K. Wah Materials Limited

Environmental Impact Assessment Study

for Cement Silos Addition Work in Tai Po Cement Depot

 


content

1       INTRODUCTION

1.1    Background

1.2    Objectives of the Environmental Impact Studies

2       PROJECT DESCRIPTION

2.1    Background

2.2    Design of the Project

2.3    Scenarios with or without the Project

2.4    Demerit of other Alternatives

2.5    Construction Methodology and Programme

2.6    Interactions with Other Projects

3       Relevant environmental Ligistation

3.1    Introduction

3.2    Environmental Impact Assessment (EIA)

3.3    Air

3.4    Noise

3.5    Water

3.6    Visual Impact Assessment

3.7    Waste Management

4       AIR QUALITY ASSESSMENT

4.1    Introduction

4.2    Assessment Criteria

4.3    Air Sensitive Receivers

4.4    Methodology

4.5    Emission Factors

4.6    Air Quality Impact

4.6.1   Construction Phase

4.6.2   Operational Phase

4.7    Conclusion

5       Noise Assessment

5.1    Introduction

5.2    Assessment Criteria

5.2.1   Construction Noise

5.2.2   Operational Noise

5.3    Noise Sensitive Receivers

5.4    Methodology

5.5    Construction Noise Impact

5.5.1   Unmitigated Case

5.5.2   Mitigation Measures

5.6    Operational Noise Impacts

5.6.1   Ocean Going Vessel

5.6.2   On site Activities

5.6.3   Off-site Activitie

5.7    Conclusion

6       WATER QUALITY ASSESsMENT

6.1    Introduction

6.2    Assessment Criteria

6.3    Water  Sensitive Receivers

6.4    Description of Environmental Baseline Conditions

6.5    Water Quality Impact

6.6    Mitigation Measures

6.7    Conclusion

7       Visual impact Assessment

7.1    Introduction

7.2    Assessment Criteria

7.3    Assessment Methodology

7.3.1   Baseline Survey

7.3.2   Visual Impact Assessment

7.4    Methodology for Determination of Mitigation Measures

7.5    Residual Impact

7.6    Review of Planning and Development Control Framework

7.7    Assessment Results

7.7.1   Existing Visual Context and Visually Sensitive Receivers (VSRs)

7.7.2   Visual Impact

7.8    Recommended Mitigation Measures

7.9    Conclusion

8       Waste Management

8.1    Introduction

8.2    Assessment Criteria and Methodology

8.3    Prediction and Evaluation of Environmental Impacts

8.3.1   Construction Phase

8.3.2   Operational Phase

8.3.3   Mitigation Measures

8.4    Conclusion

9       Ecology

10     Cultural Heritage

11     Implementation schedules

12     environmental monitoring & audit requirement

12.1  Air Quality

12.2  Noise

12.3  Water Quality

13     environmental OUTCOME

14     CONCLUSION

 


TABLES

Table 2.1:       Tentative construction schedule

Table 4.1:       Air Quality Objectives

Table 4.2:       Air Sensitive Receivers

Table 4.3:       Average Diameter and percentage of each class in TSP and RSP modelling

Table 4.4:       Daily operation program of the cement plant during construction period

Table 4.5:       Daily operation program of the cement plant during operational period

Table 5.1:       Construction Noise Guidelines (Leq(30min) dB(A)) within non-restricted hours

Table 5.2:       TM-EIA Industrial Noise Guidelines for different Area Sensitive Rating (ASR)

Table 5.3:       TM-EIA Traffic Noise Guideline

Table 5.4:       Noise sensitive receivers in the vicinity of the project site

Table 5.5:       Off-site noise sensitive receivers

Table 5.6:       Sound power level of the powered mechanical equipment

Table 5.7:       Noise Inventory for the concrete batching plant activities and the existing/ Proposed cement works

Table 5.8:       Predicted Façade Noise Levels without mitigation measures at NSRs

Table 5.9:       Proposed Mitigation Measures for Construction Phase

Table 5.10:     Predicted Façade Noise Levels at NSRs with quieter powered mechanical equipment

Table 5.11:     Predicted Façade Noise Levels at NSRs due to the operation of the ocean going vessel

Table 5.12:     Predicted Façade Noise Levels without mitigation measures at NSRs

Table 5.13:     Characteristics of the proposed noise mitigation measures

Table 5.14:     Predicted Façade Noise Levels at NSRs with mitigation measure

Table 5.15      Traffic Noise due to off-site transportation

Table 6.1:       Water Quality Objectives – Tolo Harbour and Channel Water Control Zone

Table 6.2:       Summary statistics of 1999 water quality of Tolo Harbour and Channel WCZ

Table 7.1:       Impact Matrix

Table 7.2:       Overall evaluation of visual impact.

Table 7.3:       Summary of Visually Sensitive Receivers

Table 7.4:       Summary of Visual Impact

Table 14.1:  Major Mitigation Measures for Construction and Operational Phases

 

FIGURES

Figure 2.1         Site Location Plan

Figure 2.2         Existing Cement Depot and Ocean Going Vessel

Figure 2.3         Schematic Diagram for Existing Cement Work Process

Figure 2.4         Site Layout Plan

Figure 2.5         Schematic Diagram for the planned Cement Work Process

Figure 4.1         Predicted Traffic Flow in 2018

Figure 4.2         Locations of Air Sensitive Receivers

Figure 4.3         Cumulative 1-hr TSP Contour at 5m in Daytime (Construction)

Figure 4.4         Cumulative 24-hr TSP Contour at 5m (Construction)

Figure 4.5         Cumulative 24-hr TSP Contour at 1.5m (Operation)

Figure 4.6         Cumulative 24-hr RSP Contour at 1.5m (Operation)

Figure 5.1         Location of Noise Sensitive Receivers in the Vicinity of Project Site

Figure 5.2a       Location of off site Noise Sensitive Receivers in Pak Shek Kok, Ma On Shan and planned Whitehead

Figure 5.2b       Site Plan of Ma Shi Chau

Figure 5.3a       Location of Operational Noise Sources and Construction Site Boundary

Figure 5.3b       Location of Noise Sources and NSRs

Figure 5.4         Vertical Barrier below Silos

Figure 5.5         Extension of Noise Barriers for Cement Silos

Figure 5.6         Proposed location of Vessel Anchorage Region

Figure 5.7         Constraints within Tolo Harbour

Figure 6.1a       Locations of Water Sensitive Receivers and Monitoring Stations

Figure 6.1b       Locations of Ecological Sensitive Receivers

Figure 6.2         Schematic Diagram of Site Drainage

Figure 7.1         Visual Envelope and VSR

Figure 7.2         Side View of Cement Depot from Casa Marina III

Figure 7.3         Elevation View of Cement Depot from Tolo Harbour

Figure 7.4         Photomontage of View from Casa Marina III

Figure 7.5         Photomontage of View from Fortune Garden

Figure 7.6         Photomontage of View from Tolo Harbour

Figure 7.7         Photomontage of View from Ting Kok Road

 


APPENDICES

Appendix 4a       Emission Factors during Construction and Operational Phases

Appendix 4b       Detail Calculation for Emission Factors of Proposed Cement Depot

Appendix 4c       Emission Factors of adjacent Concrete Batching Plants and Cement Depot

Appendix 4d1    Relevant pages of Air Pollution Control Plan for K. Wah Concrete Batching Plant

Appendix 4d2    Emission due to vehicle movement for East and West Wing K Wah Concrete Batching Plant and K. Wah Stone Plant

Appendix 4e       Emission Factors for Road Traffic

Appendix 4f        Predicted cumulative1-hr and 24-hr TSP during construction phase

Appendix 4g       Predicted cumulative 24-hr TSP for On-site Activities during Operational Phase

Appendix 4h       Predicted cumulative 24-hr RSP during Operational Phase

Appendix 4i        Sample FDM Output File for 1-hr in day time and 24-hr TSP  (Construction Phase)

Appendix 4j        Sample FDM Output File for 24-hr TSP (Operational Phase)

Appendix 4k       Sample FDM Output File for 24-hr RSP (Operational Phase)

Appendix 4l        Sample CALINE4 Output File for 1-hr RSP in day and evening time

Appendix 4m      Event Contingency Plan for Silo Explosion Accident     

Appendix 4n       Specification for the Dust Collectors

Appendix 5a       Sound Power Level (SWL) Measurement for Concrete Lorry Mixer and Cement Tankers

Appendix 5b       Sound Power Level (SWL) Measurement for Pumping Barge

Appendix 5c       Sound Power Level (SWL) Measurement for the Electric Screw Conveyor

Appendix 5d       Sound Power Level (SWL) Measurement for Cement Unloading

Appendix 5e       Sound Power Level (SWL) Measurement for the Ocean Vessel

Appendix 5f        Construction Noise Impact

Appendix 5g       Operational Noise Impact – No Mitigation Measure

Appendix 5h       Operational Noise Impact – With Mitigation Measure

Appendix 5i        Measurement Detail of the Prevailing Noise Level

Appendix 5j         Measurement Detail of the off- site Prevailing Noise Level

Appendix 5k       Traffic noise output file


 

ABBREVIATIONS

ANLs

Acceptable Noise Levels

APCO

Air Pollution Control Ordinance

APCP

Air Pollution Control Plan

Arup

Ove Arup and Partners

ASR

Air Sensitive Receptors

AQO

Air Quality Objectives

CED

Civil Engineering Department

CNP

Construction Noise Permit

DEP

Director of Environmental Protection

DO

Dissolved Oxygen

EIA

Environmental Impact Assessment

EIAO

Environmental Impact Assessment Ordinance

EM&A

Environmental Monitoring and Audit

EP

Environmental Permit

EPD

Environmental Protection Department

HKPSG

Hong Kong Planning Standards and Guidelines

NCO

Noise Control Ordinance

NSRs

Noise Sensitive Receivers

PME

Powered Mechanical Equipment

SPME

Specified Powered Mechanical Equipment

SWL

Sound Power Level

TMs

Technical Memoranda

TM-GW

Technical Memorandum on Noise from Construction Work other than Percussive Piling

TM-DA

Technical Memorandum on Noise from Construction Work in Designated Areas

TM-PP

Technical Memorandum on Noise from Percussive Piling

TM-EIA

Technical Memorandum on Environmental Impact Assessment Process

TM-IND

Technical Memorandum for the Assessment of Noise from Places other than Domestic Premises, Public Places or Construction Sites

TM-Water

Technical Memorandum on Standards for Effluents Discharged into Drainage and Sewerage Systems, Inland and Coastal Waters

VSR

Visual Sensitive Receiver

WCZ

Water Control Zone

WDO

Waste Disposal Ordinance

WQO

Water Quality Objectives

 


1                          INTRODUCTION

1.1                    Background

The existing Tai Po cement depot has been 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 of total capacity at 8,500 MT. Currently, cement is delivered to the depot through cement barges. Existing cement silo capacity is not capable of storing all the cement from a single shipment load. Current practice is to unload the cement from the silos by cement tankers for immediate delivery to the client, thus free up the silos for further storage. As a result, the barge is required to berth alongside the shore for a period of time and uploading of cement can only be operated in batch mode.

In order to reduce potential nuisance of the barge operation, the only way is to increase the depot storage capacity. K. Wah 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 involves cement works greater than 10,000MT, it is 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 Environment Permit is therefore required for the construction and operation of the cement depot. K. Wah has commissioned Ove Arup & Partners Hong Kong Ltd (Arup) to provide environmental consultancy services for this application. A study brief (ESB-084/2001) was issued on 30 October 2001 outlining the requirements of the EIA Study.

The objective of this report is to provide an Environmental Impact Assessment (EIA) for the proposed project. This report presents the assessment criteria, methodologies, and results for the potential noise, dust, water quality and visual impacts, during construction and operational phases, with and without mitigation measures.

1.2                    Objectives of the Environmental Impact Studies

The main objectives of this EIA report are summarized as follows:

·        To give an account of the considerations given to different alternative sites

·        To identify and describe the elements of the community and environment likely to be affected by the Project

·        To identify and quantify emission sources and determine the significant of impacts on sensitive receivers and potential affected uses

·        To propose mitigation measures so as to minimize pollution, environmental disturbance and nuisance arising from the Project

·        To identify, predict and evaluate the residual environmental impacts and the cumulative effects expected to arise from the construction and the operation of the Project in relation to the sensitive receivers and potential affected uses

·        To identify, assess and specify methods, measures and standards, to be included in the detailed design, construction and operation of the Project, which are necessary to mitigate these environmental impacts and reducing them to acceptable levels

·        To investigate the extent of side-effects of proposed mitigation measures that may lead to other forms of impacts and to identify the constraints associated with the mitigation measures

·        To identify, design and specify the environmental monitoring and audit requirements, to ensure the implementation and the effectiveness of the environmental protection control measures adopted

 


2                          PROJECT DESCRIPTION

2.1                    Background

The proposed project site is within the existing site of cement depot, which is located at 18 Yu On Street, Sam Mun Tsai, Tai Po. The present site is owned and has been operated by Project Proponent since 1992. A location plan of the site is shown in Fig 2.1. The existing cement depot consists of 6 cement silos of total capacity at 8,500 MT- four at 1,500 MT and two at 1,250 MT (Fig. 2.2). The silos are located at about 13 - 24 m from the existing seawall. Average daily cement dispatching rate is 1,400 – 1,500 MT.

In the existing depot, amongst the six silos, two of the 1,500MT cement silos and two of the 1,250MT cement silos are interconnected. This allows the existing six silos to be connected to four dust collectors. In addition, another three dust collectors are installed at the three loading points for the cement tankers. A total of seven dust collectors are employed in the existing plant to mitigate any fugitive emissions (Fig.2.3). In normal situation, only two loading points are operated. The remaining loading point is for backup purpose.

Cement is delivered to the depot by cement barges (loading capacity of 400 MT) from the ocean going vessel (not owned by project proponent but of loading capacity 10,000 MT, Fig. 2.2), which is located in Tolo Harbour Channel. Cement unloading from the ocean going vessel to the barge is through enclosed pipelines. The barge then travels to the depot and the cement is uploaded to the cement silos via enclosed pipelines and Bucket Elevator. The entire uploading process is performed within a totally enclosed system in order to suppress dust emissions (Fig. 2.3). Cement is stored inside the silos until unloading to cement tankers for delivery. This process is also conducted in totally enclosed connections.

The operation of depot will be powered by mains. There are no additional gaseous emissions from the mechanical plant (e.g. generators).

2.2                    Design of the Project

Due to the limited capacity of existing silos, 3 additional silos of total capacity at 7,500MT are proposed to be constructed. The new silos are located adjacent to the existing silos and occupy a floor area of approximately 400m2 (Fig 2.4). Each planned silo will be fitted with a dust collector. Besides, the planned silos are also interconnected to the existing unloading points. Fig.2.5 shows the schematic diagram of the planned process. There will not be any increased throughput or operational capacity to the existing operations as a result of the increased silo capacity.

A Concrete Batching Plant and a Stone Plant, operated by other companies are identified within 500m of the proposed development (Fig. 2.1). The Concrete Batching Plant consists of 2 legs, hereafter referred to as East Wing Concrete Batching Plant and West Wing Concrete Batching Plant respectively.  These plants will contribute to cumulative impacts of noise and fugitive dust emissions on the nearby sensitive receivers. 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.

2.3                    Scenarios with or without the Project

The existing operation requires uploading from the ocean going vessel to be stopped when the silos are full. Until space inside the silos is freed from cement dispatched by the cement tankers, the barge will have to remain at berth. This causes long lag time and frequent startup of the pumping barge, which results in intermittent transient noise nuisance to the nearby sensitive receivers.

By increasing the silo capacity, cement uploading from the barge can be completed in one batch. The proposed additional silos will therefore eliminate the intermittent transient noise due to the frequent startup of the pumping barge. Also, the berthing time of the ocean vessel will be shortened, thus reducing the marine traffic impact in Tolo Harbour.

2.4                    Demerit of other Alternatives

In arriving at the selected option, different alternative locations including outside the existing depot area (off-site) have been evaluated from the environmental point of view. The demerits of the alternative options are summarized as follows.

(i)           The construction of a new cement depot off site would require a new jetty and a large site formation area. This will introduce impact on marine water quality, marine ecology and air quality.

(ii)         More cement barges will need to be deployed for serving the two depots at different locations, thus leading to an increase in air quality (such as dark smoke emission from generator), noise and marine traffic impacts.

(iii)       Additional cement unloading bays will be required, which will give rise to dust emission, visual and noise impact and safety concerns.

(iv)        There is also a need to introduce a new conveyor system for cement unloading which will increase the risk of accidental leakage.

(v)          Locating the additional silos at further distance from the existing silos will also give rise to demerits of an offsite location as described in (iii) and (iv).

2.5                    Construction Methodology and Programme

The construction of the new cement silos will consist of three stages: ground excavation, setting of foundation and the silo erection works. Ground excavation work will employ excavator mounted breaker and drilling rig. Foundation works will employ concrete lorry mixer, concrete pump and vibratory poker. Silos erection works will employ sky-crane and arc welders. The proposed new silos will be fabricated off-site and transport to the existing depot by barge such that the transportation and construction noise nuisance can be reduced. The tentative construction programme is shown in Table 2.1

Table 2.1: Tentative construction schedule

Description

Commencement Date

Completion Date

Construction of addition 3 silos

Feb 2003

Nov 2003

During the construction period, the existing cement depot will continue operation. Therefore, the cumulative impact due to the operation of the existing cement depot is taken into account in this study. The addition three silos will start immediately operation upon completion of works in November 2003.

2.6                    Interactions with Other Projects

There are no other projects likely to interface with this proposed project. As the construction of the Casa Marina III is nearly finished, it will not cause cumulative impact on the environment.


3                          Relevant environmental Ligistation

3.1                    Introduction

This section presents a summary of current and relevant environmental legislation, which relate to the assessment of potential environmental impacts from the proposed development.

3.2                    Environmental Impact Assessment (EIA)

Preparation of the EIA itself has been undertaken in accordance with the Environmental Impact Assessment Ordinance (EIAO) and associated Technical Memorandum on Environmental Impact Assessment Process (TM-EIA) (EIAO, Cap.499, S.16).

3.3                    Air

The Air Pollution Control Ordinance (APCO) provides the statutory authority for controlling air pollutants from a variety of stationary and mobile sources, including fugitive dust emissions from construction sites. It encompasses a number of Air Quality Objectives (AQOs) which stipulate concentrations for a range of pollutants including Sulphur Dioxide (SO2), Nitrogen Dioxide (NO2), Respirable Suspended Particulars (RSP) and Total Suspended Particulates (TSP).

In addition to the AQOs, Annex 4 of TM-EIA also outlines criteria for evaluating the construction dust and odour impacts.

The Air Pollution Control (Construction Dust) Regulations will also be relevant during the construction phase of the development.

3.4                    Noise

With reference to Table 1B of the TM-EIA regarding noise standards for daytime construction activities, a limit of 75 dB(A) in Leq(30 min) has been proposed for all domestic premises including temporary housing accommodation, hotels and hostels. For schools, a daytime noise level of 70 dB(A) in Leq(30 min), lowered to 65 dB(A) during examination periods is recommended.

Subsidiary regulations of the NCO include the Noise Control (Hand Held Percussive Breakers) and Noise Control (Air Compressors) Regulations, which require compliance with relevant noise emission standards and the fixing of noise emission labels to hand-held percussive breaker and air compressor respectively.

The control of construction noise during restricted periods (anytime for percussive piling) is carried out under the Noise Control Ordinance (NCO) and three subsidiary Technical Memoranda (TMs) covering Noise from Percussive Piling (TM-PP), Noise from Construction Work Other Than Percussive Piling (TM-GW) and Noise from Construction Work in Designated Areas (TM-DA). The TMs establish the permitted noise levels for construction work depending upon working hours and the existing noise climate.

A Construction Noise Permit (CNP) is required by the regulations of the NCO for the use of all PME during restricted hours. The procedures set out in TM-GW, TM-PP, TM-DA are used by EPD to determine whether or not a CNP should be issued. CNPs will not automatically be granted and will be assessed on a case by case basis by the Authority. Nothing in this report will bind the Noise Control Authority in the assessment of an application for a Construction Noise Permit pursuant to the NCO. Instead, the Authority will consider each application based on the contemporary conditions/situations.

Noises from fixed sources, including that from industrial-type establishments, is governed by the TM-EIAO and Technical Memorandum for the Assessment of Noise from Places Other Than Domestic Premises, Public Places or Construction Site (TM-IND).

For the operational traffic noise, annex 5 of “Criteria for Evaluating Noise Impact” of the TM-EIA defines the L10 (1 hr) at various NSRs.

3.5                    Water

The principal legislation governing marine water quality in Hong Kong is the Water Pollution Control Ordinance (Cap 358), 1980 (WPCO). Under an amendment to the original Ordinance of 1980, the Territorial Waters of Hong Kong Waters have been subdivided into 10 Water Control Zones (WCZs) with each WCZ being assigned a designated set of statutory Water Quality Objectives (WQOs). These WQOs relate to the Beneficial Uses (BU) and assimilative capacity of the particular water body or part thereof. The WCZ relevant to this study is the Tolo Harbour and Channel Water Control Zone.

Effluents generated during the construction and operational phases requiring disposal must comply with the discharge standards stipulated within the Technical Memorandum on Standards for Effluents (TM-Water) into Drainage and Sewerage Systems, Inland and Coastal Waters prior to entering the receiving water.

3.6                    Visual Impact Assessment

The assessment will be conducted in accordance with the study brief and Annex 18 of the TM-EIA. The evaluation of landscape and visual impact will be classified into five levels of significance, beneficial, acceptable, acceptable with mitigation measures, unacceptable and determined in accordance with Annex 10 of the TM-EIA.

3.7                    Waste Management

The assessment will be conducted in accordance with the Annex 7 & 15 of the TM-EIA. Under the Waste Disposal Ordinance (Cap. 354), construction waste is classified as a trade waste. The Waste Disposal (Chemical Waste) (General) Regulation (Cap. 354) stipulates the special handling, storage and subsequent disposal requirements for chemical waste. The Dumping at Sea Ordinance (Cap. 466) stipulates the requirements for permits for dumping at sea as well as designating areas within Hong Kong waters as a marine dumping area. The Land (Miscellaneous Provisions) Ordinance (Cap. 28) requires that dumping licenses are obtained by individuals or companies who deliver C&D waste to public filling areas. The Public Cleansing and Prevention of Nuisances Regulations under the Public Health and Municipal Services Ordinance (Cap 132) provides a further control on the illegal tipping of wastes on unauthorized sites.

Other guideline documents, which detail how the waste-related regulations shall be complied with during the construction of the works are as follows:

 

 

 

 


4                          AIR QUALITY ASSESSMENT

4.1                    Introduction

This section evaluates the likely air quality impact associated with the construction and operation of additional cement silos in the existing Tai Po cement depot. During the construction phase, the potential emission sources are identified as:

·              Construction works : material handling, excavation of material and wind erosion

·              Emission from dust collectors of existing cement silos and barge

·              On-site vehicle movement

·              Emission from the adjacent concrete batching plants, Stone Plant and associated facilities

During normal operation of the additional silos, the potential emission in the vicinity include:

·             Emission from dust collectors of existing cement silos and barge

·             Emission from dust collectors of planned cement silos

·             Emission from adjacent concrete batching plants, Stone Plant and associated facilities

·             On site movement of the heavy vehicles

·             Off site road traffic emission in 2018 (Fig.4.1 shows the predicted traffic flow in 2018)

Cement from the ocean going vessel is unloaded onto the cement barges in Tolo Harbour. The process is either through enclosed air slide or enclosed pneumatic system. Three dust collectors are equipped on the barge to reduce the dust emission. In normal case, activation of one dust collector will be adequate. The emission limit of the dust collectors are all in compliance with the ‘Guidance note on the Best Practicable Means BPM 3/1’ and the specification of the dust collectors is given in Appendix 4n. Given the long distance (greater than 500m) from the anchorage position to the planned and existing air sensitive receivers (ASRs), no adverse air quality impact is anticipated (Fig 5.6). 

The barge will carry the cement to the cement depot. Cement in the barge is discharged by screw conveyor to the enclosed Bucket Elevator through an enclosed Barge Air Slide. The Bucket Elevator then uploads the cement to the top of the silo for storage. The entire uploading process is totally enclosed. Fig. 2.5 shows the schematic diagram of the planned process. The emission points will be from the dust collectors on top of the silos and the unloading points , which will be designed for compliance with the ‘Guidance note on the Best Practicable Means BPM 3/1’.

4.2                    Assessment Criteria

According to the APCO, the relevant AQOs for this study are listed in Table 4.1.

Table 4.1: Air quality objectives

 

Concentration in micrograms per cubic metre (i)

Pollutant

1 Hour (ii)

24 Hours (iii)

1 Year (iv)

Total Suspended Particulates

500(v)

260

80

Respirable Suspended Particulates

-----

180

55

Notes:

(i)         Measured at 298K(25 oC) and 101.325 kPa (one atmosphere).

(ii)        Not to be exceeded more than three times per year.

(iii)        Not to be exceeded more than once per year.

(iv)        Arithmetic means.

(v)         Not stipulated in AQO but provide from the EPD guidelines for construction dust assessment.

The corresponding guidelines for air quality assessment is laid down in Annex 12 of the TM-EIA, respectively.

For the operation of the cement depot, a specified process licence under the Air Pollution Control Ordinance is required. The “Guidance Note on the Best Practicable Means for Cement Works (Cement Depot) BPM 3/1” issued by the EPD will provide general guidelines for the depot operation.

4.3                    Air Sensitive Receivers

The existing and planned air sensitive receivers (ASR) in the vicinity of the project site have been identified (Fig.4.2). The details of the ASR are tabulated in Table 4.2.

Table 4.2: Air sensitive receivers

ASR

Air Sensitive Receivers

Description

Distance[2]  (m)

1

Fortune Garden

Residential

274

2

Tycoon Place

Residential

372

3

Village House

Residential

184

4

Sha Lan Villa

Residential

184

5

Wu York Yu Care and Attention Home

Home for the aged

504

6

TWGHs Pao Siu Loong Care & Attention Home

Home for the aged

592

7

Casa Marina III1

Residential

50

8

Shipyard

Industrial

40

9

Tai Po Marine Office

Commercial

64

10

Wholesale Fish Market

Commercial

172

Note 1: Planned Receiver

Note 2: Distance are measured to the site boundary

4.4                    Methodology

Dispersion modeling has been taken using USEPA approved Fugitive Dust Model (FDM) to assess potential dust impacts arising from construction activities and fugitive dust sources. In order to assess the traffic emissions impact, the USEPA approved CALINE4 dispersion method was used.

In the TSP and RSP modelling, particle size distribution was estimated based on the most appropriate particle size multipliers as stated in the Appendix B of AP42. In the modelling exercise, 9 particle size classes were used in the FDM model. Table 4.3 shows the average diameters and percentage of each class for TSP and RSP.

Table 4.3: Average diameter and percentage of each particle class in TSP and RSP modelling

Particle range (mm)

Average Particle Size (mm)

TSP (%)

RSP (%)

0 – 1

0.5

4

7.84

1 – 2

1.5

7

13.73

2 – 2.5

2.25

4

7.84

2.5 – 3

2.75

3

5.89

3 – 4

3.5

7

13.73

4 – 5

4.5

5

9.80

5 – 6

5.5

4

7.84

6 – 10

8

17

33.33

10 – 30

20

49

---

 

According to the Guideline on Choice of Models and Model Parameters, the meteorological parameter used in FDM and CALINE4 modelling are:

FDM Modelling

Surface Roughness          : 100cm

Terrain                               : Rural

Meteorological Data        : Meteorological data in Tai Mei Tuk Automatic Weather Station in 2001

CALINE 4 modelling

Mixing height                     : 500m

Stability Class                   : D (day time); F (night time)

Surface Roughness          : 100cm

Terrain                               : Rural

Wind Direction                  : Worst case wind angle (in 1° interval)

Wind Speed                             : 1m/s (10m height)

Background concentrations of TSP and RSP in Tai Po were taken to be 63 mg/m3 and 45 mg/m3 according to Air Quality in Hong Kong 2000.

4.5                    Emission Factors

During construction, major sources of dust on site are expected to be from excavation, materials handling and wind erosion. The dust emission during construction was modelled as heavy construction according to USEPA, AP42 S13.2.3.

The emission factors for the operation of existing cement depot, construction and operation of the planned silos are tabulated in Appendix 4a. The detailed calculations of the air emission factors are shown in Appendix 4b. In existing cement works operation, the cement depot is in compliance with the requirement listed in the Specific Process Licence (Licence No. L – 3-070(2)).

On gaining the additional silo capacity, all cement in each barge shipment can be transferred into the additional silos for storage within one batch. The corresponding number of vehicles and emission duration from the emission points are estimated and summarized in Table 4.4 below.

Table 4.4: Estimated vehicle number and emission duration of the planned process

Description

Quantity

No. of Cement Tanker Use

The planned normal worst unloading rate to cement tanker in daytime (DR1)

3300 MT

The planned normal worst unloading rate to cement tanker in evening time (DR2)

700 MT

The planned normal worst unloading rate to cement tanker per day (DR = DR1 + DR2)

4000 MT

The capacity of one cement tanker for offsite delivery (CT)

26 MT

Day operation hour (OT1)

12 hr (0700 –1900)

Evening operation hour (OT2)

4 hr (1900 – 2300)

The number of cement tanker per hour in daytime N1 = DR1 / CT /OT1

11 veh /hr[1]

The number of cement tanker per hour in evening time N2 = DR2 / CT /OT2

7 veh /hr[2]

Emission Duration

The unloading rate for each vehicle (ULR)

6 min / veh

No. of unloading points operating per time (S)

2

The cement unloading point emission duration per day

OD  =  (OT1 ´ N1+OT2 ´ N2) ´ ULR/ S /60]

8 hr

The planned uploading cement into silos per day (PR = DR)

4000 MT

The hourly uploading rate from Pumping Barge(UPR)

400 MT / hr

The uploading duration from Pumping Barge per day (LR = PR /UPR)

10 hr

Note [1]: In daytime, among the 11 vehicles, 4 vehicles will serve for West Wing and East Wing Concrete Batching Plants

               [2]: In evening time, among the 7 vehicles, 2 vehicles will serve for West Wing and East Wing Concrete Batching Plants

Apart from the dust sources from the cement depot, other dust sources from the east wing and west wing of the 2-leg concrete batching plants and stone plant (operated by other companies) also contribute to the cumulative impact. The emission factors of the adjacent concrete batching plant and stone plant were obtained from the Air Pollution Control Plan submitted for the specific process licence application. Appendix 4c and 4d summarize the details.

In determining the traffic emission, the vehicles were divided into different categories, namely Car/PV, LGV, HGV and Bus/Coach. Vehicle emission factors were taken from the Fleet Average Emission Factors – EURO3 Model provided by EPD. The fleet average emission factors of year 2011 (the last future year forecast) were adopted in this assessment as conservative estimates for the emissions 15 years after the operation estimated at year 2018. The highest emission factors among the vehicle types included in each vehicle category were taken for conservative assessment. In this study, the fleet average emission factors for RSP for different vehicle categories are summarized in Appendix 4e.

4.6                    Air Quality Impact

4.6.1               Construction Phase

The normal daily operation of the cement depot during construction phase is listed in Table 4.5. The operation of the cement depot is controlled by BPM 3/1. The specification of the dust collector is shown in Appendix 4n for reference. K. Wah Concrete Ltd. agreed that their West Wing Concrete Batching Plant will not be operated during the construction phase.

The present site is equipped with an automated water spraying system. Water will be sprayed to wet the ground in every 30 mins. Hence, the dust removal efficiency will exceed 85% (“Control Techniques for Particulate Emissions from Stationary Sources: Volume 1”, September, 1992, 450381005A, USEPA).

Table 4.5: Daily operation schedule of the cement plant during construction period

Activities

0700 – 1900

(Daytime, 12 hrs)

1900 – 2300

(Evening Time, 4 hrs)

2300 –0700

(Night Time, 8 hrs)

Emission Duration of Existing Cement Work (include on-site traffic)

Ö

Ö

 

Emission Duration of East Wing Concrete Batching Work (include on-site traffic)

Ö

Ö

 

Operation of West Wing Concrete Batching Plant

No operation during construction period

Construction work (Foundation)

Ö

 

 

Wind Erosion

Ö

Ö

Ö

As there is no construction in evening time, only the 1-hr TSP cumulative impact in daytime is present. The daytime meteorological data (i.e. 0700 – 1900) in Tai Mei Tuk in 2001 is extracted for the 1-hr TSP modelling. The predicted cumulative 1-hr TSP concentrations in daytime (0700-1900) due to construction at the ASRs are summarized in Appendix 4f. Maximum 1-hr TSP is predicted at 5m above ground at ASR8 and the pollution contour is shown in Fig. 4.3.

Based on the meteorological data in Tai Mei Tuk in 2001, the predicted cumulative 24-hr TSP concentrations due to construction at the ASRs are summarized in Appendix 4f. Maximum 24-hr TSP is predicted at 5m above the ground. Hence, the pollution contour of cumulative 24-hr TSP at 5m is plotted and shown in Fig.4.4. The FDM output files are listed in Appendix 4i.

As shown in Appendix 4f and the pollution contours, the predicted cumulative 1-hr and 24-hr TSP concentrations at all the air sensitive receivers will comply with the 1 hr and 24 hr TSP limits. No adverse air quality impact during construction phase is anticipated.

Apart from regular watering the site by an automated watering system at an interval of every 30 minutes, the contractor is still required to implement the mitigation measures stipulated in the Air Pollution Control Regulation (Construction Dust) as far as practical. The mitigation measures shall be incorporated in the Contract Specification in order to minimize any potential dust nuisance arising from the construction activities of the project that are in excess of the acceptable levels.

4.6.2               Operational Phase

On site operation

During the operational phase of the cement silos, additional dust emission sources are identified as follows:

·        Emissions from vents (EP8, EP9, EP10) of the proposed silos. The vents will be housed with dust collector to achieve the particulate emission limit of 50mg/m3 as specified in the BPM 3/1. The specification for these dust collectors are shown in Appendix 4n.

·        Off site road traffic emission at 2018

The normal daily operation of the cement depot during operational phase is listed in Table 4.6. The operation of the cement depot is controlled by BPM 3/1. The present site is equipped with an automated water spraying system. Water will be sprayed in every 30 mins. Hence, the dust removal efficient will exceed 85% (“Control Techniques for Particulate Emissions from Stationary Sources: Volume 1”, September, 1992, 450381005A, USEPA).

Table 4.6: Daily operation schedule of the cement plant during operational period

Activities

0700 – 1900

(Daytime, 12 hrs)

1900 – 2300

(Evening Time, 4 hrs)

Emission Duration of Proposed Cement Work (include on-site traffic)

Ö

Ö

Emission Duration of East Wing Concrete Batching Work (include on-site traffic)

Ö

Ö

Emission Duration of West Wing Concrete Batching Plant (include on-site traffic)

Ö

Ö

 

The 24-hour TSP due to the on-site activities is predicted based on meteorological data in Tai Mei Tuk in 2001 and shown in Appendix 4g.The FDM output file is listed in Appendix 4j.

Maximum 24-hr TSP is predicted at 1.5m above the ground and the pollution contour is shown in Fig 4.5. Results indicate that the predicted 24-hr TSP at all ASRs will comply with the 24-hr TSP limit of 260 mg/m3 as stipulated in AQO.

Procedures to prevent silo explosion accident

The cement uploading process will be operated by mechanically means, which is different from the pneumatic mode system used in the concrete batching plant explosion accident in Yuen Long area several years ago. Additional safety mechanisms and procedures have also been introduced to offer further protection as follows.

a.      Installation of a dual sensors alarm system: The dual sensors act as a back up for each other. They will be activated when the cement reaches the safety level during uploading and triggered the termination of screw conveyor pump operation immediately to prevent overflow. Should the two sensors be not functioning, the system will also stop when the cement are jammed inside the screw convey system due to blockage of the screw conveyor outlet by the cement.

b.      Audio alarm and automatic stop interlocking system: The audio alarm will be activated when the cement reaches the safety level and this will trigger the automatic stop interlocking system to stop the screw conveyor from further uploading of cement.

c.      Water pipe and water spraying system: The system will be operated manually when bursting of dust collectors occurs.

d.      Routine system checking, maintenance and drills: Routine check, maintenance and drills will be performed regularly to ensure the system function properly.

An event contingency plan for silo explosion accident has also been established for enhancing safety and it is given in Appendix 4m.

Off Site Traffic on Pubic Road

CALINE4 dispersion modelling was used to predict the air quality impact due to traffic emission in 2018. As the major impact in this study will be from the cumulative impact of RSP from the on-site activities and off-site traffic, only RSP concentration is modelled. The RSP output from the CALINE4 file is in 1-hr average. A multiple factor of 0.4 is used to convert to 24hr RSP.

The predicted 24-hr RSP due to traffic flow in 2018 and the cumulative impact with the on-site operation are shown in Appendix 4h.

The cumulative 24-hour RSP is calculated as follows:

RSP (24-hour) = [RSP (24-hour, on site activities)] +  RSP(24-hour, traffic) + Background RSP

The output file of the FDM and CALINE 4 are shown in Appendix 4k and 4l. Maximum RSP level is predicted at 1.5m above ground at ASR8 and the pollution contour is shown in Fig.4.6.

The predicted cumulative 24-hr RSP at ASR will comply with the AQO limits of 180mg/m3. Other than watering by an automated watering system at an interval of every 30 minutes, those measures specified under the Guidance Note on the Best Available Means for Cement Works (Cement Depot) BPM 3/1 have to be strictly followed.

However, the operator is required to apply for a revised licence for the Specified Process (cement works) operation. The licensing conditions should be strictly followed to ensure that there is no environmental impact on the nearby sensitive receivers.

4.7                    Conclusion

During the construction and operational phases, adverse air quality impact is not anticipated provided that the following mitigation measures are incorporated:

Construction Phase

·        No operation of the West Wing Concrete Batching Plant

·        Regular watering of the site by an automated watering system at an interval of every 30 minutes

 

Operational Phase

·        Regular watering of the site by an automated watering system at an interval of every 30 minutes

 

In addition, the requirements stipulated in the Best Practical Means Requirement for Cement Works (Cement Depot) BPM 3/1 and the Air Pollution Control (Construction Dust) Regulation for dust control should be strictly followed.


5                          Noise Assessment

5.1                    Introduction

This section presents an assessment for the noise impacts arising from construction and operation of the additional cement silos in Tai Po Cement Depot (Tai Po Town Lot No. 102). During the construction phase, noise is generated from the Powered Mechanical Equipment (PME), together with the operational noises from existing cement works and the adjacent concrete batching plants, owned by another company.

During the operational phase, both on-site and off-site operational noises are identified. On-site operational noises are generated from the operation of cement works and the adjacent concrete batching plants, running by another company. The off-site operational noise is originated from the unloading activities from the ocean going vessels and the vehicles travelling on the public road.

5.2                    Assessment Criteria

5.2.1               Construction Noise

Reference to Table 1B of the TM-EIA regarding noise standards for daytime construction activities, the noise limits are tabulated in Table 5.1.

Table 5.1: Construction noise guidelines (Leq(30min) dB(A)) within non-restricted hours


Land Uses

Noise Standards

Leq(30min)  dB(A)

Domestic premises

75

Educational institutions (normal period)

70

Educational institutions (during examination)

65

The control of construction noise during restricted periods is enforced under the Noise Control Ordinance (NCO) and three subsidiary Technical Memoranda (TMs) covering Noise from Percussive Piling (TM-PP), Noise from Construction Work Other Than Percussive Piling (TM-GW) and Noise from Construction Work in Designated Areas (TM-DA). The TMs establish the permissible noise levels for construction works in regard to working time period and the area sensitivity use.

 

5.2.2               Operational Noise

For fixed noise sources, the operational noise limit stipulated in TM-EIA is :

·        5 dB(A) below the appropriate Acceptable Noise Levels (ANL) shown in Table 3 of the Technical Memorandum for the Assessment of Noise from Places Other than Domestic Premises, Public Places or Construction Sites, (TM-IND). Table 5.2 shows the area sensitivity rating and the corresponding recommended noise standard


Table 5.2:  TM-EIA industrial noise guidelines for different Area Sensitivity Ratings (ASR)

Time Period

SPL dB(A)

ASR C

ASR B

 ASR A

Day and Evening (0700 – 2300)

65

60

55

Night (2300 - 0700)

55

50

45

or

·        the prevailing background noise level (for quiet area with level 5dB below ANL)

In any event, the Area Sensitivity Rating (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 Nose Control Authority in the context of law enforcement against all the fixed noise sources being assessed.

For the traffic noise, according to the TM-EIAO, the L10, 1 hr limits for road traffic noise at various NSRs are summarized in Table 5.3

Table 5.3     TM-EIA traffic noise guideline

Noise sensitive Use

Peak Hour Traffic L10 (1-hr) dB(A)

All domestic premises including temporary housing accommodation

70

Educational institutions including kindergartens, nurseries and all others where unaided voice communication is required

65

Hospitals, clinics, convalescences and homes for aged, diagnostic rooms, ward

55

The noise generated from ocean going vessel in public place is governed under Section 4 and 5 of the Noise Control Ordinance. There is no acceptable noise limit under NCO. However the operation of the ocean going vessel involves the pumping of cement into small barges. Due to the industrial nature of the operation, it is proposed to adopt the fixed noise limit as stipulated in TM-EIA.

5.3                    Noise Sensitive Receivers

The existing and planned noise sensitive receivers (NSRs) in the vicinity of the project site have been identified and are tabulated in Table 5.4. The locations of the NSRs are shown in Fig 5.1.

Table 5.4:  Noise sensitive receivers in the vicinity of the project site

NSR

Noise Sensitive Receivers

Description

Distance[1]  (m)

ASR

Prevailing Noise Level[3] Leq(30min)

1

Fortune Garden

Residential

274

A

60 – 68

2

Tycoon Place

Residential

372

A

61 – 69

3

Village House

Residential

184

A

58 – 67

4

Sha Lan Villa

Residential

184

A

55 – 59

5

Wu York Yu Care and Attention Home

Home for the aged

504

A

55 – 60

6

TWGHs Pao Siu Loong Care & Attention Home

Home for the aged

592

A

55 – 60

7

Casa Marina III[2]

Residential

50

B

65 – 73

7a

Casa Marina III[2]

Residential

44

B

60 – 70

Note [1]: Distance is measured from the sensitive receivers to the site boundary of the depot

[2]: Planned Receivers. Due to the contribution of the traffic noise in Ting Kok Road and Sam Mun Tsai Road, the existing cement depot and concrete batching plant (IF) are not the dominant feature of the noise climate of the NSR. According to TM-IND, Casa Marina III will be “indirectly affected” by the IF and hence, ASR “B” is adopted.

[3]: Measurement details of Prevailing Level is shown in Appendix 5i

The potential NSRs along the coastal area of Ma On Shan, planned Whitehead development and planned Pak Shek Kok Development which are likely affected by the operation of the ocean going vessel are tabulated in Table 5.5 and shown in Fig.5.2.

Table 5.5: Off-site noise sensitive receivers

NSR

Noise Sensitive Receivers

Description

Distance[1]  (m)

ASR

Prevailing Noise Level[3]  Leq(30min)  dB(A)

13

Villa Oceania

Residential

1500

B

59 – 65

14

Bayshore Tower

Residential

1500

B

59 – 66

15

Fok On Garden

Residential

1500

B

58 – 65

16

Chung On Estate

Residential

1500

B

60 – 66

17

Planned whitehead development

Residential

1340

A

59 – 67

18

Planned Pak Shek Kok development

Residential

2100

B[2]

59 – 67

Note [1]:   Distance is measured from the sensitive receivers to the anchorage of the vessel. The anchorage of the vessel was assigned by Marine Department.

[2]:  The planned Pak Shek Kok Reclamation will be affected by Tolo Highway, which is an influence Factor as considered in the TM

[3]:  Measurement detail of the prevailing noise level is shown in Appendix 5j.

 

5.4                    Methodology

The noise prediction methodology was undertaken according to the TM-GW and TM-IND. Additional information was obtained from “A Practical Guide to Reduction of Noise from Construction Work” and BS5228 Part I: 1997 “Noise and Vibration Control on Construction and Open Sites”

5.5                    Construction Noise Impact

5.5.1               Unmitigated Case

In order to minimize the construction noise impact, the additional cement silos will be fabricated off-site and transported to the depot by barge for installation. Therefore, major on-site noisy construction activities will be from the ground excavation, setting of foundation and silos erection. The construction time will be from 0700 – 1900. No evening and night time work are expected. Table 5.6 summarizes the powered mechanical equipment to be used for each stage of work. The location of the construction site is shown in Fig.5.3a and Fig5.3b.

 

 

Table 5.6:  Sound power level of the powered mechanical equipment in construction phase

Equipment

CNP Code

Number

Sound Power Level dB(A)

Total Sound Power Level dB(A)

Ground Excavation

Excavator (Breaker mounted)

CNP 028

1

122

122

Dumper

CNP 066

1

106

106

Drilling Rig

CNP 167

1

114

114

Total

122.7

Setting of Foundation

Concrete Lorry Mixer

CNP 044

2

109

112

Concrete Pump

CNP 047

1

109

109

Electric Vibratory Poker

CNP 173

3

102

107

Total

115

Silos Erection

Sky Crane

CNP 048

1

112

112

Electric Saw

CNP 205

1

101

101

Arc Welders

----

1

---

---

Total

112

 

The predicted maximum façade noise levels at the sensitive receivers without mitigation are shown in Table 5.7.

Table 5.7:  Predicted façade noise levels without mitigation measures at NSRs

NSR

Noise Sensitive Receiver

Construction Noise

Leq (30min)

dB(A)

1

Fortune Garden

68.1

2

Tycoon Place

65.5

3

Village House

61.4

4

Sha Lan Villa

58.7

5

Wu York Yu Care and Attention Home

51.9

6

TWGHs Pao Siu Loong Care & Attention Home

50.5

7

Casa Marina III

75.6

7a

Casa Marina III

74.1

Note :  Detail calculation of the construction  noise are shown in Appendix 5f

Bold values indicate the exceedance in noise criterion

 

Almost all NSRs, except NSR7, will comply with the construction noise limit. In case that there is no resident in Casa Marina III during construction period, no mitigation measures are required. Should there be residents in Casa Marina III during the construction period, construction noise impact shall be alleviated by the use of quieter construction Power Mechanical Equipment and the use of portable barrier.

 

5.5.2               Mitigation Measures

Table 5.8 summarizes the proposed mitigation measures and the sound power level of the PME after attenuation.


Table 5.8:  Proposed mitigation measures for construction phase

Equipment

CNP Code

Number

Barrier

Total Sound Power Level dB(A)

Ground Excavation

Excavator (Breaker mounted)

BS 5228: C8.13

1

---

110

Dumper

CNP066

1

---

106

Drilling Rig

CNP 167

1

5

109

Total

 

113

Setting of Foundation

Concrete Lorry Mixer

CNP 044

2

---

112

Concrete Pump

CNP 047

1

---

109

Electric Vibratory Poker

CNP 173

3

---

107

Total

 

115

Silos Erection

Sky Crane

CNP 048

1

---

112

Electric Saw

CNP 205

1

---

101

Arc Welders

----

1

---

---

Total

 

112

With the use of quieter excavator and the use of portable barrier for Drilling Rig, the maximum sound power level will drop to 115 dB(A). The predicted maximum façade noise levels at the sensitive receivers are shown in Table 5.9.

Table 5.9:  Predicted façade noise levels at NSRs with quieter powered mechanical equipment and other mitigation measures

NSR

Noise Sensitive Receiver

Construction Noise

Leq (30min)

dB(A)

1

Fortune Garden

59.9

2

Tycoon Place

57.4

3

Village House

53.2

4

Sha Lan Villa

50.5

5

Wu York Yu Care and Attention Home

43.7

6

TWGHs Pao Siu Loong Care & Attention Home

42.3

7

Casa Marina III

67.4

7a

Casa Marina III

65.9

Note: Detail calculation of the construction  noise are shown in Appendix 5f

        Bold values indicate the exceedance in noise criterion

Predicted results indicate that the façade noise levels at NSR7 will comply with the day-time construction noise limit.

Apart from the above proposed mitigation measures, the contractors shall adopt good site practices and noise management to reduce the impact of the construction site activities on nearby NSRs.  The following measures are recommended to incorporate into the contract specifications.

·        Only well maintained plants shall be operated on-site and plant should be serviced regularly during the construction period.

·        Machines and plants used intermittently shall be shut down between work periods or should be throttled down to a minimum.

·        Silencers or mufflers on construction equipment shall be utilized and should be properly maintained during the construction period.

·        Existing structures shall be effectively utilized to screen the noise.

·        Portable noise barriers shall be positioned within a few metres of noisy plant items.

5.6                    Operational Noise Impacts

5.6.1               Ocean Going Vessel

An ocean going vessel (not owned by the project proponent) will be used by the cement supplier in Japan / Philippines to deliver cement to the project proponent once or twice a week. As the vessel movement is transient, it will not have significant impact on the nearby NSRs.

Due to the limited capacity of the existing jetty, the ocean going vessel cannot be berthed to the existing cement depot to upload the cement into the silos. The ocean going vessel is thus anchored at a location inside Tolo Harbour assigned by Marine Department. Small barge (owned by project proponent) is then used to deliver the cement from the ocean going vessel to the depot. The operation time of the cement depot is from 0700 to 2300. There is no nighttime work (2300 to 0700) for the cement depot. It is proposed that all barges will be berthed on shore at 2300hr and the barge operator will report to the plant manager afterwards. This can ensure that the ocean going vessel will not be operated during nighttime.

The most significant noise source identified will be from the unloading of cement from the vessel to the barge. On board measurement (Appendix 5e) on the ocean-going vessel during its unloading to the barge indicated that the dominant noise source is from the pumping facilities and engine room of cement unloading side (measurement position G in Appendix 5e) with maximum sound pressure level of 97.6 dB (A) at the most outer edge of the ocean going vessel. On the other hand, the maximum sound pressure level of the opposite side (measurement position C in Appendix 5e) of the ocean going vessel is 91 dB(A). As there is no NSR along the shore of Ma Shi Chau facing the Tolo Harbour (Fig.5.2b), in order to minimize the noise nuisance towards the existing and planned noise sensitive receivers, it is proposed that the cement unloading side of the cement vessel (measurement position G) should be faced away from the sensitive receivers in Ma On Shan and the planned Whitehead development such that the unloading part of the ocean vessel do not have a direct line of sight from the sensitive receivers.

The predicted minimum distances required by the vessel to comply with the noise limits at the nearby noise sensitive receivers are shown in Table 5.10.

Table 5.10:         Predicted façade noise levels at NSRs due to the operation of the ocean going vessel

NSR

Noise Sensitive Receiver

Noise Limit

Leq (30min)  dB(A)

Air Absorption[3]

dB(A)

Façade Correction

dB(A)

Predicted distance required

m

13

Villa Oceania[1]

59

-2.8

3

> 920 m

14

Bayshore Tower[1]

59

-2.8

3

> 920 m

15

Fok On Garden[1]

58

-3

3

> 1000 m

16

Chung On Estate[1]

60

-2.5

3

> 845 m

17

Planned Whitehead development[2]

55

-2.1

3

> 710 m

18

Planned Pak Shek Kok Reclamation[1]

59

-2.8

3

> 920 m

Note [1]: As these locations are not directly facing away from the unloading side of the vessel, the maximum SPL of 97.6 dB(A) is adopted for calculation.

         [2]: As this location is directly facing away from the unloading side of the vessel, the maximum SPL of 91dB(A) is adopted for calculation.

         [3]: The dominant frequency during operation is at 500Hz. Assuming typical Relative humidity is at 70% and Temperature is at 25°C, based on ANSI S1.26 –1995 “Method for calculation of the Absorption of Sound By the Atmosphere”, the air absorption is ~3dB / km

Figure 5.6 shows the proposed anchorage region for the ocean going vessel. With the maximum sound pressure level at the outermost boundary of the vessel facing towards the Planned Whitehead Development less than 91 dB(A), the proposed anchorage region will fulfill the distance requirement as listed in Table 5.10. Double anchoring will be applied on the vessel in order to prevent its swing.

Alternative anchorage positions were also explored. However, different constraints were identified and those positions are not suitable for ocean vessel anchorage (Fig.5.7). To the west of the proposed anchorage position (Region 1 in Fig.5.7), according to the BA chart 1915 published by Marine Department, the water depth (7 – 9m) is not deep enough for the anchorage of ocean vessel (which will require water depth of 9 – 10m). To the north of the proposed anchorage position (Region 2 in Fig.5.7), an oil pipeline was identified under the seabed. Anchorage near the oil pipeline may have potential to cause damage on the pipeline and increase the risk of oil spill. To the east of the proposed anchorage position (Region 3 in Fig.5.7), coral were identified on the seabed (Fig.6.1b and reported by “Apple Daily” on 4, Nov, 2002). Vessel anchorage may, thus, cause damage to the coral. In addition, due to the 500m near-shore constraints, Regions 4 and 5 (Fig.5.7) are also not suitable for anchorage. Therefore, the present proposed anchorage region is the most suitable position in term of environmental and operational constraints.

Noise from a trade/activities in public places, e.g. cement loading in Tolo Harbour, causing annoyance to any person is an offence under Section 4 and 5 of NCO which is enforced by HK Police Force and Marine Department despite the assessment in this EIA.

5.6.2               On site Activities

During normal operation, the major on-site noise sources in the vicinity of the proposed project site will be from the operation of the proposed cement works, the traffic noise due to the on-site cement tankers movement, the adjacent concrete batching plants (run by another company) and the adjacent shipyards.

The noise sources generated from the operation of the planned cement works and the concrete batching plant (as advised by project proponent) are summarized in Table 5.11. The locations of the noise sources are shown in Fig.5.3a and Fig.5.3b.

Table 5.11 Noise inventory for the concrete batching plant activities and the proposed cement works

Equipment

CNP Code

Number

Source Height [2] (m)

Sound Power Level dB(A)

Total Sound Power Level dB(A)

Adjacent Concrete Batching Plant Activities (operated by another company)

Concrete Batching Plant

CNP022

2

0.5

108

111

Concrete Lorry Mixing Bay

CNP044

1 Lorry each time

0.5

109

109

Derrick Barge

CNP061

1

3

104

104

Concrete Lorry Mixer Travelling

On-site Measurement[1]

31 vehicles / hour

0.5

101.5

----

Concrete Lorry Washing Bay

CNP044

2

0.5

109

112

Proposed Cement Works

Pumping Barge

On-site Measurement[1]

1

0[3]

116.0

116

Cement Unloading Facilities

(Blowers)

On-site Measurement[1]

2

8

108.0

111

Cement Tanker Travelling

On-site Measurement[1]

11 [4] vehicles / hour

0.5

98.5

----

Note: 1. The measurement details are shown in Appendix 5a –5d

          2. The source height is relative to the local ground level

          3. The engine room in the barge is at the similar level of the ground

 4. Please refer to Table 4.4 for detailed calculation

For the adjacent shipyards, the measured noise levels were 57 – 65 dB(A) at a distance of ~10m from the site boundary. The predicted noise level at Casa Marina III from the shipyards is 51 – 59 dB(A), which were far below the prevailing noise level (65 – 73 dB(A)) at Casa Marina III, which is 40m from the site boundary of shipyards. Therefore, the cumulative effect of the shipyards is considered as insignificant.

The predicted sound pressure levels at the NSRs are summarized in Table 5.12. Detailed calculations for the un-mitigated case and the location of the noise sources are shown in Appendix 5h and Fig. 5.3 respectively.

 Table 5.12:  Predicted façade noise levels without mitigation measures at NSRs

NSR

Noise Sensitive Receivers

Operational Noise Leq(30min)

dB(A)

 

 

Proposed Cement Work

Concrete Batching Plants

Cumulative

Criterion

1

Fortune Garden

60.5

60.0

63.2

55

2

Tycoon Place

58.4

58.2

61.3

55

3

Village House

55.0

54.3

57.7

55

4

Sha Lan Villa

53.9

54.6

57.3

55

5

Wu York Yu Care and Attention Home

46.5

47.4

50.0

55

6

TWGHs Pao Siu Loong Care & Attention Home

45.4

46.3

48.9

55

7

Casa Marina III

71.7

73.6

75.8

60

7a

Casa Marina III

69.9

74.1

75.5

60

Note: Detail calculation are shown in Appendix 5g

 Bold values indicate the exceedance of noise criterion

From Table 5.12, only the predicted cumulative noise levels at NSR5 & NSR6 will comply with the operational noise limit. However, the predicted cumulative noise levels at other NSRs are ~2 - 16 dB(A) higher than the operational noise criterion.

As shown in Table 5.12, the contribution due to the operation of the adjacent concrete batching plants (owned by another company) is quite significant. At some NSRs, the predicted noise levels due to the concrete batching plants will exceed the operational noise limit. As the concrete batching plants belong to another company, several negotiations on imposing noise mitigation measure on their site were unsuccessful. The target is to reduce the noise level of the proposed work to an acceptable level, i.e,

·         The operation noise level due to the proposed activities is below the noise limit listed in TM-EIAO, and

·         The contribution due to the operation of the proposed activities on the cumulative noise level is limited to within 1dB.

Table 5.13 summarizes the proposed noise mitigation measures and their predicted noise reduction.

Table 5.13 Characteristics of the Proposed Noise Mitigation Measures

Noise Source

Mitigation Measures

Attenuation Level dB(A)

Dimension

Remark

Proposed Cement Depot

Pumping Barge

Replaced by electric driven Screw conveyor Barge,

14[1]

 

---

Please refer to Appendix 5c for the measurement data

Unloading Facilities

Vertical Barrier below the silos

10

16m high

Please refer to Fig.5.4 - 5.5 for the design

Note [1]: Onsite measurement. For a typical pumping barge, the SWL is 116 dB (Appendix 5b). However for the proposed Screw Conveyor Barge, in which the screw conveyor will be operated by electricity from the shore, the measured noise level is 102 dB(A) (Appendix 5c). Hence, the attenuation is 14 dB(A).

With the incorporation of the noise mitigation measures, the predicted façade noise levels at all NSRs are shown in Table 5.14. Appendix 5i shows the detailed calculations.

Table 5.14:  Predicted Façade Noise Levels with Mitigation Measure at NSRs

NSR

Noise Sensitive Receiver

Operational Noise Leq(30min)

dB(A)

 

 

Proposed Cement Work (P)

Concrete Batching Plants

(E)

Cumulative

(C)

Criterion

(C) – (E)

1

Fortune Garden

50.2

60.2

60.6

55

0.4

2

Tycoon Place

48.5

58.4

58.8

55

0.4

3

Village House

43.8

54.6

54.9

55

---

4

Sha Lan Villa

42.6

55.0

55.2

55

0.2

5

Wu York Yu Care and Attention Home

36.7

47.6

48.0

55

---

6

TWGHs Pao Siu Loong Care & Attention Home

35.9

46.5

46.9

55

---

7

Casa Marina III

59.6

74.2

74.3

60

0.1

7a

Casa Marina III

57.8

74.5

74.5

60

~ 0

Note: Please refer to Appendix 5h for detailed calculation

        Bold values indicate the exceedance of noise criterion

With the proposed mitigation measure incorporated, the predicted noise levels due to the proposed cement works are within an acceptable noise limit. In addition, its contribution on predictive cumulative noise impact due to the proposed cement work is within 1 dB(A).

The project proponent has committed that the operational hour of the cement depot is restricted from 7am to 11pm. EPD and HK Police are able to check the status of the cement silo site easily by visiting the site outside the restricted hour. Should the project proponent violates the condition of NCO, EPD or HK Police could take necessary action against the project proponent according to the ordinance after investigation.

5.6.3               Off-site Activities

The off-site activity will consist of the noise generated by the on road traffic vehicles. The traffic flow in 2018 is shown in Fig.4.1. The number of cement tankers for off-site delivery will be 7 veh /hour. Table 5.15 shows the traffic noise due to the cement tankers from the cement depot and the road traffic noise (excluding those from cement tankers) from existing road. Only the NSRs that are likely affected are considered. The roadplot and output file are shown in Appendix 5j.

Table 5.15 Predicted Traffic Noise due to off-site transportation

NSR

Noise Sensitive Receiver

Operational Noise L10 (1-hr)

dB(A)

 

 

Traffic from cement tankers

(A)

Road traffic noise (exclude tankers) from existing roads

(B)

Cumulative

 

 

(C=A+B)

Difference

For C > 70

 

(D=C-B)

1

Fortune Garden

 

1/F

34.3

41.7

42.4

---

 

2/F

34.3

41.7

42.4

---

 

3/F

34.3

41.7

42.4

---

2

Tycoon Place

 

1/F

49.6

62.9

63.1

---

 

2/F

50.6

63.9

64.1

---

 

3/F

50.6

63.9

64.1

---

7

Casa Marina III

 

1/F

60.5

70.2

70.6

0.4

 

2/F

61.3

70.7

71.2

0.5

 

3/F

61.2

70.2

70.7

0.5

7a

Casa Marina III

 

1/F

60.5

68.9

69.5

---

 

2/F

61.6

70

70.6

0.6

 

3/F

61.5

69.6

70.2

---

As shown in Table 5.15, the predicted cumulative traffic noise at Fortune Garden and Tycoon Place are within the traffic noise criteria of 70 dB(A). The predicted cumulative noise levels at the Casa Marina III will exceed the operational traffic noise limit. However, the breakdown analysis indicates that the cumulative noise level is dominated by the traffic from existing roads. The noise due to the cement tankers is well below the noise limit. It only contributes less than 1 dB(A) on the overall noise level, which is considered as insignificant to the overall noise level. Any mitigation measures on the vehicles will not be effective on the cumulative road noise level. Therefore, no mitigation measures on the cement tankers are recommended.

5.7                    Conclusion

During the construction phase, assessment results indicate that the un-mitigated noise level at Casa Marina III due to the construction activity will exceed the noise limit. In case that there is resident in the Casa Marina III, mitigation measures inside the cement depot such as the use of quieter equipment in ground excavation and portable barriers for Drilling Rig will be adopted.

For the operational phase, assessment results indicate that the predicted noise levels without mitigation measures at Casa Marina III due to the on-site activity will exceed the noise limit. Different noise mitigation measures inside the cement depot are proposed, which include:

·        Adoption of quieter electric- driven screw conveyor barge for the cement depot

·        Barriers for the cement unloading bay

With the recommended mitigation measures implemented, the predicted construction and operational noise impacts on all the neighbouring NSRs will comply with the relevant  standards and requirements.

In order to reduce the noise impact from the ocean going vessel, the anchorage position of the ocean vessel shall refer to Fig.5.6. In addition, the unloading part of the ocean vessel shall be positioned to face away from the existing and planned noise sensitive receivers in Ma On Shan and the planned Whitehead development.


6                          WATER QUALITY ASSESsMENT

6.1                    Introduction

The potential water quality impact associated with the construction and operation of the proposed cement works are investigated in this section. If necessary, mitigation measures are proposed to ensure that all residual impacts are in compliance with the relevant environmental legislation, standard and guideline.

6.2                    Assessment Criteria

The Water Control Zone (WCZ) relevant to this study is the Tolo Harbour and Channel Water Control Zone. All Water Quality Objectives parameters, unless specified, refer to subzones including Harbour, Buffer and Channel subzones. The corresponding Water Quality Objectives are shown in Table 6.1.

Table 6.1:   Water Quality Objectives – Tolo Harbour and Channel Water Control Zone

Parameters

Criterion

Aesthetic Appearance

a.       Odours, taints and colors

Waste discharges shall cause no noxious or offensive odour or offensive taint or colour in either waters or edible aquatic organisms in the subzone to be present in concentrations detectable by bioassay or organoleptic tests

b.       Visible matter

Waste discharges shall cause no visible foam, oil, grease, scum, litter or other objectable matter in waters of the subzone.

Bacteria

Secondary contact recreation sub zone and Fish culture subzone

The level of E coli shall not exceed 610 / ml, calculated as the geometric mean of all samples collected in one calendar year

Chlorophyll – a

Harbour Subzone

Waste discharges shall not cause the level of Chlorophyll-a in waters of the subzone to exceed 20mg/m3, calculated as a running arithmetic mean of 5 daily measurements for any single location and depth

Buffer Subzone

Waste discharges shall not cause the level of Chlorophyll-a in waters of the subzone to exceed 10mg/m3, calculated as a running arithmetic mean of 5 daily measurements for any single location and depth

Channel Subzone

Waste discharges shall not cause the level of Chlorophyll-a in waters of the subzone to exceed 6mg/m3, calculated as a running arithmetic mean of 5 daily measurements for any single location and depth

Dissolved Oxygen

Harbour Subzone

Waste discharges shall not cause the level of dissolved oxygen in waters of the subzone to be less than 2 mg/L within 2m of the bottom, or to be less than 4mg/L in the reminder of the water column

Buffer Subzone

Waste discharges shall not cause the level of dissolved oxygen in waters of the subzone to be less than 3 mg/L within 2m of the bottom, or to be less than 4mg/L in the reminder of the water column

Channel Subzone

Waste discharges shall not cause the level of dissolved oxygen in waters of the subzone to be less than 4 mg/L at any point in the water column

Light Penetration

Harbour Subzone

No changes in turbidity, suspended material, colour or other parameters arising from waste discharges shall reduce light transmission by more than 20% of the normal level in the subzone at any location or any time

 

Buffer Subzone

No changes in turbidity, suspended material, colour or other parameters arising from waste discharges shall reduce light transmission by more than 15% of the normal level in the subzone at any location or any time

Channel Subzone

No changes in turbidity, suspended material, colour or other parameters arising from waste discharges shall reduce light transmission by more than 10% of the normal level in the subzone at any location or any time

pH

Harbour Subzone

Waste discharges shall not cause the normal pH range of any waters of the subzone to be extended by greater than ± 0.5 pH units at any time

Buffer Subzone

Waste discharges shall not cause the normal pH range of any waters of the subzone to be extended by greater than ± 0.3 pH units at any time

Channel Subzone

Waste discharges shall not cause the normal pH range of any waters of the subzone to be extended by greater than ± 0.1 pH units at any time

 

Salinity

Waste discharges shall not cause the normal salinity range of any waters of the subzone to be extended by greater than ± 3 parts per thousand at any time

Settleable material

Waste discharges shall give rise to no bottom deposits or submerged objects which adversely influence bottom-living communities, alter the basic Harbour geometry or shipping channels, prevent any harzard to shipping or diving activities, or affect any other beneficial use of the waters of the subzone

Temperature

Waste discharges shall not cause the natural daily temperature change shall not exceed 0.5° per hour at any location, unless due to natural phenomena.

Toxicants

Waste discharges shall not cause the toxicants in waters of the subzone to attain such a level as to produce significant toxic effects in humans, fish or any aquatic organism, which due regard to biologically cumulative effects in food chains and to toxicant inter-actions with each other.

 

6.3                    Water  Sensitive Receivers

Fig. 6.1a and 6.1b show the locations of the water and ecological sensitive receivers. The potential water and ecological sensitive receivers in the vicinity of the project site include:

·        Fish Culture Zone in Sam Mun Tsai (including those in Yim Tin Tsai & Yim Tin Tsai (East))

·        Sea water abstraction point for flushing in Tai Po Industrial Estate and other uses

·        Secondary contact recreation zone

·        Typhoon shelter in Shuen Wan

·        Non Gazetted Beaches along Plover Cove (near Sha Lan and Lung Mei)

6.4                    Description of Environmental Baseline Conditions

The existing ambient marine water quality in the area was established based on the EPD routine monitoring data for year 1999 at marine water quality monitoring stations TM2-TM8 and Typhoon shelter water sampling station. Table 6.2 summarizes the key monitoring data in different sub-zones within Tolo Harbour. Locations of the monitoring locations are shown in Fig. 6.1. The marine water quality data in 1998, which can be found in ‘Marine Water Quality in Hong Kong in 98’, is not present here.

Table 6.2 Summary statistics of 1999 water quality of Tolo Harbour and Channel WCZ

 

Harbour Subzone

Buffer Subzone

Channel Subzone

Typhoon Shelter

TM2

TM3

TM4

TM5

TM6

TM7

TM8

PT3

DO (mg/L)

5.8

(2.7 – 7.7)

6.5

(3.4 –8.3)

6.0

(2.4 –9.0)

6.1

(3.6 – 9.7)

5.8

(2.6 – 7.8)

5.8

(3.0-7.2)

5.7

(3.0 – 7.8)

6.7

(5.8 – 8.3)

DO (mg/L)

Bottom

5.6

(1.9 – 7.7)

5.9

(2.2 – 8.3)

5.2

(1.0- 7.8)

5.9

(2.9-8.5)

4.9

(1.1 – 6.9)

5.1

(1.2-7.2)

5.0

(1.5 – 7.2)

6.8

(6.3 – 7.3)

SS (mg/L)

7.5

(2.7 – 24.0)

3.6

(2.1 – 8.0)

3.1

(1.7 – 5.8)

16.9

(1.6 – 120)

2.7

(1.0 – 5.6)

2.9

(1.1 – 6.1)

3.4

(0.7 – 11.1)

4.2

(0.5 – 9.7)

BOD (mg/L)

2.1

(1.5 – 2.9)

2.0

(1.2 – 3.3)

1.7

(1.1 – 2.5)

1.9

(0.7 – 3.2)

1.5

(0.9 –2.2)

1.0

(0.7 –1.4)

1.1

(0.3 – 5.4)

0.7

(0.1 – 1.4)

TIN (mg/L)

0.21

(0.08 – 0.55)

0.13

(0.06–0.34)

0.11

(0.04-0.30)

0.07

(0.03-0.15)

0.09

(0.03-0.18)

0.08

(0.03-0.15)

0.07

(0.02-0.11)

0.03

(0.01 –0.09)

Unionized Ammonia

(mg/L)

4

(1-10)

5

(2-12)

3

(1-6)

3

(1-10)

30

(1-80)

2

(<1 – 7)

2

(<1 – 5)

2

(< 1 – 6)

E. Coli (cfu/100mL)

220

(27-2200)

17

(3-140)

6

(1-80)

4

(1-740)

3

(1-20)

1

(1-3)

1

(1-1)

1

(1-1)

Note: All water Quality Objectives parameters, unless specified, refer to subzones including Harbour, Buffer and Channel subzones.

It is observed that:

·        Full compliance with E. coli WQO was achieved at all sampling stations. The E Coli concentrations at all stations in 1999 are found lower than those in 1998.

·        The compliance with the DO WQO ranged from 83% - 95%. There is a slightly lower DO at all stations in 1999 as compared with 1998.

·        The annual mean ammonia nitrogen in the Harbour showed a decrease of 34 – 59% and total nitrogen a decrease of 59 – 66% as compared with 1998

·        However, the annual mean SS showed a significant increase in stations TM3

·        The Yim Tin Tsai Typhoon Shelter was characterized by high DO and low faecal bacteria and nutrients.

6.5                    Water Quality Impact

Although the existing cement depot is located adjacent to Tolo Harbour, no wastewater will be generated from normal plant operation. Water collected from surface drainage in the works site will be re-used onsite after sedimentation.

During the excavation works, soil surfaces would be exposed. Suspended particles will be present in the surface runoff. As the construction site is located near Tolo Harbour, the coastal waters could be potentially be 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, wash water from dust suppression sprays. No fuel, oil and other lubricants from maintenance of construction vehicles and mechanical equipment will be allowed. In addition, uncontrolled discharge of debris and rubbish, such as packaging and used construction materials, could result in floating refuse with associated impacts on the aesthetic quality of the coastal waters.

Domestic sewage would be generated from the site workforce during the construction phase. It is unlikely that sewage generated from the site would have a significant water quality impact, provided that sewage is not discharged directly into storm water drains adjacent to the site.

During operational phase, there is no effluent discharge to the adjacent water body. Adverse water quality impact is not anticipated.

6.6                    Mitigation Measures

Since only land based construction activities will be undertaken, minimal water quality impact arising from the project is anticipated.  However, in order to ensure that no adverse environmental impacts will arise during construction, good practices outlined in ProPECC PN 1/94 “Construction Site Drainage” shall be followed:

Effluent generated from construction activities and surface runoff will be recirculated or recycle as far as practical. 

Surface run-off will be collected by the site drainage (Figure 6.2). The collected water shall be re-used on site via adequately designed sand/silt removal facilities and pH adjustment such as sand traps, silt traps and sediment basins. Channel or earth bunds or sand bag barriers shall be provided on site to properly direct stormwater to such silt removal facilities.

The excavated materials and open stockpile of construction material shall be covered by tarpaulin to prevent storm runoff from washing across exposed soil surface.

Earthworks final surfaces shall be well compacted and the subsequent permanent work or surface protection should be carried out as soon as practical after the final surfaces are formed to prevent erosion caused by rainstorms.

Water used in ground boring and drilling shall be recirculated as far as practicable after sedimentation. When there is need for final disposal, the wastewater shall be discharged into storm drains via silt removal facilities.

All vehicles shall be kept clean before they leave a construction site to ensure no earth, mud, debris is deposited on roads. A wheel washing facilities shall be provided at the site exit, if practicable, and wash water shall have sand and silt settled out or removed before being discharged into the storm drains.

Debris and rubbish generated on-site shall be collected, handled and disposed of properly to avoid entering the nearby coastal waters. All fuel tanks and storage area should be provided with locks and be sited on sealed areas, within bunds of a capacity equal to 110% of the storage capacity of the largest tank.

The site workforce shall use the properly maintained portable chemical toilets is on-site.

During operation, 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 illegally.

6.7                    Conclusion

The potential water quality impact arising from the construction and operation of the proposed cement silos addition works have been assessed. No wastewater will be discharged from the plant during operation. Therefore, there will have no operation phase water quality impact. It is considered that construction run-off and drainage generated during the construction works for the project will have minimal impacts on the receiving waters provided that mitigation measures are implemented. With the adoption and incorporation of the recommended mitigation measures for the construction phase, adverse residual impacts on water quality are not anticipated.


7                          Visual impact Assessment

7.1                    Introduction

This section assesses the likely visual impact of the new cement silos and proposes mitigation measures to alleviate the impact caused.

 

The existing cement depot is located at the junction of Ting Kok Road and Yu On Street, Tai Po.  It is located at the edge of a rocky shore, facing Tolo Harbour to the south and surrounded by hills and residential developments on the other sides.  The Shuen Wan Golf Driving Range is located to the west of the shore.  Several workplaces, e.g. a wholesale fish market, a shipyard and a government Marine Department office, are located adjacent to the cement depot.

 

7.2                    Assessment Criteria

The visual impact evaluation and assessment have been carried out in accordance with the project study brief, criteria and guidelines stated in Annexes 10 and 18 of the TM-EIA.

 

7.3                    Assessment Methodology

The assessment of the potential visual impact of the proposed works has two distinct stages:

l        Baseline survey and,

l        Visual impact assessment.

 

7.3.1               Baseline Survey

The baseline survey of views towards the proposed development is carried out by identifying:

l        The visual envelope within which the proposed development maybe contained either wholly or partially within views.  This also includes indirect effects such as temporary construction activities.

l        The visually sensitive receivers (VSRs) within the visual envelope whose views will be affected by the scheme.  The sensitivity of each VSR group is also influenced by the distance and direction of view to the proposed development.  The potential receivers include the following three groups:

(a)           Views from residences – the most sensitive receivers due to the potential of intrusion on the visual amenity and quality of life;

(b)           View from workplaces – less sensitive than above due to visual amenity being less important within the work environment, and;

(c)           View from public areas – including all areas apart from the above, e.g. public parks, recreation grounds, footpaths, roads etc.  Sensitivity of this group is relatively low and will depend on the transitory nature of the receiver with views being typically glimpsed rather than sustained for long periods.

 

The baseline survey described and recorded by photograph typical views from within each of the visual envelope form the basis of the visual character and quality of the sites. The sensitivity of each receiver group and quality of views are classed in accordance to the following criteria:

l        High – for example, residential properties;

l        Medium – for example, recreational facilities or partially screened views; and,

l        Low – for example, workplaces, school etc.

 

7.3.2               Visual Impact Assessment

The assessment of potential visual impact was based on:

l        Identification of the sources of visual impact and their magnitude that would be generated during construction and operation.

l        Identification of the principal visual impact with particular consideration given to the degree of change to the baseline conditions.

 

The impact assessment comprises the comparison of the typical existing views identified in the baseline survey of the key receiver groups and the potential views after construction works are completed. Both present and future VSRs are considered. The visual impact results from the consideration of the following factors:

l        character of existing view;

l        quality of existing view;

l        context, location and distance of the VSR;

l        duration of the potential impacts;

l        visual receiver group sensitivity;

l        number of viewers at VSR group;

l        degree of change to existing views; and

l        other views available to visual receiver group and cumulative effects on views of this and other neighboring developments.

 

The magnitude of change to the views is classified as follows:

l        High – for example, the majority of viewers affected / major changes in view;

l        Medium – for example, many viewers affected / moderate change in view; and,

l        Low – for example, few viewers affected / minor change in view.

 

The degree of impact is considered as follows:

l        Significant – adverse/ beneficial impact where the proposal would cause significant deterioration or improvement in existing landscape quality;

l        Moderate – adverse / beneficial impact where the proposal would cause a noticeable deterioration or improvement in existing landscape quality;

l        Slight – adverse / beneficial impact where the proposal would cause a barely perceptible deterioration or improvement in the existing landscape quality; and

l        Negligible – no discernible change in the existing landscape quality.

The analysis of the visual significance threshold, the correlation between magnitude of change and sensitivity / quality, is based on the matrix detailed in Table 7.1

 

Table 7.1: Impact matrix

Magnitude of Change

Sensitivity / Quality

Low

Medium

High

Low

Slight Impact

Slight / Moderate Impact

Moderate Impact

Medium

Slight / Moderate Impact

Moderate Impact

Moderate / Significant Impact

High

Moderate Impact

Moderate / Significant Impact

Significant Impact

 

7.4                    Methodology for Determination of Mitigation Measures

The identification of the visual impacts will highlight those sources of conflict requiring design solutions or modifications to reduce the impacts and, if possible, blend the development with the surrounding visual context.  The proposed visual mitigation measures are described and illustrated by means of simple photomontage and will take into account factors including;

l        Selection of location by taking into account the shielding effect of existing silos;

l        Shape of the proposed silos shall be compatible with the existing silos;

l        Make use of suitable colour scheme, which will be compatible with the surrounding environment. 

 

7.5                    Residual Impact

Residual impact is the impact remaining after the proposed mitigation measures have been implemented.

 

The level of impact is derived from the magnitude of change which the proposals will cause to the view which would have existed during this period if the proposed scheme had not been constructed and its ability to tolerate change. The ability to tolerate change is described as its quality and sensitivity, taking into accounts the beneficial effects of the proposed mitigation. The level of residual impacts can be derived from the matrix provided in Table 7.1 above.

 

The overall evaluation of visual impact will be classified into five levels of significance, beneficial, acceptable, acceptable with mitigation measures, unacceptable and determined in accordance with Annex 10 of the TM-EIA as shown in Table 7.2.

 

Table 7.2: Overall evaluation of visual impact.

Beneficial

Acceptable

Acceptable with mitigation measures

Unacceptable

Undetermined

The project will complement the visual character of its setting, will follow the relevant planning objectives and will improve overall visual quality

There will be no significant visual effects caused by the appearance of the project or no interference with key view

There are some adverse effects, but these can be eliminated, reduced or offset to a large extent by specific measures

The adverse effects are considered too excessive and would not be reduced to an acceptable level by mitigation

Significant adverse effects are likely but the extent to which they may occur or may be mitigated cannot be determined from the study.   Further detailed study will be required for the specific effects in question.

 

7.6                    Review of Planning and Development Control Framework

The existing cement depot and its adjacent waterfront area is neither covered by the draft Tai Po Outline Zoning Plan No. S/TP/16 nor the approved Ting Kok Outline Zoning Plan No. S/NE-TK/8. On the draft Tai Po Area 27 (Part) Layout Plan No. L/TP 27/1A, the cement depot site is zoned “Other Specified Uses” annotated ‘Sand / Cement / Aggregate Depot and /or  Marine-related industries’.  

 

7.7                    Assessment Results

7.7.1               Existing Visual Context and Visually Sensitive Receivers (VSRs)

The proposed additional cement silos are located adjacent to the existing silos.  Within the visual envelope, the Visually Sensitive Receivers (VSRs) have been identified.

A low-rise villa, Casa Marina III, which located 100m away from the centre of the project site, is under construction and was identified as VSR 1.  Two other residential areas, the Fortune Garden and Tycoon Place, were identified as VSR 2 and VSR3 respectively.  All these residents are currently enjoying the bay view of the Tolo Harbour with a partial view of the existing cement depot.

 

VSRs other than residential area within the visual envelope were also identified.  The Tolo Harbour marine traffic was identified as VSR 4.  The pedestrians, cyclists and road users of Ting Kok Road were identified as VSR 5. 

 

The visual envelope and visually sensitive receivers are shown on Fig. 7.1.  Other features within the visual envelope, for example the fish wholesale market and the Tai Po Sheun Wan Temporary Golf Diving Range, were identified having very low visual sensitivity and therefore not included in the visual impact assessment.  Details of VSRs are summarized in Table 7.3.

Table 7.3: Summary of visually sensitive receivers

VSR Number

Location

Type of viewers

Existing View

Distance to nearest visual impact source

Sensitivity to Change and Visual Intrusion

VSR 1

Casa Marina III

Resident

Bay view with a partial view of the existing cement depot, which is partially shaded by roadside village trees.

100 m

High

VSR 2

Fortune Garden

Resident

Bay view with the existing cement depot in a long distance.

400 m

Medium

VSR 3

Tycoon Place

Resident

Bay view with the existing cement depot in a long distance

500 m (from high level)

Medium

VSR 4

Tolo Harbour marine traffic

Local commuters,  fishing boats, tourist vessels, transitory views

Residential development and the existing cement depot can be seen along the shore.

Adjacent

Low

VSR 5

Ting Kok Road and the associated cycling track

Pedestrian, cyclist, road users, transitory views

Mainly shaded by roadside landscape. Existing cement depot can be seen in small section of the road.

Adjacent

Low

 

7.7.2               Visual Impact

In this study, different silo locations are considered.  The proposed silo is located adjacent to the existing silos and is considered as the best position within the site.  The present position helps to reduce the visual impact from different angles by making use of the screening effect of existing silos.  In addition, as the proposed silos is located closer to the cement tankers loading bay.  There is no need to construct a long conveyor for cement unloading, which could cause additional visual intrusion.

The visual impact on each VSR were carried out as following:

 

VSR 1 Casa Marina III

Fig. 7.2 shown the side view of the cement depot from Casa Marina III at ground level.  Two of the proposed silos will be nearly shielded off by the existing silos and leaving only one additional silo will be seen from some of the residents in Casa Marina III.  Village trees and other landscape features will further shield this additional silo.  The magnitude of change is low and the sensitivity of the viewer groups is high. Moderately adverse visual impact is predicted during construction and operation. 

 

VSR 2 Fortune Garden

A small portion of the resident has a partial view of the cement depot.  As the bay view is in front of the cement depot, it will not be obstructed by the proposed silos.  The visual impact is further reduced with the long distance between the VSR and the depot.  The magnitude of change is low and the sensitivity of the viewer group is medium.  Slight / moderate adverse visual impact is predicted during construction and operation.

 

VSR 3 Tycoon Place

Tycoon Place located at a higher level and is 500 m away from the project.  The magnitude of change is low and the sensitivity of the VSR is also low.  Slight visual impact is predicted during construction and operation.

 

VSR 4 Tolo Harbour Marine traffic

The marine traffic in the adjacent Tolo Harbour water is mainly local commuters, fishing boat, tourist vessels and transitory viewers.  These activities have relatively low sensitivity to potential visual impact.  The elevation view from the Harbour is shown in Fig. 7.3 and only one additional silo will be seen form that view.  The magnitude of change is low and slight visual impact is predicted during construction and operation.

 

VSR 5 Ting Kok Road and the associated cycling track

The existing trees planted along the Ting Kok Road will shield off the view of road users and cyclist towards the cement depot.  It is predicted that the magnitude of change is low and slight visual impact is predicted during construction and operation.


Table 7.4: Summary of visual impact

VSR number

Location

Type of viewer group

Magnitude of change and source of impact

Sensitivity to change and visual intrusion

Significance threshold of visual impact during construction (refer to Table 7.1)

Significance threshold of visual impact during operation (assuming no mitigation measures)(refer to Table 7.1)

 

VSR 1

Casa Marina III

Resident

Low

High

Moderate adverse

Moderate adverse

VSR 2

Fortune Garden

Resident

Low

Medium

Slightly / Moderate adverse

Slightly / Moderate adverse

VSR 3

Tycoon Place

Resident

Low

Medium

Slightly / Moderate adverse

Slightly / Moderate adverse

VSR 4

Tolo Harbour Marine Traffic

Local commuters, fishing boats tourist vessels, transitory views

Low

Low

Slightly adverse

Slightly adverse

VSR 5

Ting Kok Road and the associated cycling track

Cyclist, road users, transitory views

Low

Low

Slightly adverse

Slightly adverse


7.8                    Recommended Mitigation Measures

During construction stage, it will not be possible to totally screen the construction works for the silos.  As the proposed silos will be located inside the existing site boundary, the existing site boundary wall will screen the ground level work site.  Permanent mitigation measures are not required as the construction period is temporary.

 

In the operational phase, the following recommended mitigation measures are proposed to reduce the visual impact. The photomontages showing views from Casa Marina III, Fortune Garden, Tolo Harbour and Ting Kok Road are shown in Fig. 7.4 to 7.7 respectively.

 

l        The height and shape of the additional silos should be similar to those of the existing silos in order to be compatible with the existing baseline situation. 

 

l        Two options are proposed. One option is to paint all silos in deep green colour, which is more compatible with the surrounding environment (hilly mountain) when viewing from the sea and VSRs from Fortune garden (Fig 7.5 and 7.6). Another option is to leave the surface of the silos in non-reflective grey white (Fig. 7.4). This scheme will be more compatible to the background when viewing from Casa Marina III. As Casa Marina III is the major affected sensitive receiver, the second scheme is recommended.

 

l        The proposed noise barrier around the cement unloading bay should be painted deep green in order to provide screening effect and reduce the visual impact (Fig.7.7).

 

With the mentioned design options, the proposed new silos should blend in satisfactorily into the surrounding visual content.  The visual impact caused by the proposed silos is reduced and all VSRs will only have slightly or negligible visual impact.

 

7.9                    Conclusion

The proposed additional cement silos will locate adjacent to the existing silos and within the existing depot boundary.  Several visually sensitive receivers are identified and slightly to moderate visual impact will be induced by the project.

 

To reduce the visual impact on those VSRs, mitigation measures regarding the design details are recommended.  The height and shape of the additional silos will be constructed similar to those of the existing silos. Proposed noise barrier under the silos will be erected. It will provide screening effect. The surface of the barrier will also be painted deep green, while the surface of the silo is left in non-reflective grey white colour. With these measures, the proposed silos will be more compatible with the surrounding environment and planned setting.  

 

It is concluded that with the recommended mitigation measures incorporated, the visual impact will be mimimised. The overall evaluation of visual impact will be acceptable with the mitigation measures.


8                          Waste Management

8.1                    Introduction

This section identifies the types of wastes that are likely to be generated during the construction and operation of the additional silos. Potential environmental impacts associated with the handling and disposal of these waste arising are then assessed.

Mitigation measures and good site practices, including waste handling, storage and disposal, are recommended with reference to the applicable legislation and guidelines.

8.2                    Assessment Criteria and Methodology

The criteria for evaluating the potential waste management implications are set out in Annex 7 of the EIAO-TM. The method for assessing potential waste management impacts during construction and operational phases follows that presented in Annex 15 of EIAO-TM and includes the following:

·        estimation of the types and quantities of wastes generated;

·        assessment of potential secondary environmental impacts from the management of solid waste with respect to potential hazards, air and odour emissions, noise, wastewater discharges and traffic; and

·        impact on the capacity of waste collection, transfer and disposal facilities.

If not properly managed, the handling and disposal of waste materials may cause environmental nuisance and impact. The nature of each type of waste arising is discussed below, together with an evaluation of the potential environmental impacts associated with the management of these waste arisings.

8.3                    Prediction and Evaluation of Environmental Impacts

8.3.1               Construction Phase

The proposed site is within the existing cement depot boundary and no site clearance or demolition works are required. Small quantities of excavated material will be generated from the minor earthworks required for the foundation of the cement silos and this will mainly consist of fill material. The volume of excavated material is estimated to be approximately 1000m3. In order to maximize landfill life, Government policy prohibits the disposal of C&D materials to landfill if it contains more than 20% inert materials by volume. Considering the inert nature of the excavated material, the materials can be directed to the public filling area at Tuen Mun Area 38 for reclamation purpose. 

Throughout construction, the workforce will generate general refuse comprising food scraps, waste paper, empty containers etc. The storage, handling and disposal of general refuse have the potential to give rise to some environmental impacts if not properly managed. These include odour if waste is not collected frequently, windblown litter, water quality impact if waste enters water bodies, and visual impact. Rapid and effective collection of site wastes will therefore be required. With the implementation of good site practices and the recommended mitigation measures on disposal arrangements, adverse environmental impact are not expected to arise during the construction works.

8.3.2               Operational Phase

The additional cement silos are purely for storage purpose only. Therefore no cement waste is anticipated during the silo operation. In addition, maintenance of cement tankers is not allowed in the Depot, therefore no chemical waste will be generated. The only waste generated on-site will be the sediment from sediment tank and the general refuse from workforce.

8.3.3               Mitigation Measures

The following recommended measures in minimization, storage, transportation and disposal should be incorporated into an on-site waste management plan for the construction and operational phase.

Site Planning

Good site planning and design shall be adopted to reduce over-ordering and waste generation. The work site shall be arranged and managed to facilitate the proper management of waste and materials.

Storage, Collection and Transport of Waste

Permitted waste hauliers should be used to collect and transport waste to the appropriate disposal points. The following measures to minimise adverse impacts are proposed:

·        Where practicable, different types of waste should be segregated, stockpiled and stored in different containers or skips to enhance, reuse or recycle of materials and their proper disposal;

·        Handle and store waste in a manner which ensures that it is held securely without loss or leakage, thereby minimising the potential for pollution;

·        Use authorized or licensed waste hauliers to collect specific categories of waste;

·        Remove waste in a timely manner;

·        Maintain and clean waste storage areas regularly;

·        Minimise windblown litter and dust during transportation by either covering trucks or transporting waste in enclosed containers;

·        Obtain the necessary waste disposal permits from the appropriate authorities, if they are required, in accordance with the Waste Disposal Ordinance (Cap 354), Waste Disposal (Chemical Waste) (General) Regulation (Cap 354), the Land (Miscellaneous Provision) Ordinance (Cap 28);

·        Dispose of waste at licensed waste disposal facilities;

·        Develop procedures such as a ticketing system to facilitate tracking of loads, and to ensure that illegal disposal of waste does not occur; and

·        Maintain records of the quantities of waste generated, recycled and disposed.

 

General Refuse

General refuse should be stored in enclosed bins or compaction units separated from chemical wastes. A reputable waste collector should be employed by the contractor to remove general refuse from the site regularly to minimize odor, pest and litter impacts. The burning of refuse on construction sites is prohibited by law.

Training

Training shall be provided to all personnel working on site. The training shall promote the concept of general site cleanliness and encourage all workers to reduce, reuse and recycle waste.

8.4                    Conclusion

With the implementation of the recommended mitigation measures on waste management practices and pollution control measures for the construction phases of the additional silos, adverse environmental impacts are not expected. No unacceptable residual impacts are expected provided that the recommended waste management mitigation measures for the Project are implemented.


9                          Ecology

As the proposed project site is within the existing industrial premises, there will not be any impacts on local ecology.

10                      Cultural Heritage

As the proposed project site is within the existing industrial premises, there will not be any impacts on site of cultural importance or listed buildings.


11                      Implementation schedules

In order to reduce the potential impact due to the construction and operation of the cement works, the following tables summarize the implement schedules during the design, construction and operation of the cement works

Implementation Schedule of Mitigation Measures for Air Quality Control on the Cement Works

Environmental Protection Measures

Timing

Implementation Agent

Implementation Stage

Standard / Requirement

D

C

O

Fully enclosed piping system to transfer cement from barge to silos

Throughout the operation of the cement works

Plant Operator

Ö

 

Ö

Air Pollution Control Ordinance, Best Practical Means for Cement Work BPM 3/1

The unloading points and silos are equipped with dust collector in compliance with BPM 3/1