6                    WASTE management

6.1              Introduction

6.1.1          This section identifies the types of wastes that are likely to be generated during the construction phase and evaluates the potential environmental impacts that may result from these waste arisings.  The main solid waste issues are related to dredged marine sediment and other construction waste arisings, and the potential biogas risk due to the release of methane gas from the sediment underneath the reclaimed area during construction or after development.  Mitigation measures and good site practice, including waste handling, storage and disposal, will be recommended with reference to the applicable waste legislation and guidelines.  An assessment of the potential biogas emission from the undredged area at the proposed reclamation is presented in Section 11.

6.2              Environmental Legislation, Policies, Plans, Standards and Criteria

6.2.1          The criteria and guidelines for assessing waste management implications are outlined in Annex 7 and Annex 15 of the Technical Memorandum on Environmental Impact Assessment Ordinance (EIAO-TM), respectively.

6.2.2          The following legislation relates to the handling, treatment and disposal of wastes in the Hong Kong SAR and will be used in assessing potential impacts:

·            Waste Disposal Ordinance (Cap. 354);

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

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

·            Public Health and Municipal Services Ordinance (Cap. 132) - Public Cleansing and Prevention of Nuisances (Urban Council) and (Regional Council) By-laws; and

·            Dumping At Sea Ordinance (Cap. 466).

6.2.3          The following documents, circulars and guidelines which relate to waste management and disposal in the Hong Kong SAR will also be referred to during this study:

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

·            Environmental Guidelines for Planning in Hong Kong (1990), Hong Kong Planning Standards and Guidelines, Hong Kong Government;

·            New Disposal Arrangements for Construction Waste (1992), Environmental Protection Department and Civil Engineering Department;

·            Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes (1992), Environmental Protection Department;

·            Waste Reduction Framework Plan, 1998-2007 (1998), Planning, Environment and Lands Branch, Hong Kong Government Secretariat;

·            Works Bureau Technical Circular (WBTC) No. 2/93, Public Dumps;

·            WBTC No. 2/93B, Public Filling Facilities;

·            WBTC No. 16/96, Wet Soil in Public Dumps;

·            WBTC No. 4/98, Use of Public Fill in Reclamation and Earth Filling Projects;

·            WBTC No. 4/98A, Use of Public Fill in Reclamation and Earth Filling Projects;

·            WBTC No. 5/98, On Site Sorting of Construction Waste on Demolition Sites;

·            WBTC No. 5/99, Trip-ticket System for Disposal of Construction and Demolition Material;

·            WBTC No. 5/99A, Trip-ticket System for Disposal of Construction and Demolition Material;

·            WBTC No. 3/2000, Management of Dredged / Excavated Sediment;

·            WBTC No. 25/99, Incorporation of Information on Construction and Demolition Material Management in Public Works Subcommittee Papers;

·            WBTC No. 25/99A, Incorporation of Information on Construction and Demolition Material Management in Public Works Subcommittee Papers (Amendment 1);

·            WBTC No. 25/99B Incorporation of Information on Construction and Demolition Material Management in Public Works Subcommittee Papers;

·            WBTC No. 12/2000, Fill Management; and

·            WBTC No. 29/2000, Waste Management Plan.

Waste Management

6.2.4          The Waste Disposal Ordinance (WDO) prohibits the unauthorised disposal of wastes.  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 waste building, or civil engineering materials, but does not include animal waste.  Under the WDO, wastes can be disposed of at sites licensed by the EPD.

6.2.5          The Public Cleansing and Prevention of Nuisance By-Laws provides control on illegal tipping of wastes on unauthorised (unlicensed) sites.

Marine Sediment

6.2.6          The WBTC No. 3/2000 sets out the new management framework for dredged / excavated sediment. This Technical Circular outlines the new procedures to be followed in assessing and classifying the sediment and explains the marine disposal arrangement for the classified material.  All projects which involve the marine disposal of dredged / excavated sediment, except those projects or portions of projects whose construction work will commence before 31 December 2001, shall follow the new management framework.  Under the preliminary construction programme for WDII, the dredging works are scheduled to commence in 2004 and, therefore, the requirements of WBTC No. 3/2000 should be followed.  The new sediment quality criteria for the classification of sediment are presented in Table 6.1.

6.2.7          Dumping permits from EPD are required for marine disposal of dredged materials.

Chemical Waste

6.2.8          Under the Waste Disposal (Chemical Waste) (General) Regulations, all producers of chemical waste must register with EPD and treat their wastes, either utilising on-site plant licensed by EPD, or arranging for a licensed collector to transport the wastes to a licensed facility.  The regulation also prescribes the storage facilities to be provided on site, including labelling and warning signs, and requires the preparation of written procedures and training to deal with emergencies such as spillages, leakages or accidents arising from the storage of chemical wastes.

Construction and Demolition (C&D) Materials

6.2.9          The current policy related to the dumping of C&D material([1]) is documented in the Works Branch Technical Circular No. 2/93, ‘Public Dump’.  Construction and demolition materials that are wholly inert, namely public fill, should not be disposed of to landfill, but taken to public filling areas which usually form part of reclamation schemes.  The Land (Miscellaneous Provisions) Ordinance requires that dumping licences are obtained by individuals or companies who deliver public fill to public filling areas.  The licences are issued by the Civil Engineering Department (CED) under delegated powers from the Director of Lands.

6.2.10      In addition to the Works Branch Technical Circular / WBTC, EPD and CED have produced a leaflet titled ‘New Disposal Arrangements for Construction Waste’ (1992) which states that C&D material with less than 30% by weight of inert material (that is, public fill) will be accepted at landfill.  If the material contains more than 30% inert material, the waste must be sorted with suitable material and sent to public filling area and the non-inert material (that is, C&D waste) sent to landfill for final disposal.

6.3              Assessment Methodology

General

6.3.1          The criteria for assessing waste management implications are outlined in Annex 7 of the EIAO-TM.  The methods for assessing potential waste management impacts during construction follow those presented in Annex 15 of the EIAO-TM and include the following:

·            estimation of the types and quantities of the wastes generated;

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

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

Marine Dredged Materials

6.3.2          The Phase I marine site investigation works of WDII were carried out in February 2000 and included laboratory testing of contaminants to determine the level of contamination in the marine sediments at the reclamation location.  The works included vibrocoring at six locations (MV1, MV4, MV5, MV6, MV7 and MV8) around the HKCEC and near the Wan Chai waterfront to obtain sediment samples for chemical testing (Figure 6.1).  The Phase II marine site investigation works commenced in late September 2000 and included sampling locations near the Wanchai Public Cargo Working Area (PCWA) (MV20), the Royal Hong Kong Yacht Club (MV9 and MV15) and at the Causeway Bay Typhoon Shelter (MV10, MV11, MV12, MV13, MV14, MV16, MV17, MV18 and MV19).

6.3.3          Each sub-sample recovered from the Phases I and II vibrocoring was tested in the laboratory for the following parameters unless otherwise specified:

(i)                  Metals concentrations including chromium (Cr), copper (Cu), mercury (Hg), lead (Pb), cadmium (Cd), nickel (Ni), zinc (Zn), silver (Ag) and arsenic (As).

(ii)                Concentrations of organic compounds including total polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs), and tributyltin (TBT) for each sub-sample from the top three sampling depths of each vibrocoring location. 

(iii)               Redox potential.

(iv)              Total organic carbon (TOC) (Phase I samples only).

(v)                Sediment oxygen demand (SOD) (Phase I samples and those Phase II samples acquired from the Causeway Bay Typhoon Shelter).  

6.3.4          Elutriate tests were also conducted to assess the likelihood of release of contaminants from sediment to the water, when the seabed is disturbed during dredging.  If the contaminant levels are higher in the elutriates in comparison with the sample of marine water from the same site, it can be concluded that the contaminants are likely to be released into the open waters during dredging activities.  The potential water quality impacts associated with the dredging of sediment are discussed in Section 5 of this Report.

6.3.5          Under the new management and classification system, dredged sediments destined for marine disposal are classified according to their level of contamination by 13 contaminants (Table 6.1).

Table 6.1         Sediment Quality Criteria for the Classification of Sediment

Contaminants

LCEL

UCEL

Heavy Metal (mg/kg dry weight)

Cadmium (Cd)

1.5

4

Chromium (Cr)

80

160

Copper (Cu)

65

110

Mercury (Hg)

0.5

1

Nickel (Ni)

40

40

Lead (Pb)

75

110

Silver (Ag)

1

2

Zinc (Zn)

200

270

Metalloid (mg/kg dry weight)

Arsenic

12

42

Organic-PAHs (µg/kg dry weight)

PAHs (Low Molecular Weight)

550

3160

PAHs (High Molecular Weight)

1700

9600

Organic-non-PAHs (µg/kg dry weight)

Total PCBs

23

180

Organometallics (µg-TBT L-1 in interstitial water)

Tributyltin

0.15

0.15

Source:   Appendix A of WBTC No. 3/2000 Management of Dredged / Excavated Sediment

Note:      LCEL –   Lower Chemical Exceedance Level

                            UCEL –  Upper Chemical Exceedance Level

 

6.3.6          Sediments are categorised with reference to the LCEL and UCEL, as follows:

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

Category M      Sediment with any one or more contaminant levels exceeding the LCEL and 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 contaminant levels exceeding the UCEL.  The material must be dredged and transported with great care, and must be effectively isolated from the environment upon final disposal.

6.3.7          In the case of Category M and Category H contamination under the new system, the final determination of appropriate disposal options, routing and the allocation of a permit to dispose of material at a designated site will be made by EPD and the Marine Fill Committee (MFC) in accordance with the WBTC No. 3/2000.

6.4              Baseline Conditions

Existing Sediment Characteristics

6.4.1          The results of the marine sediment quality analysis from Phase I and Phase II marine site investigation works, as compared with the new sediment quality criteria for the classification of sediment, are presented in Tables 6.2 and 6.3, respectively.

6.4.2          The sediment testing results indicate that Category H sediment was found at all but two of the 18 vibrocore locations due to high contaminant levels of Ag, Cu, Pb, Zn and Hg that exceed the UCEL of these five metals.  At vibrocores MV11, MV12, MV17, MV18 and MV19, all located within the Causeway Bay Typhoon Shelter, the reported contaminant level of Total PCBs exceeds the LCEL by 10 times (in approximately the first 1 m below the seabed, except at MV11 with a depth of approximately 2 m).  It is therefore likely that Tier III biological screening would be required for future sediment sampling in the typhoon shelter to be carried out in the further ground investigation works at the design phase of the Project.  At vibrocore MV17, the reported contaminant level of high molecular weight PAHs is in exceedance of the UCEL.  It should be noted that MV17 and MV18 are located within the areas of the Causeway Bay Typhoon Shelter where mud is proposed to be left in place.  The other areas of the typhoon shelter would be fully dredged.  

6.4.3          At vibrocores MV5, MV13 and MV18 where the marine mud extends to a greater depth, there was a decrease in the level of metal contamination from surface to deeper sediments.  At vibrocore MV14, however, Category H contamination was found at sampling depth –7.0 to –7.9 mPD.  Sediment at vibrocores MV16 (located outside Causeway Bay Typhoon Shelter) and MV20 (located within the PCWA) is classified as Category L.

6.4.4          The measurements of redox potential indicate strongly anaerobic conditions within the sediments, particularly to depths of up to 3 or 4 metres.  The results of EPD’s routine monitoring of marine sediment quality also indicate that the sediment is largely anaerobic (also refer to Section 9.3.2 of this Report).   Only at vibrocore MV20 was a positive redox potential measured in the upper layer of sediment.

 

 


Table 6.2         Results of Sediment Quality Analysis from the Phase I Marine Site Investigation Works

Vibrocore

Sampling Depth (m)

Metals and Metalloid Content (mg kg-1)

(mg kg-1)

(mg-TBT L-1)

Overall Classification

 

 

Ag

As

Cd

Cr

Cu

Ni

Pb

Zn

Hg

Total PCBs

PAHs Low(1)

PAHs High(2)

TBT in Sediment

TBT in Interstitial water

 

MV1

0.55 - 0.9 m

5.7

9

0.9

67

297

32

66

314

0.62

14

<50

370

81

0.3

Category H

 

1.0 - 1.9 m

3.6

9

0.7

47

205

24

85

222

0.62

20

<50

300

68

<0.3

Category H

 

2.0 - 2.9 m

2.5

8

0.5

64

214

24

96

254

1

120

810

7400

16

<0.3

Category H

 

3.0 - 3.9 m

<0.5

3

<0.5

7

2

6

9

16

<0.05

 

 

 

 

 

Category L(5)

MV4

0.25 - 0.9 m

4.6

7

0.9

57

284

27

72

359

0.66

59

97

620

55

<0.3

Category H

 

1.0 - 1.9 m

3.8

8

0.5

44

180

24

58

204

0.35

32

93

720

39

<0.3

Category H

 

2.0 - 2.9 m

3.7

9

0.8

62

269

27

112

364

0.96

100

79

680

17

<0.3

Category H

 

3.0 - 3.9 m

3.6

8

0.7

62

133

26

115

369

1.59

 

 

 

 

 

Category H

MV5

0.3 - 1.0 m

5.6

8

1

71

331

30

71

331

1.05

21

250

820

96

<0.3

Category H

 

1.0 - 1.9 m

4.6

7

0.7

61

374

30

62

258

0.45

18

<50

310

76

<0.3

Category H

 

2.0 - 2.9 m

3.6

7

0.7

61

249

30

69

228

0.67

63

130

300

17

<0.3

Category H

 

3.0 - 3.9 m

1

5

<0.5

23

29

12

48

138

0.47

 

 

 

 

 

Category L(5)

 

6.5 - 7.0 m

<0.5

4

<0.5

7

5

5

19

22

<0.05

 

 

 

 

 

Category L(5)

 

7.0 - 7.9 m

<0.5

<1

<0.5

2

2

1

11

6

<0.05

 

 

 

 

 

Category L(5)

 

8.0 - 8.9 m

<0.5

<1

<0.5

1

<1

<1

6

<5

<0.05

 

 

 

 

 

Category L(5)

 

9.0 - 9.9 m

<0.5

<1

<0.5

<1

1

1

3

<5

<0.05

 

 

 

 

 

Category L(5)

 

10.0 - 10.9m

<0.5

<1

<0.5

<1

<1

<1

3

<5

<0.05

 

 

 

 

 

Category L(5)

 

11.0 - 11.6m

<0.5

2

<0.5

<1

<1

<1

4

<5

<0.05

 

 

 

 

 

Category L(5)

MV6

1.0 - 1.9 m

4.4

8

0.9

67

381

30

78

337

0.64

21

140

1000

74

<0.3

Category H

 

2.0 - 2.9 m

4.8

8

0.9

74

323

29

125

394

2.11

110

690

2800

40

<0.3

Category H

 

3.0 - 3.9 m

<0.5

4

<0.5

10

12

9

59

67

1.06

30

220

1300

3

<0.3

Category H

MV7

0.1 - 0.8 m

3.9

10

0.6

45

241

25

53

175

0.33

5

<50

200

34

<0.3

Category H

MV8

0.5 - 0.9 m

7.5

9

1.1

64

242

28

68

295

0.49

15

53

390

102

<0.3

Category H

 

1.0 - 1.9 m

2.7

8

0.5

48

130

19

122

281

1.12

120

1100

7200

13

<0.3

Category H

 

2.0-2.9m

<0.5

3

<0.5

12

4

10

14

28

<0.05

<2

<50

   <150

1

<0.3

(6)

 

3.0-3.9m

<0.5

4

<0.5

10

4

9

14

25

<0.05

 

 

 

 

 

Category L(5)

Notes:

1.        Low molecular weight PAHs, that is, acenaphthene, acenaphthylene, anthracene, fluorene, naphthalene and phenanthrene.

2.        High molecular weight PAHs, that is, benzo[a]anthracene, benzo[a]pyrene, chrysene, dibenzo[a,h]anthracene, fluoranthene, pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, indeno[1,2,3-c,d]pyrene and benzo[g,h,i]perylene.

3.        Values in underline indicate Category M sediment under WBTC No. 3/2000.

4.        Values in bold indicate Category H sediment under WBTC No. 3/2000.

5.        Provisional classification based on available testing results for analysis of metals and metalloid content.

6.        Classification cannot be determined due to detection limit of TBT in interstitial water being higher than UCEL (as insufficient sample size recovered from vibrocores, the testing laboratory experienced difficulties in extracting sufficient interstitial water to achieve the required detection limit).

 


Table 6.3         Results of Sediment Quality Analysis from the Phase II Marine Site Investigation Works

 

Vibrocore

Sampling Depth (m)

Metals and Metalloid Content (mg kg-1)

(mg kg-1)

(mg-TBT L-1)

Overall Classification

 

 

Cu

Cd

Cr

Pb

Ni

Zn

Hg

Ag

As

Total PCBs

PAHs Low(1)

PAHs High(2)

TBT in Sediment

TBT in Interstitial water

 

MV9      

0-0.9M   

169

0.6

48

59

20

202

0.5

5

4

58

430

730

23

<0.015

Category H

 

1.0-1.9M 

4

<0.5

8

14

5

19

0.05

<0.5

2

2

<50

<100

<0.5

 

Category L

 

2.0-2.9M 

2

<0.5

8

10

5

15

<0.05

<0.5

3

<2

<50

<100

<0.5

 

Category L

 

3.0-3.9M 

3

<0.5

16

14

7

19

<0.05

<0.5

4

<2

<50

<100

<0.5

 

Category L

 

4.0-4.6M 

3

<0.5

10

35

9

24

0.12

<0.5

3

 

 

 

 

 

Category L

MV10     

0-0.84M  

208

0.8

70

103

17

264

1.39

2.7

12

120

100

1100

2390

0.022

Category H

MV11     

0-0.9M   

346

1.3

103

158

36

415

1.36

4.5

9

460

220

1600

216

<0.015

Category H

 

1.0-1.9M 

137

0.8

65

321

27

652

1.6

1.9

9

430

680

5700

10

 

Category H

 

2.0-2.9M 

23

<0.5

42

52

29

108

0.38

<0.5

6

10

<50

190

3

 

Category L

 

3.0-3.9M 

5

<0.5

9

13

6

20

0.05

<0.5

3

<2

<50

130

1

 

Category L

 

4.0-4.9M 

2

<0.5

9

10

5

13

<0.05

<0.5

4

 

 

 

 

 

Category L

 

5.0-5.7M 

11

<0.5

35

21

15

48

<0.05

<0.5

7

 

 

 

 

 

Category L

MV12     

0-0.9M   

322

1.8

90

175

35

518

2.87

4.3

10

4200

240

3600

61

<0.015

Category H

 

1-1.9M   

140

0.7

48

260

23

400

1.46

1.8

9

200

330

3600

<0.5

 

Category H

 

2-2.9M   

21

<0.5

49

51

31

108

0.26

<0.5

5

8

<50

130

<0.5

 

Category L

 

3-3.9M    

10

<0.5

12

18

9

34

0.11

<0.5

2

4

<50

<100

<0.5

 

Category L

 

4-4.9M   

16

<0.5

38

33

26

79

<0.05

<0.5

2

 

 

 

 

 

Category L

 

 

5-5.9M   

10

<0.5

21

20

7

29

<0.05

<0.5

6

 

 

 

 

 

Category L

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

MV13     

0-0.9M   

407

1.2

94

86

37

357

1.36

7.2

10

50

99

610

77

<0.015

Category H

 

1.0-1.9M 

157

0.6

65

97

32

227

0.64

2

8

65

<50

450

202

 

Category H

 

2.0-2.9M 

59

<0.5

36

51

25

111

0.39

<0.5

4

<2

<50

410

2

 

Category L

 

3.0-3.9M 

2

0.9

10

52

4

32

<0.05

<0.5

1

<2

<50

<100

<0.5

 

Category L

 

4.0-4.9M 

2

1.1

5

75

4

38

<0.05

<0.5

2

 

 

 

 

 

Category L

 

5.0-5.9M 

2

0.8

6

111

4

22

0.11

<0.5

1

 

 

 

 

 

Category L

 

6.0-6.9M 

1

<0.5

6

9

2

<5

0.05

<0.5

<1

 

 

 

 

 

Category L

 

7.0-7.9M 

2

<0.5

6

11

2

6

0.05

<0.5

<1

 

 

 

 

 

Category L

 

8.0-8.9M 

<1

<0.5

2

5

1

<5

<0.05

<0.5

<1

 

 

 

 

 

Category L

MV14     

0-0.9M   

358

1.1

79

87

31

333

0.72

6.9

10

57

120

830

126

 

Category H

 

1.0-1.9M 

191

0.7

58

100

26

262

0.82

2.1

9

180

210

1200

57

 

Category H

 

2.0-2.9M 

193

0.7

67

120

22

289

0.84

2.4

8

92

320

110

98

 

Category H

 

3.0-3.9M 

63

<0.5

35

118

18

199

0.58

0.9

8

95

62

560

13

 

Category H

 

4.0-4.9M 

59

<0.5

37

110

18

234

0.88

0.8

8

 

 

 

 

 

Category H

 

5.0-5.9M 

35

<0.5

21

67

11

119

0.4

<0.5

4

 

 

 

 

 

Category L

 

6.0-6.9M 

22

<0.5

13

46

6

81

0.19

<0.5

4

 

 

 

 

 

Category L

 

7.0-7.9M 

58

0.5

36

115

18

271

0.58

1.3

7

 

 

 

 

 

Category H

 

8.0-8.9M 

37

<0.5

22

81

10

185

0.66

0.7

5

 

 

 

 

 

Category M

 

9.0-9.9M 

2

<0.5

4

8

2

10

<0.05

<0.5

<1

 

 

 

 

 

Category L

 

10.0-10.45

2

<0.5

4

8

2

6

<0.05

<0.5

<1

 

 

 

 

 

Category L

MV15     

0-0.9M   

151

<0.5

45

55

20

147

0.07

3

5

23

<50

<100

16

<0.015

Category H

 

1-1.9M   

5

<0.5

15

11

10

31

0.05

<0.5

3

<2

91

670

<0.5

 

Category L

 

2.0-2.9M 

1

<0.5

3

11

2

7

<0.05

<0.5

1

<2

<50

<100

<0.5

 

Category L

 

3.0-3.9M 

1

<0.5

5

12

2

8

<0.05

<0.5

<1

<2

<50

<100

<0.5

 

Category L

MV16     

0-0.9M   

15

<0.5

21

21

18

51

0.06

<0.5

2

<2

<50

<100

<0.5

<0.015

Category L

 

1.0-1.9M 

9

<0.5

24

18

20

53

<0.05

<0.5

4

7