11
Waste
management IMPLICATIONS
11.1 Introduction
11.1.1 This section identifies the types of wastes that are likely to be generated during the construction and operation phases of the Project and evaluates the potential environmental impacts that may result from these waste arisings. The main solid waste issues are related to dredged marine sediment from the construction of the WCR Phase 1 Reclamation, excavated rock from the tunnel section of the WCR and construction and demolition (C&D) material from road and engineering infrastructure. The main waste arising in the future will be domestic waste from the proposed residential developments at PSK, TCS and TKL. Mitigation measures and good site practices, including waste handling, storage and disposal, are recommended with reference to the applicable waste legislation and guidelines.
11.2 Environmental Legislation, Policies, Plans, Standards and Criteria
11.2.1 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.
11.2.2 The following legislation relates to the handling, treatment and disposal of wastes in the Hong Kong SAR and has been 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 Regulation
· Dumping At Sea Ordinance (Cap. 466).
Waste Management
11.2.3 The Waste Disposal Ordinance (WDO) prohibits the unauthorised disposal of wastes. Construction waste is defined under CAP 354N of the WDO as any substance, matter or thing that is generated from construction work and abandoned, whether or not it has been processed or stockpiled before being abandoned, but does not include any sludge, screenings or matter removed in or generated from any desludging, desilting or dredging works. Under the WDO, wastes can be disposed of at designated waste disposal facilities.
11.2.4 Under the WDO, the Chemical Waste (General) Regulation 1992 provides regulations for chemical waste control, and administers the possession, storage, collection, transport and disposal of chemical wastes. The Environmental Protection Department (EPD) has also issued a ‘guideline’ document, the Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes (1992), which details how the Contractor should comply with the regulations on chemical wastes.
11.2.5 The Public Cleansing and Prevention of Nuisances Regulation provides control on illegal tipping of wastes on unauthorised (unlicensed) sites.
Dredged Marine Sediment
11.2.6 The ETWB TCW No. 34/2002 sets out the new procedure for seeking approval to dredge/ excavate sediment and the management framework for marine disposal of dredged/ excavated sediment. This Technical Circular outlines the requirements to be followed in assessing and classifying the sediment and explains the marine disposal arrangement for the classified material. The sediment quality criteria for the classification of sediment are presented in Table 11.1.
11.2.7 Dumping permits from EPD are required for marine disposal of dredged materials.
Construction and Demolition (C&D) Materials
11.2.8 The current policy related to the dumping of C&D material 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 Civil Engineering & Development Department (CEDD) issues the licences under delegated powers from the Director of Lands.
11.2.9 Under the Waste Disposal (Charges for Disposal of Construction Waste) Regulation, enacted in January 2005, construction waste delivered to a landfill for disposal must not contain more than 50% by weight of inert material. Construction waste delivered to a sorting facility for disposal must contain more than 50% by weight of inert material, and construction waste delivered to a public fill reception facility for disposal must consist entirely of inert material.
11.2.10 Measures have recently been introduced under Environment, Transport and Works Bureau (ETWB) TCW No. 33/2002 to enhance the management of C&D material including rock, and to minimize its generation at source. The enhancement measures include: (i) drawing up a Construction and Demolition Material Management Plan (C&DMMP) at an early design stage to minimize C&D material generation and encourage proper management of such material; (ii) vetting of the C&DMMP prior to upgrading of the project to Category A in the Public Works Programme; and (iii) providing the contractor with information from the C&DMMP in order to facilitate him in the preparation of the Waste Management Plan (WMP) and to minimize C&D material generation during construction. Projects generating C&D material less than 50,000m3 or importing fill material less than 50,000m3 are exempt from the C&DMMP.
11.3 Assessment Methodology
General
11.3.1 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 the construction phase 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
· Impacts on the capacity of waste collection, transfer and disposal facilities.
Dredged Marine Material
11.3.2
The results of the marine site
investigation carried out in the Feasibility Study for Intensification and
Extension of Tseung Kwan O (IETKO) and the site investigation conducted under
this Project have been reviewed to classify the sediment quality of the
proposed dredged areas for the purpose of the EIA Study. The sampling points are presented in Figure 11.1. Five of the sampling locations conducted under the Feasibility
Study for IETKO in December 1999 were located within or in the vicinity of the
proposed reclamation area of WCR.
Sediment samples were collected at six locations under this Project in
March 2003 in the area of the WCR and CBL.
In March 2003, a site investigation
was carried out after reviewing all the available data to obtain underground
information to facilitate determination of geotechnical constraints in
establishing the feasibility of the proposed TKO further development. Opportunity was also taken to carry out an
updated marine sediment quality survey at the same time. Taking account that a second stage site
investigation would be carried out at a later stage of the study and also the
preferred development option including WCR and CBL has yet to be confirmed at
that time, the marine sediment quality survey was only carried out at six
locations as shown on Figure 11.1. Subsequent to the findings of
Traffic Impact Assessment study which showed the need for WCR to be around year
2016, CEDD has decided not to pursue with the second stage site investigation
taking account that the detailed design of the WCR project would be commenced a
few years after completion of the Study.
Since there is no second stage site investigation, it is proposed to
carry out further field investigation/sampling and chemical testings at the
detailed design stage. For the purpose
of the EIA Study, the previous investigation results should be based since the
test requirements as stipulated in the EIA Study Brief have been covered.
11.3.3 Under the new management and classification system, dredged sediments destined for marine disposal are classified according to their level of contamination by 13 contaminants as detailed in Table 11.1.
Table 11.1 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
ETWB TCW No. 34/2002 Management of Dredged / Excavated Sediment
Note: LCEL – Lower Chemical Exceedance Level
UCEL
– Upper Chemical Exceedance Level
11.3.4 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.
11.3.5 In 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 ETWB TCW No. 34/2002.
11.4 Baseline Conditions
Existing Sediment Characteristics
11.4.1 The marine sediment quality analysis results from the site investigation works for the Feasibility Study for IETKO, as compared with the sediment quality criteria for the classification of sediment, are presented in Table 11.2. The chemical testing results indicate that the sediment at VC18 was classified as Category H in accordance with ETWB TCW No. 34/2002 due to high contaminant levels of zinc, lead and nickel. The sediment at G1 was classified as Category H due to the high contaminant level of zinc. The sediment at VC3, G2 and G3 was classified as Category L.
Table 11.2 Sediment Analysis Results from Marine Ground Investigation Works under Feasibility Study for IETKO
|
Sampling Location |
Sampling Depth (m) |
Metals and Metalloid
Content (mg/kg) |
Category |
|||||||||
|
From |
To |
Cd |
Cr |
Cu |
Ni |
Pb |
Zn |
Hg |
As |
Ag |
||
|
VC3 |
0.90 |
1.00 |
<0.5 |
7 |
<10 |
<6 |
<15 |
42 |
<0.4 |
NA |
NA |
L |
|
VC3 |
1.90 |
2.00 |
<0.5 |
16 |
<10 |
9 |
<15 |
35 |
<0.4 |
NA |
NA |
L |
|
VC3 |
2.90 |
3.00 |
<0.5 |
16 |
<10 |
9 |
<15 |
35 |
<0.4 |
NA |
NA |
L |
|
VC18 |
0.90 |
1.00 |
<0.6 |
35 |
57 |
20 |
63 |
300 |
0.1 |
10 |
<1 |
H |
|
VC18 |
1.90 |
2.00 |
0.9 |
43 |
93 |
10 |
160 |
950 |
0.2 |
10 |
<1 |
H |
|
VC18 |
2.90 |
3.00 |
<0.6 |
130 |
7 |
71 |
20 |
39 |
<0.1 |
6 |
<1 |
H |
|
VC18 |
5.75 |
5.85 |
<0.6 |
42 |
9 |
24 |
20 |
71 |
<0.1 |
7 |
<1 |
L |
|
VC18 |
8.90 |
9.00 |
<0.6 |
32 |
9 |
20 |
24 |
63 |
<0.1 |
7 |
<1 |
L |
|
VC18 |
11.75 |
11.85 |
0.9 |
<10 |
<5 |
<10 |
180 |
20 |
<0.1 |
13 |
<1 |
H |
|
G1* |
NA |
NA |
<0.6 |
26 |
42 |
10 |
90 |
590 |
0.2 |
11 |
<1 |
H |
|
G2* |
NA |
NA |
<0.6 |
30 |
56 |
10 |
38 |
130 |
0.1 |
8 |
<1 |
L |
|
G3* |
NA |
NA |
<0.6 |
34 |
51 |
10 |
50 |
170 |
0.4 |
11 |
<1 |
L |
|
Criteria |
LCEL |
1.5 |
80 |
65 |
40 |
75 |
200 |
0.5 |
12 |
1 |
|
|
|
UCEL |
4 |
160 |
110 |
40 |
110 |
270 |
1 |
42 |
2 |
|
||
Note:
1.
Values in bold indicate exceedance of UCEL
under ETWB TCW No. 34/2002.
2.
Values in underline indicate exceedance of LCEL
under ETWB TCW No. 34/2002.
* Sample depth at seabed
11.4.2 In March 2003, an updated marine sediment quality survey was carried out at six locations (Figure 11.1) for the EIA Study under this Project. The results of the sediment quality analysis are presented in Table 11.3 below. The results indicate that the sediment at the reclamation/ dredging area was generally uncontaminated, except the sediment at VC5 (0.12-0.90 m) and VC13 (0.90-1.90 m), which exceeded the LCEL for the contaminants of copper and mercury, respectively. The sediments at VC5 (0.12-0.90 m) and VC13 (0.90-1.90 m) were classified as Category M. However, these vibrocore locations (VC5 and VC13) are not within the proposed reclamation area. The vibrocores VC7, VC9 and VC10 fall within the proposed reclamation area and are classified as Category L.
Table 11.3 Sediment Analysis Results from Marine Ground Investigation Works under the Project
|
Sampling Location |
Sampling Depth (m) |
Metals and Metalloid
Content (mg/kg) |
µg/kg |
µg/L |
Category |
|||||||||||
|
From |
To |
Cd |
Cr |
Cu |
Ni |
Pb |
Zn |
Hg |
As |
Ag |
LMW PAHs |
HMW PAHs |
PCBs |
TBT |
||
|
VC13 |
0.57 |
0.90 |
0.2 |
24 |
36 |
12 |
44 |
160 |
0.2 |
4.8 |
0.3 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
VC13 |
0.90 |
1.90 |
0.2 |
29 |
29 |
16 |
50 |
160 |
0.6 |
5.5 |
0.4 |
<550 |
<1700 |
<23 |
<0.15 |
M |
|
VC13 |
1.90 |
2.90 |
0.1 |
26 |
6.2 |
20 |
17 |
55 |
0.2 |
3.6 |
<0.1 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
VC13 |
2.90 |
3.90 |
0.1 |
28 |
8.5 |
21 |
21 |
130 |
0.2 |
3.9 |
<0.1 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
VC13 |
6.17 |
6.90 |
0.1 |
25 |
7.4 |
18 |
22 |
81 |
0.1 |
3.7 |
<0.1 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
VC13 |
8.90 |
9.90 |
0.1 |
26 |
8.9 |
19 |
31 |
52 |
0.1 |
5.1 |
<0.1 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
VC13 |
12.00 |
12.70 |
0.2 |
20 |
7.6 |
14 |
28 |
170 |
0.1 |
7.9 |
<0.1 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
VC5 |
0.12 |
0.90 |
0.2 |
39 |
92 |
17 |
42 |
90 |
0.2 |
4.8 |
0.7 |
<550 |
<1700 |
<23 |
<0.15 |
M |
|
VC5 |
0.90 |
1.90 |
<0.1 |
25 |
8.4 |
19 |
23 |
130 |
0.1 |
4.0 |
<0.1 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
VC5 |
1.90 |
2.90 |
0.1 |
24 |
7.0 |
18 |
19 |
170 |
0.1 |
4.0 |
<0.1 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
VC5 |
2.90 |
3.90 |
0.1 |
25 |
7.8 |
19 |
19 |
100 |
0.1 |
4.2 |
<0.1 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
VC5 |
6.10 |
6.90 |
0.2 |
25 |
19 |
16 |
27 |
90 |
0.2 |
3.9 |
0.2 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
VC5 |
8.90 |
9.90 |
0.1 |
27 |
8.6 |
20 |
27 |
70 |
0.1 |
3.9 |
<0.1 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
VC5 |
12.00 |
12.90 |
0.1 |
22 |
8.6 |
16 |
35 |
49 |
0.08 |
7.1 |
<0.1 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
VC5 |
14.90 |
15.96 |
0.2 |
20 |
8.2 |
14 |
43 |
49 |
0.08 |
8.3 |
<0.1 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
VC10 |
0.00 |
0.55 |
0.1 |
9.1 |
13 |
5.3 |
32 |
44 |
0.09 |
3.2 |
0.2 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
VC7 |
0.16 |
0.9 |
0.1 |
9.8 |
22 |
4.3 |
31 |
74 |
0.1 |
3.8 |
0.2 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
VC7 |
0.90 |
1.80 |
<0.1 |
3.7 |
2.3 |
2.8 |
8.8 |
<10 |
0.06 |
1.3 |
<0.1 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
VC9 |
0.00 |
0.90 |
<0.1 |
8.5 |
13 |
4.25 |
23 |
44 |
0.09 |
4.7 |
0.2 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
VC9 |
0.90 |
1.90 |
<0.1 |
5.0 |
3.5 |
3.9 |
15 |
23 |
0.08 |
4.4 |
<0.1 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
VC9 |
1.90 |
2.90 |
<0.1 |
5.6 |
2.5 |
3.8 |
11 |
15 |
<0.05 |
2.6 |
<0.1 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
VC9 |
2.9 |
3.15 |
<0.1 |
1.3 |
1.2 |
1.4 |
8.6 |
<10 |
0.1 |
3.9 |
<0.1 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
VC8 |
0.20 |
0.90 |
<0.1 |
15 |
6.1 |
7.4 |
29 |
46 |
0.2 |
3.9 |
0.1 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
VC8 |
0.90 |
1.90 |
<0.1 |
5.0 |
1.3 |
4.0 |
8.3 |
<10 |
0.1 |
1.0 |
<0.1 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
VC8 |
1.90 |
2.90 |
<0.1 |
5.6 |
1.5 |
4.4 |
5.9 |
13 |
0.1 |
1.3 |
<0.1 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
VC8 |
2.90 |
3.90 |
<0.1 |
8.3 |
2.6 |
6.3 |
8.0 |
17 |
0.1 |
2.0 |
<0.1 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
VC8 |
6.00 |
6.90 |
<0.1 |
11 |
3.4 |
8.4 |
11 |
22 |
0.1 |
2.4 |
<0.1 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
VC8 |
8.90 |
9.90 |
<0.1 |
6.9 |
2.3 |
4.4 |
11 |
15 |
0.2 |
3.8 |
<0.1 |
<550 |
<1700 |
<23 |
<0.15 |
L |
|
Criteria |
LCEL |
1.5 |
80 |
65 |
40 |
75 |
200 |
0.5 |
12 |
1 |
550 |
1700 |
23 |
0.15 |
|
|
|
UCEL |
4 |
160 |
110 |
40 |
110 |
270 |
1 |
42 |
2 |
3160 |
9600 |
180 |
0.15 |
|
||
Note:
1.
Values in underline indicate exceedance of LCEL
under ETWB TCW No. 34/2002.
2.
LMW
= Low molecular weight PAHs, that is, acenaphthene, acenaphthylene, anthracene,
fluorene, naphthalene and phenanthrene.
3.
HMW
= 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.
11.5 Identification and Evaluation of Environmental Impacts
11.5.1 The construction activities to be carried out for the proposed Project would generate a variety of wastes that can be divided into distinct categories based on their composition and ultimate method of disposal. The identified waste types include:
· Dredged marine sediment
· Construction and demolition (C&D) materials
· General refuse
· Chemical waste.
11.5.2 The nature of each type of waste arising is described below, together with an evaluation of the potential environmental impacts associated with these waste arisings.
Dredged Marine Sediment
11.5.3 The seabed area would be dredged for construction of the seawall and reclamation area for the Phase 1 Reclamation of the WCR. The total volume of dredged sediment was estimated to be approximately 20,000 m3. The sediment quality analysis results indicated the sediment at the WCR dredged area to be Category L. The potential environmental effects of the removal of these sediments on water quality have been assessed and are presented in Section 5 of this Report. Drained reclamation method with marine mud left in place (and using DCM beneath seawalls) is proposed for the remaining reclamation to minimize the amount of dredged sediment.
11.5.4 To minimize any potential adverse impacts arising from the dredged marine sediment, the sediment should be dredged, transported and disposed of in a manner that would minimise the loss of contaminants either into solution or by resuspension. Mitigation measures to minimise potential environmental impacts are described in Section 11.6.3. With the implementation of mitigation measures, no unacceptable impacts would be expected from the transportation and disposal of the dredged sediment.
Construction and Demolition Materials
11.5.5 Construction and demolition (C&D) material would be generated from tunnelling for the WCR and from foundation and excavation works for roadworks, drainage and sewerage, service reservoir, sewage pumping station and outfall modification (pile decking). This inert C&D material would comprise mostly public fill material and granitic rock, with an estimated total volume of approximately 3,488,500 m3. A breakdown of the estimated volumes of C&D material generated from the various works items of the Project is given in Table 11.4. A Construction and Demolition Material Management Plan (C&DMMP) has been prepared following CEDD TC No. 05/2005 and is provided in Appendix 11.1.
11.5.6 The C&D material should be re-used on-site as far as possible to minimize the net amount of C&D material generated from the Project. It is anticipated that approximately 3,809,600 m3 of C&D material would be reused or imported on-site as fill material for backfilling. Surplus C&D material would require disposal to the designated public filling area. The granitic rock generated from the tunnel section of WCR would be reused for WCR reclamation and seawall construction.
11.5.7 The amount of C&D material expected to be generated would be quantified in the site Waste Management Plan to be prepared by the Contractor. Since the construction activities would be located near the coast, improper management of C&D materials may introduce debris and pollutants to the marine waters, and mitigation measures, including adoption of good site practices, would be required for control of impacts.
Table 11.4 Summary of C&D Material Volumes
General Refuse
11.5.8 Throughout construction, the workforce would generate refuse comprising food scraps, waste paper, empty containers, etc. Release of general refuse into marine waters should not be permitted, as introduction of these wastes is likely to have detrimental effects on water quality in the area. Rapid and effective collection of site wastes would be required to prevent waste materials being blown around by wind, flushed or leached into the marine environment, and odour nuisance. The work sites may also attract pests and vermin if the waste storage area is not well maintained and cleaned regularly. Disposal of refuse at sites other than approved waste transfer or disposal facilities can also result in similar impacts. With the implementation of good waste management practices at the site, adverse environmental impacts would not be expected to arise from the storage, handling and transportation of workforce wastes.
Chemical Waste
11.5.9 The maintenance and servicing of construction plant and equipment may possibly generate some chemical wastes, for instance, cleaning fluids, solvents, lubrication oil and fuel. Maintenance of vehicles may also involve the use of a variety of chemicals, oil and lubricants. It is not possible to quantify the amount of chemical waste that will arise from the construction activities, since it will be dependent on the Contractor’s on-site maintenance requirements and the amount of plant utilised. The amount of chemical waste expected to be generated will be quantified in the site Waste Management Plan to be prepared by the Contractor.
11.5.10 Chemical wastes arising during the construction phase may pose environmental, health and safety hazards if not stored and disposed of in an appropriate manner as stipulated in the Waste Disposal (Chemical Waste) (General) Regulations. The potential hazards include:
· Toxic effects to workers
· Adverse impacts on water quality from spills
· Fire hazards.
11.5.11 Materials classified as chemical wastes will require special handling and storage arrangements before removal for appropriate treatment at the Chemical Waste Treatment Facility at Tsing Yi. Wherever possible opportunities should be taken to reuse and recycle materials. Mitigation and control requirements for chemical wastes are detailed in Section 11.6.9. Provided that the handling, storage and disposal of chemical wastes are in accordance with these requirements, adverse environmental impacts are not expected to result.
Domestic Waste Arising
11.5.12 The main waste type in the future will be domestic waste from the proposed residential use at the development areas of PSK, TCS and TKL. Waste generation rates will depend on the population build-up. The estimated quantities of domestic waste at 2016 when the full development would be completed are given in Table 11.5. The quantity of waste arising is estimated using the best available information on the proposed land uses and planned population at the time of reporting. These estimates will be updated when more detailed information is available on the population intakes for each development area at the detailed design stage. A projected generation rate of domestic waste of 1.48 kg/person/day is adopted for the year 2016, as forecast in the Monitoring of Solid Waste in Hong Kong 1999 prepared by EPD.
Table 11.5 Estimated Domestic Waste Arising (2016) in TKO Further Development
|
Planned Residential Population |
Per capita generation rate (kg/person/day) |
Quantity (tpd) |
|
|
Pak Shing Kok |
5,244 |
1.48 |
7.8 |
|
Town Centre South |
32,753 |
1.48 |
48.5 |
|
Tiu Keng Leng (remaining
area) |
12,540 |
1.48 |
18.6 |
|
Total |
|
|
75 |
11.5.13 Domestic waste generated in the development area would be directed to the SENT Landfill. Since there is no existing refuse transfer station for the South East New Territories, waste would be transported directly to SENT Landfill site. The consultancy study “Agreement No. CE 45/99 – Extension of Existing Landfills and Identification of Potential New Waste Disposal Sites”indicated that the capacity of SENT Landfill would be exhausted between 2008 and 2010 for the different scenarios studied. An extension site adjacent to the existing SENT landfill has been identified by the Government. The Government intends to commence comprehensive feasibility and environmental impact assessment (EIA) studies for the planned extension site of SENT Landfill within the year 2005.
11.6 Mitigation of Adverse Environmental Impacts
Dredged Marine Sediments
11.6.1 The basic requirements and procedures for dredged mud disposal are specified under the ETWB TCW No. 34/2002. The management of the dredging, use and disposal of marine mud is monitored by the MFC, while the licensing of marine dumping is the responsibility of the Director of Environmental Protection (DEP).
11.6.2 The dredged marine sediments would be loaded onto barges and transported to the designated disposal site. Based on the review of the sediment testing results, it was estimated that some 20,000 m3 of sediments would be suitable for open sea disposal.
11.6.3 During transportation and disposal of the dredged marine sediments, the following measures should be taken to minimise potential impacts on water quality:
· Bottom opening of barges should be fitted with tight fitting seals to prevent leakage of material. Excess material should be cleaned from the decks and exposed fittings of barges and hopper dredgers before the vessel is moved.
· Monitoring of the barge loading should be conducted to ensure that loss of material does not take place during transportation.
· Transport barges or vessels should be equipped with automatic self-monitoring devices as specified by the DEP.
· Barges or hopper barges should not be filled to a level that would cause the overflow of materials or sediment-laden water during loading or transportation.
Good Site Practices
11.6.4 Adverse impacts related to waste management are not expected to arise, provided that good site practices are strictly followed. Recommendations for good site practices during the construction activities include:
· Nomination of an approved person, such as a site manager, to be responsible for good 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 of waste
· Appropriate measures to minimise windblown litter and dust during transportation of waste by either covering trucks or by transporting wastes in enclosed containers
· Regular cleaning and maintenance programme for drainage systems, sumps and oil interceptors.
Waste Reduction Measures
11.6.5 Good management and control can prevent the generation of a significant amount of waste. Waste reduction is best achieved at the planning and design stage, as well as by ensuring the implementation of good 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 materials and their proper disposal
· Encourage collection of aluminium cans by individual collectors by providing separate labelled bins to enable this waste to be segregated from other general refuse generated by the work force
· Proper storage and site practices to minimise the potential for damage or contamination of construction materials
· Plan and stock construction materials carefully to minimise amount of waste generated and avoid unnecessary generation of waste.
11.6.6 In addition to the above measures, specific mitigation measures are recommended below for the identified waste arising to minimise environmental impacts during handling, transportation and disposal of these wastes.
General Refuse
11.6.7 General refuse should be stored in enclosed bins or compaction units separate from C&D material. A reputable waste collector should be employed by the contractor to remove general refuse from the site, separately from C&D material. Preferably an enclosed and covered area should be provided to reduce the occurrence of 'wind blown' light material.
Construction and Demolition Material
11.6.8 In order to minimise the impact resulting from collection and transportation of C&D material for off-site disposal, the C&D material from the excavation works for road formation and engineering infrastructure should be reused on-site as backfilling material as far as practicable. In addition, granitic rock generated from the tunnelling works for WCR would be reused for WCR reclamation as rockfill material. Other mitigation requirements are listed below:
·
A Waste Management Plan should be
prepared in accordance with ETWB TCW No.15/2003.
·
A recording system for the amount of
wastes generated, recycled and disposed (including the disposal sites) should
be proposed.
·
In order to monitor the disposal of
C&D and solid wastes at public filling facilities and landfills and to
control fly-tipping, a trip-ticket system should be included. One may make
reference to ETWB TCW No.31/2004 for details.
Chemical Wastes
11.6.9 If chemical wastes are produced at the construction site, the Contractor would be required to register with the EPD as a Chemical Waste Producer and to follow the guidelines stated in the Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes. Good quality containers compatible with the chemical wastes should be used, and incompatible chemicals should be stored separately. Appropriate labels should be securely attached on each chemical waste container indicating the corresponding chemical characteristics of the chemical waste, such as explosive, flammable, oxidizing, irritant, toxic, harmful, corrosive, etc. The Contractor shall use a licensed collector to transport and dispose of the chemical wastes, to either the Chemical Waste Treatment Centre at Tsing Yi, or another licensed facility, in accordance with the Waste Disposal (Chemical Waste) (General) Regulation.
11.6.10 Table 11.6 provides a summary of the various waste types likely to be generated during the construction works for the Project, together with the recommended handling and disposal methods.
Table 11.6 Summary of Waste Handling Procedures and Disposal Routes
|
Waste
Material Type |
Generated from works item |
Total Quantities
Generated |
Quantities to be disposed
off-site |
Disposal |
Handling |
|
Dredged Sediments Type 1 – Open Sea Disposal |
WCR
Phase 1 reclamation area |
20,000 m3 |
20,000 m3 |
MFC gazetted marine disposal ground |
Techniques to minimise resuspension (tight seal on barges, controlled
loading and transfer) |
|
C&D Material |
Roadworks, Drainage & Sewerage, Service Reservoir, Sewage Pumping Station, Seawall Modification |
3,488,500 m3 |
- |
To be reused on site for backfilling (3,809,600 m3) Granitic rock exported for reclamation (1,155,000 m3) |
Segregate granitic rock to avoid contamination from other waste
arisings |
|
General Refuse |
Waste paper, empty container generated from workforce |
Unknown at this stage |
- |
Refuse station for compaction and containerisation and then to
landfill |
Provide on-site refuse collection points |
|
Chemical Waste |
Cleansing fluids, solvent, lubrication oil and fuel from construction
plants and equipment |
Unknown at this stage |
- |
Chemical Waste Treatment Centre |
Recycle on-site or by licensed companies Stored on-site within suitably designed containers |
11.7 Evaluation of Residual Impacts
11.7.1 With the implementation of the recommended mitigation measures for the handling, transportation and disposal of the identified waste arising, no residual impact is expected to arise during the construction and operation of the proposed Project.
11.8 Environmental Monitoring and Audit
11.8.1 Waste management would be the contractor’s responsibility to ensure that all wastes produced during the construction of the Project are handled, stored and disposed of in accordance with good waste management practices and EPD’s regulations and requirements. The recommended mitigation measures should form the basis of the site Waste Management Plan to be developed by the Contractor in the construction stage.