Agreement No. CE 35/2006(CE)

Kai Tak Development Engineering Study

cum Design and Construction of Advance Works

– Investigation, Design and Construction

 

 

Kai Tak Development

Environmental Impact Assessment Report

 

 

Contents

 

 

6............ AIR QUALITY Impact. 6-1

6.1        Introduction. 6-1

6.2        Environmental Legislation, Policies, Plans, Standards and Criteria. 6-1

6.3        Description of the Environment 6-1

6.4        Air Quality Sensitive Receivers. 6-1

6.5        Assessment Methodology. 6-1

6.6        Identification of Environmental Impacts. 6-1

6.7        Prediction and Evaluation of Environmental Impacts. 6-1

6.8        Mitigation of Environmental Impacts. 6-1

6.9        Residual of Environmental Impacts. 6-1

6.10      Environmental Monitoring and Audit 6-1

6.11      Summary. 6-1

 

Lists of Tables

Table 6.1           Hong Kong Air Quality Objectives

Table 6.2           Annual Average Concentrations of Pollutants in Year 2006 at EPD’s Sham Shui Po and Kwun Tong Air Quality Monitoring Stations

Table 6.3           Summary of Representative Air Sensitive Receivers

Table 6.4           Representative ASRs selected for Odour Impact Assessment

Table 6.5           Emission Factors for Construction Activities

Table 6.6           Major Dust Generating Activities in the Worst Case Scenarios during Construction Phase

Table 6.7           Annual Average Concentrations of Pollutants in the Latest Five Years at Sham Shui Po and Kwun Tong Air Quality Monitoring Stations

Table 6.8           Emission Factor for of Twin Engine T58-GE-8F

Table 6.9           Cruise Air Pollutants Emission Rates

Table 6.10         Sensitivity Test Scenarios

Table 6.11         Existing Odour Emission Rates of KTN, KTAC, and KTTS

Table 6.12         Conversion Factors for Hourly to 5-second Average Concentration

Table 6.13         Predicted Cumulative Maximum 1-hour Average TSP Concentrations at 1.5m above ground

Table 6.14         Summary of Predicted Results

Table 6.15         Odour Emission Rates (SOER (ou/m2/s) of KTN, KTAC, and KTTS under Different Modelling Scenarios

Table 6.16         Predicted Odour Concentrations at Representative ASRs under Different Assessment Scenarios 

Table 6.17         Predicted Frequency of Exceedance of Odour Criterion at Representative ASRs under Mitigated Scenarios A1 and B1

Table 6.18         Predicted Frequency of Exceedance of Odour Criterion at Representative ASRs under Mitigated Scenarios A2 and B2

 

 

 

 


6                          AIR QUALITY Impact

6.1                    Introduction

6.1.1               This section presents an air quality impact assessment for the construction and operational phases of the Kai Tak Development.  Existing and planned air sensitive receivers in the vicinity of the study area are determined.  Potential air quality impacts associated with the Project have been identified together with the proposed methodology for the respective impact assessments.

6.2                    Environmental Legislation, Policies, Plans, Standards and Criteria

6.2.1               The criteria for evaluating air quality impacts and the guidelines for air quality impact assessment are set out in Annex 4 and Annex 12 of the Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM).

Air Quality Objectives and EIAO-TM

6.2.2               The Air Pollution Control Ordinance (APCO) provides the statutory authority for controlling air pollutants from a variety of sources.  The Hong Kong Air Quality Objectives (AQOs), which must be satisfied, stipulate the maximum allowable concentrations over specific periods for typical pollutants.  The relevant AQOs are listed in Table 6.1.

Table 6.1                           Hong Kong Air Quality Objectives

Pollutant

Maximum Concentration (µg m-3) (1)

Averaging Time

1 hour (2)

8 hour (3)

24 hour (3)

Annual (4)

Total Suspended Particulates (TSP)

-

-

260

80

Respirable Suspended Particulates (RSP) (5)

-

-

180

55

Sulphur Dioxide (SO2)

800

-

350

80

Nitrogen Dioxide (NO2)

300

-

150

80

Carbon Monoxide (CO)

30,000

10,000

-

-

Photochemical Oxidants (as Ozone, O3) (6)

240

-

-

-

Notes:

(1)    Measured at 298 K and 101.325 kPa.

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

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

(4)    Arithmetic mean.

(5)    Suspended particulates in air with a nominal aerodynamic diameter of 10 mm or smaller.

(6)    Photochemical oxidants are determined by measurement of ozone only.

6.2.3               The EIAO-TM stipulates that the hourly TSP level should not exceed 500 mgm-3 (measured at 25°C and one atmosphere) for construction dust impact assessment.  Standard mitigation measures for construction sites are specified in the Air Pollution Control (Construction Dust) Regulation.

6.2.4               In accordance with the EIAO-TM, odour level at an air sensitive receiver should meet 5 odour units based on an averaging time of 5 seconds for odour prediction assessment.


Air Pollution Control (Construction Dust) Regulation

6.2.5               Notifiable and regulatory works are under the control of Air Pollution Control (Construction Dust) Regulation.  Notifiable works are site formation, reclamation, demolition, foundation and superstructure construction for buildings and road construction.  Regulatory works are building renovation, road opening and resurfacing slope stabilisation, and other activities including stockpiling, dusty material handling, excavation, concrete works, stockpiling, dusty material handling etc.  This Project is expected to include both notifiable works and regulatory works.  Contractors and site agents are required to inform the Environmental Protection Department (EPD) on carrying out construction works and to adopt dust reduction measures to reduce dust emission to the acceptable level.

6.3                    Description of the Environment

6.3.1               The Project is located in the southeastern part of Kowloon Peninsula, comprising the apron and runway areas of the former Kai Tak Airport and existing waterfront areas at To Kwa Wan, Ma Tau Kok, Kowloon Bay, Kwun Tong and Cha Kwo Ling.  It covers a land area of about 328 hectares.  It also covers Kowloon Bay and Kwun Tong Typhoon Shelter and adjacent water bodies.  There is no air quality monitoring station located in the study area.  EPD’s Sham Shui Po and Kwun Tong air quality monitoring stations are the nearest stations to the Project site.  Table 6.2 summarizes the annual average concentrations of the air pollutants recorded at these two monitoring stations in Year 2006.

Table 6.2                           Annual Average Concentrations of Pollutants in Year 2006 at EPD’s Sham Shui Po and Kwun Tong Air Quality Monitoring Stations

Pollutant

Annual Average AQO

(mg m-3)

Year 2006 Annual Average Concentration (mg m-3)

Sham Shui Po station

Kwun Tong station

TSP

80

79

75

RSP

55

55

55

NO2

80

67

61

SO2

80

24

19

 

 

6.4                    Air Quality Sensitive Receivers

6.4.1               In accordance with Annex 12 of the EIAO-TM, any domestic premises, hotel, hostel, hospital, clinic, nursery, temporary housing accommodation, school, educational institution, office, factory, shop, shopping centre, place of public worship, library, court of law, sports stadium or performing arts centre are considered to be an air sensitive receiver (ASR).  Any other place with which, in terms of duration or number of people affected, has a similar sensitivity to the air pollutants as the aforelisted places are also considered to be an ASR, for example, playground, sitting area of parks / promenade.

6.4.2               In accordance with Section 3.4.5.3 of the EIA Study Brief No. ESB-152/2006, the air quality impact assessment area is defined by a distance of 500m expanded from the boundary of the Project.  The study areas of air quality impact assessment are shown in Figure 3.1

6.4.3               The identified representative ASRs are listed in Table 6.3 and the corresponding locations are shown in Figure 3.1.  The assessment height taken for the construction dust impact assessment was 1.5m above ground in view of the fact that the majority of the dust emissions would be emitted from the ground level, 1.5m is the height of normal human breathing zone.  For operational phase impact assessment, the assessment heights were taken as 1.5m, 5m, 10m, 15m, 20m above ground and so on up to the maximum building height of the respective ASR.  

Table 6.3                           Summary of Representative Air Sensitive Receivers 

ASRs

District (1)

Location

Existing / Planned Land Use

Max. Building Height, m (2)

Distance to Project Boundary, m

A1

KT

Cha Kwo Ling Tusen

Residential

5

17

A2

KT

Cha Kwo Ling

Residential

15

17

A3

KT

Laguna City IV

Residential

81

26

A4

KT

Laguna Park

Recreation

1.5

40

A5

KT

Hoi Bun Industrial Centre

Industrial

42

9

A6

KT

Seapower Industrial Centre

Industrial

33

19

A7

KT

CAC Tower

Commercial

57

11

A8

KT

Bite Industrial Building

Industrial

30

12

A9

KT

Wharf T&T Square

Commercial

45

15

A10

KT

Hoi Bun Road Park

Recreation

1.5

27

A11

NTK

Kowloon Bay Factory Estate

Industrial

24

8

A12

NTK

Kowloon Bay Motor Vehicle Exam Centre

Industrial

6

45

A13

NTK

New Kowloon Bay Motor Vehicle Exam Centre

Industrial

3

14

A14

NTK

Kai Fok Industrial Centre

Industrial

24

38

A15

KB

Sing Tao Building

Commercial

30

45

A16

KB

WSD Kowloon Bay Pipe Yard

Industrial

1.5

16

A17

KB

Hong Kong International Trade & Exhibition Centre

Commercial

54

146

A18

KB

Hong Kong Bank New Treasury Building

Commercial

12

12

A19

KB

Electrical & Mechanical Services Department Headquarters

G/IC

21

105

A20

KB

Sino Industrial Plaza

Industrial

30

5

A21

KB

Skyline Tower

Commercial

117

11

A22

KB

Football field

Recreation

1.5

100

A23

KB

Kowloon Health Centre

G/IC

30

153

A24

KB

Bicycle Track Near Richland Garden

Recreation

1.5

40

A25

NCW

Richland Gardens Shopping Centre

Shopping Center

30

56

A26

NCW

Richland Gardens

Residential

99

60

A27

NCW

Kam Bik House, Choi Hung Estate

Residential

60

102

A28

NCW

Pik Hoi House, Choi Hung Estate 

Residential

60

105

A29

NCW

Rhythm Garden

Residential

87

49

A30

SPK

Cognitio College

Educational

18

35

A31

SPK

Sir Robert Black Health Centre

Clinic

9

67

A32

SPK

Lee Kau Yan Memorial School

Educational

10

77

A33

SPK

Shek Ku Lung Road Playground

Recreation

1.5

50

A34

SPK

Regal Oriental Hotel

Hotel

42

56

A35

SPK

South Mansion

Residential

15

64

A36

SPK

Jenford Building

Residential

12

57

A37

KC

Sung Wong Toi Playground

Recreation

1.5

5

A38

KC

Sung Wong Toi Garden

Recreation

1.5

9

A39

TKW

Parc 22

Residential

33

16

A40

TKW

Sky Tower

Residential

141

5

A41

TKW

Freder Centre

Industrial

153

3

A42

TKW

K K Industrial Building

Industrial

12

5

A43

TKW

HK Society for Blind hostel

Hostel

9

23

A44

TKW

Mok Cheong Street Residential District

Residential

18

22

A45

TKW

China Gas Company

Commercial

15

21

A46

TKW

Ming Lun Street Residential District

Residential

21

136

A47

TKW

Grand Waterfront

Residential

153

115

A48

TKW

Merit Industrial Center

Industrial

36

24

A49

TKW

Wei Chien Court 

Residential

39

9

A51

TKW

United Daily

Industrial

48

28

A52

TKW

Holly Carpenter Primary School

Educational

18

41

A53

TKW

Oblate Father’s Primary School

Educational

21

7

A54

TKW

Sui Ying Industrial Building

Industrial

33

9

A55

TKW

Fook Shing Industrial Building

Industrial

36

14

A56

TKW

Sunrise Villa

Residential

90

18

A57

TKW

Wing Kwong Street Residential District

Residential

21

17

A58

TKW

CCC Kei To Secondary School

Educational

24

0

A59

TKW

Po Leung Kuk Ngan Po Ling College

Educational

27

70

A60

HH

Sunrise Plaza

Residential

39

101

A61

HH

Peninsula Square

Commercial

69

68

A62

HH

A.P.B Centre

Industrial

1.5

15

A63

HH

DSD To Kwan Wan PTW Workshop

G/IC

27

21

PA1

KTD

Site 1A1 (Planned)

Residential

115

N/A

PA2

KTD

Site 1A1 (Planned)

Residential

115

N/A

PA3

KTD

Site 1A1 (Planned)

Residential

115

N/A

PA4

KTD

Site 1A1 (Planned)

Residential

115

N/A

PA5

KTD

Site 1A1 (Planned)

Residential

115

N/A

PA6

KTD

Site 1A2 (Planned)

Educational

40

N/A

PA7

KTD

Site 1A3 (Planned)

Educational

40

N/A

PA8

KTD

Site 1A4 (Planned)

Educational

40

N/A

PA9

KTD

Site 1B1 (Planned)

Residential

115

N/A

PA10

KTD

Site 1B1 (Planned)

Residential

115

N/A

PA11

KTD

Site 1B1 (Planned)

Residential

115

N/A

PA12

KTD

Site 1B1 (Planned)

Residential

115

N/A

PA13

KTD

Site 1B1 (Planned)

Residential

115

N/A

PA14

KTD

Site 1B1 (Planned)

Residential

115

N/A

PA15

KTD

Site 1B4 (Planned)

Educational

40

N/A

PA16

KTD

Site 1C1 (Planned)

G/IC

85

N/A

PA17

KTD

Site 1D2 (Planned)

Commercial

95

N/A

PA18

KTD

Site 1D3 (Planned)

G/IC

55

N/A

PA19

KTD

Site 1D4 (Planned)

G/IC

95

N/A

PA20

KTD

Site 1E1 (Planned)

G/IC

95

N/A

PA21

KTD

Site 1E1 (Planned)

G/IC

95

N/A

PA22

KTD

Site 1F1 (Planned)

Commercial

145

N/A

PA23

KTD

Site 1F2 (Planned)

Commercial

170

N/A

PA24

KTD

Site 1G2 (Planned)

G/IC

75

N/A

PA25

KTD

Site 1H1 (Planned)

Residential

105

N/A

PA26

KTD

Site 1H2 (Planned)

Residential

105

N/A

PA27

KTD

Site 1H3 (Planned)

Residential

105

N/A

PA28

KTD

Site 1I1 (Planned)

Residential

95

N/A

PA29

KTD

Site 1I2 (Planned)

Residential

95

N/A

PA30

KTD

Site 1I3 (Planned)

Residential

95

N/A

PA31

KTD

Site 1J1 (Planned)

G/IC

55

N/A

PA32

KTD

Site 1J3 (Planned)

G/IC

25

N/A

PA33

KTD

Site 1K1 (Planned)

Residential

105

N/A

PA34

KTD

Site 1K2 (Planned)

Residential

105

N/A

PA35

KTD

Site 1K3 (Planned)

Residential

95

N/A

PA36

KTD

Site 1L1 (Planned)

Residential

95

N/A

PA37

KTD

Site 1L2 (Planned)

Residential

95

N/A

PA38

KTD

Site 1L3 (Planned)

Residential

95

N/A

PA39

KTD

Site 1L4 (Planned)

Residential

25

N/A

PA40

KTD

Site 1M1 (Planned)

Commercial

35

N/A

PA41

KTD

Site 1M1 (Planned)

Commercial

35

N/A

PA42

KTD

Site 1M2 (Planned)

Commercial

35

N/A

PA43

KTD

Site 2A1 (Planned)

G/IC

65

N/A

PA44

KTD

Site 2A2 (Planned)

G/IC

65

N/A

PA45

KTD

Site 2A3 (Planned)

G/IC

65

N/A

PA46

KTD

Site 2A4 (Planned)

G/IC

65

N/A

PA47

KTD

Site 2A5 (Planned)

G/IC

65

N/A

PA48

KTD

Site 2A6 (Planned)

G/IC

40

N/A

PA49

KTD

Site 2B1 (Planned)

Residential

105

N/A

PA50

KTD

Site 2B1 (Planned)

Residential

105

N/A

PA51

KTD

Site 2B2 (Planned)

Residential

95

N/A

PA52

KTD

Site 2B3 (Planned)

Residential

80

N/A

PA53

KTD

Site 2B4 (Planned)

Residential

80

N/A

PA54

KTD

Site 2B5 (Planned)

Residential

80

N/A

PA55

KTD

Site 2B6 (Planned)

Residential

80

N/A

PA56

KTD

Site 2D1 (Planned)

Recreation

40

N/A

PA57

KTD

Site 2D1 (Planned)

Recreation

40

N/A

PA58

KTD

Site 3C1 (Planned)

Hospital

55

N/A

PA59

KTD

Site 3C1 (Planned)

Hospital

55

N/A

PA60

KTD

Site 3C1 (Planned)

G/IC

55

N/A

PA61

KTD

Site 3C1 (Planned)

Hospital

55

N/A

PA62

KTD

Site 3D1 (Planned)

Commercial

95

N/A

PA63

KTD

Site 3D2 (Planned)

Commercial

95

N/A

PA64

KTD

Site 3D3 (Existing)/

Site 3D3 (Planned)

Industrial /

Commercial

168/

95

N/A

PA65

KTD

Site 3D4 (Planned)

Commercial

95

N/A

PA66

KTD

Site 3D4 (Planned)

Commercial

95

N/A

PA67

KTD

Site 4A1 (Planned)

Residential

60

N/A

PA68

KTD

Site 4A1 (Planned)

Residential

60

N/A

PA69

KTD

Site 4A2 (Planned)

Commercial

40

N/A

PA70

KTD

Site 4A3 (Planned)

Commercial

75

N/A

PA71

KTD

Site 4A (Planned)

Recreation

1.5

N/A

PA72

KTD

Site 4A (Planned)

Recreation

1.5

N/A

PA73

KTD

Site 4A (Planned)

Recreation

1.5

N/A

PA74

KTD

Site 4A (Planned)

Recreation

1.5

N/A

PA75

KTD

Site 4A (Planned)

Recreation

1.5

N/A

PA76

KTD

Site 4A (Planned)

Recreation

1.5

N/A

PA77

KTD

Site 4B1 (Planned)

Residential

50

N/A

PA78

KTD

Site 4B1 (Planned)

Residential

50

N/A

PA79

KTD

Site 4B2 (Planned)

Residential

50

N/A

PA80

KTD

Site 4B2 (Planned)

Residential

50

N/A

PA81

KTD

Site 4B3 (Planned)

Residential

60

N/A

PA82

KTD

Site 4B3 (Planned)

Residential

60

N/A

PA83

KTD

Site 4B4 (Planned)

Residential

50

N/A

PA84

KTD

Site 4B4 (Planned)

Residential

50

N/A

PA85

KTD

Site 4B5 (Planned)

Residential

40

N/A

PA86

KTD

Site 4B5 (Planned)

Residential

40

N/A

PA87

KTD

Site 4B5 (Planned)

Residential

40

N/A

PA88

KTD

Site 4B5 (Planned)

Residential

40

N/A

PA89

KTD

Site 4C1 (Planned)

Commercial

40

N/A

PA90

KTD

Site 4C2 (Planned)

Commercial

50

N/A

PA91

KTD

Site 4C3 (Planned)

Commercial

40

N/A

PA92

KTD

Site 4C4 (Planned)

Commercial

40

N/A

PA93

KTD

Site 4C5 (Planned)

Commercial

40

N/A

PA94

KTD

Site 4D2 (Planned)

G/IC

1.5

N/A

PA95

KTD

Site 4D2 (Planned)

G/IC

1.5

N/A

PA96

KTD

Site 4D2 (Planned)

G/IC

1.5

N/A

PA97

KTD

Site 4D2 (Planned)

G/IC

1.5

N/A

PA98

KTD

Site 4D3 (Planned)

Commercial

30

N/A

PA99

KTD

Site 4D3 (Planned)

Commercial

30

N/A

PA100

KTD

Site 4D3 (Planned)

Commercial

30

N/A

PA101

KTD

Site 4D3 (Planned)

Commercial

30

N/A

PA102

KTD

Site 5A4 (Planned)

Residential

60

N/A

PA103

KTD

Site 5A4 (Planned)

Residential

105

N/A

PA104

KTD

Site 3B1 (Planned)

Undesignated

40

N/A

PA105

KTD

Site 3B2 (Planned)

Undesignated

40

N/A

PA106

KTD

Site 3B3 (Planned)

Undesignated

40

N/A

PA107

KTD

Site 3B4 (Planned)

Undesignated

40

N/A

PA108

KTD

Site 4D2 (Planned) Tourism node

Other Specified Uses

95

N/A

PA109

KTD

Site 4D2 (Planned) Tourism node

Other Specified Uses

95

N/A

PA110

KTD

Site 4D2 (Planned) Tourism node

Other Specified Uses

95

N/A

PA111

KTD

Site 4D2 (Planned) Tourism node

Other Specified Uses

95

N/A

PA112

KTD

Site 4D2 (Planned) Tourism node

Other Specified Uses

95

N/A

PA113

KTD

Site 4D2 (Planned) Tourism node

Other Specified Uses

95

N/A

Note:   (1)  KT – Kwun Tong; NTK – Ngau Tau Kok; KB – Kowloon Bay; NCW – Ngau Chi Wah; SPK – San Po Kong; KC – Kowloon City, TKW – To Kwa Wan; HH – Hung Hom; KTD – Kai Tak Development

(2)    The maximum height for Planned ASR was made reference to the RODP.

 

6.4.4               A number of representative planned and existing ASRs located in close proximity to the Kai Tak Nullah (KTN), Kai Tak Approach Channel (KTAC) and Kwun Tong Typhoon Shelter (KTTS) were selected for the purpose of odour impact assessment.  The selected ASRs are listed in Table 6.4 below and shown in Figure 6.1.  The major odour emission sources of concern in this assessment are KTN, KTAC and KTTS, which are area sources near ground level.  Therefore, worst-case odour impacts would also be expected near ground level.  The assessment heights at the ASRs were taken as 1.5m above local ground level to represent the height of normal breathing zone of human.  In addition, the odour impacts at assessment heights of 10m, 20m and 30m above local ground level at the ASRs were also examined in the odour impact assessment.


Table 6.4                           Representative ASRs selected for Odour Impact Assessment

ASR ID

Description

Region

OA1

Planned stadium, site2D

North apron area of Kai Tak Development

OA2

Planned residential site 1L3

OA3

Existing EMSD Headquarters, site 1N

OA4

Planned government site 3B1

South apron area of Kai Tak Development

OA5

Planned government site 3B2

OA6

Planned government site 3B3

OA7

Planned government site 3B4

OA8

Planned hospital site

OA9

Planned hospital site

OA10

Planned district open space, site 3E2

OA11

Planned commercial site 3D4

OA12

Existing World Trade Square

Existing Kwun Tong area

OA13

Existing Kwong Sang Hong Building

OA14

Existing Seapower Industrial Centre

OA15

Planned Runway Park, site 4D1

Runway area of Kai Tak Development

OA16

Planned Runway Park, site 4D1

OA17

Planned Runway Park, site 4D1

OA18

Planned tourism node, site 4D1

OA19

Planned cruise terminal building, site 4D3

OA20

Planned cruise terminal building, site 4D3

OA21

Planned cruise terminal building, site4D3

OA22

Planned local open space, site 4B5

Runway area of Kai Tak Development

OA23

Planned residential site 4B5

OA24

Planned residential site 4B4

OA25

Planned residential site 4B3

OA26

Planned residential site 4B2

OA27

Planned residential site 4B1

OA28

Planned residential site 4A1

OA29

Planned commercial site 4A3

OA30

Planned regional open space, site 4A

OA31

Planned regional open space, site 4A

OA32

Planned regional open space, site 4A

OA33

Planned Site 1L4

North apron area of Kai Tak Development

OA34

Planned government site 1J3

OA35

Planned Site 1L1

OA36

Planned Site 1I3

OA37

Planned Site 1K1

OA38

Planned Site 1H3

OA39

Planned Site 1M1

OA40

Planned Site 1M2

OA41

Existing Lee Kau Yan Memorial School

Existing Kowloon City Area

OA42

Existing Sir Robert Black Health Centre

 

6.5                    Assessment Methodology

CONSTRUCTION PHASE (CONSTRUCTION DUST)

6.5.1               Fugitive Dust Model (FDM) was used to assess the potential dust impact from the construction works.  Dust emission was predicted based on emission factors from USEPA Compilation of Air Pollution Emission Factors (AP-42), 5th Edition.  The major construction activities for the Project, which would be potential sources of construction dust in the Study Area, include soil excavation activities at work site and wind erosion of open site.  Table 6.5 gives the relevant clauses in AP-42 for emission factors adopted in this assessment.  The detailed calculations of emission rates are presented in Appendix 3.1.

Table 6.5                           Emission Factors for Construction Activities

Construction Activities

Emission Rate (g/m2/s)

Remark

All construction work

E = 1.49684E-05

-    50% of works area with active dust emitting construction activities

-    87.5% reduction by water suppression (watering eight times a day)

-    USEPA AP-42 5th ED., S.13.2.3.3

Barging point serving the Development at Anderson Road Project

E = 2.04236E-05

-       USEPA AP-42 5th ED., S. 13.2.4

-       Information for emission rate calculation was provided by Anderson Road Project Engineer

-       75% reduction by water suppression for each unloading

Wind erosion for all construction work (including barging point)

E = 1.34767E-06

 

-    50% of works area with active construction activities

-    AP-42 5th ED., S.11.9  Table 11.9.4

 

6.5.2               The Air Pollution Control (Construction Dust) Regulation specifies that dust suppression measures such as watering should be applied for the construction site.  Dust emission from the site would be reduced by 87.5% if watering with complete coverage of active construction area eight times a day.  This assumption was adopted in the construction dust impact assessment.

6.5.3               For the purpose of this assessment, 12 working hours per day (08:00-18:00) and 26 working days per month were assumed for the dusty construction works in the assessment.  Wind erosion of open work sites would take place over the whole day.

6.5.4               Based on the construction programme (Appendix 2.2), the early population intake at Sites1A1 & 1B1 and Phase 1 Berth of the cruise terminal would be around late 2012 and second quarter of 2013 respectively.  Two worst-case scenarios namely before and after the early population intake period of late 2012 / mid 2013 have been examined in the construction dust impact assessment.  The construction activities under the two scenarios are detailed in Table 6.6.  The scenarios presented are considered to be representative of the worst case situation.  The figures showing locations of dusty construction site areas for each scenario are presented in Appendix 3.1For construction of electricity substation, footbridge and subway enhancement, most of the works would involve superstructure construction and concreting works which are not dusty construction activities.  Therefore, construction of electricity substation, footbridge and subway enhancement were not included in the model run.  The construction activity for Package C is bioremediation treatment of sediment at Kai Tak Approach Channel which are mostly marine-based with no dusty activities, thus fugitive dust impact is not anticipated.


Table 6.6                           Major Dust Generating Activities in the Worst Case Scenarios during Construction Phase

Activities

Period

Mid 2009 to Mid 2013

Mid 2013 to Late 2016

Scenario 1

Scenario 2

Package A - Cruise Terminal Development (Phase 1 Berth), related advance works and Runway Park

Phase 1 Berth

 

Road TD3, TD4, L14 and minor road works in Kowloon Bay

 

Modification off Taxiway Bridge

 

Pumping Station PS6

 

Fireboat Berth

 

Runway Park

 

Package B - Infrastructure works at North Apron, Phase 1 - Housing Sites and Government Offices

Construction of Road D1 (part)

 

Local Roads L2, L3, L15 and associated footpaths at North Apron

 

Local Roads L4 & L5

Construction of Box Culvert (2.5m x 2.5m)

 

Construction of Box Culvert (3m x 2.8m)

 

Construction of Pumping Station PS1A

Construction of Road D1

 

Construction of Road D2 (part)

 

Construction of Road L1

Construction of Road L2 & L11 (part)

 

Construction of Road L4 (Part) & L5

 

Construction of Slip Road S7 & S8 of CKR/T2 Interchange

 

Construction of Box Culvert (5m x 2.5m)

Upgrading of Pumping Station PS1

Package D - Kai Tak Nullah modification works

Rebuild Kai Tak Nullah

Construction of DSD's Desilting Compounds at Kai Tak Nullah

Package E - Infrastructure works at runway and Metro Park

600m Wide Opening in Runway

Construction of Road D3 (near at Metro Park)

 

Construction of Road L12 & L13

 

Conversion of TD3 into D3 with Street Lighting/ Landscaping Works(include Road L14)

Conversion of TD4 into D4

 

Elevated Landscape Deck above Road D3

Package F - Infrastructure works at North Apron, Phase 2

Construction of Road D1, L7, L8, L9 & L16

 

Construction of Drainage Culvert (2.5x2.5m)

Construction of Drainage Culvert (4x3m)

Construction of Drainage Culvert (5x4m)

Construction of Road D2, D3, L6, L17 & L19

 

Pumping Station PS2

 

Pumping Station NPS

 

Upgrading of Pumping Station PS3

Stadium Complex

 

Package G - Trunk Road T2 and infrastructure works at South Apron

Construction of Trunk Road T2, Local Roads L10, L18 and associated footpaths at South Apron

Cut and Cover Section of T2

Kwun Tong Transportation Link

Other concurrent projects

SCL Construction

CKR Construction

Anderson Road Project

 

6.5.5               The impact of fugitive dust sources on air quality depends upon the quantity as well as the drift potential of the dust particles emitted into the atmosphere.  Large dust particles (i.e. over 100 mm in diameter) will settle out near the source and particles that are between 30 and 100 mm in diameter are likely to undergo impeded settling.  The main dust impacts are likely to arise from particles less than 30 mm in diameter, which have a greater potential to disperse over greater distances.

6.5.6               According to the Table of Aerodynamic Particle Size Multiplier for Equation 1 stated in S13.2.4.3 of USEPA AP-42, construction dust particles may be grouped into five particle size classes.  Their size ranges are 0 – 2.5 mm, 2.5 – 5 mm, 5 – 10 mm, 10 – 15 mm and 15 – 30 mm, and the percentage of particles in each class was estimated to be 7%, 20%, 20%, 18% and 35%, respectively.

6.5.7               One year sequential meteorological data for the year 2006 from the South East Kowloon Weather Station were used to predict the 1-hour and 24-hour average TSP concentrations at representative discrete ASRs close to the construction works.  As South East Kowloon Weather Station does not record temperature data, the ambient temperature data at the King’s Park Weather Station were adopted.  Since the construction activities would be undertaken at ground level, the worst dust impact on the ASRs would be at the ground floor of the ASRs.  The height of 1.5m above ground, which is the breathing level of human, was adopted for construction dust impact assessment.

6.5.8               The background pollutant values adopted for this assessment are derived based on EPD’s “Guideline on Assessing the ‘TOTAL’ Air Quality Impacts”.  The annual average concentrations of the pollutants measured at EPD’s Sham Shui Po and Kwun Tong air quality monitoring stations in the latest five years (Year 2002 to 2006) are adopted as the background air quality as their locations are within and adjacent to the Project area.  As most of the monitoring data in Year 2002 at Kwun Tong air quality station was missing, therefore the data of Year 2002 recorded at this station has not been taken into account in the calculation of background concentration.  The five years TSP average monitoring data recorded at EPD’s Kwun Tong and Sham Shui Po air quality monitoring stations are 78mg/m3 and 79mg/m3 respectively.  For this assessment, 79mg/m3 was taken as the TSP background concentration.

 

OPERATIONAL PHASE (GENERAL AIR QUALITY)

6.5.9               Potential air quality impacts during the operational phase of the Project would be associated with the following pollution sources.

Ÿ         Background pollutant concentrations based on five years averaged monitoring data from EPD monitoring stations at Sham Shui Po and Kwun Tong;

Ÿ         Vehicle emissions from open sections of existing and proposed road networks in KTD and roads within 500m from the project site boundary;


Ÿ         Portal emissions from Road T2 Tunnel, proposed Road L1 tunnel, decked Road D2, tunnel section of Tseung Kwan O – Lam Tin Tunnel (near TKO/T2 interface), existing Kai Tak Tunnel and existing Eastern Harbour Crossing Tunnel (EHC) portal;

Ÿ         Emissions from idling traffic at the toll plaza of EHC near Yau Tong

Ÿ         Ventilation building emissions from Road T2 Tunnel, planned Central Kowloon Route (CKR), existing Kai Tak Tunnel and existing EHC;

Ÿ         All industrial chimneys within 500m from the Project boundary;

Ÿ         Emission from the proposed hospital within KTD;

Ÿ         Cruise ship emissions from the proposed cruise terminal at Kai Tak;

Ÿ         Emission from existing Typhoon Shelters;

Ÿ         Emission from Sai Tso Wan Landfill; and

Ÿ         Planned heliport emission at the end of runway.

 

Background Pollutant Concentrations

6.5.10           The background pollutant values adopted for this assessment are derived based on EPD’s “Guideline on Assessing the ‘TOTAL’ Air Quality Impacts”.  The annual average concentrations of the pollutants measured at EPD’s Sham Shui Po and Kwun Tong air quality monitoring stations in the latest five years (Year 2002 to 2006) are adopted as the background air quality as their locations are within and adjacent to the Project area.  As most of the monitoring data in Year 2002 at Kwun Tong air quality station was missing, therefore the data of Year 2002 recorded at this station has not been taken into account in the calculation of background concentration.  Table 6.7 summarises the annual average concentrations of the pollutants (NO2, RSP and SO2) recorded at the two monitoring stations.  For the purpose of this assessment, RSP, NO2 and SO2 concentration of 57, 67 and 24 mg/m3 respectively are taken as background concentration for the operational phase assessment.

Table 6.7                           Annual Average Concentrations of Pollutants in the Latest Five Years at Sham Shui Po and Kwun Tong Air Quality Monitoring Stations

Pollutant

Annual Average Concentration in Latest Five Years (2002-2006)

(mg m-3)

Sham Shui Po station

Kwun Tong station

RSP

55

57

NO2

67

63

SO2

24

19

 

Vehicle Emissions from Open Road, Portals and Ventilation Shafts

6.5.11           The CALINE4 and the ISCST3 dispersion models were used for the prediction of the 1-hour average NO2, 24-hour average NO2, and 24-hour average RSP concentrations.  The predicted highest peak hour traffic flows and vehicle mixes for the road network within the next 15 years upon commencement of operation of the proposed road network at Year 2016 were taken to assess the worst-case air quality impacts.  For the Kwun Tong Transportation Link (KTTL), the capacity traffic flow was assumed for conservative assessment.  It is noted that some of planned land use such as Sites 1A, 1B, 1D4, 1J1 3C2 & 4D3 will be occupied prior to Year 2016 say around 2012.  With reference to the Hong Kong Planning Standard and Guideline (HKPSG), the recommended buffer distance are at least 5m for local distributor road and 10m for district distributor road.  The minimum buffer distance between the road and the site boundary of above mentioned site is 10m which is fulfil the HKPSG’s recommendation.  Adverse the vehicular impact for Sites 1A, 1B, 1D4, 1J1 3C2 & 4D3 when occupied prior to Year 2016 is not anticipated.  Therefore, the adoption of the traffic forecast within the next 15 years upon commencement of operation of all road networks (i.e. next 15 years upon Year 2016) would be a conservative approach to represent the worst case scenario.  Details of the emission calculations and assessment methodology are presented in Section 3.2 of this report.

 

Chimney Emissions from Nearby Industrial Areas

6.5.12           The Industrial Source Complex Short Term (ISCST3) dispersion model was used to predict the chimney emissions.  Since the inventory of industrial chimneys cannot be obtained from EPD, it is extracted from the previous approved EIA report of SEKDCFS and verified by site survey.  For the Ma Tau Kok Gas Works North Plant, the emissions data made reference to the information presented in the latest Specified Process License of the Gas Works.  The emission rate for those new chimneys not listed in the SEKDCFS EIA report, the averaged fuel consumption for those valid chimneys was adopted to assess the impacts from the industrial chimney emissions on the ASRs within the Project area.  The detailed emission inventory is presented in Appendix 6.1.

 

Emission from Proposed Hospital within KTD

6.5.13           A hospital is proposed at the Area 3C in KTD.  The emission impact from the chimney of the hospital was modelled as point source by employing the ISCST3 model. 

6.5.14           Based on recent checking with the relevant parties, no detailed information for the proposed hospital is available.  The following emission factor and chimney diameter as adopted in the approved EIA report of SEKDCFS were therefore taken in this assessment:

Ÿ         Height of Chimney          :    60m

Ÿ         Fuel consumption           :    600 L/hr

Ÿ         Exit Velocity                  :    6m/s

Ÿ         Temperature                   :    298K

Ÿ         Diameter of Chimney       :    0.5m

 

Emission from Proposed Heliport

6.5.15           A heliport is proposed at the end of runway.  The emission impact from the heliport was modelled as point source by employing the ISCST3 model. 

6.5.16           As there is no detailed information for the proposed heliport at the time of carrying out of this EIA, the following emission factor and parameters as adopted in the approved EIA report of Expansion of Heliport Facilities at Macau Ferry Terminal (HFMFT) (Register No.: AEIAR-095/2006) were taken in this assessment:

Ÿ       NO2 Emission Rate               : based on the HFMFT EIA Report (Register No.: AEIAR-095/2006)

Ÿ       SO2 & RSP Emission Rate    : Helicopter Safety Advisory Conference (HSAC) 2001.  Helicopter safety advisory conference (HSAC) Gulf of Mexico offshore helicopter operations and safety review

Ÿ       Flight frequency                    : Assume 4 flight/hr for both daytime and nighttime as a worst case scenario.

6.5.17           The emission rates adopted in this assessment are presented in Table 6.8 and the detailed of the emission calculations are presented in Appendix 6.2.

Table 6.8                         Emission Factor for of Twin Engine T58-GE-8F 

Helicopter Mode

NOx (lb/min)

SO2 (lb/min)

RSP (lb/min)

Approach (Approach + Hovering to Landing)

0.098

0.011

0.027

Idling

0.006

0.002

0.003

Takeoff (Hovering to Take Off + Take Off)

0.143

0.014

0.027

 


Cruise Ship Emissions from the Proposed Cruise Terminal at Kai Tak

6.5.18           A two-berth cruise terminal is proposed at the south west tip of the former Kai Tak runway.  The major sources of cruise emission would be expected during manoeuvring and hotelling.  The cruise emission impact was considered in this assessment.

6.5.19           For the purpose of this assessment, it is assumed that for each of the two berths within a 24 hour period in a day, the cruise vessel will perform the following movements:

(i)      Berthing at the cruise terminal (for a period of 1 hour):

For the purpose of this assessment, berthing include all the manoeuvring motions of the cruise vessel from the navigation channel to near the cruise terminal (for a period of 15 minutes), final manoeuvring around the berth (for a period of 15 minutes) and 30 minutes hotelling before connecting to / after disconnecting from the on-shore power supply if required.  It is assumed that the berthing of two cruise vessels will not happen concurrently.  Based on the vessel track simulation results, the entire manoeuvring motions of cruise vessels between the navigation channel and the berth would be completed within 30 minutes including the necessary turn and berth motions.  Besides, with reference to a literature “Going Cold Iron in Alaska, R.Maddison & D.H. Smith”, connecting to on-shore power supply for vessels equipped with cold-ironing would normally be completed within 30 minutes.

(ii)      Hotelling at the cruise terminal (for a period of 23 hours):

If the cruise vessel is equipped with cold-ironing, it is assumed that the cruise vessel will be connected to the on-shore power supply within 30 minutes (as assumed during the one hour berthing period) and thus no air emissions will be generated during this hotelling period.  On the other hand, if the cruise vessel is not equipped with cold-ironing, the cruise vessel will emit during its entire period of hotelling at the cruise terminal.

6.5.20           A sensitivity test to evaluate the dominant emission mode among two operation modes described above has been conducted.  The first scenario is to have cruise ships hotelling at both berth 1 and 2 for 24 hours.  The second and the third scenarios are to have one cruise ship hotelling at either berth 1 or berth 2, and another cruise ship manoeuvring around the other berth also for 24 hours.  The detail results for the sensitivity test are presented in Appendix 6.3.  The predicted maximum 1-hr average SO2 concentration for the second and third scenarios were compared with the first scenario.  The predicted highest 1-hr average SO2 concentration among all the assessment points for the first scenario is much higher than the third scenario and is similar to the second scenario.  This indicates that hotelling mode is the dominant emission mode for cruise operation near the cruise terminal with regards to the potential air quality on the ASRs on shore.  Therefore, the above assumed cruise operation with 24 hours hotelling at the cruise terminal would result in a conservative assessment.   

6.5.21           The emission rates of air pollutants from the operation of the propulsion engine, auxiliary engine and boiler of cruise vessels were estimated based on the approach stipulated in Current Methodologies and Best Practices in Preparing Port Emission Inventories, Final Report, January 2006 prepared by ICF Consulting for USEPA except on the estimation of auxiliary load for cruise ships with very high propulsion engine power.  The assumptions made in this assessment in estimating the emission rates are described in the following paragraphs.   

6.5.22           The emission rates for Panamax cruise vessel are estimated based on the power rating of the propulsion engine of Queen Elizabeth II (i.e. 2 x 44MW diesel electric engines).  Whereas the emission rates for Post-Panamax and Super Post-Panamax cruise vessel are estimated based on the power rating of the propulsion engine of Queen Mary II (i.e. 4 x 21.5MW diesel electric engines).  Queen Elizabeth II and Queen Mary II are representative of the large to mega size cruise vessels listed in the Kai Tak Planning Review.  Queen Elizabeth II and Queen Mary II have an overall length of 293.5m and 345m respectively which is at or near the maximum length of cruise vessels at the Panamax and Post-Panamax classes; the emission rates of these two cruise vessels are thus taken in this assessment as conservative assumptions.

6.5.23           Apart from these two bigger cruise vessels, emission rates for vessel size smaller than Panamax (say sub-Panamax) and a much smaller vessel compare with sub-Panamax (say super sub-Panamax) are also estimated for completeness of the assessment.  Costa Allegra, one of the planned vessels operating in Hong Kong which has an overall length of 187.8m and power rating of the diesel propulsion engine of 19.2MW, is selected to represent the emissions from the sub-Panamax cruise vessel.  Wasa Queen, one of the vessels previously operated in Hong Kong which has an overall length of 153m and gross tonnage of 16,546, is selected to represent the emissions from the super sub-Panamax.  The engine power rating of Costa Allegro was adopted for Wasa Queen as conservative assumption.

6.5.24           According to the Current Methodologies and Best Practices in Preparing Port Emission Inventories, Final Report, January 2006, an auxiliary engine power ratio for cruise ships is estimated at 27.8% based on an average total auxiliary engine power of 11MW to an average propulsion engine power of 39.6MW.  Also mentioned in the report is that, prior practice has been to use a fixed power rating for auxiliaries based on ship type and activity mode or to assume auxiliary power is equivalent to 10% of propulsion power.

6.5.25           Further research of the available information on auxiliary load for cruise ships or marine vessels had been conducted.  With reference to the Controlling Air Emissions from Marine Vessels: Problems and Opportunities, Anthony Fournier, University of California Santa Barbara, February 2006, the auxiliary engine power for large marine vessels (with propulsion engine power of 15MW or above) is about 9.9% that of the propulsion engine.  This also agrees with the practice described in the Commercial Marine Emission Inventory Development, ENVIRON International Corporation, April 2002 prepared for USEPA, to assume auxiliary power is equivalent to 10% of propulsion power.  With this 10% practice, the auxiliary load for Panamax, Post-Panamax and Super Post-Panamax cruise vessels during hotelling would be estimated based on the propulsion engine power of Queen Elizabeth II and Queen Mary II to be around 88MW x 10% x load factor for hoteling of 0.64 = 5.6MW.

6.5.26           Additionally, in accordance with the Draft White Paper on Use of Shore-side Power for Ocean-going Vessels, May 2007 prepared for the American Association of Port Authorities, the average power requirement for cruise ships at berth is 7MW.  In the Final Report on Shoreside Power Feasibility Study for Cruise Ships Berthed at Port of San Francisco, September 2005, prepared for the Port of San Francisco, the auxiliary load of cruise ships at berth as provided by the operators are estimated to be from less than 2MW to a maximum of 9.5MW.

6.5.27           As in the case of Queen Elizabeth II, the total propulsion engine power of 88MW and the auxiliary engine power is only 7MW.  The ratio of auxiliary engine to propulsion engine power is about 8%.  While it should be noted that the auxiliary engine power ratio of 27.8% suggested in the Current Methodologies and Best Practices in Preparing Port Emission Inventories, Final Report is only an average figure for a particular approach, this average auxiliary engine ratio is however considered not applicable for cruise ships with very high propulsion engine power (e.g., 88MW vs 39.6MW), which would lead to overly conservative estimates of cruise emissions.

6.5.28           Based on the estimates and data presented in the above references, an auxiliary load of 9.5MW for Panamax, Post-Panamax and Super Post-Panamax cruise vessels during hotelling was adopted for the air quality impact assessment as a reasonable and conservative estimate.  For sub-Panamax and super sub-Panamax cruise vessels, the auxiliary engine power is estimated as 27.8% of the propulsion engine power of 19.2MW of Costa Allegra.


6.5.29           The stack height of the cruise vessel was also made reference to the above four cruise vessels and is about 34.2m, 46m, 52m and 62m above water surface for super sub-Panamax, sub-Panamax, Panamax and Post-Panamax (or Super Post-Panamax) cruise vessels respectively.  With reference to the Modeling Sulfur Oxides (SOx) Emission Transport from Ship at Sea, July 2007, USPEA, the average chimney exhaust velocity, temperature and stack diameter assumed for ocean-going vessels (including cruise vessels) were 24.6m/s, 537K and 1.9m. 

6.5.30           Besides, with reference to the Current Methodologies and Best Practices in Preparing Port Emission Inventories, Final Report, practically all ocean-going vessels operate their main propulsion engines on residual oil and most cruise vessels also use residual oil (with sulphur content of 2.7 percent) for their auxiliary engines.  However, in accordance to the Merchant Shipping (Prevention of Air Pollution) Regulation in Hong Kong, the sulphur content of ship’s fuel should refer to Annex VI of the International Convention for the Prevention of Pollution from Ships (MARPOL).  For the local fuel suppliers, the average sulphur content of fuel supplied/used in Hong Kong is 3.8%.  With reference to the Current Methodologies and Best Practices in Preparing Port Emission Inventories, Final Report, SO2 and particulates emission factors are directly proportional to the sulphur content of the fuel, SO2 and particulates emission factors should be adjusted if the sulphur content of the fuel is different from the assumption of 2.7% assumed in the reference.  Therefore, for the purpose of this assessment, a correction factor of 1.41 (i.e. 3.8/2.7) was applied in the estimation of emission rates of SO2 and particulates for propulsion engines and auxiliary engines. 

6.5.31           In this assessment, it is also assumed that the cruise vessel will be assisted by two tug boats during the 30 minutes berthing in or berthing out motions.  The emission rates of the tug boats were also estimated in accordance with the Current Methodologies and Best Practices in Preparing Port Emission Inventories, Final Report based on average engine power and load factor for tug boats.  The detailed calculations of the emissions from tug boats are shown in Appendix 6.4.

6.5.32           Table 6.9 summarizes the air pollutants emission rates estimated for different classes of cruise vessel under different movement mode.  The emissions during hotelling are applicable for cruise vessels that are not equipped with cold-ironing during the short period of berthing in and berthing out.  The detailed calculations of cruise emissions are presented in Appendix 6.4.

Table 6.9                           Cruise Air Pollutants Emission Rates

Engine

Movement Mode

Air Pollutant

Super Sub-Panamax / Sub-Panamax

Panamax vessel

Post-Panamax and Super Post-Panamax vessel

Propulsion Engine

Manoeuvring

NOx, kg/hr

24.89

24.64

24.08

SO2, kg/hr

6.00

27.50

26.87

RSP, kg/hr

4.49

2.83

2.76

CO, kg/hr

4.22

1.94

1.89

Hotelling

NOx, kg/hr

0.00

0.00

0.00

SO2, kg/hr

0.00

0.00

0.00

RSP, kg/hr

0.00

0.00

0.00

CO, kg/hr

0.00

0.00

0.00

Auxiliary Engine

Manoeuvring

NOx, kg/hr

62.77

174.56

174.56

SO2, kg/hr

66.71

185.50

185.50

RSP, kg/hr

6.85

19.05

19.05

CO, kg/hr

4.70

13.06

13.06

Hotelling*

NOx, kg/hr

50.22

139.65

139.65

SO2, kg/hr

53.37

148.41

148.41

RSP, kg/hr

5.48

15.24

15.24

CO, kg/hr

3.76

10.45

10.45  

Boiler

Manoeuvring

NOx, kg/hr

0.15

0.15

0.15

SO2, kg/hr

0.95

0.95

0.95

RSP, kg/hr

0.02

0.02

0.02

CO, kg/hr

0.06

0.06

0.06

Hotelling*

NOx, kg/hr

0.15

0.15

0.15

SO2, kg/hr

0.95

0.95

0.95

RSP, kg/hr

0.02

0.02

0.02

CO, kg/hr

0.06

0.06

0.06

Total Emission

Manoeuvring

NOx, kg/hr

87.81

199.36

198.80

SO2, kg/hr

73.66

213.96

213.33

RSP, kg/hr

11.37

21.90

21.84

CO, kg/hr

8.98

15.06

15.01

Hotelling*

NOx, kg/hr

50.37

139.80

139.80

SO2, kg/hr

54.32

149.36

149.36

RSP, kg/hr

5.50

15.27

15.27

CO, kg/hr

3.82

10.51

10.51

Note:     *   Estimated emissions for cruise vessels not equipped with cold-ironing.

               #     The correction factors 1.41 for 3.8% sulphur content were included for calculating SO2 and RSP emission rates.

 

Sensitivity Test Scenarios

6.5.33           Table 6.10 summarizes the sensitivity test scenarios to be examined under the cruise emission impact assessment.  Scenarios 1 to 10 in are the scenarios with both berths occupied by different combinations of cruise vessels without cold-ironing.

Table 6.10                         Sensitivity Test Scenarios

Scenario

Berth 1 (south)

Berth 2 (north)

Vessel class

Vessel class

1

Super Sub-Panamax

Super Sub-Panamax

2

Sub-Panamax

Sub-Panamax

3

Sub-Panamax

Panamax

4

Sub-Panamax

Post-panamax or Super post-panamax

5

Panamax

Sub-Panamax

6

Panamax

Panamax

7

Panamax

Post-panamax or Super post-panamax

8

Post-panamax or Super post-panamax

Sub-Panamax

9

Post-panamax or Super post-panamax

Panamax

10

Post-panamax or Super post-panamax

Post-panamax or Super post-panamax

 

6.5.34           The sensitive test results are presented in Appendix 6.5.  It was identified that Scenario 6 with Panamax vessels berthed at both Phase 1 and Phase II Berths is the worst case scenario by comparing the highest impacts among the ASRs.  Scenario 6 was therefore adopted in the cumulative air quality assessment.


6.5.35           With reference to the total emission data for the Panamax vessel during manoeuvring presented in Table 6.9, the ratio of total NO2 (as 20% of NOX), SO2, RSP, and CO emissions to the corresponding 24-hour average AQO (there is no 24-hour average AQO for CO, the AQO of CO for shorter period of 8-hour CO is used) is 0.266, 0.611, 0.122, and 0.0015 respectively.  This indicates that NO2 and SO2 are the two most critical air pollutants of concern for the Panamax vessel during manoeuvring.  In other words, if the predicted NO2 and SO2 concentrations comply with the corresponding AQO, air pollutants like RSP and CO with lower ratio will also comply with their respective AQO.  Similar observations are also noted for other vessel types during both manoeuvring and hotelling.  NO2 and SO2 were therefore the two most critical air pollutants for cruise emissions.  For the purpose of cumulative assessment, NO2, SO2 and RSP emissions were considered.

6.5.36           ISCST3 Model was used for the prediction of the hourly and daily average NO2 and SO2 and daily RSP concentrations arising from the manoeuvring and hotelling of cruise vessels at the proposed cruise terminal.  The conversion factor from NOx to NO2 was assumed to be 20% in accordance with EPD’s Guidelines on Choice of Models and Model Parameters on predicting near field traffic emission impacts.

6.5.37           With some preliminary review of the stack position of cruise vessels, it is note that the stacks of cruise vessels are typically located at 1/4th to 1/3rd of the vessel length from the stern of the vessels.  In this assessment, it was assumed that the cruise vessels are pointing south and that the stack of the cruise vessels is located at 1/4th of the vessel length from the stern of the vessels such that the stacks are located closer to the elevated ASRs as a conservative assumption.  For the purpose of this assessment, the cruise emissions during manoeuvring and hotelling were modelled as point sources at the stack location of the cruise vessels.  During the manoeuvring between the navigation channel and the cruise terminal, the point source is located mid way between the berth and the navigation channel in the ISCST3 model.  During the final manoeuvring near the berth and during hotelling, the point source is located at the stack location of final berthing position described above.

6.5.38           Hourly meteorological data for the Year 2006 (including wind speed, wind direction, air temperature, Pasquill stability class and mixing height) of the South East Kowloon Weather Station was employed for the model run.  As South East Kowloon Weather Station does not record temperature data, the ambient temperature data at the King’s Park Weather Station were adopted.  The urban dispersion mode in ISCST3 model was selected.

Emissions from the Kwun Tong Typhoon Shelter and To Kwa Wan Typhoon Shelter

6.5.39           The loading/unloading are the major activities within typhoon shelters.  Based on the site observation, around 40 & 20 barges were parking within Kwun Tong Typhoon Shelter and To Kwa Wan Typhoon Shelter, respectively.  Around 20 barges have loading / unloading activities at Kwun Tong Typhoon Shelter.  For those barges parked in the To Kwa Wan Typhoon Shelter, it was observed no loading / unloading activities and without started engine.  For this assessment, we assumed 60 barges at both typhoon shelters for conservative assessment.

6.5.40           The emission rates of air pollutants from the operation of the auxiliary engine of barges were estimated based on the approach stipulated in the Current Methodologies and Best Practices in Preparing Port Emission Inventories, Final Report, January 2006 prepared by ICF Consulting for USEPA.  The power rating of 82 kW for auxiliary engine and emission height of the barges of about 5m above water surface were adopted for this assessment.  The detailed emission calculations are presented in Appendix 6.6.


Cumulative Impact of Criteria Air Pollutants

6.5.41           As mentioned above, background pollutant levels within and adjacent to the Study Area, vehicle emissions from open sections of the existing and planned road networks, tunnel portal and ventilation building emissions, all of these will contribute to the cumulative impact. The assessment methodology of road emission, tunnel portal and ventilation building emissions are presented in Section 3.2.

6.5.42           The pollutant concentrations at the ASRs was predicted by both CALINE4 and ISCST3 models, where

Ÿ         the CALINE4 model was used to predict the open road emissions from the existing and planned road networks; and

Ÿ         the ISCST3 model was used to predict all the portal emissions and ventilation shaft emissions, chimney emissions, emission from hospital, cruise ship, proposed heliport and typhoon shelters.

6.5.43           To obtain the cumulative pollutant concentration at each receptor, the predicted values from the CALINE4 and the ISCST3 models are added together with the background pollutant concentrations. 

OPERATIONAL PHASE (ODOUR)

6.5.44           A number of previous studies had been conducted to understand and to address the existing environmental problems associated with the Kai Tak Development.  Based on the data collected from previous studies, the key odour problems being identified are at KTAC and its vicinity such as the lower KTN in North Apron, the Jordan Valley Box Culvert (JVBC) and KTTS.  Other odour sources in the vicinity of the KTD include the planned sewage pumping stations and the existing sewage treatment works at To Kwa Wan and Kwun Tong.  The potential odour impacts associated with the planned sewage pumping stations would be localized and are readily controlled with proper design and odour abatement measures.  Details of the environmental assessments for the planned sewage pumping stations in KTD are presented in Section 4 of this EIA Report.  With regards to the existing sewage treatment works at To Kwa Wan and Kwun Tong, these sewage treatment works are existing facilities with ASRs located in the close proximity, odour mitigation measures have been implemented at these sewage treatment works to prevent adverse odour impacts at the surrounding ASRs, adverse odour impacts at the planned ASRs within KTD is therefore not expected.  The proposed upgrading of Kwun Tong PTW is classified as a DP under Item F.1, Part I, Schedule 2 of the EIAO.  The associated environmental impacts will be adequately addressed in a further detailed EIA study to be prepared and submitted under the EIAO by EPD.

6.5.45           A detailed study with further detailed field surveys and laboratory testing are conducted under this assignment to delineate the odour emitting areas and to determine the mechanism of odour generation of the three key areas namely KTN in North Apron, KTAC and KTTS.  Details of the study are included in Annex A of this EIA Report with the relevant material on odour impact assessment extracted and presented in this section.

 

Odour Source Sampling and Analysis

6.5.46           Further detailed field survey was conducted to collect relevant environmental data at different sampling locations within KTAC and KTTS for subsequent analysis of their potential correlation with the odour emission strength.  The scopes of the detailed survey include:

Ÿ         Conduct odour sampling using a wind tunnel method and in-situ H2S measurements at the designated sampling locations (including one QA/QC station) within KTN, KTAC and KTTS;

Ÿ         Conduct air sampling using sampling tube and in-situ H2S measurements at Jordan Valley Culvert Outfall (JVCO) and two box culverts at KTN;


Ÿ         Carry out H2S analysis, olfactometry and hedonic tone tests for the collected samples in the laboratory;

Ÿ         Carry out in-situ measurements of marine water for dissolved oxygen (% saturation and mg/L), water depth (m), salinity (ppt), redox potential (mV) and pH, and ambient air and water temperature (oC);

Ÿ         Conduct water sampling at culvert discharges of KTN and odour potential test on water samples in the laboratory; and

Ÿ         Record site conditions during each sampling.

 

6.5.47           In order to capture more representative results, all measurements and sampling for KTN, KTAC and KTTS were carried out during neap ebb tide with reference to the tidal chart of the Hong Kong Observatory.  For JVC and box culverts, measurements were measured during neap tide at both flood and ebb tides.

 

6.5.48           On-site observations including odour intensity, odour nature, and possible sources were recorded by the odour panel members during the field odour sampling.  Besides, relevant meteorological data such as ambient temperature, relative humidity, wind speed and wind direction, etc. recorded at the Hong Kong Observatory station during the measurement / sampling period were taken for reference purpose.

 

6.5.49           The detailed field survey was conducted during the hottest days in the summer of 2007 during low tide periods to capture the reasonable worst case odour emissions from KTN, KTAC and KTTS.  Odour source samples were collected at a total of 91 sampling locations at 4 water zones namely KTN, northern KTAC (NKTAC), southern KTAC (SKTAC) and KTTS for determining odour emission rate.  The sampling locations are shown in Figure 6.3

Determination of Specific Odour Emission Rate

6.5.50           To determine the odour emission rate of an area source such as water surface, odour source sampling was performed by using “hood” method, whereby a wind tunnel was placed on the odour emission surface of the designated measurement locations and a stream of odour-free nitrogen gas from a certified gas cylinder was supplied to generate an air inflow at a fixed velocity inside the wind tunnel.  The most appropriate and reliable inflow rate inside the wind tunnel was determined by the wind speed inflow rate sensitivity test.

6.5.51           The emission rate was determined by the air flow rate through the hood and the odour concentration of the exit air.  A specific odour emission rate (SOER) of each area source was calculated by the following equation:

Olfactometry Analysis

 

6.5.52           The odour concentration of the collected air sample was determined by a Forced-choice Dynamic Olfactometer (Olfactomat-n2) with a panel of human assessors being the sensor in accordance with the European Standard Method: Air Quality – Determination of Odour Concentration by Dynamic Olfactometry (EN13725).  The odour concentration is measured by determining the dilution factor required to reach the detection threshold.

6.5.53           The odour laboratory was ventilated so as to maintain an odour-free environment and to provide fresh air to the panel members.  Each odour testing session was comprised at least five qualified panellists.  All of the panellists were screened beforehand by using 50 ppm solution / mixture of certified n-butanol standard gas.

 

Odour Emission Inventory

 

6.5.54           A detailed odour survey was conducted in the summer of 2007 to estimate the worst case existing odour emission strength of KTN, KTAC and KTTS.  During the odour survey, odour source samples were collected from KTAC, KTTS, and the section of KTN within the north apron of the former Kai Tak Airport.  Details of the odour survey are presented in Annex A (Section 3).

6.5.55           Odour source samples were collected from a total of 91 sampling locations including 7 locations at KTN, 58 locations at KTAC, and 26 locations at KTTS.  The existing specific odour emission rates (SOER) derived from the odour concentration of collected samples for each source area are listed in Table 6.11.  The water depth and bottom dissolved oxygen level measured at the sampling locations during the odour survey are also listed in the table.  The odour survey was carried out during the hottest days and under with low tide periods in the summer.  Because these conditions are conducive to release of trapped gases, the estimated odour emission rates are considered to represent a reasonable worst-case condition for the existing situation.  Figure 6.3 shows the distribution and ID of the sampling locations and Figure 6.4 shows a contour plot of the existing odour strength of KTN, KTAC and KTTS based on the findings of odour survey.

Table 6.11     Existing Odour Emission Rates of KTN, KTAC, and KTTS

Location ID

Water Depth (m)

Bottom DO (mg/l)

SOER (ou/m2/s)

KTN

A section of the KTN further to the north within 500m away from the project boundary of KTD

0.22

(taken as the SOER of KTN7, see discussion in S.6.5.58)

KTN7

0.60

6.66

0.22

KTN6

0.50

5.55

3.79

KTN5

0.50

5.50

0.90

KTN4

0.80

6.04

0.21

KTN3

0.86

5.79

1.21

KTN2

1.08

3.46

44.58

KTN1

1.04

2.63

9.45

KTAC

NKTAC93

2.4

0.36

1.83

NKTAC92

1.7

13.15

23.30

NKTAC91

0.8

1.59

18.19

NKTAC85

4.3

0.39

0.61

NKTAC84

3.9

0.46

1.16

NKTAC83

2.2

0.56

2.89

NKTAC82

1.8

5.04

10.25

NKTAC81

0.8

2.30

3.50

NKTAC75

3.7

0.23

0.20

NKTAC74

5.0

0.25

0.36

NKTAC73

3.8

0.47

0.61

NKTAC72

1.9

4.55

9.56

NKTAC71

1.9

0.83

2.46

NKTAC65

4.1

0.39

0.36

NKTAC64

4.2

0.41

0.63

NKTAC63

3.7

0.41

1.35

NKTAC62

2.2

0.41

19.74

NKTAC61

1.3

8.75

24.83

NKTAC55

4.2

0.43

0.44

NKTAC54

4.5

2.48

0.93

NKTAC53

4.0

0.47

1.16

NKTAC52

4.2

0.55

7.41

NKTAC51

1.2

3.02

13.51

NKTAC45

4.4

0.39

1.16

NKTAC44

4.2

0.37

0.98

NKTAC43

4.2

0.52

2.30

NKTAC42

4.0

0.34

1.97

NKTAC41

1.9

1.96

1.16

NKTAC35

1.1

3.95

17.10

NKTAC34

3.3

3.49

0.19

NKTAC33

4.0

3.22

0.19

NKTAC32

3.5

4.23

0.20

NKTAC31

1.5

5.77

2.13

NKTAC25

4.3

2.30

2.90

NKTAC24

4.2

2.76

0.86

NKTAC23

3.5

3.04

0.13

NKTAC22

3.1

2.22

0.13

NKTAC21

1.9

2.85

0.83

NKTAC15

4.3

4.20

0.31

NKTAC14

4.9

2.87

1.07

NKTAC13

4.4

2.71

0.30

NKTAC12

3.5

2.06

1.44

NKTAC11

1.9

6.73

1.90

SKTAC35

4.2

8.43

0.33

SKTAC34

4.8

13.20

0.22

SKTAC33

5.1

8.41

0.16

SKTAC32

4.8

7.85

0.19

SKTAC31

3.2

1.70

8.76

SKTAC25

3.9

0.60

2.20

SKTAC24

5.3

0.11

4.87

SKTAC23

5.2

0.12

2.05

SKTAC22

5.5

0.12

4.86

SKTAC21

4.1

5.00

0.15

SKTAC15

3.4

2.34

3.64

SKTAC14

6.2

0.09

3.37

SKTAC13

5.7

0.10

2.05

SKTAC12

5.5

0.13

2.13

SKTAC11

3.5

2.79

2.05

KTTS

KTTS74

6.8

0.52

0.13

KTTS73

5.8

1.26

0.38

KTTS72

5.7

0.07

1.90

KTTS71

5.2

0.11

1.11

KTTS61

6.1

0.42

0.54

KTTS54

6.1

1.43

0.11

KTTS53

6.0

1.83

0.15

KTTS52

6.2

0.46

1.02

KTTS51

6.0

0.40

0.47

KTTS45

7.3

1.93

0.19

KTTS44

6.2

2.01

0.48

KTTS43

6.2

1.00

0.51

KTTS42

5.1

2.54

0.10

KTTS41

5.6

1.02

0.17

KTTS34

6.2

0.46

0.13

KTTS33

6.2

1.57

0.61

KTTS32

6.3

1.30

0.19

KTTS31

5.6

1.50

0.21

KTTS25

6.2

5.29

0.12

KTTS24

6.0

5.23

0.08

KTTS23

7.1

6.51

0.08

KTTS22

6.7

7.22

0.10

KTTS21

7.2

8.00

0.11

KTTS13

7.1

6.40

0.12

KTTS12

6.8

8.30

0.08

KTTS11

6.2

8.17

0.08

 

Air Dispersion Model

 

6.5.56           Odour impacts were assessed using the Industrial Source Complex Short Term 3 Model (ISCST3), an air dispersion model acceptable to the Environmental Protection Department (EPD).  Hourly meteorological data for year 2006 (including wind speed, wind direction, air temperature, Pasquill stability class and mixing height) recorded at the Hong Kong Observatory King’s Park Meteorological Station was employed for the model run.  Because the study area is in an urban area, the “Urban” dispersion model option was selected.

6.5.57           The modelled hourly odour concentrations at the ASRs were converted into peak 5-second odour concentrations so as to compare with the EIAO-TM odour criteria.  EPD’s “Guidelines on Choice of Models and Model Parameters”, recommends the methodologies proposed by Duffee et al.[1] and Keddie[2] in performing the conversion from hourly to 5-second average concentration.  However, it is noted that these methodologies are based on findings of earlier researchers on dispersion of odour emissions from point sources.  More recent researchers have indicated that the peak-to-mean ratio used for odour dispersion assessments would depend upon the type of source, atmospheric stability and distance downwind.  For example, depending on the physical size of source in relation to the distance to the ASR, the peak-to-mean ratio of odour dispersion from area source could be far smaller than that from point source.  In this assessment, the major odour sources to be studied, namely the water surfaces of KTN, KTAC and KTTS, are in the form of large area sources.  Therefore, for the purpose of this assessment, to produce more realistic predictions for odour dispersion from area sources, reference was made to the peak-to-mean ratio for area sources stipulated in “Approved Methods for Modelling and Assessment of Air Pollutants in New South Wales” published by the Department of Environment and Conservation, New South Wales, Australia (NSW Approved Method).

6.5.58           The dispersion modelling techniques employed for this assessment followed those described in EPD’s “Guidelines on Choice of Models and Model Parameters” using ISCST3 model except the use of alternative peak-to-mean ratios discussed above.  However, it should be noted that the peak-to-mean ratios stated in the NSW Approved Method are derived based on experimental and theoretical analyses and assuming a 0.1% exceedance level (Ref.: Statistical Elements of Predicting the Impact of a Variety of Odour Sources, Peter R. Best, Karen E. Lunney and Christine A. Killip, Water Science and Technology, Australia, 44: 9 pp 157-164 2001).  In other words, there would be a 0.1% probability that the actual peak concentration would be higher than those derived with the peak-to-mean ratios stated in the NSW Approved Method.

6.5.59           In accordance with the NSW Approved Method, the conversion factors are used for converting the maximum modelled 1-hour average concentrations to corresponding maximum 1-second average concentrations that could occur during that hour.  As a conservative approach, these conversion factors were directly adopted for converting the 1-hour average concentrations predicted by the ISCST3 model to 5-second average concentrations for compliance checking with the odour criteria.  In this case, the odour sources are located in the vicinity of the ASRs, therefore, the ASRs are considered to be located in the near field region with regards to the odour sources as per the NSW Approved Method.  The conversion factors adopted in this assessment for different stability classes are shown in Table 6.12.

Table 6.12                      Conversion Factors for Hourly to 5-second Average Concentration 

Pasquill Stability Class

Conversion Factor (1-hour to 5-second average)

A

2.5

B

2.5

C

2.5

D

2.5

E

2.3

F

2.3

 

6.5.60           Under the existing (unmitigated) scenario, all the odour source areas listed in Table 6.11 above were included in the dispersion model for assessing the existing odour impact.  In addition, a section of the KTN further to the north within 500m away from the project boundary of KTD was also included in the odour impact assessment as existing odour source under both the existing (unmitigated) scenario and the mitigated scenarios.  The location of KTN7 is the northernmost section of KTN with odour survey data and it well represents the potential odour emissions from the section of KTN immediate further north of the apron area.  Thus the SOER measured at this location is taken to represent the existing section of KTN further north of the apron area.

6.5.61           The potential odour emissions from the headspace of KTN and JVC and from the accumulated sediment on the northern seawall of former Kai Tak Runway would have transient effect to the cumulative odour impacts at ASRs.  However, these potential odour emissions are difficult to quantify and are not included in the odour modelling for the unmitigated scenario.  Therefore, there would be certain degree of underestimation in the predicted odour impacts at ASRs under the unmitigated scenario.

Presentation of Assessment Results

 

6.5.62           The predicted odour concentrations at representative planned ASRs at KTD were determined.  The odour concentrations within the study area under existing odour strength scenario and the mitigated scenario(s) are presented in the form of contour plots.

6.6                    Identification of Environmental Impacts 

Construction Dust

6.6.1               The major potential air quality impact during the construction phase of the Project will be dust arising from haul road emissions, open site erosion, excavation and filling activities.  Civil works related to the demolition of existing structures and construction of infrastructure will also cause emissions.

6.6.2               The concurrent works for the SCL, CKR, Road T2 and Anderson Road projects have also been taken into account in assessing the impacts. 

Operational Phase

Vehicular Emissions, Cruise Ship Emissions from the proposed Cruise Terminal at Kai Tak, Chimney Emissions from the San Po Kong and Kwun Tong Industrial Areas, Emission from the Planned Hospital and Planned Heliport in Kai Tak and Emission from Typhoon Shelters

6.6.3               The major air pollutant sources during operational phase of the Project would be vehicular emissions (include the planned KTTL), portal emission from the proposed Road T2 tunnel, as well as the emissions from CKR Ventilation Building, Kai Tak Tunnel Ventilation Building and Road T2 Ventilation Building.  Other than emissions from tunnel portals, long sections of landscape deck/deckovers may also result in portal emissions.  Within the study area, it was identified that decked section of Road D2 may generate portal emissions.


6.6.4               Besides the vehicular emissions, emissions from the cruise ships using the cruise terminal at Kai Tak, emission from the proposed hospital at Kai Tak, chimney emissions within 500m from the Project boundary, planned Heliport and emission from typhoon shelters would also contribute to the cumulative air quality impact.  The locations of emission are presented in Figure 6.2

Odour Impact from KTN, KTAC and KTTS

6.6.5               An odour study for KTAC and KTTS had been carried out under the Stage 1 Planning Review and based on its findings, further detailed field surveys and laboratory testing were conducted in order to delineate the odour emitting areas and to determine the mechanism of odour generation of the three key areas namely KTN in North Apron, KTAC and KTTS.  Details of the KTAC and KTTS studies are included in Annex A of this EIA Report.

6.6.6               Based on the findings of the Phase 1 Planning Review and the results from the further detailed field surveys and laboratory testing, the decomposition of organic matters in the sediments were considered to be the main source of odour.  There are considered to be four distinct types of odour emissions within the Study Area.  The types of odour emissions include (i) the main channel area, (ii) culvert / outfall openings, (iii) seawall along the former Kai Tak runway and (iv) the Kai Tak Nullah (KTN).

 

Main Channel Area

 

6.6.7               The main channel area consisted of the whole of KTAC and KTTS and is considered to be the major contributors to odour emissions.  The odour mainly generated from the high AVS contained sediments under highly negative redox conditions, which result in the release of H2S gas to the overlying water and atmosphere.  The key factors that affect this type of odour generation are:

-             Overlying water depths, influenced by tidal effects;

-             Water quality, in particular dissolved oxygen concentration and stratification effect;

-             Temperature;

-             Sediment quality including total organic content (TOC), redox potential and AVS levels; and

-             Water circulation which influence the water quality and rate of sediment deposition in the water system.

 

Culvert Opening

 

6.6.8               Based on site observations, odour emissions were detected at the culvert / outfall openings.  The culvert / outfall openings include the Jordan Valley Culvert Outfall (JVCO), discharging to north KTAC and three major existing culvert systems discharging to KTN.  The three major culvert systems serve the Kowloon City, San Po Kong and Diamond Hill / Ngau Chi Wan catchment areas.

 

6.6.9               Flows from the culverts were observed to be contaminated with polluted discharges from possible expedient connections.  The polluted discharges would cause the deposition of contaminated silts / sediments, releasing odorous chemicals to the overlying water and headspace.  During high tide, when the water level rises, odour accumulated in the headspace would be emitted to the atmosphere, outside of the culverts.

 

6.6.10           The key factors that affect this type of odour generation are:

-             Effluent quality of the culverts;

-             Culvert dimensions and headspace size; and

-             Amount of contaminated silts / sediments deposited onto the bottom of the culverts.

 


Northern Seawall of Former Kai Tak Runway

6.6.11           The northern seawall of the former Kai Tak runway is sloped and consisted of a relatively flat bench before sloping to the seabed (see Figure 5.1 of Annex A).  It is constructed of rectangular boulders with gaps in between.  Based on site observations, sediments were noted deposited at the gaps and bench area and when the sediments were exposed to air during low tide, odour would be released.

 

6.6.12           The key factors that affect this type of odour generation are:

-             Duration of low tide when sediment is exposed to the atmosphere;

-             Size of gaps / bench area for the accumulation of contaminated sediments; and

-             Water flow, which influenced the rate of sediment deposition.

 

Kai Tak Nullah

 

6.6.13           The KTN can be divided into two sections.  The downstream section of KTN is located at the North Apron of the former Kai Tak Airport and is more or less flat in gradient.  The section starting from the middle part of the North Apron is affected by the tidal influx and always flooded with water.  The water quality starts to deteriorate at this section as there are culverts from the hinterland discharging polluted runoffs into the KTN.  While the tidal influence caused backup of seawater, sediments originated from polluted discharges starts to deposit at the channel bed.  Bubbles of odorous gases were observed evolving from the deposit of the channel bottom with smell of H2S.

 

6.6.14           The flow from the upstream section of KTN is contributed mainly from the THEES (Tolo Harbour Effluent Export Scheme) discharges:- secondary treated effluent from the Tai Po and Sha Tin Sewage Treatment Works.  The treated effluent is exported through a tunnel system connecting Sha Tin Sewage Treatment Works to KTN.  The THEES effluent is discharging at a location near Wong Tai Sin Police Station.  The treated effluent would have some characteristics odour but is not necessarily irritating.  As observed on site, it was like “soil odour after rain”.  The long standing time inside the tunnel system may give rise to some odour generation possibly from the anoxic conditions of the tunnel.  The origin is different from the sediment oriented odour of KTAC.  The turbulent water surface resulted from the high flow rate promotes the release of odorous chemicals to the atmosphere at the local level.  This type of odour was reduced significantly further downstream, as observed.  The downstream area of KTN is benefited by the large base flow and the flushing effects provided by THEES.

6.6.15           The key factors that affect this type of odour generation are:

-             Effluent quality of the THEES and culverts;

-             Temperature; and

-             Water depths, influenced by tidal effects.

 


Odour Impact from existing sewage treatment works at To Kwa Wan and Kwun Tong, Pumping Station No. 6 (PS6), Desilting compound at KTN and DWFI Compound for JVBC

6.6.16           For the existing sewage treatment works (STW) at To Kwa Wan and Kwun Tong, proper odour mitigation measures have been implemented to prevent any adverse odour impacts at their existing adjacent ASRs.  With reference to the odour complaint record maintained by EPD, there was no and only one odour related complaint for the Kwun Tong STW and To Kwa Wan STW respectively in the past 5 years.  Besides, both the existing Kwun Tong STW and the proposed upgrading of Kwun Tong STW (in Site 6B1) are located at more than 500m from the nearest planned ASRs in KTD, cumulative odour impacts at the planned ASRs in KTD due to Kwun Tong STW and its proposed upgrading is not expected.  The proposed upgrading of Kwun Tong STW is classified as a Designated Project under EIAO, the associated environmental impacts will be addressed in a further detailed EIA study to be prepared by the future project proponent.  For the existing To Kwa Wan STW, a new deodorisation system has recently been commissioned in year 2006 to mitigate the potential odour emissions from the STW and no odour complaint was received thereafter.  Therefore, unacceptable odour impacts associated with the existing To Kwa Wan STW at the surrounding existing and planned ASRs shall not be expected.  Cumulative odour impacts at the planned ASRs in KTD are thus also not expected.

6.6.17           Two desilting compounds are proposed for KTN (at Site 1D6 and Site 1P1) and a dry weather flow interceptor (DWFI) compound is proposed for JVC (at Site 3A3) to contain pollution in drainage systems entering the KTAC and KTTS by interception facilities until the ultimate removal of the pollution sources.  It is noted that under the Project “Upgrading of Central & East Kowloon Sewerage - Packages 1 to 4”, upgrading and construction of about 21km long sewers and associated sewerage works would be carried out for the central and east Kowloon region.  This will include upgrading of the existing DWFIs for the drainage catchment of KTN.  It is expected that these existing DWFIs at the upstream of KTN can effectively control the polluted flows after upgrading.  In addition, under the “Kai Tak Approach Channel – Expedient Connection Survey Study”, surveys will be undertaken to identify expedient connections in public drains/sewers and domestic buildings in Kowloon City, Ngau Tau Kok, Kowloon Bay, Wong Tai Sin and Choi Hung, for subsequent rectification.  With these improvement works already planned for the upstream of KTN, DWFIs are therefore not recommended for the KTD de-silting compounds.  Tidal barrier in form of penstock will be provided at the DWFI compound for JVC.  Desiliting facilities will form part of the desilting and DWFI compounds and regular desilting will be carried out by the maintenance department at KTN and JVC to minimize accumulation of sediment within the downstream section of KTN and JVC, and hence fully mitigate the potential odour emissions from the headspace of KTN and JVC near the existing discharge locations.  Inspection will be carried out at KTN and JVC in regular intervals each year to monitor silt levels and the requirement to desilt.  In the event that unacceptable odour due to headspace emissions from KTN and JVC are noticed by the inspection staff, de-silting can be arranged to clear up the silt accumulated in the box culverts to mitigate the odour problem.  The odour generating operations within the proposed desilting compounds and DWFI compound will be fully enclosed and the odorous air will be collected and treated by high efficiency deodorizers before discharge to the atmosphere.  Besides, all the three proposed desilting compounds and DWFI compound are separated from the immediate adjacent existing and/or planned ASRs with roads and/or amenity area.  The compounds mainly serve to remove, dry and dispose of the sediment deposited at the box culvert of KTN and JVC.  The detailed processes will be subjected to the detailed design of the compounds.  With regards to the desilting operation, it is anticipated that the operation will be conducted within dry season.  Five months from November to March are defined as the dry season and hence all desilting activities shall be scheduled to complete within this period each year as a cycle.  Since the dry season is also the period with lower ambient temperature, odour nuisance associated with the operation of the desilting or DWFI compound during this period should also be lower.  Therefore, it is anticipated that the residual odour impacts associated with the desilting compounds and the DWFI compound should be minimal and localized if any, and cumulative odour impacts with odour emissions from KTAC and KTTS are not expected.

6.6.18           Potential odour emission from wet well and discharge chamber are possible odour sources of PS6.  Wet well and other sewage facilities would be covered and foul air would be ventilated to deodorizer for treatment before discharge to the environment.  The ventilation system would also maintain a slight negative pressure within the facilities.  Similar odour mitigation measures have also been implemented at other SPS in urban area to successfully control the potential odour impacts.  With proper implementation of these odour mitigation measures, adverse odour impact from PS6 would not be expected.

6.6.19           For the other SPSs within KTD including PS1, PS1A, PS2, PN3 and NPS, their environmental impact are addressed in Section 4 of this EIA report.

6.6.20           Therefore, cumulative odour impacts with odour emissions from the above potential odour sources are not expected.

 

Odour Impact from Maintenance of Box Culvert in KTD

6.6.21           There is a potential for short-term release of odorous gas due to disturbance of the sediments during the maintenance activities of the box culverts in KTD.  Nevertheless any odour impacts during the maintenance will be temporary and confined to an area close to odour generating activities.  The extent of impacts depends on the amount and duration of exposure of odour sources.  Also, maintenance works area likely to be carried out in dry cold conditions during the winter when bioactivity and thus odorous gas production is low.

6.7                    Prediction and Evaluation of Environmental Impacts

Construction Dust

6.7.1               The maximum predicted cumulative 1-hour and 24-hour average TSP levels for construction of the Project are summarised in Table 6.13.  Based on results indicated in Table 6.13, no exceedance of 1-hour average and 24-hour average TSP guideline and AQO is predicted at the ASRs 1.5m above ground.  The predicted cumulative maximum 1-hour average and 24-hour average TSP concentration contours at 1.5m above local ground are shown in Figures 3.3 to 3.6 (the bolded contours represent the respective AQOs) and no air sensitive uses are identified within the areas with predicted exceedances.

Table 6.13                      Predicted Cumulative Maximum 1-hour Average TSP Concentrations at 1.5m above ground

ASRs

Scenario 1

(Mid 2009 to Mid 2013)

Scenario 2

(Mid 2013 to Late 2016)

Predicted 1-hr TSP conc.[1]

Predicted 24-hr TSP conc.[2]

Predicted 1-hr TSP conc.[1]

Predicted 24-hr TSP conc.[2]

A1

228

131

250

133

A2

163

117

165

116

A3

161

114

183

112

A4

163

115

189

114

A5

187

117

174

114

A6

170

111

188

118

A7

170

114

196

124

A8

191

118

208

130

A9

203

124

211

137

A10

218

125

224

139

A11

234

128

240

144

A12

210

123

219

140

A13

238

140

247

159

A14

267

161

280

169

A15

251

152

304

170

A16

250

149

325

173

A17

304

168

384

220

A18

212

133

267