7                                            Waste Management Assessment

7.1                                      Introduction

This section identifies the potential wastes arising from the construction and operation of the two proposed submarine gas pipelines and Gas Receiving Stations (GRSs) to the north of the Black Point Power Station (BPPS), and assesses the environmental impacts associated with waste handling and disposal.  The main issues are:

·           Management of dredged marine sediment;

·           Handling and disposal of contaminated soil/sediments;

·           Handling and disposal of construction and demolition (C&D) materials ([1]) arising from the reclamation works; and

·           Chemical wastes, sewage, general refuse and industrial wastes from work vessels and equipment.

7.2                                      Relevant Legislation & Assessment Criteria

The following discussion on legislative requirements and evaluation criteria applies to both the construction and operation phases of the proposed Project.

The criteria and guidelines for evaluating potential waste management implications are laid out in Annexes 7 and 15 of the EIAO TM under the EIAO (Cap 499).  The following legislation covers, or has some bearing upon the handling, treatment and disposal of the wastes generated from the construction and operation of the proposed Project.

·           Waste Disposal Ordinance (Cap 354);

·           Waste Disposal (Chemical Waste) (General) Regulation (Cap 354C);

·           Land (Miscellaneous Provisions) Ordinance (Cap 28);

·           Public Health and Municipal Services Ordinance (Cap 132) - Public Cleansing and Prevention of Nuisances Regulation; and

·           Dumping at Sea Ordinance (Cap 466).

Details on each of the above are presented below.

7.2.1                                Waste Disposal Ordinance (Cap 354)

The Waste Disposal Ordinance (WDO) prohibits the unauthorised disposal of wastes, with waste defined as any substance or article, which is abandoned.  Construction waste is not directly defined in the WDO but is considered to fall within the category of ‘trade waste’.  Trade waste is defined as waste from any trade, manufacturer or business or any wasted building, or civil engineering materials, but does not include animal waste.

Under the WDO, wastes can only be disposed of at a licensed site.  The WDO provides for the issuing of licences for the collection and transport of wastes.  Licences are not, however, currently issued for the collection and transport of construction waste or trade waste.

The Waste Disposal (Charges for Disposal of Construction Waste) Regulation defined construction waste as any substance, matters or things that is generated from construction work and abandoned, whether or not it has been processed or stockpiled before being abandoned.  It does not include any sludge, screening or matter removed in or generated from any desludging, desilting or dredging works.

The Construction Waste Disposal Charging Scheme entered into operation on 1 December 2005.  From that time, the main contractor who undertakes construction work under a contract with value of HK$1 million or above is required to open a billing account solely for the contract for waste disposal.  Application shall be made within 21 days after the contract is awarded.

For construction work under a contract with value less than $1 million, such as minor construction or renovation work, any person such as the owner of the premises where the construction work takes place or his/her contractor can open a billing account; the account can also be used for contracts each with value less than $1 million.  The premises owner concerned may also engage a contractor with a valid billing account to make arrangement for disposal of construction waste.

Under the Construction Waste Disposal Charging Scheme, charging for disposal of construction waste started on 20 January 2006 and therefore will apply to this Project.

Depending on the percentage of inert materials in the construction waste, inert construction waste can be disposed of at public fill reception facilities.  However mixed construction waste can be disposed of at construction waste sorting facilities, landfills and outlying islands transfer facilities which have different disposal costs.  The scheme encourages reducing, reusing and sorting of construction waste such that the waste producer can reduce their disposal fee.  Table 7.1 summarises the government construction waste disposal facilities, types of waste accepted and disposal cost.

Table 7.1        Government Facilities for Disposal of C&D Materials

Government Waste Disposal Facilities

Type of Construction Waste Accepted

Charge (HK$/ Tonne)

Public Fill Reception Facilities

Consisting entirely of inert construction waste

$27

Sorting Facilities

Containing more than 50% by weight of inert

construction waste

$100

Landfills

Containing not more than 50% by weight of inert

construction waste

$125

Outlying Islands Transfer

Facilities

Containing any percentage of inert construction

waste

$125

 

7.2.2                                Waste Disposal (Chemical Waste) (General) Regulation (Cap 354C)

Chemical waste as defined under the Waste Disposal (Chemical Waste) (General) Regulation includes any substance being scrap material, or unwanted substances specified under Schedule 1 of the Regulation, if the specified substance or chemical occurs in such a form, quantity or concentration so as to cause pollution or constitute a danger to health or risk of pollution to the environment.

A person should not produce, or cause to be produced, chemical wastes without registration with the EPD.  Chemical wastes must either be treated using on-site facility licensed by EPD or be collected by a licensed collector for off-site treatment at a licensed facility.  Under EPD regulations, the waste producer, collector and disposal facility must sign all relevant parts of a computerised trip ticket for each consignment of waste.  The computerized system is designed to allow the transfer of wastes to be traced from cradle-to-grave.

The EPD Regulation prescribes storage facilities to be provided on site which include labelling and warning signs.  To reduce the risks of pollution and danger to human health or life, the waste producer is required to prepare and make available written emergency procedures for spillage, leakage or accidents arising from the storage of chemical wastes.  They must also provide their employees with training on such procedures.

7.2.3                                Land (Miscellaneous Provisions) Ordinance (Cap 28)

The inert portion of C&D materials (also called public fill) may be taken to public fill reception facilities.  Public fill reception facilities usually form part of land reclamation schemes and are operated by the Civil Engineering and Development Department (CEDD) and others.  The Land (Miscellaneous Provisions) Ordinance requires that individuals or companies who deliver public fill to the public fill reception facilities to obtain a Dumping Licence from the CEDD.  Individual licences and windscreen stickers are issued for each vehicle involved. 

Under the licence conditions, public fill reception facilities will only accept earth, soil, sand, rubble, brick, tile, rock, boulder, concrete, asphalt, masonry or used bentonite.  In addition, in accordance with Paragraph 11 of the ETWBTC(W) No. 31/2004 ([2]), Public Fill Committee will advise on the acceptance criteria (e.g. no mixing of construction waste, nominal size of the materials less than 250 mm, etc).  The material should, however, be free from marine mud, household refuse, plastic, metal, industrial and chemical wastes, animal and vegetable matter and any other materials considered unsuitable by the public fill reception facility supervisor.

7.2.4                                Public Health and Municipal Services Ordinance (Cap 132) - Public Cleansing and Prevention of Nuisances Regulation

This Regulation provides a further control on the illegal dumping of wastes on unauthorised (unlicensed) sites.

7.2.5                                Dumping at Sea Ordinance (Cap 466)

The Dumping at Sea Ordinance (DASO) came into operation in April 1995 and empowers the Director of Environmental Protection (DEP) to control the disposal and incineration of substances and articles at sea for the protection of the marine environment.  Under the DASO, a permit from the DEP is required for the disposal of regulated substances within and outside the waters of the Hong Kong SAR.  The permit contains terms and conditions that includes the following specifications:

·           Type and quantity of substances permitted to be dumped;

·           Location of the disposal grounds;

·           Requirement of equipment for monitoring the disposal operations; and

·           Environmental monitoring requirements.

Management of Dredged/ Excavated Sediments for Marine Disposal

Marine disposal of any dredged/excavated sediment is subject to control under the Dumping at Sea Ordinance (DASO).  Dredged/ excavated sediment destined for marine disposal is classified based on its contaminant levels with reference to the Chemical Exceedance Levels (CEL), as stipulated in PNAP 252: Management Framework for Disposal of Dredged/ Excavated Sediment ([3]).  This practice note includes a set of sediment quality criteria, as presented in Table 7.2, which includes heavy metals and metalloids, organic pollutants and a class of contamination level for highly contaminated sediment not suitable for marine disposal.

Table 7.2        Dredged/ Excavated Sediment Quality Criteria for the Classification under the PNAP 252

Contaminant

Lower Chemical Exceedance Level (LCEL)

Upper Chemical Exceedance Level (UCEL)

Metal (mg kg-1 dry weight)

Cadmium (Cd)

1.5

4

Chromium (Cr)

80

160

Copper (Cu)

65

110

Mercury (Hg)

0.5

1

Nickel (Ni) (a)

40

40

Lead (Pb)

75

110

Silver (Ag)

1

2

Zinc (Zn)

200

270

Metalloid (mg kg-1 dry weight)

Arsenic (As)

12

42

Organic-PAHs (mg kg-1 dry weight)

Low Molecular Weight (LMW) PAHs

550

3,160

High Molecular Weight (HMW) PAHs

1,700

9,600

Organic-non-PAHs (mg kg-1 dry weight)

Total PCBs

23

180

Organometallics (mg TBT l-1 in interstitial water)

Tributyl-tin (a)

0.15

0.15

(a) The contaminant level is considered to have exceeded the UCEL if it is greater than the value shown.

The DEP, as the Authority under the DASO, will classify sediments based on their contaminant levels with reference to the CEL laid down in Table 7.2.  In accordance with PNAP 252, the sediment is classified into three categories based on its contamination levels:

Category L:         Sediment with all contaminant levels not exceeding the LCEL.  The material must be dredged, transported and disposed of in a manner which reduces the loss of contaminants either into solution or by re-suspension.

Category M:        Sediment with any one or more contaminants in the sediment exceeding the LCEL with none exceeding the UCEL.  The material must be dredged and transported with care, and must be effectively isolated from the environment upon final disposal unless appropriate biological tests demonstrate that the material will not adversely affect the marine environment.

Category H:        Sediment with any one or more contaminants in the sediment exceeding the UCEL.  The material must be dredged and transported with great care, and must be effectively isolated from the environment upon final disposal.

Figure 7.1 summarises the sediment classification and disposal arrangements. EPD will use the sediment and biological test results to determine the most appropriate disposal site (e.g. open sea or confined marine disposal site).

In addition, in accordance with Building Ordinance Office Practice Note for Authorised Persons and Registered Structural Engineers No 155, any proposal to remove more than 500,000 m3 of clean mud or any quantity of contaminated mud must be justified on both cost and environmental grounds.  The rationale for such removal will also be provided to enable an allocation for disposal to be considered.  Therefore it is desirable to demonstrate that any proposed mud dredging has been reduced as far as reasonably and safely practicable and to obtain, in-principle, an agreement from the Secretary of the Marine Fill Committee (MFC) of the CEDD at an early stage.

7.2.6                                Other Relevant Guidelines

Other guideline documents which detail how the Contractor will comply with the WDO and its associated regulations include:

·           Waste Disposal Plan for Hong Kong (December 1989), Planning, Environment and Lands Branch Government Secretariat, Hong Kong Government;

·           Chapter 9 - Environment (1999), Hong Kong Planning Standards and Guidelines, Hong Kong Government;

·           New Disposal Arrangements for Construction Waste (1992), EPD & CED, Hong Kong Government;

·           Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes (1992), EPD, Hong Kong Government;

·           Works Branch Technical Circular (WBTC) No. 32/92, The Use of Tropical Hard Wood on Construction Site, Works Branch, Hong Kong Government;

·           WBTC No. 2/93, Public Dumps, Works Branch, Hong Kong Government;

·           WBTC No. 2/93B, Public Filling Facilities, Works Branch, Hong Kong Government;

·           WBTC No. 16/96, Wet Soil in Public Dumps, Works Branch, Hong Kong Government;

·           WBTC Nos. 4/98 and 4/98A, Use of Public Fill in Reclamation and Earth Filling Projects, Works Bureau, Hong Kong SAR Government;

·           Waste Reduction Framework Plan, 1998 to 2007, Planning, Environment and Lands Bureau, Government Secretariat, 5 November 1998;

·           WBTC Nos. 25/99, 25/99A and 25/99C, Incorporation of Information on Construction and Demolition Material Management in Public Works Subcommittee Papers; Works Bureau, Hong Kong SAR Government;

·           WBTC No. 12/2000, Fill Management, Works Bureau, Hong Kong SAR Government;

·           WBTC No. 19/2001, Metallic Site Hoardings and Signboards, Works Bureau, Hong Kong SAR Government;

·           WBTC Nos. 6/2002 and 6/2002A, Enhanced Specification for Site Cleanliness and Tidiness, Works Bureau, Hong Kong SAR Government;

·           WBTC No. 11/2002, Control of Site Crusher, Works Bureau, Hong Kong SAR Government;

·           WBTC No. 12/2002, Specification Facilitating the Use of Recycled Aggregates. Works Bureau, Hong Kong SAR Government;

·           ETWBTC(W) No. 33/2002, Management of Construction and Demolition Material Including Rock; Environment, Transport and Works Bureau, Hong Kong SAR Government;

·           PNAP 252 (ADV-21), Management Framework for Disposal of Dredged/ Excavated Sediment; Buildings Department, Hong Kong SAR Government;

·           ETWBTC(W) No. 31/2004, Trip Ticket System for Disposal of Construction & Demolition Materials, Environment, Transport and Works Bureau, Hong Kong SAR Government; and

·           ETWBTC(W) No. 19/2005, Environmental Management of Construction Site, Environment, Transport and Works Bureau, Hong Kong SAR Government.

7.3                                      Expected Waste Sources

7.3.1                                Construction Phase

Optioneering has been conducted to try to avoid waste generation and reuse and recycling of waste generated from the construction of the proposed facilities.  During the planning and design stages, options for layout, construction methods and programme have been considered and the proposed scheme comprises the proposed best balance.  Section 2 contains more discussion on the alternatives that were considered to reduce the volumes of dredged mud generated by this Project.

During the construction phase, the main activities that will result in generation of waste include dredging, reclamation, seawall construction, filling and concreting.  The typical waste types associated with these activities include:

·           Dredged marine sediment;

·           C&D materials;

·           Chemical wastes;

·           Sewage; and

·           General refuse.

7.3.2                                Operation Phase

The proposed Project facilities are expected to be automated and unmanned during the operation phase.  However it is expected that during the early operation phase a few personnel will work at the GRSs and thus a small amount of solid wastes/ by-products and sewage may be generated.

It is also envisaged that a very small amount of wastes, primarily industrial wastes and chemical wastes, will be generated from routine maintenance activities.

7.4                                      Waste Management Assessment

7.4.1                                Assessment Methodology

The potential environmental impacts associated with the handling and disposal of waste arising from the construction and operation of the Project facilities at BPPS were assessed in accordance with the criteria presented in Annexes 7 and 15 of the EIAO-TM and summarised as follows:

·           Estimation of the types (i.e. quality), timing and quantities of the wastes to be generated based on information provided by the engineering design team and the relevant researches and studies on waste generation;

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

·           Assessment of the potential impacts on the capacity of waste collection, transfer and disposal facilities.

7.4.2                                Construction Phase Impact Assessment

Dredged Marine Sediment

Marine dredging will be required for the construction of the submarine pipelines and the GRS reclamation (see Section 3.2 for further details).  The quantities of sediment to be dredged are considered as the best estimate based on the preliminary engineering design and available geotechnical investigation data (e.g. depth of marine deposits) (see Table 3.1).

The first pipeline and GRS (i.e. First Phase) must be completed in 2012 to provide facilities to accommodate a timely replacement for the Yacheng 13-1 gas supply.  It is expected that the Second Phase could commence construction within 24 months of commissioning of the First Phase.

For the construction of submarine gas pipelines (approximately 5 km in HKSAR waters) dredging will be required for certain sections of the pipeline alignment for trenching to provide the necessary burial depths (1.5 m to 3 m below the existing seabed level to the top of the pipe; see Section 3.3.3).  Approximately 0.194 Mm3 (in situ volume, 0.253 Mm3 for bulk volume) of marine sediment will be dredged for each pipeline (Table 7.3).

Approximately 0.5 ha of land will be reclaimed next to the BPPS to provide land for a GRS.  Works will also include the construction of an approximately 200 m long vertical seawall.  The seawall trenches will be constructed with minimal dredging (see Section 2.2), and a total of approximately 0.12 Mm3 of marine sediment (in situ volume) will be dredged (Table 7.3).  The dredging work will be carried out for approximately two months, not expected to commence earlier than the second half of 2013 during the Second Phase construction ([4]) (Table 7.4, Figure 3.8).

The dredging work for the first pipeline (Pipeline 1) will commence in 2011 during the First Phase Construction, while that for the second pipeline (Pipeline 2) is expected to commence at the same time as the dredging work for the reclamation, i.e. no earlier than the second half of 2013 during the Second Phase construction (Table 7.4).  Dredging work for each pipeline is expected to be completed within three months.

Table 7.3        Summary of Dredging Volume of this Project (Phased Construction)

Proposed Facility

Estimated Dredging Volume (Mm3)

 

In situ

Bulk *

Reclamation with Vertical Seawall

0.108

0.140

Additional Dredging for Reclamation Construction Barge

0.012

0.016

Pipeline 1

0.194

0.253

Pipeline 2

0.194

0.253

Total Volume

0.508

0.662

*Bulk Factor: 1.3

 

Table 7.4        Summary of Dredged Material Arisings of this Project (Phased Construction)

Year

Sediment disposal requirement as per PNAP 252 (in Mm3)

 

In situ

Bulk *

1st Half of 2011 (First Phase Construction)

0.194

0.253

2nd Half of 2011

--

--

1st Half of 2012

--

--

2nd Half of 2012

--

--

1st Half of 2013

--

--

2nd Half of 2013 (Second Phase Construction)

0.314

0.409

Total Volume

0.508

0.662

*Bulk Factor: 1.3

 

Contaminated Dredged Marine Sediment

A marine sediment sampling programme has been undertaken as part of this EIA Study to provide an indication of the quality of the sediment and the volumes of different types of sediment to be dredged.  The sediment sampling programme (including the sampling stations, the chemical analysis suite and the biological testing programmes) was developed based on the guidelines described in PNAP 252 ([5]).  The contaminants tested include all the contaminants stated in Table 1 - Analytical Methodology in Appendix B of PNAP 252, and all sediment samples were evaluated for sediment quality parameters as listed in the Appendix A of the PNAP 252.

The sampling and testing programmes are summarised in Table 7.5 and the sampling locations presented in Figure 7.2.  A combination of grab samples and vibrocore samples were taken within the proposed Project area. Whilst grab samples were taken from the seabed, vibrocore samples were taken vertically either down to the proposed dredging depth (i.e. at seabed, 0.9 m, 1.9 m, 2.9 m below the seabed, every 3 m thereafter and at the end of the vibrocore sampling) or upon refusal, or when encountering rock head in order to determine the depth of contaminated marine deposit.  The grab sampling programme was conducted in March 2009, whereas the vibrocore sampling programme was conducted in July-August 2009.

Table 7.5        Marine Sediment Sampling and Testing Programme

Sampling Location

PNAP 252 Grab

(March 2009 – Chemical Screening only)(a)

PNAP 252 Vibrocore

(July-August 2009 – Chemical & Biological Screening) (b)

Pipeline Corridor

 

 

GS 09-01

ü

 

GS 09-02

ü

 

GS 09-03

ü

 

GS 09-04

ü

 

GS 09-05

ü

 

GS 09-06

ü

 

GS 09-07

ü

 

GS 09-08

ü

 

GS 09-09

ü

 

GS 09-10

ü

 

GSVB1

 

ü

GSVB2

 

ü

GSVB3

 

ü

GSVB4

 

ü

GSVB5

 

ü

GSVB6

 

ü

GSVB7

 

ü

GSVB8

 

ü

GSVB9

 

ü

GSVB10

 

ü

Proposed GRS Reclamation

 

 

GSVB11

 

ü

GSVB12

 

ü

Notes:

(a)       All sediment grab samples were analysed for sediment quality parameters as listed in the Appendix A of the PNAP 252.

(b)       Vibrocore samplings were conducted and samples analysed for sediment quality parameters as listed in the Appendix A of the PNAP 252 at these locations.

 

Results of the grab sampling programme indicated that all 10 grab samples tested have negligible concentration of toxic organics since they were all below the detection limits of the chemical analysis (Table 7.6).  Heavy metal concentrations, aside from the arsenic metalloid, in sediment samples obtained in all 10 locations (GV 09-01 to GV 09-10) within the proposed dredging areas were below the LCEL.  Concentrations of arsenic in all 10 samples exceeded the LCEL but were below the UCEL.

Similarly, results of the vibrocore sampling programme showed that all 50 vibrocore samples tested have negligible concentration of toxic organics (Table 7.6).  Sediment from 9 of the 50 samples tested were found to be uncontaminated (i.e. sediment with all contaminant levels not exceeding the LCEL).  Concentrations of arsenic in the remaining 41 samples tested, exceeded the LCEL but were below the UCEL.  All other heavy metal concentrations in these sediment samples were below the LCEL, except in three samples in which the copper (GSBV9 1.9-2.9m) and lead (GSBV5 0.0-0.9m and GSBV10 2.9-3.9m) concentrations exceeded the LCEL but were below the UCEL.  Sediment from these locations and depths were thus classified as Category M contaminated materials.

 

Table 7.6        Results of Marine Sediment Testing in March and July/ August2009

Sample Reference

Heavy Metals (mg kg-1)

Organics (mg kg-1)

Organo-metallics

(mg TBT l-1)

Biological

Sample No.

Failed Biological Test

Sediment Category

Disposal Option

Sample ID

Depth (m)

From-To

Silver (Ag)

Arsenic (As)

Cadmium (Cd)

Chromium (Cr)

Copper (Cu)

Nickel (Ni)

Lead (Pb)

Zinc (Zn)

Mercury (Hg)

Total PCB

LMW PAHs

HMW PAHs

Tributyl-tin

(TBT)

Amphipod

Bivalve

Polychaete

Reporting Limits

0.1

1

0.2

1

1

1

1

1

0.05

3

550

1700

0.005

 

 

 

 

 

 

LCEL

1

12

1.5

80

65

40

75

200

0.5

23

550

1700

0.15

 

 

 

 

 

 

UCEL

2

42

4

160

110

40

110

270

1

180

3160

9600

0.15

 

 

 

 

 

 

GS 09-01

 

0.5

15

< 0.2

54

63

37

55

155

0.14

< 3

< 550

< 1700

--

-

 

 

 

M

-

GS 09-02

 

0.3

14

< 0.2

41

41

26

42

134

0.09

< 3

< 550

< 1700

--

-

 

 

 

M

-

GS 09-03

 

0.3

13

< 0.2

35

34

23

41

122

0.08

< 3

< 550

< 1700

--

-

 

 

 

M

-

GS 09-04

 

0.1

24

< 0.2

28

17

21

72

126

< 0.05

< 3

< 550

< 1700

--

-

 

 

 

M

-

GS 09-05

 

0.1

16

< 0.2

28

12

14

29

70

< 0.05

< 3

< 550

< 1700

--

-

 

 

 

M

-

GS 09-06

 

0.4

20

0.2

47

45

29

40

128

0.10

< 3

< 550

< 1700

--

-

 

 

 

M

-

GS 09-07

 

0.2

14

< 0.2

29

23

18

28

80

0.06

< 3

< 550

< 1700

--

-

 

 

 

M

-

GS 09-08

 

0.1

14

< 0.2

39

16

22

34

92

< 0.05

< 3

< 550

< 1700

--

-

 

 

 

M

-

GS 09-09

 

0.2

18

< 0.2

41

22

25

40

107

< 0.05

< 3

< 550

< 1700

--

-

 

 

 

M

-

GS 09-10

 

0.2

18

< 0.2

43

26

28

40

111

0.08

< 3

< 550

< 1700

--

-

 

 

 

M

-

GSVB1

0.1-0.9m

0.4

18

0.2

51

43

32

57

135

0.15

< 3

< 550

< 1700

--

1

 

 

 

M

Type 1 Dedicated

 

0.9-1.9m

0.4

22

0.3

57

56

35

59

147

0.18

< 3

< 550

< 1700

--

2

 

 

 

M

Type 1 Dedicated

 

1.9-2.9m

0.3

18

< 0.2

53

46

30

66

132

0.16

< 3

< 550

< 1700

--

3

 

 

 

M

Type 1 Dedicated

 

6.0-6.9m

0.3

18

< 0.2

49

40

30

52

124

0.11

< 3

< 550

< 1700

--

4

 

 

 

M

Type 1 Dedicated

 

6.9-7.9m

< 0.1

11

< 0.2

25

12

15

28

53

0.07

< 3

< 550

< 1700

--

5

 

 

 

L

Type 1

GSVB2

0.5-0.9m

0.3

17

< 0.2

51

46

31

50

124

0.13

< 3

< 550

< 1700

--

6

 

 

 

M

Type 1 Dedicated

 

0.9-1.9m

0.2

15

< 0.2

46

36

26

54

107

0.12

< 3

< 550

< 1700

--

7

 

 

 

M

Type 1 Dedicated

 

1.9-2.9m

0.1

17

< 0.2

34

21

19

41

76

0.14

< 3

< 550

< 1700

--

8

x

 

 

Mfail

Type 2

 

6.0-6.4m

< 0.1

14

< 0.2

40

17

18

34

67

< 0.05

< 3

< 550

< 1700

--

9

 

 

 

M

Type 1 Dedicated

GSVB3

0.8-0.9m

0.3

14

< 0.2

41

42

25

38

104

0.14

< 3

< 550

< 1700

--

-+

 

 

 

M

Type 1 Dedicated

 

0.9-1.9m

0.1

18

< 0.2

37

23

22

43

87

0.11

< 3

< 550

< 1700

--

10

x

 

 

Mfail

Type 2

 

1.9-2.9m

0.1

14

< 0.2

41

17

27

30

94

0.07

< 3

< 550

< 1700

--

11

 

 

 

M

Type 1 Dedicated

 

2.9-3.9m

0.1

14

< 0.2

44

18

29

33

98

0.07

< 3

< 550

< 1700

--

12

x

 

 

Mfail

Type 2

GSVB4

0.1-0.9m

0.1

10

< 0.2

30

12

17

40

80

0.08

< 3

< 550

< 1700

--

13

x

 

 

Mfail

Type 2

 

0.9-1.9m

0.1

16

< 0.2

40

15

25

34

94

0.09

< 3

< 550

< 1700

--

14

x

 

 

Mfail

Type 2

 

1.9-2.9m

0.1

14

< 0.2

39

16

25

34

93

0.09

< 3

< 550

< 1700

--

15

x

 

 

Mfail

Type 2

 

2.9-3.9m

0.2

17

< 0.2

44

16

26

35

96

0.07

< 3

< 550

< 1700

--

16

x

 

x

Mfail

Type 2

GSVB5

0.0-0.9m

0.2

27

< 0.2

32

19

22

81

111

0.06

< 3

< 550

< 1700

--

17

 

 

 

M

Type 1 Dedicated

 

0.9-1.9m

0.1

16

< 0.2

45

18

30

35

105

0.09

< 3

< 550

< 1700

--

18

x

 

 

Mfail

Type 2

 

1.9-2.9m

0.1

14

< 0.2

38

16

25

29

89

0.07

< 3

< 550

< 1700

--

19

 

 

x

Mfail

Type 2

 

2.9-3.9m

0.1

18

< 0.2

39

16

25

29

88

0.09

< 3

< 550

< 1700

--

20

 

 

 

M

Type 1 Dedicated

GSVB6

0.1-0.9m

0.1

15

< 0.2

29

12

17

55

78

< 0.05

< 3

< 550

< 1700

--

21

 

 

 

M

Type 1 Dedicated

 

0.9-1.9m

< 0.1

7

< 0.2

29

7

15

44

71

< 0.05

< 3

< 550

< 1700

--

22

 

 

 

L

Type 1

 

1.9-2.9m

< 0.1

7

< 0.2

32

8

17

34

73

< 0.05

< 3

< 550

< 1700

--

23

 

 

 

L

Type 1

 

2.9-3.9m

0.1

15

< 0.2

38

15

24

33

90

0.08

< 3

< 550

< 1700

--

24

 

 

 

M

Type 1 Dedicated

GSVB7

0.1-0.9m

0.1

13

< 0.2

30

14

14

28

62

0.06

< 3

< 550

< 1700

--

25

 

 

 

M

Type 1 Dedicated

 

0.9-1.9m

0.1

14

< 0.2

43

16

24

42

96

0.06

< 3

< 550

< 1700

--

26

 

 

 

M

Type 1 Dedicated

 

1.9-2.9m

0.1

12

< 0.2

40

15

23

32

83

0.07

< 3

< 550

< 1700

--

27

 

 

 

L

Type 1

 

2.9-3.9m

0.1

14

< 0.2

40

16

23

33

83

0.07

< 3

< 550

< 1700

--

28

x

 

 

Mfail

Type 2

GSVB8

0.5-0.9m

0.2

13

< 0.2

40

38

24

48

128

0.13

< 3

< 550

< 1700

--

29

x

 

 

Mfail

Type 2

 

0.9-1.9m

0.5

17

0.2

47

44

27

43

135

0.13

< 3

< 550

< 1700

--

30

 

 

 

M

Type 1 Dedicated

 

1.9-2.9m

0.2

19

0.3

40

26

24

36

97

0.11

< 3

< 550

< 1700

--

31

 

 

 

M

Type 1 Dedicated

 

2.9-3.9m

0.2

16

< 0.2

47

30

29

39

107

0.09

< 3

< 550

< 1700

--

32

 

 

 

M

Type 1 Dedicated

GSVB9

0.3-0.9m

< 0.1

9

< 0.2

32

10

17

25

60

0.06

< 3

< 550

< 1700

--

33

 

 

 

L

Type 1

 

0.9-1.9m

< 0.1

13

< 0.2

23

22

11

25

79

0.08

< 3

< 550

< 1700

--

34

 

 

 

M

Type 1 Dedicated

 

1.9-2.9m

0.5

26

0.4

65

81

38

52

163

0.18

< 3

< 550

< 1700

--

35

 

 

 

M

Type 1 Dedicated

 

2.9-3.9m

0.5

22

0.2

53

55

32

48

142

0.2

< 3

< 550

< 1700

--

36

 

 

 

M

Type 1 Dedicated

GSVB10

0.3-0.9m

0.1

13

< 0.2

31

13

18

29

70

0.07

< 3

< 550

< 1700

--

37

 

 

 

M

Type 1 Dedicated

 

0.9-1.9m

0.2

13

< 0.2

43

18

26

38

88

0.06

< 3

< 550

< 1700

--

38

 

 

 

M

Type 1 Dedicated

 

1.9-2.9m

0.6

29

0.4

55

48

35

60

169

0.22

< 3

< 550

< 1700

--

39

 

x

 

Mfail

Type 2

 

2.9-3.9m

0.4

38

1.2

60

52

38

76

192

0.24

< 3

< 550

< 1700

--

40

 

 

 

M

Type 1 Dedicated

GSVB11

0.0-0.9m

0.6

19

0.2

57

52

34

54

151

0.13

< 3

< 550

< 1700

--

41

 

 

 

M

Type 1 Dedicated

 

0.9-1.9m

0.3

18

0.3

58

44

34

60

152

0.14

< 3

< 550

< 1700

--

42

 

 

 

M

Type 1 Dedicated

 

1.9-2.9m

0.3

18

0.2

52

51

29

59

129

0.12

< 3

< 550

< 1700

--

43

 

 

 

M

Type 1 Dedicated

 

6.0-6.9m

0.1

2

< 0.2

28

14

10

26

38

0.12

< 3

< 550

< 1700

--

44

 

x

 

Mfail

Type 2

 

6.9-7.4m

< 0.1

< 1

< 0.2

8

10

2

24

7

0.09

< 3

< 550

< 1700

--

45

x

 

 

Mfail

Type 2

GSVB12

0.1-0.9m

0.5

19

< 0.2

57

52

35

55

152

0.15

< 3

< 550

< 1700

--

46

 

 

 

M

Type 1 Dedicated

 

0.9-1.9m

0.5

20

0.2

58

52

35

55

150

0.15

< 3

< 550

< 1700

--

47

 

 

 

M

Type 1 Dedicated

 

1.9-2.9m

0.2

15

< 0.2

39

34

23

50

104

0.1

< 3

< 550

< 1700

--

48

 

 

 

M

Type 1 Dedicated

 

6.0-6.8m

0.1

3

< 0.2

13

8

6

61

33

0.09

< 3

< 550

< 1700

--

49

 

 

 

L

Type 1

Notes:

(a)       Shaded Cell = Exceeding LCEL, classified as Category M, which requires biological screening to determine the types of disposal site (i.e. Type 1 Dedicated or Type 2 Disposal).

(b)       Shaded Cell and underlined = Exceeding UCEL, classified as Category H, Type 3 Disposal.

(c)       Type 1 Disposal = open sea disposal.

(d)       Type 1 (Dedicated) Disposal = disposal at dedicated site.

(e)       Type 2 Disposal = disposal at confined marine disposal site.

(f)        L: Category L material; M: Category Mpass material; Mfail: Category Mfail material

+       Not tested for biological screening due to insufficient sample as a result of significant core loss

 

Tier III biological screening was required to identify the most appropriate disposal option for the Category M contaminated materials arising from this Project.  This consisted of ecotoxicological testing programmes on three phylogenetically distinct species (amphipod, polychaete and bivalve larvae), which was undertaken to determine if there are any potential risks of toxicological impacts from the sediment to the marine biota, and whether there is any difference in the toxicity of the sediment samples taken from the Project site and the reference station (collected from a clean area in Port Shelter, New Territories).

Results of the biological screening indicated that of the 49 vibrocore sediment samples tested ([6]), sediment from 14 samples failed in at least one of the three toxicity tests and sediment from these locations are thus regarded as Category Mfail material (Table 7.6).  These 14 samples were from different sections of the proposed pipelines and also from the proposed reclamation site.  Sediments from the remaining samples have passed the biological screening tests and are regarded as either Category L or Category Mpass material (Table 7.6).

In summary, a total of 0.508 Mm3 (in situ volume) of marine sediments would be dredged.  This assumes that dredging will be required for suitable sections of the pipeline route and jetting will be adopted for the remaining sections of the route.  About 0.044 Mm3 (in situ volume) would be Category L sediment.  About 0.312 Mm3 (in situ volume) would be Category M contaminated marine sediments (passed biological screening), whereas about 0.152 Mm3 (in situ volume) would be Category M contaminated (failed biological screening) sediments.  The detailed breakdown of estimated quantities of different types of marine sediments to be dredged from this Project is summarised in Table 7.7.

Table 7.7        Estimated Quantities of Different Types of Marine Sediment to be Dredged

Sediment Type

In situ Volume (Mm3)

Bulk Volume (Mm3)

First Phase Construction

Category L

0.022

0.029

Category M pass

0.126

0.164

Category M fail

0.046

0.060

Sub-Total

0.194

0.253

Second Phase Construction

Category L

0.022

0.029

Category M pass

0.186

0.242

Category M fail

0.106

0.138

Sub-Total

0.314

0.409

Total

0.508

0.662

 

The testing results presented in this Report are for EIA purposes only.  The procedures detailed below will be followed prior to applying for a marine dumping permit.  A proposal for sampling and chemical testing of the sediment will be prepared and submitted to the EPD for approval.  The approved detailed sampling and chemical testing will be carried out prior to the commencement of the dredging activities to confirm the sediment disposal method.  After carrying out the sampling and testing, a Sediment Quality Report (SQR) will be prepared for EPD approval as required under the Dumping at Sea Ordinance.  The SQR will include the sampling details, chemical testing results, quality control records, proposed classification and delineation of sediment according to the requirements of the Appendix A of PNAP 252 ([7]).

At present, the East of Sha Chau Mud Pits are designated for confined marine disposal of contaminated sediment.  For the First Phase of this Project, MFC has no objection in-principle to allocating disposal space for the Mfail sediment dredged from Sections 1 and 3 of the pipeline route (Figure 3.6), subject to the availability of disposal space at the time of CAPCO's application and at the proposed programme for disposal.  The actual quantity and disposal site(s) to be allocated will be based on the results of the SQR to be approved by DEP.  The project proponent will implement the project in accordance with the DASO and the requirements as stipulated in the PNAP 252, prior to the application and allocation of space for dredging and disposal of sediment arising from the project.  The proposed disposal options for the respective categories of marine sediment arising from the First Phase of this Project are presented in Table 7.8.

Table 7.8        Proposed Disposal Options for Different Types of Marine Sediment to be Dredged along the Alignment of Pipeline 1

Sediment Type

In situ Volume (Mm3)

Bulk Volume (Mm3)

Proposed Disposal Option

Category L

0.022

0.029

Type 1 Open Sea Disposal to the areas managed by the CEDD

Category M pass

0.126

0.164

To the extent accepted and approved by the local authorities, Cross Boundary Disposal to Mainland China (a)

Category M fail

0.046

0.060

Type 2 Confined Marine Disposal to the facilities managed by the CEDD

Total

0.194

0.253

 

Note:

(a)       At the time of reporting CAPCO is liaising with relevant authorities for the preparation of a submission to the PRC

Due to the size of the East of Sha Chau mud pits as well as ongoing re-evaluations of project priorities by Government, it is noted that capacity may not be available for the Second Phase material at the time of disposal.  In view of such a situation, an alternative site(s) / option(s) for contaminated sediment disposal for the Second Phase mud arisings would be identified in consultation with the MFC and the EPD.  The feasibility of the use of these alternatives site(s) / option(s )(for Second Phase) has not been confirmed at the time of writing this report and hence further study may be involved prior to confirmation of a disposal site(s) / alternative option(s) as suitable.

It is important to note that at this stage, the construction of the two phases is expected to be separate.  Such a Phased Construction approach is a result of an optimisation of the Project’s implementation schedule to resolve potential concerns regarding dredged material management.  Other possibilities of reducing dredged mud volumes by optimisation of project design, including the use of jetting for installing suitable pipeline sections, have also been explored and discussed (see Section 2 and Table 3.2).  The present proposed work scheme represents a concerted effort to reduce and manage dredged material generation.  Also, it is noted that the First Phase Construction is expected to generate no more than 0.253 Mm3 (bulk volume) of contaminated marine sediments for off-site disposal.

The dredging works for the proposed Second Phase reclamation (bulk volume of approximately 0.156 Mm3) will take about two months with an estimated approximate maximum of 10 barge trips per day ([8]).  For the dredging works for the submarine pipelines (bulk volume of 0.253 Mm3 for each pipeline), they will take about three months with approximately 5 to 10 barge trips per day ([9]).

The dredged marine sediments will be loaded onto barges and transported to the appropriate disposal site depending on their level of contamination.  In accordance with the requirements of PNAP 252, Category M sediment will be dredged and transported with care in order to avoid leakage of contaminated sediment into the sea.  With the implementation of the mitigation measures recommended in Section 7.5, sediment disposal at the designated disposal sites is not expected to cause adverse environmental impacts.

The potential water quality impacts due to the dredging of these sediments have been assessed and are presented in Section 6 Water Quality Impact Assessment.  The assessment concluded that the dredging works will meet the relevant water quality assessment criteria in the EIAO-TM with the implementation of mitigation measures recommended in Section 6.

C&D Materials

For the new reclamation adjacent to the BPPS, approximately 0.17 Mm3 of suitable inert fill materials (primarily sand, rock and public fill) will be required for backfilling at the reclamation.  The backfilling work for the reclamation is expected to commence in early 2014 for approximately four months.

For the backfilling of submarine gas pipelines using armour rock and other suitable fill materials, the backfilling work is expected to be completed within four months starting in 2011 for Pipeline 1.  Backfilling of the trench of Pipeline 2 is expected to commence within 24 months of commissioning of Pipeline 1.  Approximately, 0.329 Mm3 of rock/ inert fill materials will be used for backfilling of one pipeline.

A total bulk volume of 0.828 Mm3 of fill materials are, therefore, required for this Project.  A breakdown of the quantities of fill materials is presented in Table 7.8.  The quantities of materials to be used for backfilling are considered as the best estimate based on the available site investigation data.

Table 7.9        Summary of Quantity of Fill Materials (Bulk Volume) *

Fill Material

First Phase

Second Phase

Total (Mm3)

 

Pipeline 1 (Mm3)

Pipeline 2

(Mm3)

Reclamation

 (Mm3)

 

Rock Fill

0.319

0.319

0.115

0.905

Sand Fill

0.010

0.010

0.035

0.035

Public Fill

--

--

0.020

0.020

Total

0.329

0.329

0.170

0.828

* Bulk Factor: Rock Fill = 1.2; Public Fill = 1.2; Sand Fill = 1.3

 

Since blasting / land excavation works are not needed during GRS and onshore pipeline construction, excavated materials are not anticipated to arise from this Project for disposal or for reuse as backfilling materials and potential concern for contaminated soil excavation is not expected.  At this stage it is assumed that materials for backfilling will either be suitable sorted public fill materials obtained from Fill Bank, or will be marine sand sourced within the Pearl River Delta region.  Fill materials will be brought in to the site by self-propelled pelican barges when needed.  Rock and soil may be excavated from minor site formation works and that will be reused as fill material for the reclamation within the Project as far as practicable.  Surplus fill material is not anticipated.

C&D materials arising from this Project will be sorted on site into inert waste (public fill) and non-inert waste (construction waste).  Public fill will either be reused or be disposed of at public fill reception facilities (e.g. Tuen Mun Area 38 or other locations as agreed with CEDD).  Construction waste, such as timber, paper, plastics and general refuse, cannot be reused and need to be disposed of at the West New Territories (WENT) Landfill.  Small quantities of construction waste that cannot be reused (about 0.01 Mm3 ([10])) are expected to be produced, and the production of these wastes will be minimised in order to reduce the amount of wastes to be disposed of at landfills and the cost for disposal of the C&D materials arising from the Project.

With proper implementation of standard construction site practices and the mitigation measures recommended in Section 7.5, the handling and transportation of C&D materials to the disposal sites will not cause adverse dust, noise or water quality impacts.

Chemical wastes

Chemical waste, as defined under the Waste Disposal (Chemical Waste) (General) Regulation, includes any substance being scrap material, or unwanted substances specified under Schedule 1 of the Regulation.  A complete list of such substances is provided under the Regulation; however, substances likely to be generated from the construction of this Project will, for the most part, arise from the equipment and vessels associated with the dredging works.  These may include, but not limited to the following:

·           Scrap batteries or spent acid/alkali from their maintenance;

·           Used engine oils, hydraulic fluids and waste fuel;

·           Spent mineral oils/cleaning fluids from mechanical machinery; and

·           Spent solvents/solutions from equipment cleaning activities.

Chemical wastes may pose environmental, health and safety hazards if not stored and disposed of in an appropriate manner as outlined in the Waste Disposal (Chemical Waste) (General) Regulation and the Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes.  These hazards may include:

·       Toxic effects to workers;

·       Adverse effects on air, water and land from spills; and

·       Fire hazards.

The amount of chemical waste that will arise from the construction activities will be highly dependent on the Contractor’s on-site maintenance activities and the quantity of plant and equipment utilized.  With respect to the nature of construction works and the number of vessels and equipment to be used on site, it is estimated that about a few hundred litres of used lubricant oil will be generated per month during the construction period.  It is anticipated that the quantities of waste solvent and wasted oils will be minimal.

With the incorporation of suitable arrangements for the storage, handling, transportation and disposal of chemical wastes under the requirements stated in the Code of Practice on the Packaging, Labelling and Storage of Chemical Waste, no adverse environmental and health impacts, and hazards will result from the handling, transportation and disposal of chemical waste arising from the Project.

Sewage

Sewage will arise from the construction workforce, portable toilets and sanitary facilities from the barges/ dredgers.  If not properly managed, these materials could cause odour and potential health risks to the workforce by attracting pests and other disease vectors.

It is conservatively estimated that up to 100 construction workers, including both land- and marine-based workforce, will be involved in the construction of the proposed Project.  With a sewage generation rate of 0.15 m3/worker/day ([11]), about 15 m3 of sewage will be generated per day.  The sewage generated is expected to be either conveyed to sewage treatment works (STW) at BPPS (for land-based site work at BPPS) or collected in the onboard sewage tank in the case of barges/ dredgers for off-site disposal.  Given the small quantity of sewage generated the sewage treatment works of the BPPS will be able to handle the additional sewage flow from the construction work force at the GRS site.  Therefore no adverse water quality impacts are envisaged.

General refuse

The presence of a construction site with workers and associated site facilities will result in the generation of general refuse (mainly consist of food waste, aluminium cans and waste paper) which requires off-site disposal.  The storage of general refuse has the potential to give rise to adverse environmental impacts.  These include odour if the waste is not collected frequently (for example, daily), windblown litter, water quality impacts if waste enters water bodies, and visual impact. 

It is conservatively estimated that up to 100 construction workers will be working on site at any one time, with a general refuse generation rate of 0.65 kg per worker per day ([12]), the amount of general refuse to be generated will only be about 65 kg per day.

Recyclable materials such as paper and aluminium cans will be separated and delivered to the recyclers.  The non-recyclable waste will be collected and disposed of together with the general waste arising from the operation of the BPPS at the WENT Landfill on daily basis.  With respect to the small quantity of additional general refuse to be transferred to the WENT Landfill, it is not anticipated that it will cause adverse operational impact to these facilities.

Provided that the mitigation measures recommended in Section 7.5 are adopted, no adverse environmental impacts caused by the storage, handling, transport and disposal of general refuse are expected.

7.4.3                                Operation Phase Impact Assessment

As discussed in Section 7.3.2, it is expected that during the early operation phase a few personnel will work at the GRSs and thus a small amount of solid wastes/ by-products and sewage may be generated.  Whilst solid wastes will be disposed properly with the existing waste management practices at BPPS, sewage is expected to be treated by the sewage treatment works of the BPPS.

Industrial Waste

Industrial waste will arise from the maintenance activities at the GRSs.  The materials may include very small quantities of scrap materials from maintenance of gas metering/ treatment facilities and equipment and cleaning materials.  Provided the scrap materials are collected regularly for recycling, it is not expected that storage, handling, transport and disposal of industrial waste will cause any adverse environmental impacts.  General industrial waste such as plastic, metal cans and waste paper, will be disposed of together with the general waste arising from the operation of the BPPS at the WENT Landfill.

Chemical Waste

With respect to the operation activities of the GRSs, it is anticipated that chemical waste will be generated from maintenance activities anticipated to be conducted once a year.  The quantity of the chemical wastes to be generated is very small.  The chemical waste will be collected by a licensed chemical waste collector for disposal at the Chemical Waste Treatment Centre at Tsing Yi.  The handling, storage, collection and transportation of chemical waste will be undertaken in accordance with requirement stated in the Code of Practice on the Packaging, Labelling and Storage of Chemical Waste, and no adverse environmental impacts and hazards are anticipated.

7.5                                      Mitigation Measures

This Section recommends the mitigation measures to avoid or reduce potential adverse environmental impacts associated with handling, collection and disposal of waste arising from the construction and operation of the proposed Project.

The Contractors will incorporate these recommendations into a Waste Management Plan for the construction works.  The Contractors will submit the plan to CAPCO’s Engineer Representative for endorsement prior to the commencement of the construction works.  Such plan will incorporate site-specific factors, such as the designation of areas for the segregation and temporary storage of reusable and recyclable materials.

It is the Contractor’s responsibility to confirm that only reputable licensed waste collectors are used and that appropriate measures to reduce adverse impacts, including windblown litter and dust from the transportation of these wastes, are employed.  In addition, the Contractor must confirm that all the necessary permits or licences required under the Waste Disposal Ordinance are obtained for the construction and operation phases.

7.5.1                                Waste Management Hierarchy

The various waste management options are categorised in terms of preference from an environmental viewpoint.  The options considered to be most preferable have the least environmental impacts and are more sustainable in the long term.  The hierarchy is as follows:

·           Avoidance and reduction;

·           Reuse of materials;

·           Recovery and recycling; and,

·           Treatment and disposal.

The above hierarchy has been used to evaluate and select waste management options.  The aim has been to reduce waste generation and reduce waste handling and disposal costs.

CAPCO will confirm that their contractors consult the EPD for the final disposal of wastes and as appropriate implement the standard site practices and mitigation measures recommended in this Study and those given below.

·           Nomination of approved personnel to be responsible for standard site practices, arrangements for collection and effective disposal to an appropriate facility of all wastes generated at the site;

·           Training of site personnel in proper waste management and chemical handling procedures;

·           Provision of sufficient waste disposal points and regular collection for disposal;

·           Appropriate measures to reduce windblown litter and dust transportation of waste by either covering trucks or by transporting wastes in enclosed containers;

·           Separation of chemical wastes for special handling and appropriate treatment at the Chemical Waste Treatment Centre at Tsing Yi.;

·           Regular cleaning and maintenance programme for drainage systems, sumps and oil interceptors; and

·           A recording system for the amount of wastes generated/ recycled and disposal sites.

7.5.2                                Waste Reduction Measures

Good management and control can prevent generation of significant amount of waste.  Waste reduction is best achieved at the planning and design stage, as well as by ensuring the implementation of standard site practices.  Recommendations to achieve waste reduction include:

·           Segregation and storage of different types of waste in different containers, skips or stockpiles to enhance reuse or recycling of material and their proper disposal;

·           Encourage collection of aluminium cans and waste paper by individual collectors during construction with separate labelled bins provided to segregate these wastes from other general refuse by the workforce;

·           Any unused chemicals and those with remaining functional capacity will be recycled as far as possible;

·           Use of reusable non-timber formwork to reduce the amount of C&D materials;

·           Prior to disposal of construction waste, wood, steel and other metals will be separated to the extent practical, for re-use and/or recycling to reduce the quantity of waste to be disposed of to landfill;

·           Proper storage and site practices to reduce the potential for damage or contamination of construction materials; and

·           Plan and stock construction materials carefully to reduce amount of waste generated and avoid unnecessary generation of waste.

7.5.3                                Dredged Materials

For sediments dredged during the construction of the GRS reclamation and submarine pipelines, their disposal will be as indicated in Section 7.4.2, and in accordance with the requirements of the PNAP 252.

Detailed sampling and chemical testing will be carried out prior to the commencement of the dredging activities to confirm the sediment disposal method.  The final disposal site will be determined by the MFC and a dumping licence will be obtained from EPD prior to the commencement of the dredging works.  Uncontaminated sediments will be disposed of at open sea disposal sites designated by the MFC.  For contaminated sediments requiring Type 2 confined marine disposal, CAPCO will confirm that the relevant contract documents will specify the allocation conditions of the MFC and EPD.

7.5.4                                Excavated Materials

Management of Waste Disposal

The contractor will open a billing account with EPD in accordance with the Waste Disposal (Charges for Disposal of Construction Waste) Regulation for the payment of disposal charges.  Every waste load transferred to Government waste disposal facilities such as public fill, sorting facilities, landfills or transfer station will require a valid “Chit” which contains the information of the account holder to facilitate waste transaction recording and billing to the waste producer.  A trip-ticket system will be established in accordance with ETWBTC(W) No. 31/2004 to monitor the reuse of surplus excavated materials off-site and disposal of construction waste and general refuse at transfer stations/ landfills, and to control fly-tipping.  The billing “chit” and trip ticket system will be included as one of the contractual requirements and implemented by the contractor.  CAPCO will also conduct regular inspection of the waste management measures implemented on site as described in the Waste Management Plan to be prepared before commencement of construction.

A recording system (similar to summary table as shown in Annex 5 and Annex 6 of Appendix G of ETWBTC(W) No. 19/2005) for the amount of waste generated, recycled and disposed of (including the disposal sites) will be established during the construction stage.

Measures for the Reduction of C&D Materials Generation

Majority of the inert C&D materials (rock and soil) will be reused within the Project.  Public fill and construction waste shall be segregated and stored in different containers or skips to facilitate reuse or recycling of materials and their proper disposal.  Specific areas of the work site will be designated for such segregation and storage if immediate use is not practicable.

To reduce the potential dust and water quality impacts of site formation works, C&D materials will be wetted as quickly as possible to the extent practice after filling.

7.5.5                                Chemical Waste

Chemical waste producers will be registered with the EPD.

Chemical waste, as defined by Schedule 1 of the Waste Disposal (Chemical Waste) (General) Regulation, will be handled in accordance with the Code of Practice on the Packaging, Handling and Storage of Chemical Wastes as follows.  Containers used for storage of chemical wastes will:

·           Be suitable for the substance they are holding, resistant to corrosion, maintained in a good condition, and securely closed;

·           Have a capacity of less than 450 L unless the specifications have been approved by the EPD; and

·           Display a label in English and Chinese in accordance with instructions prescribed in Schedule 2 of the Regulations.

The storage area for chemical wastes will:

·           Be clearly labelled and used solely for the storage of chemical waste;

·           Be enclosed on at least 3 sides;

·           Have an impermeable floor and bunding, of capacity to accommodate 110% of the volume of the largest container or 20% by volume of the chemical waste stored in that area, whichever is the greatest;

·           Have adequate ventilation;

·           Be covered to prevent rainfall entering (water collected within the bund must be tested and disposed of as chemical waste, if necessary); and

·           Be arranged so that incompatible materials are appropriately separated.

Chemical waste will be disposed of:

·       Via a licensed waste collector; and

·       To a facility licensed to receive chemical waste, such as the Chemical Waste Treatment Facility which also offers a chemical waste collection service and can supply the necessary storage containers.

7.5.6                                Sewage

Sanitary facilities, such as portable toilets, will be provided for the on-site construction workforce.  The sewage generated from the construction works will either be conveyed to sewage treatment works (STW) at BPPS or collected in the onboard sewage tank in the case of barges/ dredgers for off-site disposal.  The small amount of sewage generated during the operation phase is also expected to be conveyed to the STW at BPPS.

7.5.7                                General Refuse

General refuse will be stored in enclosed bins or compaction units separately from construction and chemical wastes.  Adequate number of waste containers will be provided to avoid over-spillage of waste.  A reputable waste collector will be employed by the Contractor to remove general refuse from the site, separately from construction and chemical wastes, on a daily basis to minimise odour, pest and litter impacts.  The burning of refuse on construction sites is prohibited by law.

Recycling bins will be provided at strategic locations to facilitate recovery of aluminium can and waste paper from the site.  Materials recovered will be sold for recycling.

7.5.8                                Industrial Wastes

Industrial waste arising from maintenance activities will be segregated.  It is recommended to send scrap metals for recycling to reduce the overall quantity of waste disposed from these activities.

7.5.9                                Staff Training

Training will be provided to workers on the concepts of site cleanliness and appropriate waste management procedures, including waste reduction, reuse and recycling at the beginning of the construction works.

7.6                                      Residual Environmental Impacts

With the implementation of the recommended mitigation measures no adverse residual impacts are anticipated from the construction and operation of the GRSs and submarine gas pipelines.

7.7                                      Environmental Monitoring & Audit

7.7.1                                Construction Phase

To facilitate monitoring and control over the contractors’ performance on waste management, a waste monitoring and audit programme will be implemented throughout the construction phase.  The aims of the monitoring and audit programme are:

·           To review the Contractor’s Waste Management Plan (WMP) including the quantities and types of C&D materials generated, reused and disposed of off-site; the amount of fill materials exported from/imported to the site and the quantity of timber used in temporary works construction for each process/activity;

·           To monitor the implementation and achievement of the WMP on site to assess its effectiveness; and

·           To monitor the follow-up action on deficiencies identified.

Joint site inspections by CAPCO and the contractor will be undertaken each month.  Particular attention will be given to the contractor’s provision of sufficient spaces, adequacy of resources and facilities for on-site sorting and temporary storage of C&D materials.  The C&D materials to be disposed of from the site will be visually inspected.  The public fill for delivery to the off-site stockpiling area will contain no observable non-inert materials (e.g. general refuse, timber, etc).  Furthermore, the waste to be disposed of at refuse transfer stations or landfills will as practicable contains no observable inert or reusable/recyclable C&D materials (e.g. soil, broken rock, metal, and paper/cardboard packaging, etc).  Any irregularities observed during the site inspections will be raised promptly to the contractor for rectification.

The findings of the waste inspections will be reported in the Environmental Monitoring and Audit Reports.

7.7.2                                Operation Phase

As the operation of the GRSs will generate minimal quantity of waste and no adverse environmental impacts will arise with the implementation of standard waste management practices, waste monitoring and audit programme for the operation phase of the facilities is not required.

7.8                                      Summary & Conclusions

7.8.1                                Construction Phase

Optioneering has been conducted to try to avoid waste generation and reuse and recycling of waste generated from the construction of the proposed Project during the planning and design stages and consideration of options for layout, construction methods and programme, and the proposed scheme comprises the proposed best balance.  The key potential impacts during the construction phase are related to wastes generated from dredging, reclamation, seawall construction, filling and concreting.

The Project is planned to take place in phases.  For the First Phase of the Project, Sections 1 and 3 of the pipeline would be installed by dredging while Sections 2 and 4 of the pipeline would be installed by jetting.  About 0.253 Mm3 (bulk volume) sediment will be generated from Sections 1 and 3 of the pipeline.  The final volumes will be subject to detailed sediment sampling, testing and analysis in accordance with the PNAP 252 and disposal method reviewed prior to the commencement of the dredging activities.  About 0.029 Mm3 (bulk volume) of the dredged sediment is expected to be Category L sediment.  MFC has no objection in-principle to allocating disposal space for the Mfail sediment dredged from Sections 1 and 3 of the pipeline route (about 0.060 Mm3 bulk volume), subject to the availability of disposal space at the time of CAPCO's application and at the proposed programme for disposal.  CAPCO is exploring alternative disposal sites (such as cross boundary disposal to Mainland China([13])) for the remaining 0.164 Mm3 (bulk volume) of Category Mpass sediment.  A dumping permit will be applied from the DEP prior to the commencement of the dredging work.

The Second Phase of the Project is expected to also generate approximately 0.253 Mm3 (bulk volume) from the installation of the submarine pipeline.  At present the dredging works for the reclamation for the second GRS are expected to give rise to a bulk volume of 0.156 Mm3 of contaminated mud.

As for C&D materials, they will be sorted on site into inert waste (public fill) and non-inert waste (construction waste).  Public fill will either be reused or be disposed of at public fill reception facilities (e.g. Tuen Mun Area 38 or other locations as agreed with CEDD).  Construction waste, such as timber, paper, plastics and general refuse, cannot be reused and need to be disposed of at the West New Territories (WENT) Landfill.  It is estimated that a total bulk volume of 0.828 Mm3 of fill materials are required for this Project, and surplus public fill material is not anticipated.

The construction programme is preliminary and subject to reduce, therefore, the Contractor's programme will be reviewed by CAPCO when the construction programme is finalized.

A few hundred litres of used lubrication oil is expected to be generated per month and a maximum of about 65 kg of general refuse will be generated each day.  In view of the small quantity of waste generated, the handling and disposal of the waste generated from construction activities, chemical wastes and general refuse will not cause any significant environmental impacts.  With the implementation of the recommendations in Section 7.5, the potential environmental impacts arising from storage, handling, collection, transport and disposal of wastes is expected to meet the criteria specified in the EIAO TM.  No adverse waste management impact is anticipated based on the information available.  No residual and cumulative environmental impacts and hazards associated with handling and disposal of wastes arising from the construction of the proposed Project are anticipated.

A Waste Management Plan will be prepared by the Contractors and will be audited through the environmental monitoring and auditing (EM&A) programme recommended in Section 7.7 to reduce the potential environmental impact arising from waste management.

7.8.2                                Operation Phase

With standard site practice, the potential environmental impacts associated with the storage, handling, collection, transport and disposal of a small quantity of industrial and chemical wastes arising from the operation of the GRSs at BPPS will meet the criteria specified in the EIAO TM and no unacceptable waste management impact is anticipated.

No residual and cumulative environmental impacts and hazards associated with handling and disposal of wastes arising from the operation of the GRSs at BPPS are anticipated.

 

 


([1])         “C&D materials” refers to materials arising from any land excavation or formation, civil/building construction, road works, building renovation or demolition activities.  It includes various types of reusable materials, building debris, rubble, earth, concrete, timber and mixed site clearance materials.  When sorted properly, materials suitable for land reclamation and site formation (known as public fill) will be reused at a public filling area or other land formation /reclamation projects.  The rock and concrete can be crushed and processed to produce rock fill or aggregates for various civil and building engineering applications.  The remaining construction waste (comprising timber, paper, plastics and general refuse) are to be disposed of at landfills.

([2])         ETWB Technical Circular #31/2004 (ETWBTC(W)W No. 31/2004): Trip Ticket System for Disposal of Construction & Demolition Materials

([3])         Buildings Department Practice Note for Authorised Persons and Registered Structural Engineers (PNAP) No. 252: Management Framework for Disposal of Dredged/Excavated Sediment

([4])         First Phase construction will commence in 2011 to allow for First gas to arrive by 2012, while Second Phase construction is expected to commence within 24 months following commissioning of the first pipeline and GRS

([5])         Buildings Department Practice Note for Authorized Persons and Registered Structural Engineers (PNAP) 252 – Management Framework for Disposal of Dredged/Excavated Sediment

([6])         One sample was not tested for biological screening due to insufficient sample as a result of significant core loss

([7])         PNAP 252 (April 2007 Rev).  Practice Note for Authorized Persons and Registered Structural Engineers 252. Management Framework for Disposal of Dredged/Excavated Sediment.  Buildings Department.

([8])         Dredging rates are calculated at a total of 8,000 m3 for two dredgers per day.  Number of trips required for transportation of dredged sediment from dredging area(s) to disposal site(s) was calculated using a 900 m3 (bulked volume) loading on each barge.

([9])         Dredging rates are calculated at a range of 4,000 to 8,000 m3 for one dredger per day.  Number of trips required for transportation of dredged sediment from dredging area(s) to disposal site(s) was calculated using a 900 m3 (bulked volume) loading on the barge.

([10])       This is the best estimate based on the latest site layout.

([11])       Based on Table 2 of the Drainage Services Department's Sewerage Manual

([12])       This is considered as a conservative estimate based on the number reported in a number of EIA reports approved under the EIAO.

([13])       At the time of this EIA CAPCO is preparing a submission to the relevant authorities to determine the feasibility of this option.