1.4 Purpose of this Environmental Monitoring and Audit
(EM&A) Manual
2.4 Engineer’s Representatives (ER)
2.5 Independent Environmental Checker (IEC)
3.9 Air Quality Performance Limit
5.3 Operational Phase EM&A (Effluent Quality)
5.4 Operational Phase EM&A (Marine Water Quality)
5.6 Water Quality Performance Limit
9 Waste Management and Land contamination
12.3 Compliance with Legal and Contractual Requirements
13.2 Baseline Monitoring Report
13.6 Quarterly EM&A Summary Reports
13.9 Interim Notification of Environmental Quality Limit Exceedances
LIST OF TABLES
Table 3.1 Proposed
Dust Monitoring Stations
Table 3.2 Action and Limit Levels for Air Quality
Table 4.1 Proposed Construction Noise Monitoring
Locations
Table 4.2 Action and Limit Levels for Noise
Table 5.1 Marine Water Monitoring Locations in
Construction Phase
Table 5.2 Overall
Summary of Monitoring Requirements in Construction and Operational Phases
Table 5.3 Analytical Methods and Detection Limits
for Marine Water Samples
Table 5.4 Action / Limit Levels for Water Quality
LIST OF FIGURES
Figure 1-1 Layout Plan of Proposed
Sewerage Works in Po Toi O
Figure 2-1 Project Organisation for Environmental Works
Figure 3-1 Location of Air and
Noise Monitoring Stations
Figure 5-1 Location of Water
Monitoring Stations
Figure 11-1 Location of Built
Heritage Resources
LIST OF APPENDICES
Appendix A Implementation Schedule of
Recommended Mitigation Measures
Appendix
B Sample Data Sheet
Appendix C Event and Action Plan
Appendix D Interim Notifications of
Exceedances
1.1.1
The
proposed sewerage works in Po Toi O is an environmental enhancement project
that aims to improve environmental hygiene of the Po Toi O area.
1.1.2
Po
Toi O is located in the southern part of Sai Kung District, next to Clear Water Bay. There is a small
settlement called Po Toi O village around the bay. There is currently no public
sewerage system for the village. Sewage and wastewater generated by local
residents and local restaurants are treated by septic tanks/soakaway system (STS).
1.1.3
Provision
of proper sewerage system to unsewered villages is a
general government policy. Without centralized public sewage treatment
facility, villagers have to regularly desludge the
STS to maintain the cleaning performance and to avoid overflow of sewage.
However, the desludging process may bring along potential hygiene and
associated odour issues. Under the Port Shelter Sewerage Master Plan (SMP), Drainage Services Department (DSD) has
proposed sewerage works at Po Toi. In addition to improving local hygiene
conditions and removing associated odour problem, the provision of sewerage is
a preventive measure to avoid potential environmental problems due to
insufficient desludging or structural defect of the STS. This can also relieve villagers’ burden to maintain
their STS (e.g. desludging).
1.1.4
The
proposed sewerage works at Po Toi O comprise sewage collection, treatment and
disposal facilities at Po Toi O under Port Shelter Sewerage, Stage 3 – Sewerage
Works at Po Toi O (hereinafter referred to as “the Project”). The location and details of the
facilities are illustrated in Figure
1-1.
1.1.5
Cinotech Consultants Ltd. (Cinotech) has been commissioned by DSD in
January 2014 to conduct an environmental impact assessment for the Project in
order to investigate the environmental acceptability during construction and
operation of the proposed sewerage works. Black
& Veatch Hong Kong Limited (hereafter called “the Engineer”) is the
consulting engineer employed by DSD to design the proposed sewerage facilities in
this Project, among other tasks. Urbis
Limited and LWK & Partners (HK)
Limited provided expert input in landscape and visual impact and built
heritage impact assessments respectively.
1.2.1
The
Project mainly comprises the following works:
i. Provision of village sewerage to the unsewered areas of Po Toi O. The works involve construction of about 800m of gravity sewers and 400m of rising mains;
ii. Construction of a local sewage treatment plant (STP) with Average Dry Weather Flow (ADWF) of about 139m3/day; and
iii. Construction of a submarine outfall of about 385m in length.
1.2.2
The
Project consists of the following designated projects under Part I, Schedule 2
of the Environmental Impact Assessment Ordinance (EIAO):
l Item Q.1 – A sewage treatment plant and portion of sewer alignments in a conservation area;
l Item C.12 (a) (v) and (vii) – A dredging operation which is less than 500m from the nearest boundary of an existing fish culture zone and coastal protection area; and
l Item F.6 – A submarine sewage outfall.
1.3.1
The
construction works for this Project are expected to commence in mid-2017 and
complete in 2021 with one more year for defect
correction.
1.4.1
The purpose of this EM&A Manual (hereafter called the “Manual”) is
to guide the establishment of an EM&A programme to assure compliance with
the standards and predictions in the EIA study involving the construction and
operation of Po Toi O Sewage Treatment Works (PTOSTW). The environmental
performance will be regularly monitored and audited for evaluating the
effectiveness of the recommended mitigation measures and to investigate any
further need for additional mitigation measures or remedial action.
1.4.2
This EM&A Manual is prepared based on the findings and
recommendations in the EIA and with reference to the requirements stipulated in
Annex 21 Technical Memorandum under the Environmental Impact Assessment
Ordinance (EIAO-TM):
(i)
To
propose EM&A programme to monitor the environmental performance of the
project
(ii)
To
check the implementation status of mitigation measures to minimize construction
and operational impacts on the environment
(iii)
To
identify the need for additional mitigation measures
(iv)
To
advise the responsibilities of different parties involved in the project and
communication flow among them
(v)
To
detail monitoring requirements (locations, environmental parameters, frequency,
duration) before and during the construction period and in the operational
period
(vi)
To
propose monitoring equipment required and quality assurance
(vii)
To
determine action and limit levels of each environmental parameter based on the
legislative criteria and standards for compliance checking
(viii)
To
set up event and action plans for remedial actions if exceedance of compliance
is identified
(ix)
To
devise procedures for handling complaint/consultation
(x)
To
detail reporting requirement
1.5.1
This
EM&A Manual comprises
the following Chapters:
l Ch.1
Introduction
l Ch. 2 Project Organization
l Ch. 3 Air Quality
l Ch. 4 Noise
l Ch. 5 Water Quality
l Ch. 6 Terrestrial Ecology
l Ch. 7 Marine Ecology
l Ch. 8 Fisheries
l Ch. 9 Waste Management and Land Contamination
l Ch. 10 Landscape and Visual
l Ch. 11 Built Heritage
l Ch. 12 Site Environmental Audit
l Ch. 13 Reporting
l Ch. 14 Conclusion
2.1.1
The implementation of the
recommended EM&A programme requires participation of relevant parties in a
correlative and collaborative manner. The project organization and lines of
communication with respect to the recommended EM&A works are shown in Figure 2-1. The roles and responsibilities of the key
EM&A programme participants involved are described in the following
sections.
2.2.1 The Project Proponent (Drainage Services Department) shall employ the Independent Environmental Checker (IEC) to audit and check the EM&A works carried out by the Environmental Team (ET).
2.3.1 The Contractor implies all construction contractors and sub-contractors working on the Project Site (within work boundary demarcated in Figure 1-1). He should:
(i)
Engage
the ET to carry out EM&A works
(ii)
Notify
the ET the construction activities that may have environmental concern
(iii)
Participate
in the site inspection carried out by the ET and to rectify any environmental
deficiency identified
(iv)
Propose
and implement necessary measures to mitigate any exceedance in Action/Limit
Levels recorded in accordance to the Event/Action Plans
(v)
Investigate
complaints according to the agreed procedures
2.4 Engineer’s Representatives (ER)
2.4.1 The ER shall be responsible to oversee the construction work of all contractors to ensure that the contract specifications are met. He should:
(i)
Supervise
the Contractor’s activities to ensure that they comply with the requirements in
the EIA, EM&A Manual, Environmental Permit (EP) and the contract
specifications
(ii)
Follow
the agreed procedures in the Event/Action Plan in case of any exceedance and
instruct the Contractor to carry out remedial actions
(iii)
Participate in joint site inspections
and audits undertaken by the ET
(iv)
Investigate
complaints according to the agreed procedures and instruct the Contractor to
follow up
(v)
Assist
the ET in implementation of EM&A programme when required
2.5 Independent Environmental Checker (IEC)
2.5.1 The IEC shall be appointed by the Project Proponent to audit and verify the EM&A works carried out by the ET and to oversee the environmental performance of the Project site. He shall not have any association with the Contractor, ER or ET. The IEC should possess at least 7 years of experience in EM&A. The IEC should:
(i)
Review
and verify EM&A Reports and submissions for EP prepared by the ET and
advise for improvement
(ii)
Audit
and confirm the validity and accuracy of monitoring activities and results. He
may carry out random sample check and audit on monitoring data and sampling
procedures, etc
(iii)
Audit
the EIA recommendations and requirements against the status of
implementation of environmental protection measures on site
(iv)
Review
the implementation status and effectiveness of mitigation measures onsite and
ensure that they are carried out properly
(v)
Conduct
monthly and ad-hoc site inspections
(vi)
Investigate
complaints according to the agreed procedures
(vii)
Review
the proposal of mitigation measures by the Contractor in an event of exceedance
according to the Event/Action Plan
2.6.1 The ET shall be led and managed by the ET Leader. The ET Leader shall be an independent party from the Contractor and have relevant professional qualifications, or have sufficient relevant EM&A experience subject to the approval of the Engineer’s Representative (ER). The ET Leader shall possess at least 7 years of experience in EM&A and/or environmental management. The ET should carry out the EM&A programme and to check the Contractor’s compliance with the environmental protection requirements in the EIA, EM&A Manual and EP. The ET should:
(i)
Set
up monitoring stations to carry out monitoring works, statistical analysis and
compliance checking against legislative standard and guidelines
(ii)
Repeat
field measurement in case of exceedance and propose mitigation measures for
improvement
(iii)
Conduct
weekly and ad-hoc site inspections to audit the Contractor’s site practice on
pollution prevention and the effectiveness and adequacy of mitigation measures
(iv)
Advise
the Contractor rectification work required when environmental deficiency is
identified
(v)
Prepare
monthly and quarterly EM&A reports to summarise environmental performance
and to anticipate future key issues
(vi)
Review
and comment on work schedule and methodology as necessary
(vii)
Support
the Contractor for submissions required under the EP
(viii)
Investigate
complaints and propose corrective measures according to the agreed procedures
(ix)
Liaise
with the IEC on environmental performance matters and timely submission
of all EM&A proforma for IEC’s approval
2.6.2 The ET Leader shall keep a contemporaneous logbook for recording each and every instance or circumstance or change of circumstances that may affect the compliance with the recommendations of the EIA report. This logbook shall be kept readily available for inspection by the IEC, and the Director of Environmental Protection (DEP) or his authorised officers.
3.1.1
Major air quality impact in construction phase would arise from excavation
of slope at the proposed sewage treatment plant. With implementation of dust
suppression measures, it is anticipated that the dust impact would be acceptable. Regular air quality monitoring should be conducted at representative
ASRs to ensure that relevant air quality standard can be met.
3.1.2
During the operational phase of the Project, odour
will be generated from the operation
of the proposed sewage treatment plant. With enclosure
of odour sources underground, deodourization before exhaust into the atmosphere
and adoption of enclosed container during transportation, odour impact is expected to be acceptable. According to the modelled results in the EIA Report, the odour levels at representative ASRs are far below the EIAO TM assessment criterion. Therefore, operational phase
air quality monitoring is considered unnecessary.
3.1.3
This section outlines the requirements, methodology, equipment and
locations for monitoring air quality impacts during the construction phase of
the Po Toi O STW.
3.2.1
The ET shall evaluate the construction air quality impact by conducting
1-hour and 24-hour Total Suspended Particulates (TSP) measurements.
3.3.1
1-hour and 24-hour TSP levels will be measured in accordance to the
standard high volume sampling method as set out in the Title 40 of the Code of
Federal Regulations, Chapter 1 (Part 50), Appendix A.
3.3.2
Other than using high volume sampler, 1-hour TSP levels can be measured
alternatively by direct reading from portable dust meters upon approval from
ER. The meters should be capable of producing comparable results as that by the
high volume sampling method, to indicate short event impacts.
High Volume Sampler
3.4.1
The ET shall provide sufficient number of high volume samplers (HVSs)
for measurement at different ASRs during each monitoring. The HVSs shall comply
with the following specifications for carrying out the 1-hour and 24-hour TSP
monitoring:
(a)
0.6 -
1.7 m3 per minute adjustable flow range;
(b)
equipped
with a timing / control device with +/- 5 minutes accuracy for 24 hours
operation;
(c)
installed
with elapsed-time meter with +/- 2 minutes accuracy for 24 hours operation;
(d)
capable
of providing a minimum exposed area of 406 cm2;
(e)
flow
control accuracy: +/- 2.5% deviation over 24-hour sampling period;
(f)
equipped
with a shelter to protect the filter and sampler;
(g)
incorporated
with an electronic mass flow rate controller or other equivalent devices;
(h)
equipped
with a flow recorder for continuous monitoring;
(i)
provided
with a peaked roof inlet;
(j)
incorporated
with a manometer;
(k)
able
to hold and seal the filter paper to the sampler housing at horizontal
position;
(l)
equipped
with easily changeable filter; and
(m)
capable
of operating continuously for a 24-hour period.
3.4.2
Clearly labelled calibration kit and filter papers shall also be
provided. The HVSs should be equipped with an electronic mass flow controller
and be calibrated against a traceable standard at regular intervals.
3.4.3
Calibration should first be conducted after installing the HVSs and
repeated on bi-monthly basis. The transfer standard shall be traceable to the
internationally recognised primary standard and be calibrated annually. The
concern parties such as IEC shall properly document the calibration data for
future reference. All the data should be converted into standard temperature
and pressure condition.
3.4.4
The flow-rate of the sampler before and after the sampling exercise
with the filter in position shall be verified to be constant and be recorded in
the data sheet in Appendix B.
Direct Reading Meter
3.4.5
If the ET prefers to adopt direct reading method for 1-hour TSP, he
should provide adequate support to the IEC for verifying the capacity of the
meter as with the HVSs in obtaining comparable measurements. The meter shall be
calibrated at regular intervals in accordance to the specification in the
manufacturer’s manual. The calibration certificates shall be available to the
IEC for checking upon request. The validity and accuracy of the meter shall
also be tested against the results by the HVS periodically. Sample data sheet is
available in Appendix B.
Collection of Wind Data
3.4.6
For recording wind speed and wind direction, the ET shall install wind
data monitoring equipment near the dust monitoring locations. The installation
location shall be proposed by the ET and agreed with the IEC. The installation
and operation of the equipment shall meet the following criteria:
(a)
The
wind sensors should be installed 10 m above ground so that they are clear of
obstructions or turbulence caused by buildings.
(b)
The
wind data should be captured by a data logger. The data shall be downloaded for
analysis at least once a month.
(c)
The
wind data monitoring equipment should be re-calibrated at least once every six
months.
(d)
Wind
direction should be divided into 16 sectors of 22.5 degrees each.
3.4.7
If agreed by the ER and the IEC, the ET may obtain wind data using
alternative method.
Laboratory Testing
3.4.8
Filter paper to be placed in the HVSs should have a size of 8" x
10" and be labelled before sampling. It should be clean without pinholes, and
be conditioned in a humidity-controlled chamber for over 24-hours and be
pre-weighed before use for the sampling.
3.4.9
After air is passed through the HVSs, the filter paper inside will be
loaded with dust. It shall be collected inside a clean and tightly sealed
plastic bag for transporting to a laboratory. It shall be reconditioned in the
humidity-controlled chamber followed by accurate weighing by an electronic
balance with accuracy up to 0.1 mg. The balance shall be regularly calibrated
against a traceable standard.
3.4.10
All samples should be kept in good condition for 6 months before
disposal.
3.4.11
The testing laboratory should be HOKLAS accredited. It should be clean
and can maintain a stable temperature and humidity. Measuring and conditioning
instruments should be available for handling the dust samples. It should be
able to carry out result analysis, equipment calibration and maintenance.
3.4.12
If a site or non-HOKLAS laboratory will be responsible for conducting
the testing, the laboratory equipment shall be approved by the ER and the
measurement procedures shall be witnessed by the IEC. Any measurement performed
by the laboratory shall be demonstrated to the satisfaction of the ER and the
IEC. The IEC shall regularly audit the measurement performed by the laboratory
to ensure the accuracy of measurement results. The ET Leader shall provide the
ER with one copy of the Title 40 of the Code of Federal Regulations, Chapter 1
(Part 50), Appendix A for his reference.
3.5.1
Four representative Air Quality Monitoring stations (AMSs) are proposed
as follows:
Table 3.1 Proposed Dust Monitoring Stations
|
Monitoring Stations |
Location |
|
AMS1 |
Po Toi O Tsuen Road, House
No. 28 |
|
AMS2 |
In front of Hung Shing
Temple |
|
AMS3 |
Temporary Structure
(House) near Rocky Shore |
|
AMS4 |
Fairway
Vista |
3.5.2
The location of the stations can be found in Figure 3-1.
3.5.3
The status and locations of dust sensitive receivers may change after
issuing this manual. In this case, the ET Leader shall propose alternative
monitoring locations taken into account the following considerations and seek
approval from the ER and the IEC:
(a)
locate
at the work boundary or such locations close to the major dust emission source;
(b)
locate
close to the sensitive receivers; and
(c)
take
into account the prevailing meteorological conditions.
3.6.1
The ET shall agree with the ER in consultation with the IEC on the
position of the HVS for the installation of the monitoring equipment. When
positioning the samplers, the following points shall be noted:
(a)
a
horizontal platform with appropriate support to secure the samplers against
gusty wind should be provided;
(b)
no two
samplers should be placed less than 2 meters apart;
(c)
the
distance between the sampler and an obstacle, such as buildings, must be at
least twice the height that the obstacle protrudes above the sampler;
(d)
a
minimum of 2 meters of separation from walls, parapets and penthouses is
required for rooftop samplers;
(e)
a
minimum of 2 meters separation from any supporting structure, measured
horizontally is required;
(f)
no furnace
or incinerator flue is nearby;
(g)
airflow
around the sampler is unrestricted;
(h)
the
sampler is more than 20 meters from the dripline;
(i)
any
wire fence and gate, to protect the sampler, should not cause any obstruction
during monitoring;
(j)
permission
must be obtained to set up the samplers and to obtain access to the monitoring
stations; and
(k)
a
secured supply of electricity is needed to operate the samplers.
3.7.1
Baseline monitoring shall be conducted to determine the existing air
quality in terms of 1-hour and 24-hour TSP levels before commencement of
construction work. A consecutive measurement for 14 days shall be done for
24-hour TSP at all monitoring stations. At least 3 sets of 1-hour TSP data
shall also be collected every day during this period, at the predicted time in
which greatest impact is expected.
3.7.2
During the baseline monitoring, there should be no major construction
or dust generating activities near the monitoring stations. The ET shall
propose a monitoring schedule to the IEC so that he can conduct onsite audit to
ensure the accuracy of the measurement where necessary.
3.7.3
Alternative baseline AMS that can give representative baseline result
may be proposed for ER and IEC’s approval with justifications.
3.7.4
In exceptional cases, when insufficient baseline monitoring data or
questionable results are obtained, the ET shall liaise with the IEC and ER to
agree on an appropriate set of data to be used as a baseline reference and
submit to EPD for approval.
3.7.5
The baseline monitoring data shall be reviewed once every three months.
When there is seasonal change to ambient conditions, the baseline condition may
need to be updated. Repeated measurement shall be conducted during which no
dust generating activity is being carried out near the AMS. If a change in
ambient condition is recorded, the baseline levels and therefore air quality
criteria should be revised accordingly and agreed with the IEC and EPD.
3.8.1
Impact monitoring shall be carried out throughout the construction
period at all AMSs. 24-hour TSP sampling shall be conducted at a frequency of
at least once in every 6 days, while that for 1-hour TSP shall be at least 3
times in every 6 days when the highest dust impact takes place. Similar to
baseline monitoring, the ET shall submit a monitoring schedule to the IEC for
onsite audit of the accuracy of the monitoring result where necessary.
3.8.2
The ET shall clearly define and strictly follow the starting and ending
time for 24-hour TSP monitoring for each AMS.
3.8.3
If exceedance of air quality criteria is recorded, more frequent
measurement shall be done within the specified timeframe in accordance to the
Action Plan. The additional monitoring shall be continued until the excessive
dust emission or the deterioration in air quality is rectified, and upon
agreement with the IEC.
3.9 Air Quality Performance Limit
3.9.1
The following table shows the action and limit levels for 1-hour and
24-hour TSP levels, while the baseline monitoring results shall be interpreted to derive
the action levels.
Table 3.2 Action and Limit Levels
for Air Quality
|
Parameters |
Action |
Limit |
|
24-hour TSP Level in µg m-3 |
For baseline level £ 200 µg m-3, Action level = (baseline level * 1.3 + Limit
level)/2; For baseline level > 200 µg m-3 Action level = Limit
level |
260 µg/m3 |
|
1-hour TSP Level in µg m-3 |
For baseline level £ 384 µg m-3, Action level = (baseline level * 1.3 + Limit
level)/2; For baseline level > 384 µg m-3, Action level = Limit
level |
500µg/m3 |
3.10.1
Should non-compliance of the air quality criteria occur, actions in
accordance with the Action Plan in Appendix C shall be carried out.
3.11.1
The EIA proposed a number of construction phase mitigation measures,
examples as follows:
Construction Phase
(a)
Hoarding of not less than 2.4 m high shall be erected from ground level
to surround the work area along Po Toi O Chuen Road except for a site entrance
or exit.
(b) Good housekeeping to minimize dust
generation, e.g. by properly handling and storing dusty materials.
(c) Adopt dust control measures, such as dust
suppression using water spray on exposed soil, in areas with dusty construction
activities and during material handling.
(d) Minimize exposed earth after completion of
work in a certain area by hydroseeding, vegetating,
soil compacting or covering with bitumen.
(e) Provide wheel washing at site exit to
prevent carrying dust outside of the site.
(f) Cover materials on trucks before leaving
the site.
(g) Limit traffic speed of construction trucks
within the construction site and in Po Toi O, maximum at 10km/hr.
(h) As there is limited space in Po Toi O,
stockpiling should be avoided. However, if found necessary, the materials
should be covered by impervious materials such as tarpaulin.
Operational Phase
(a)
Conduct regular inspection of the tanks to check for leakage of gas.
(b)
Direct odorous gas to odour removal system for treatment prior to
exhausting into the atmosphere.
(c)
Maintain the removal efficiency of screenings and grits by flushing the screens and grit sump regularly to prevent build-up of solids.
(d)
Maintain the efficiency of MBR membrane by removing organic and inorganic
debris with sodium hypochlorite and oxalic acid .
(e)
Replace worn filters to maintain the odour removal efficiency at 99.5%.
(f)
Remove sludge regularly to prevent build-up of odourous
gas.
(g)
Sludge tanker should be parked inside the sewage treatment plant for
sludge removal where the air is extracted for deodourization.
(h)
Sludge should be transferred to sludge tanker by coupling method to
prevent odour leakage.
(i)
Screenings, grits and worn filters should be stored in sealed containers
inside the STP and during removal for disposal.
(j)
Clean all the tanks with water regularly.
3.11.2
Detailed mitigation measures are listed out in the Implementation Schedule of Recommended Mitigation Measures in Appendix A. Implementation status and the effectiveness of these measures shall
be audited through regular site inspection.
4.1.1 In the construction phase, the major noise impact will arise from the use of powered mechanical equipment. With implementation of noise mitigation measures, it is anticipated that the construction noise impact would be reduced to acceptable level. Regular monitoring of noise level should be carried out at noise monitoring stations near representative sensitive receivers before and throughout construction work to ensure that relevant noise standard can be met.
4.1.2 As most of the plant equipment for sewage treatment are stored underground and the STP is enclosed by a concrete structure, operational noise impact is expected to be acceptable. Therefore, no monitoring or audit is proposed.
4.1.3
In this section, the equipment, requirements,
monitoring locations, criteria and protocols for the monitoring and audit of
noise impacts during the construction of the proposed sewerage works under the
Project are presented.
4.2.1
Construction noise level shall be measured in terms of the A-weighted
equivalent continuous sound pressure level (Leq).
Leq 30min shall be used as the
monitoring parameter for the time period between 0700 and 1900 hours on normal
weekdays. For all other time periods, Leq
5min shall be employed for comparison with the Noise Control Ordinance
(NCO) criteria.
4.2.2
As supplementary information for data auditing, statistical results such
as L10 and L90 shall also be obtained for reference.
4.3.1
Sound level meters shall be employed to measure the construction noise
level. It should comply with the International Electrotechnical
Commission Publications 651: 1979 (Type 1) and 804: 1985 (Type 1)
specifications in accordance to the Technical Memorandum (TM) issued under the
NCO.
4.3.2
An acoustic calibrator shall be used to validate the accuracy of the
sound level meter before and after each noise measurement. The calibrator can
generate a known sound pressure level at a known frequency. The noise record
will only be accepted if the calibration level from before and after the noise
measurement agrees to within 1.0 dB.
4.3.3
Sufficient number of the above equipment shall be provided by the ET,
who will also be responsible for installation, operation, maintenance and
dismantlement. All equipment and instrumentation shall be clearly labelled.
4.4.1
Noise measurement shall normally be at a point 1 m from the exterior of
the sensitive receiver building façade and be at a position 1.2 m above the ground.
If the normal monitoring position cannot be accessed, an alternative position
may be chosen, and a correction to the measurements shall be made. For
reference, a correction of +3 dB(A) shall be made to the free field
measurements. The ET shall agree with the IEC on the monitoring position and
the corrections adopted. The agreed position shall be chosen in subsequent
baseline and impact monitoring.
4.4.2
Noise measurements should be made in accordance with standard acoustical
principles and practices in relation to weather conditions.
4.5.1
There are three kinds of construction work near the sensitive receivers:
(1) construction of STP, (2) gravity sewers and rising mains installation and
(3) horizontal directional drilling for submarine outfall. As such, four representative
Noise Monitoring Stations (NMSs) are proposed near these work sites as follows:
Table 4.1 Proposed Construction
Noise Monitoring Locations
|
Monitoring Stations |
Location |
|
NMS1 |
Po Toi O Tsuen Road, House
No. 28 |
|
NMS2 |
In front of Hung Shing
Temple |
|
NMS3 |
Temporary Structure
(House) near Rocky Shore |
|
NMS4 |
Fairway
Vista |
4.5.2
The location of the stations can be found in Figure 3-1.
4.5.3
The status and locations of noise sensitive receivers may change after
issuing this manual. In this case, the ET Leader shall propose alternative
monitoring locations taken into account the following considerations and seek
approval from the ER and the IEC:
(a)
locate close to the major site activities which are likely to have noise
impacts;
(b)
locate close to the most affected existing NSRs; and
(c)
take into account the possibility of minimizing disturbance to occupants at
the NSRs during monitoring.
4.6.1
Baseline noise measurement shall be conducted to determine the
background noise before commencement of work. Daily measurement of A-weighted
levels Leq, L10 and L90
shall be conducted for at least two weeks. The sample period shall be 30
minutes between 0700 and 1900.
4.6.2
During the baseline monitoring, there should be no major construction
or noise generating activities near the monitoring stations. The ET shall
propose a monitoring schedule to the IEC so that he can conduct onsite audit to
ensure the accuracy of the measurement where necessary.
4.6.3
Alternative baseline NMS that can give representative baseline result
may be proposed for ER and IEC’s approval with justifications.
4.6.4
In exceptional cases, when insufficient baseline monitoring data or
questionable results are obtained, the ET shall liaise with the IEC and ER to
agree on an appropriate set of data to be used as a baseline reference and
submit to EPD for approval.
4.7.1
For daytime construction work on normal weekdays (0700-1900 Monday to
Saturday), one set of 30-min measurement shall be carried out at each NMS every
week based on the measurement procedures under the Noise Control Ordinance-TM.
Similar to baseline monitoring, the ET shall submit a monitoring schedule to
the IEC beforehand.
4.7.2
If noise exceedance is being recorded, additional noise monitoring shall
be conducted in accordance to the Event Action Plan. The monitoring shall
consider complete if the exceedance is being rectified or proved to be from
source other than the project construction work.
4.7.3
Sample data sheet can be found in Appendix B.
4.8.1
The EIAO-TM sets the statutory limit for noise level produced during
construction work.
Table 4.2 Action and Limit Levels
for Noise
|
Time Period |
Action Level |
Limit Level |
|
0700-1900 hrs on normal weekdays |
When one documented complaint is
received |
75dB(A) |
4.9.1
Should non-compliance of the noise criteria occur, actions in accordance
with the Action Plan in Appendix C shall be carried out.
4.10.1
The EIA proposed a number of construction phase mitigation measures,
examples as follows:
(a) Adopt good site practice, such as regular
maintenance of plant equipment, throttle down unused machines.
(b) Use Quality Powered Mechanical Equipment
(QPME).
(c) Erect
(d) Operate air compressor, generator and concrete pump within enclosure.
(e) Cover the noisy part of piling machine with acoustic mat.
(f) Orient noisy
plant equipment so that noise emitted will not be directed towards the NSRs.
(g) Strategic location
and scheduling of the construction work front to minimize cumulative effect
(e.g. the work front of village sewer installation near NSRs PTO_N1 and PTO_N3
shall not be conducted concurrently with installation of Po Toi O Chuen Road
sewer and horizontal directional drilling respectively).
(h) Vibratory poker shall only be operated 4m
away from NSR and with noise barrier properly erected. Surfacing work within 4m
from NSR shall be carried out by manual method.
(i) Hand-held breaker shall be fitted with
mufflers. A movable enclosure
made up of plywood is proposed to surround both worker and breaker during
breaking process.
(j) Should there be
concurrent project in the vicinity, continuous discussion between contractors
shall be conducted to plan the location and programme of construction work to
minimize cumulative impact.
4.10.2 Detailed mitigation measures are listed out in the Implementation Schedule of Recommended Mitigation Measures in Appendix A. Implementation status and the effectiveness of these measures shall be audited through regular site inspection.
5.1.1 Potential water quality impact arising from the construction activities (for examples, site runoff of exposed soil, earthworks and stockpiles during rainstorms and sewage generated from construction workforce) would be minimized by implementing appropriate mitigation measures and good site management practices.
5.1.2 Dredging and backfilling works associated with the diffuser of the submarine outfall at outer Poi Toi O Bay shall be confined within fully enclosed cofferdam. Dredger barge will be anchored outside the cofferdam and no opening of cofferdam is required during dredging and filling works. No release of suspended solids is expected. Minor displacement of bottom sediment may arise during installation of cofferdam.
5.1.3 Construction phase monitoring is proposed to keep track of the variation in water quality to identify any unacceptable impact at the sensitive receivers during installation and extraction of cofferdam and dredging works. Site audit shall be conducted regularly to ensure that the mitigation measures recommended in the EIA Report and this EM&A Manual are fully implemented.
5.1.4 Treated effluent will be discharged at outer Po Toi O Bay during the normal operation of the STP. The effluent quality shall be regularly monitored in accordance with the requirements under Discharge License. No substantial change in water quality in the Po Toi O Bay is expected. However, in view of the sensitivity of fish culture zone, corals and amphioxus to water quality change, marine water quality monitoring is proposed for the first commencement year to ensure that no unacceptable deterioration of water quality arises in the enclosed bay.
5.1.5 Practical and well sufficient mitigation measures have been proposed to protect water quality during marine construction works, such as no open dredging for submarine outfall by adopting HDD, dredging and filling within fully enclosed cofferdam and use of closed grab for dredging. During operation of the proposed STP, effluent that meets the water quality requirements under WPCO will be discharged. As no adverse water deterioration is expected during construction and operational phases, real-time reporting of monitoring data for the Project through a dedicated internet website is considered not necessary.
Monitoring Requirement
5.2.1 Major water quality impact will be originated from minor displacement of suspended solids during installation and extraction of cofferdam around the proposed diffuser. Regular monitoring of water quality should be carried out at water quality monitoring stations (WMS) near the cofferdam (impact station), upstream of the impact (control stations), and near representative water sensitive receivers (WSRs) (e.g. Fish Culture Zone, coral and Amphioxus) before and throughout installation and extraction works. Although no sediment is expected to be released during dredging, water quality monitoring during dredging works will also be proposed.
Monitoring Parameters
5.2.2 Suspended solids (SS) and in-situ water quality data (temperature, pH, turbidity, water depth, salinity, dissolved oxygen and percentage of saturation) shall be collected.
5.2.3 Other relevant data should also be recorded, including monitoring location/position, time, tidal stages, weather conditions and any special observation or works that may affect the monitoring results in the vicinity.
5.2.4 To ensure sufficient data for robust analysis, duplicate in-situ data shall be collected. In case the difference in the duplicate in-situ measurement results is larger than 25%, the third set of in-situ measurement shall be carried out for result confirmation purpose.
5.2.5 A sample data sheet can be found in Appendix B.
Monitoring Location
5.2.6 Six water monitoring stations are proposed at Po Toi O Fish Culture Zone (FCZ), major amphioxus habitat and rocky shores near the dredging point where coral thrives. Based on the prediction of Delft-3D model, water current flows from the open sea through Clear Water Bay towards Po Toi O bay during flood tide while the reverse happens during ebb tide. Therefore, three control stations will be allocated at where fresh marine water is not affected by the cofferdam installation/extraction works and two impact stations will be set near the cofferdam under different tidal periods. The location of the stations can be found in Figure 5-1.
Table 5.1 Marine Water Monitoring Locations in Construction
Phase
|
Station |
Monitoring Period |
Description |
Easting |
Northing |
|
WMS1 |
Mid-Ebb, Mid-Flood |
Po Toi O Fish Culture Zone |
848387 |
815201 |
|
WMS2 |
Po Toi O Fish Culture Zone |
848479 |
815378 |
|
|
WMS3 |
Rocky Shore with Corals |
848644 |
815391 |
|
|
WMS4 |
Rocky Shore with Corals |
848774 |
815602 |
|
|
WMS5 |
Rocky Shore with Corals |
848578 |
815591 |
|
|
WMS6 |
Major Amphioxus Habitat |
848639 |
815523 |
|
|
I1 |
Mid-Flood |
Impact Monitoring Station |
848643 |
815692 |
|
I2 |
Mid-Ebb |
Impact Monitoring Station |
848722 |
815810 |
|
C1 |
Mid-Flood |
Control Station |
848904 |
816052 |
|
C2 |
Mid-Ebb |
Control Station |
848529 |
815373 |
|
C3 |
Mid-Ebb |
Control Station |
848243 |
815710 |
5.2.7 Water samples shall be extracted at 1m below surface, 1m above seabed and the mid-depth level at where the water depth is at least 6m. However, if the water depth is less than 3m, water samples shall only be collected at the mid-depth level. For stations with depth less than 6m, the mid-depth sample can be omitted.
Monitoring Frequency
5.2.8 Baseline monitoring shall be carried out 3 days per week, at mid-flood and mid-ebb tides (within ± 1.75 hour of the predicted time), for a period of 4 weeks prior to the commencement of the marine works. The interval between two sets of monitoring shall not be less than 36 hours. The monitoring period should avoid concurrent marine project in the vicinity.
5.2.9 Impact monitoring shall also be conducted at the same frequency throughout the whole cofferdam installation/extraction work and during dredging works. In case exceedance of Action/Limit Level is recorded, the frequency shall be increased as per the Event and Action Plan.
Construction Phase Site Inspection
5.2.10 Weekly
site audit is recommended to monitor the implementation of the proposed water
quality mitigation measures and check the Contractor’s work practice on water
pollution prevention during construction phase.
5.2.11 Should water pollution is observed (e.g. discharge of silty water into storm drains), the ET should record the environmental deficiency for investigation. The Contractor should be notified and responsible for carrying out rectification work immediately. The ET shall re-inspect the Project Site described in Section 2.3.1 and review the effectiveness of the remedial measure performed until satisfaction. The Contractor shall implement preventive measure to avoid causing the same problem.
5.3 Operational Phase EM&A (Effluent Quality)
5.3.1 The water quality of the effluent should meet the requirements under Technical Memorandum on Effluent Discharge Standard before discharge. Therefore, effluent testing should be carried out at the discharge outlet at interval stipulated in the discharge license issued by the EPD. The water quality parameters shall be referred to the discharge license as well. Should exceedance be recorded, the plant operator should be notified, who shall identify the cause of non-compliance and formulate remedial measures. The monitoring frequency should increase until the effluent quality can meet the criteria. No effluent should be discharged until the effluent quality meets the required standard.
5.4 Operational Phase EM&A (Marine Water Quality)
5.4.1 Effluent will be discharged at the diffuser. Regular monitoring of marine water quality should be carried out at WMS to check whether the Water Quality Objectives (WQO) can be fulfilled. The monitoring should commence prior to operation of the STP to establish the baseline water quality condition.
5.4.2 Water quality parameters under the WQO that may be affected by effluent discharge shall be monitored at the nearby sensitive receivers: E. coli, DO, salinity, SS, ammonia (NH3-N) and total inorganic nitrogen (TIN). As in the construction phase, other in-situ water quality data shall also be collected (temperature, pH, turbidity, water depth and percentage of saturation for DO).
5.4.3 Other relevant data should also be recorded, including monitoring location/position, time, tidal stages, weather conditions and any special observation or works that may affect the monitoring results in the vicinity.
5.4.4 To ensure sufficient data for robust analysis, duplicate in-situ data shall be collected. In case the difference in the duplicate in-situ measurement results is larger than 25%, the third set of in-situ measurement shall be carried out for result confirmation purpose.
5.4.5 A sample data sheet can be found in Appendix B.
5.4.6 The water monitoring stations shall follow those in the construction phase (WMS1-WMS6).
5.4.7 Water samples shall be extracted at 1m below surface, 1m above seabed and at the mid-depth level at where the water depth is at least 6m. However, if the water depth is less than 3m, water samples shall only be collected at the mid-depth level. For stations with depth less than 6m, the mid-depth sample can be omitted.
5.4.8 Baseline Monitoring shall be carried out for two times per month for a period of 6 months prior to the commencement of the operation of the PTOSTW. The 6-month period shall cover both wet and dry seasons. Water samples shall be collected during mid-ebb and mid-flood tides (within ± 1.75 hour of the predicted time) on each monitoring day. The monitoring period should avoid concurrent marine project in the vicinity.
5.4.9 Operational phase monitoring shall also be conducted at the same frequency as in baseline for the first three months of operation of PTOSTW (i.e. twice per month). If the results are satisfactory, the frequency will be reduced to once per month. However, if exceedance is subsequently recorded, the frequency shall return to twice per month until satisfactory results are obtained again for three consecutive months. The whole monitoring shall last for one year. If no exceedance is recorded due to operation of the PTOSTW, no further monitoring is required.
Table 5.2 Overall Summary of Monitoring Requirements in Construction and
Operational Phases
|
Monitoring
Stations |
Parameters |
Duration |
Frequency |
|
Construction
Phase |
|||
|
WMS1-WMS6, I1,
I2, C1-C3 |
·
Temperature(°C) ·
pH(pH unit) ·
Turbidity (NTU) ·
Water depth (m) ·
Salinity (ppt) ·
DO (mg/L and % of saturation) ·
SS (mg/L) |
Baseline: 4 weeks |
·
3 days per week |
|
Construction: |
|||
|
Operational
Phase |
|||
|
WMS1-WMS6 |
·
Temperature(°C) ·
pH(pH unit) ·
Turbidity (NTU) ·
Water depth (m) ·
Salinity (ppt) ·
DO (mg/L and % of saturation) ·
SS (mg/L) ·
NH-N (mg/L) ·
TIN (mg/L) ·
E. coli (no./100ml) |
Baseline: 6 months
before operation, covering wet and dry seasons |
·
2 days per month |
|
Operation: at least one
year from operation |
·
First 3 months: ·
Subsequent months: ·
If exceedance is recorded, frequency increases
back to 2 days per month until no further deterioration is recorded for 3
months ·
Completed in one year |
||
|
Notes: ·
water depths: 1m below sea surface, mid-depth
and 1m above sea bed ·
If the water depth is less than 3m, mid-depth
sampling only ·
If water depth less than 6m, mid-depth may be
omitted. 2. Sampling
time for all monitoring: Mid-Ebb, Mid-Flood |
|||
Position System
5.4.1 A hand held Global Positioning System (GPS) shall be used during water quality monitoring to ensure the monitoring vessel is at the correct location before taking measurements. GPS shall be calibrated at checkpoint (e.g. Quarry Bay Survey Nail at Easting 840683.49 and Northing 816709.55) to ensure the monitoring station is at the correct position before taking measurement and water samples.
Water Depth Detector
5.4.2 A portable, battery-operated echo sounder shall be used for the determination of water depth at each designated monitoring station.
Salinity
5.4.3 A portable salinometer capable of recording salinity within the range of 0-40 ppt shall be used for salinity measurements.
Dissolved Oxygen (DO)
and Temperature Measuring Equipment
5.4.4 The instrument for measuring dissolved oxygen and temperature shall be portable and weatherproof complete with cable, sensor, comprehensive operation manuals and use DC power source. It shall be capable of measuring:
· A dissolved oxygen level in the range of 0-20 mg/L and
0-200% saturation; and
· A temperature of 0-45 degree Celsius.
5.4.5 It shall have a membrane electrode with automatic temperature compensation complete with a cable.
5.4.6 Sufficient stocks of spare electrodes and cables shall be available for replacement where necessary.
5.4.7 The instrument for measuring DO shall obtain built-in salinity compensation.
Turbidity Measurement
Equipment
5.4.8 Nephelometric method shall be used in measuring in-situ turbidity. The instrument shall be portable, weatherproof complete with a cable, sensor, comprehensive operation manuals and DC power source. It shall have a photoelectric sensor capable of measuring turbidity between 0-1000 NTU and complete with a cable with at least 25 m in length. The meter shall be calibrated in order to establish the relationship between NTU units and suspended solids level. Turbidity shall be measured on split water sample collected from the same depths of suspended solid samples.
pH
5.4.9 The instrument shall consist of a potentiometer, a glass electrode, a reference electrode and a temperature-compensating device. It shall be readable to 0.1pH in a range of 0 to 14. Standard buffer solutions of at least pH 7 and pH 10 shall be used for calibration of the instrument before and after use.
Sampler
5.4.10 A water sampler, consisting of a transparent PVC or glass cylinder of a capacity of not less than two litres which can be effectively sealed with cups at both ends shall be used. The water sampler shall have a positive latching system to keep it open and prevent premature closure until released by a messenger when the sampler is at the selected water depth.
Sample Container and
Storage
5.4.11
Following collection, water
samples for laboratory analysis shall be stored in high density polythene
bottles with appropriate preservatives added, packed in ice (cooled to
5.4.12 Water samples for E. coli shall be collected in sterile bottles with leak-proof lids.
5.4.13 Water samples for suspended solids determinations shall be stored in high density polythene bottles with no preservative added.
Calibration of In-situ Instruments
5.4.14 All in-situ monitoring instruments shall be checked, calibrated and certified by a laboratory accredited under HOKLAS or other international accreditation scheme before use, and subsequently re-calibrated at 3 monthly intervals throughout all stages of the water quality monitoring programme. Responses of sensors and electrodes shall be checked with certified standard solutions before each use. Wet bulb calibration for a DO meter shall be carried out before measurement at each monitoring event.
5.4.15 For the on-site calibration of field equipment (Multi-parameter Water Quality System), the BS 1427:2009, "Guide to on-site test methods for the analysis of waters" shall be observed.
5.4.16 Sufficient stocks of spare parts shall be maintained for replacements when necessary. Backup monitoring equipment shall also be made available so that monitoring can proceed uninterrupted even when some equipment is under maintenance, calibration, etc.
Laboratory Measurement
or Analysis
5.4.17 The testing of all parameters shall be conducted by a HOKLAS accredited laboratory or operator of the