located on roof top, barge
and gantry at the jetty and the tankers at the loading/unloading area, all
other noisy equipment in the fat preparation plant, wastewater treatment plant,
steam boiler room and process building will be located within completely
enclosed buildings or provided with complete noise
enclosures. The complete noise
enclosures will be internally lined with minimum 50mm thick sound absorbing
material and will be provided with silencers at outlet and inlet of the
enclosure. A noise reduction of 20dB(A) with the provision of complete noise enclosure was included in the noise assessment as per the Good
Practices on Pumping System Noise Control prepared by EPD.
The water cooling tower and air cooled chiller will be located outdoor on roof top of
the fat preparation plant and site
office buildings. A 3 dB(A) correction was included in the noise assessment to
account for the potential reflection from any nearby hard surface as detailed
building layout is not available at this stage. The assessment is therefore conservative.
The Design Engineer confirmed that the
operation time for the barge, gantry and the tankers will be about 50% during
any 30 minutes ([3]).
This assumption was included in the noise assessment to present the real
operational practice.
The noise
assessment for fixed plant operation did not take account of the atmospheric
absorption. Therefore, the noise
levels at the NSRs in real situation will be less
than the predicted noise levels presented in Table 5.6b.
While adverse noise impact is not expected
during the construction phase of the Project, good site practices will be
implemented by the Contractor to minimise construction noise impact. The site practices listed below will be
adopted during the construction phase:
·
Only
well-maintained plant will be operated on-site and plant will be serviced
regularly during the construction program;
·
Silencers
or mufflers on construction equipment will be utilized and will be properly maintained
during the construction phase;
·
Mobile
plant, if any, will be sited as far from NSRs as
possible;
·
Machines
and plant (such as trucks) that may be in intermittent use will be shut down
between work periods or will be throttled down to a minimum;
·
Plant
known to emit noise strongly in one direction will, wherever possible, be
orientated so that the noise is directed away from the nearby NSRs; and
·
Material
stockpiles and other structures will be effectively utilised, wherever
practicable, in screening noise from on-site construction activities.
Although no adverse noise impact is
expected during the operational phase of the Project, the following measures
will be implemented as far as practicable:
·
Choose
quieter equipment;
·
Include
noise levels specification when ordering new plant items;
·
Locate
fixed plant items or noise emission points away from the NSRs
as far as practicable;
·
Provide
complete noise enclosures for all outdoor pumps with no opening facing the LO
·
Locate
noisy machines in enclosed plant rooms or buildings; and
·
Develop
and implement a regularly scheduled plant maintenance programme so that plant
items are properly operated and serviced.
The programme will be implemented by properly trained personnel.
There will be no other construction activity in the
vicinity of the site during the construction of the Project and hence it is
expected that no cumulative noise impacts will be resulted.
Given the large separation
distance between the identified representative NSRs
and the Project Site, and the predicted noise levels at the NSRs
during the construction and operational phases are well below the stipulated
noise criteria, noise monitoring is not required during construction and
operational phases.
No adverse noise impacts are anticipated
at the representative NSRs during the construction
and operation of the Project as a result of the implementation of noise control
measures in the design of the facility and the large horizontal separation
between the identified NSRs and the Project
Site. To further minimise the noise
impacts, good site practices and noise reduction measures are recommended
during the construction and operational phases of the Project. No noise monitoring and audit programme
is required.