TABLE OF
CONTENTs
6 Waste Management Implications
6.2 Environmental Legislation, Standards and Guidelines
6.3 Description of the Environment
6.4 Identification and Evaluation of Waste Management
Implications
6.5 Mitigation of Adverse Waste Management Implications
6.6 Evaluation of Residual Environmental Impacts
6.7 Environmental Monitoring and Audit Requirement
TABLES
Table 6.1 Summary
of C&D Materials Quantities Generated
Table 6.2 Summary
of Chemical Screening Results
Table 6.3 Summary
of Biological Screening Results
Table 6.4 Number
of Relevant Sediment Samples under each Sediment Category in the EIA Study for
HZMB HKBCF
Table 6.5 Summary
of Sediment Quantities Generated and Recommended Handling Methods
Table 6.6 Tentative
Transportation Routings for Waste Disposal during Construction Phase
FIGURES
Figure 6.1 Proposed
Excavated Sediment and As-Built Sampling Locations
APPENDICES
Appendix 6.1 Summary
of Screening Results and Disposal Options
Appendix 6.2 Summary
of Biological Screening Results
Appendix 6.3 Sediment
Sampling and Testing Plan
6.1.1 This section identifies the type of wastes that are likely to be generated from the construction activities of the Project and evaluates the potential environmental impacts that may result from waste generated. Mitigation measures and good site practices, including waste handling, storage and disposal, have been recommended with reference to applicable waste legislation and management guidelines.
6.1.2 The waste management implications have been assessed in accordance with the requirements outlined in Annexes 7 and 15 of the Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM) as well as the requirements set out under Clause 3.4.6 and Appendix D of the EIA Study Brief (No. ESB-302/2017).
6.2 Environmental Legislation, Standards and Guidelines
ĄP
Waste Disposal Ordinance (Cap.354);
ĄP
Waste Disposal (Chemical Waste) (General) Regulation (Cap.354C);
ĄP
Waste Disposal (Charges for Disposal of Construction Waste) Regulation
(Cap.354N);
ĄP
Land (Miscellaneous Provisions) Ordinance (Cap.28);
ĄP
Public Health and Municipal Services Ordinance (Cap.132BK) ĄV Public
Cleansing and Prevention of Nuisances Regulation;
ĄP
Dumping at Sea Ordinance (Cap. 466);
ĄP
Air Pollution Control Ordinance (Cap. 311); and
ĄP
Water Pollution Control Ordinance (Cap. 358).
ĄP
Type and quantity of substances permitted to be dumped;
ĄP
Location of the disposal grounds;
ĄP
Requirement of equipment for monitoring the disposal operations; and
ĄP
Environmental monitoring requirements.
ĄP
Works Branch Technical Circular (WBTC) No. 2/93, Public Dumps;
ĄP
WBTC No. 2/93B, Public Filling Facilities;
ĄP
Section 4.1.3 of Chapter 4 of the Project Administration Handbook (PAH)
for Civil Engineering Works, Management of Construction/Demolition Materials
including Rocks;
ĄP
PNAP No. 252 (ADV-21) ĄV Management Framework for Disposal of
Dredged/Excavated Sediment;
ĄP
PNAP No. 243 (ADV-19) ĄV Construction and Demolition Waste; and
ĄP
DevB TC(W) No.6/2010, Trip-ticket System for Disposal of Construction
and Demolition Materials.
ĄP
Type 1 ĄV Open Sea Disposal or Open Sea Disposal in Dedicated Sites;
ĄP
Type 2 ĄV Confined Marine Disposal; and
ĄP Type 3 ĄV Special Treatment / Disposal. For Type 3 disposal, the Authorized Persons / Registered Structural Engineers shall be responsible for identifying and agreeing with the DEP the most appropriate treatment and/or disposal arrangement.
6.3 Description of the Environment
6.4 Identification and Evaluation of Waste Management Implications
6.4.1 The criteria and methodology of assessing potential waste management implications during the construction and operation phases follows Annexes 7 and 15 of the EIAO-TM respectively, with assessment approaches provided below:
ĄP
Estimation of the types and quantities of the wastes generated;
ĄP
Evaluation of opportunities for waste reduction and re-use;
ĄP
Identification of disposal options for each type of wastes;
ĄP
Assessment of potential environmental impacts arising from the wastes
management with respect of potential hazards, air and odour emissions, noise,
wastewater discharges; and
ĄP Assessment of impacts on the capacity of waste collection, transfer and disposal facilities.
6.4.2 The construction activities to be carried out for the 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 wastes types are:
ĄP
Construction and demolition (C&D) materials from construction
works;
ĄP
General refuse from workforce;
ĄP
Chemical wastes from any maintenance of construction plant and
equipment;
ĄP
Excavated sediment from sea
portion of the bridge foundation construction and land-based bridge piers and
abutment construction; and
ĄP
Potential floating refuse from
workforce.
Construction and
Demolition (C&D) Materials
6.4.3 C&D materials would be generated from construction works of this Project such as minor excavation and site clearance. These C&D materials comprise both inert (e.g. rocks, soil, broken concrete) and non-inert components (e.g. vegetation and wood). During general layout design, devising construction method and planning of construction programme, considerations have been given to minimise the generation of inert C&D materials and maximise the use of these generated inert C&D materials for other construction works.
6.4.4 Based on preliminary design information, it was estimated that the total volume of C&D materials to be approximately 13,160 m3, with 12,160 m3 being inert materials (i.e. public fill) and approximately 1,000 m3 being non-inert materials. However, it should be noted that these quantities are initial estimates only and would need to be further reviewed and updated as the design progresses.
6.4.5 A summary of the C&D materials generated during construction phase is shown in Table 6.1. For inert C&D materials, they would be reused on-site as far as practicable subject to the review of detailed design stage before exported off-site for reuse at other concurrent projects or delivered to Public Fill Reception Facilities for beneficial use in other projects. For non-inert C&D materials, upon exhaustion of reuse/ recycling effort, they will be delivered to landfills. Provided that the handling of C&D materials are in accordance with the requirements presented in Section 6.5, the potential waste management implications, including potential hazards, air and odour emissions, noise and wastewater discharge, associated with handling of C&D waste during the construction phase of the Project are not expected. In addition, the total quantity of C&D materials generated are relatively small, the amount of C&D materials to be generated daily is anticipated to be small, and the collection, transfer and disposal facilities would be able to cater for the C&D materials to be disposed.
Table 6.1 Summary of C&D
Materials Quantities Generated
|
Materials Generated |
Total Quantity Generated |
Handling Methods / Reuse |
Destinations |
|
Inert C&D materials ĄV Soft Public Fill, Broken Concrete and
Asphalt |
12,160
m3 |
ĄP
Segregation from non-inert C&D materials
during stockpiling and transportation ĄP
Stockpile area (if required) should be well
managed with covers and/or water spraying system ĄP
Reuse on-site as far as practicable subject to
the review of detailed design stage before exported off-site for reuse at
other concurrent projects ĄP
Delivered to other concurrent projects or to
PFRFs for beneficial use in other projects |
Public
Fill Reception Facilities |
|
Non-inert C&D materials ĄV Timber, Papers & Plastics |
1,000
m3 |
ĄP
Upon exhaustion of reuse/ recycling effort, the
remaining non-inert C&D materials will be delivered to landfills. ĄP
Segregation from inert C&D materials during
stockpiling and transportation ĄP
Reusable materials should be separated and
recycled as far as practicable |
Landfills |
6.4.6 The presence of a construction site with workers and site office will result in the generation of a variety of general refuse requiring disposal. General refuse will mainly consist of food waste, aluminium cans and waste paper. Accidental or intentional release of these refuse to the surrounding environment is not permitted and may cause negative environmental impacts. Storage of general refuse on-site will generate adverse environmental impacts like water contamination, odour nuisance and visual impact if they are not managed in a proper manner. The site may also attract vermin and pests if the waste containers are not cleaned or maintained properly and frequently.
6.4.7 The exact number of work force (workers) to be employed for the project is not available at this stage, but is anticipated to be around 30 to 40 staff. On this basis, the total refuse generated per day would be around 19 kg/day to 26 kg/day, assuming the refuse generation rate is 0.65 kg/head/day.
6.4.8 The refuse should be stored in enclosed bin to avoid adverse impacts to the surroundings. Recycling bins should be provided to maximise reuse and recycle volume. A reputable waste collector should be employed to collect the general refuse for later disposal of at landfills.
6.4.9 With proper implementation of waste management practices as detailed in Section 6.5, it is anticipated that the potential waste management implications, including potential hazards, air and odour emissions, noise and wastewater discharge, associated with handling, storage and disposal of general refuse during the construction phase of the Project are not expected. With the small amount of general refuse generated, the collection, transfer and disposal facilities would be able to cater for the amount of general refuse to be disposed.
6.4.10 The maintenance and servicing of construction plant and equipment may possibly generate a variety of chemical wastes, for instance, cleaning fluids, solvents, lubrication oil and waste fuel.
6.4.11 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:
ĄP
Toxic effects on the workforce;
ĄP
Adverse impacts on water quality and aquatic biota from spills; and
ĄP
Fire hazards.
6.4.12 Chemical waste producers are required to apply for registration as specified in the Guide to the Registration of Chemical Waste Producers. Materials classified as chemical wastes will be handled and stored on-site according to the requirements specified in Code of Practice on Packaging, Labelling and Storage of Chemical Wastes before collection by licensed collectors and disposal of at the Chemical Waste Treatment Centre (CWTC) at Tsing Yi or other licensed facilities. Wherever possible, opportunities will be taken to reuse and recycle materials. It is difficult to quantify the amount of chemical waste that would arise from the construction activities since it would depend on the ContractorĄŠs on-site maintenance requirements and the amount of plant utilised. However, it is anticipated that the quantity of chemical waste, such as lubricating oil and solvent produced from plant maintenance, would be small to in the order of a few hundred litres per month. Mitigation and control requirements for chemical wastes are detailed in Section 6.5. Potential hazards, air and odour emissions, noise and wastewater discharge impacts associated with handling, storage and disposal of chemical waste during the construction phase of the Project are not expected. In addition, the amount of chemical waste generated are relatively small, the collection, transfer and disposal facilities would be able to cater for the amount of chemical waste to be disposed.
Excavated Sediment
Marine-Based Sediment
6.4.13 Marine bored piles with casing will be adopted for construction of the sea portion of the bridge foundation. To keep sediment in place as far as possible, no open sea dredging of seabed will be involved during construction. However, it is inevitable that the marine-based sediment within the bored piles for the bridge foundation construction will need to be excavated. The areas of the proposed excavated marine-based sediment are shown in Figure 6.1.
Sediment Sampling and Testing Plan
6.4.14 A Sediment Sampling and Testing Plan (SSTP) is prepared to serve the purpose of fulfilling this EIA Study under the EIAO. It should be noted that separate submissions (e.g. SSTP/ Sediment Quality Report (SQR)) should be submitted to the Dumping at the Sea Ordinance (DASO) team/ EPD when applying for the dumping permit under DASO (refer to Section 6.5.18). The SSTP is enclosed in Appendix 6.3. Based on the SSTP, the expected sediment contamination level in the vicinity of the proposed marine viaduct is Category L and M. As Category M sediment are expected, a 200 m x 200 m sampling grid arrangement with reference to paragraph 4(a) of memo issued by Development Bureau on 6 October 2010, Ą§Control Measures for Management of Dredged/Excavated Contaminated SedimentĄš (ref: 0 in DevB(W) 515/83/04) was adopted. Based on the sampling grid arrangement, 2 marine-based sediment sampling locations (viz. MBS01 and MBS02) are proposed. The as-built sampling locations are shown in Figure 6.1.
6.4.15 The sediment sampling was carried out on 12 and 13 March 2018 at MBS01 and MBS02. Surface grab (using modified Van Veen grab sampler) and vibrocore samples were taken at the sampling locations. For vibrocores, sediment samples were collected at seabed, 0.9 m down, 1.9 m down, 2.9 m down, and thereafter every 3 m to the bottom of the marine deposit.
6.4.16 Surface grab sediment sample using modified Van Veen grab sampler was also collected from EPDĄŠs routine sediment monitoring station PS6 at Port Shelter (E850234, N820057) on 19 March 2018 as the reference sample.
Chemical and Biological Screening
6.4.17 Chemical and, if necessary, biological screening were carried out on the collected vibrocore samples according to PNAP No. 252 (ADV-21).
6.4.18 A total of 15 samples from the 2 sampling locations were subject to chemical screening. In addition, the reference sample, collected at sediment monitoring station PS6, was also tested. Summary of the chemical screening results are presented in Table 6.2 with details provided in Appendix 6.1.
6.4.19 Based on the chemical screening results, Category M sediments were identified in 4 samples from the 2 sampling locations with Arsenic exceeded the LCEL but below the UCEL. The remaining samples were identified as Category L sediment.
Table 6.2 Summary
of Chemical Screening Results
|
Category |
No. of Samples |
Percentage of Samples Collected |
|
Category
L (equal to or below LCEL) |
11 |
73.3% |
|
Category
M (above LCEL but equal to or below UCEL) |
4 |
26.7% |
|
Category
H (above UCEL but equal to or below 10x LCEL ) |
0 |
0% |
|
Category
H (above 10x LCEL) |
0 |
0% |
|
TOTAL |
15 |
100% |
*
Excluded the reference sample results.
6.4.20 Based on the chemical screening results, Tier III biological screening was conducted on the 4 Category M sediment samples. All of the 4 samples have passed the screening. The results of the biological screening are summarised in Table 6.3 with details provided in Appendix 6.2.
Table 6.3 Summary
of Biological Screening Results
|
Sampling Location ID |
Sampling Depth (m below seabed) |
Category |
Biological Screening Results |
|
MBS01 |
0.00
- 0.90 |
Category
M |
Pass |
|
MBS02 |
0.00
ĄV 0.90 |
Category
M |
Pass |
|
0.90
ĄV 1.90 |
Category
M |
Pass |
|
|
14.90
ĄV 15.90 |
Category
M |
Pass |
Sediment Disposal Options and Quantities
6.4.21 Based on the screening results above, the disposal options for each of the sediment samples were determined in accordance with the PNAP No. 252 (ADV-21) and are shown in Appendix 6.1.
6.4.22 The quantities of marine-based sediments to be generated under each disposal option is then estimated with consideration of (i) the dimension and number of the marine bored piles, (ii) thickness of the sediment layer and (iii) the determined disposal options of the sediment samples. The volume of marine-based sediment generated is estimated to be approximately 650 m3. The estimated quantities for each disposal option, along with the possible disposal outlets, are presented in Table 6.5.
6.4.23 As discussed above, it is inevitable that the marine-based sediment will need to be excavated for the bridge foundation construction. Given the high water content and low strength of the sediment, it would be difficult to reuse this type of sediment. The excavated marine-based sediment is therefore recommended to be disposed of at the designated marine disposal sites allocated by the Marine Fill Committee (MFC) in accordance with PNAP No. 252 (ADV-21). The disposal options for the excavated marine-based sediment should follow the procedures in PNAP No. 252 (ADV-21). The transportation routing and frequency for marine disposal to designated disposal outlets shall be agreed with EPD/CEDD during the construction phase prior to marine disposal. The recommended mitigation measures for marine disposal are discussed in Section 6.5. No adverse waste management implications are anticipated if the recommended mitigation measures are implemented.
Land-Based Sediment
6.4.24 The HKBCF Island is a reclaimed land and there is land-based sediment underlying the existing fill stratum. Under the Project, the southern end of the land viaduct within the HKBCF, connecting to the marine viaduct, would require the construction of bridge piers and abutment. The bridge piers and abutment would be constructed using bored pile method and there may be some land-based sediment generated during the works. The quantities of sediment excavated is expected to be 400 m3. The area of the proposed excavated sediment are shown in Figure 6.1.
6.4.25 The concerned area is currently occupied by Highways Department and, as advised by AAHK, the area would not be accessible to carry out any site investigation works at this stage in time.
6.4.26 However, as reference, under the EIA Study for HZMB HKBCF[1], sediment samples were collected from 16 sampling locations for the proposed reclamation site of HKBCF and Hong Kong Link Road (HKLR) and were subject to chemical and/or biological screening. The sampling works were carried out in 2008 and 2009. The as-built locations and sediment quality data are shown in Appendix 3.3 of the SSTP.
6.4.27 Of the 16 sampling locations, 11 locations (viz. BCF/VC-A01 to BCF/VC-A04, BCF/VC-B05 to BCF/VC-B10 and BCF/VC-C11) were located within or near the HKBCF. 86 sediment samples from the 11 locations were tested and reported in the EIA Study for HZMB HKBCF. Based on the laboratory testing results, 60 samples were classified as uncontaminated Category L and 26 samples as Category M. For Category M samples, the contaminant that exceeded the LCEL is arsenic, with one sample also exhibited elevated lead level. Table 6.4 summarised the number of relevant sediment samples under each sediment category as presented in the EIA Study for HZMB HKBCF. From the findings of the EIA Study for HZMB HKBCF, most of the land-based sediment to be excavated under this Project is likely to be uncontaminated Category L sediment. However, some Category M sediment, with elevated arsenic / lead levels, may be presented.
Table 6.4 Number of Relevant
Sediment Samples under each Sediment Category in the EIA Study for HZMB HKBCF
|
Relevant Sampling Location |
Category |
Disposal Option |
No. of Samples |
Percentage of Samples |
|
BCF/VC-A01
to BCF/VC-A04; BCF/VC-B05 to BCF/VC-B10; BCF/VC-C11 |
Category
L Sediment |
Type
1 - Open sea disposal |
60 |
70% |
|
Category
M Sediment (passed the Tier III biological screening) |
Type
1 - Open sea disposal in dedicated site |
21 |
24% |
|
|
Category
M Sediment (failed the Tier III biological screening) |
Type
2 -Confined marine disposal |
5 |
6% |
|
|
|
|
TOTAL |
86 |
100% |
6.4.28 In order to minimise off-site disposal, the excavated land-based sediment is proposed to be reused on site under the Project (e.g. as backfilling materials). The land-based sediment would be treated using stabilization / solidification (S/S) technique prior to reuse by mixing with cement (e.g. Portland cement). Arsenic and lead, observed to be in elevated levels in some sediment samples under the EIA Study for HZMB and HKBCF, will be immobilised in the cement/sediment mix after the S/S process. The treated materials will be tested for the Toxicity Characteristic Leaching Procedure (TCLP) and Unconfined Compressive Strength (UCS) and should meet the Universal Treatment Standards (UTS) with reference to EPDĄŠs Practice Guide for Investigation and Remediation of Contaminated Land and the UCS standard prior to reuse. If the treated materials did not meet the UTS and UCS standards, the materials will be re-treated and re-tested. Pilot-scale trial should be carried out before the commencement of treatment to determine the cement/sediment ratio that could achieve the treatment standards.
6.4.29 The estimated quantities of land-based sediment and the proposed handling methods are summarised in Table 6.5 below Sediments that meet with the treatment standards are considered to be suitable for reuse on site. The recommended mitigation measures are discussed in Section 6.5. Provided that the recommended mitigation measures are implemented, the potential waste management implications, including potential hazards, air and odour emissions, noise and wastewater discharge, associated with handling and disposal of sediments during the construction phase of the Project are not expected. The collection, transfer and disposal facilities would be able to cater for small amount of sediment to be disposed.
Table 6.5 Summary of Sediment Quantities Generated and Recommended
Handling Methods
|
Materials Generated |
Category |
Estimated In-situ
Quantity (1) |
Handling Methods / Reuse |
Destinations |
|
Marine-Based
Sediment from Sea Portion of the Bridge Foundation Construction |
Category
L Sediment |
590
m3 |
Type
1 - open sea disposal at disposal site(s) allocated by the Marine Fill
Committee (MFC). |
Final disposal site
shall be determined by MFC; typically South Cheung Chau / East of Ninepin. |
|
Category
M Sediment (passed the Tier III biological screening) |
60 m3 |
Type
1 - open sea disposal in dedicated site at disposal site(s) allocated by the
MFC. |
Final disposal site
shall be determined by MFC; typically East Sha Chau. |
|
|
Category
M Sediment (failed the Tier III biological screening) |
Nil |
|
|
|
|
Land-Based
Sediment from Bridge Piers and Abutment Construction |
N/A |
400
m3 |
Treatment
by S/S technique to treatment standards and reuse on site. |
On site reuse (e.g. as
backfilling materials). |
|
|
TOTAL: |
1,050
m3 |
|
|
(1)
The quantities shown in the table are
estimates only and will be subject to further review during the later stage of
the Project (e.g. detailed design or construction stages).
Potential Floating Refuse
6.4.30 In view that the construction work area is located on sea channel and along coast area, construction site workers may potentially generate floating refuse during construction works, such as aluminium cans and waste paper. In view of the estimated number of workforce and estimated quantities of general refuse as discussed in Section 6.4.7, it is anticipated that the quantities of floating refuse generated would be limited to a few kg/month. Proper management and education would be given to construction site workers such that accidental release or intentional disposal would be avoided. The refuse should be stored in enclosed bin to avoid adverse impacts to the surroundings, including marine environment.
Transportation Arrangement for Waste
Disposal during Construction Phase
6.4.31 Land transport should be used to deliver and dispose of the waste generated from the Project area to the designated disposal outlets. It is expected there will be a maximum of 10 vehicles per day for transporting waste during the construction phase of the Project. The tentative transportation routings for the disposal of various types of wastes generated during the construction phase of the Project are shown in Table 6.6. The transportation routings may change subject to the actual traffic conditions of the roads. Nevertheless, with the implementation of appropriate mitigation measures (e.g. using water-tight containers and covered trucks), no adverse environmental impacts are expected due to the transportation of waste.
6.4.32 No barging points or conveyor systems will be established in the Project area. Since the amount of C&D materials generated are relatively small, the amount of C&D materials to be generated daily is anticipated to be small, and the destined collection, transfer and disposal facilities would be able to cater for the C&D materials to be disposed. The materials will be reused or recycled on-site as much as practicable and any surplus would be timely transported out of construction work area. Hence, no designated stockpiling area is planned within the construction site. In case stockpiling areas are found required, they would be implemented with mitigation measures such as covering the materials during heavy rainfall.
Table 6.6 Tentative
Transportation Routings for Waste Disposal During Construction Phase
|
Disposal Outlet |
Type of Waste |
Tentative Transportation Routing |
|
Tuen
Mun Area 38 Fill Bank |
Inert
C&D Materials |
Via
Airport Road, North Lantau Highway, Lantau Link, Tsing Long Highway, Tuen Mun
Road, Wong Chu Road, Lung Fu Road and Lung Mun Road |
|
WENT
Landfill |
Non-inert
C&D Materials and General Refuse |
Via
Airport Road, North Lantau Highway, Lantau Link, Tsing Long Highway, Tuen Mun
Road, Wong Chu Road, Lung Fu Road, Lung Mun Road, Lung Kwu Tang Road and Nim
Wan Road |
|
CWTC |
Chemical
Waste |
Via
Airport Road, North Lantau Highway, Lantau Link, Tsing Sha Highway, Tsing Yi
Road |
Operation Phase
6.4.33 During operation of the Project, the major types of wastes generated include chemical waste and municipal solid waste as discussed below.
6.4.34 Chemical wastes such as paints and lubricants may be generated during maintenance activities. This waste may pose environmental, health and safety hazards. Measures as stipulated in the Waste Disposal (Chemical Waste) (general) Regulation and the Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes would be strictly followed for the handling and disposal of chemical waste.
6.4.35 Should any chemical waste be generated, the operator must register with EPD as a Chemical Waste Producer. The chemical waste would be readily accepted for disposal of at the CWTC at Tsing Yi or other licensed facilities. It is difficult to quantify the amount of chemical waste that would arise from the maintenance activities, however it is anticipated that the quantity of chemical waste, such as solvent produced from maintenance activities would be limited to a few cubic metres per month. This chemical waste should be collected periodically in drum-type containers by licensed chemical waste collectors. With proper storage, handling and disposal of this waste, the potential waste management implications, including potential hazards, air and odour emissions, noise and wastewater discharge, associated with handling, storage and disposal of chemical waste during the operation phase of the Project are not expected. In addition, since the amount of chemical waste generated are relatively small, the collection, transfer and disposal facilities would be able to cater for small amount of chemical waste to be disposed.
6.4.36 During the operation phase, MSW such as paper, plastic and office waste would be generated by staff on site, and scrap materials from road and vehicular bridge maintenance, and discarded materials from maintenance of the vehicles.
6.4.37 The number of staff to be employed for the Project during its operation is not available at this stage, but is anticipated to be around 20 staff. On this basis, the total MSW (refuse) generated per day would be about 13 kg/day, assuming the refuse generated rate is 0.65 kg/head/day. As the passengers are only transient population and will not stay in the bonded bridge and associated roads area, the quantities of MSW (general refuse) generated from passengers are negligible.
6.4.38 For the MSW generated from maintenance activities, it is expected that small to a few hundred kg per month will be generated during the operation period. Plastics, papers and other recyclable wastes should be separated from general refuse and recycled as far as possible. The remaining refuse would be collected by waste collectors and disposed of at landfills. Provided that the recommended measures as presented in Section 6.5 are followed, no waste management implications, including potential hazards, air and odour emissions, noise and wastewater discharge, associated with handling, storage and disposal of MSW during the operation phase of the Project are expected and the collection, transfer and disposal facilities would be able to cater for small amount of MSW to be disposed.
6.5 Mitigation of Adverse Waste Management Implications
6.5.1 The waste management hierarchy has been applied in the assessment and development of mitigation measures for waste which aims at evaluating the desirability of waste management methods and includes the followings in descending preference:
ĄP
Avoidance and reduction of waste generation;
ĄP
Reuse of materials as far as practicable;
ĄP
Recovery and recycling of residual materials where possible; and
ĄP
Treatment and disposal according to relevant laws, guidelines and good
practices.
6.5.2 Based on the waste management hierarchy, waste reduction measures are recommended as follow to reduce impacts and costs arisen from the Project. Recommendations of good site practices and waste reduction measures have been stated in order to achieve avoidance and minimisation of waste generation in the hierarchy.
6.5.3 Adverse impacts would not arise in the construction site, provided that good site practices are strictly followed. Recommendations for good site practices during the construction phase include:
ĄP
Nomination of approved personnel, such as a site manager, to be
responsible for implementation of good site practices, arrangements for waste
collection and effective disposal to an appropriate facility;
ĄP
Training of site personnel in site cleanliness, concepts of waste
reduction, reuse and recycling, proper waste management and chemical waste
handling procedures;
ĄP
Provision of sufficient waste reception/ disposal points, and regular collection
of waste;
ĄP
Adoption of appropriate measures to minimise windblown litter and dust
during transportation of waste by either covering trucks or by transporting
wastes in enclosed containers;
ĄP
Provision of regular cleaning and maintenance programme for drainage
systems, sumps and oil interceptors;
ĄP
Adoption of a recording system for the amount of wastes generated,
recycled and disposed (including the disposal sites); and
ĄP
Preparation of Waste Management Plan (WMP), as part of the
Environmental Management Plan (EMP).
6.5.4 Good management and control of construction site activities / processes can minimise the generation 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 are discussed as follow:
ĄP
Segregate and store different types of construction related waste in
different containers, skips or stockpiles to enhance reuse or recycling of
materials and their proper disposal;
ĄP
Provide separate labelled bins to segregate recyclable waste such as
aluminium cans from other general refuse generated by the work force, and to
encourage collection by individual collectors;
ĄP
Recycle any unused chemicals or those with remaining functional
capacity;
ĄP
Maximise the use of reusable steel formwork to reduce the amount of
C&D materials;
ĄP
Adopt proper storage and site practices to minimise the potential for
damage to, or contamination of construction materials;
ĄP
Plan the delivery and stock of construction materials carefully to
minimise the amount of waste generated; and
ĄP
Minimise over ordering and wastage through careful planning during
purchasing of construction materials.
6.5.5 In addition to the above measures, other specific mitigation measures are recommended below to minimise environmental impacts during handling, transportation and disposal of wastes.
6.5.6 The C&D materials generated should be sorted on-site into inert C&D materials (that is, public fill) and non-inert (C&D waste). To minimise the impact resulting from collection and transportation of C&D materials as far as practicable, C&D waste, such as wood, plastic, steel and other metals should be reused or recycled and, as a last resort, disposed to landfill. Any surplus would be timely transported out of construction work area, therefore no designated stockpiling area is planned within the construction site. In case stockpiling areas are found required, mitigation measures should be implemented. Within the stockpile areas, the following measures should be taken to control potential environmental impacts or nuisance.
ĄP
Proper handling and storage of waste such as soil by means of covers
and/or water spraying system to minimise the potential environmental impact and
to prevent materials from wind-blown or being washed away;
ĄP
Covering materials during heavy rainfall;
ĄP
Locating stockpiles to minimise potential visual impacts;
ĄP
Minimising land intake of stockpile areas as far as possible;
ĄP
Adopting GPS or equivalent system for tracking and monitoring of all
dump trucks engaged for the Project in recording their travel routings and
parking locations to prohibit illegal dumping and landfilling of C&D
materials; and
ĄP
Keeping record and analysis of data collected by GPS or equivalent
system related to travel routings and parking locations of dump trucks engaged
on site.
6.5.7 General refuse should be stored in enclosed bins or compaction units separately from C&D materials and chemical waste. A reputable waste collector should be employed by the contractor to remove general refuse from the site, separately from C&D materials and chemical wastes. An enclosed and covered area is preferred to reduce the occurrence of 'wind blown' light materials.
6.5.8 The recyclable component of general refuse, such as aluminium cans, paper and cleansed plastic containers shall be separated from other waste. Provision and collection of recycling bins for different types of recyclable waste shall be set up by the Contractor. The Contractor shall also be responsible for arranging recycling companies to collect these materials.
6.5.9 The Contractor shall carry out an education programme for workers in avoiding, reducing, reusing and recycling of materials generation. Posters and leaflets advising on the use of the bins shall also be provided in the sites as reminders.
6.5.10 If chemical wastes were to be 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.
6.5.11 Appropriate containers with proper labels should be used for storage of chemical wastes. Chemical wastes should be collected and delivered to designated outlet by a licensed collector. Chemical wastes (e.g. spent lubricant oil) should be recycled at an appropriate facility as far as possible, while the chemical waste that cannot be recycled should be disposed of at either the CWTC, or another licensed facility, in accordance with the Waste Disposal (Chemical Waste) (General) Regulation.
6.5.12 Any unused chemicals or those with remaining functional capacity should be collected for reuse as far as practicable.
Excavated Sediments
6.5.13 The sediment should be excavated, handled, treated, transported and/or disposed of in a manner that would minimise adverse environmental impacts.
6.5.14 Requirements of the Air Pollution Ordinance (Construction Dust) Regulation, where relevant, shall be adhered to during excavation, treatment, transportation and disposal of the sediment.
6.5.15 Any treatment area for the land-based sediment should be confined for carrying out the cement S/S process and any temporary stockpiling. The area should be designed to prevent leachate from entering the ground. Leachate, if any, should be collected and discharged according to the Water Pollution Control Ordinance (WPCO).
6.5.16 In order to minimise the exposure to contaminated materials, workers shall, if necessary, wear appropriate personal protective equipments (PPE) when handling contaminated sediments. Adequate washing and cleaning facilities shall also be provided on site.
6.5.17 For off-site disposal, the basic requirements and procedures specified under PNAP No. 252 (ADV-21) shall be followed. Marine Fill Committee (MFC) of CEDD is managing the disposal facilities in Hong Kong for the excavated sediment, while EPD is the authority of issuing marine dumping permit under the Dumping at Sea Ordinance (DASO).
6.5.18 For the purpose of site allocation and application of marine dumping permit and if considered necessary by DASO team/ EPD, separate submissions (e.g. SSTP/SQR) shall be submitted to DASO team/ EPD for agreement under DASO. Additional SI works, based on the SSTP, shall then be carried out in order to confirm the disposal arrangements of the excavated sediment. A Sediment Quality Report (SQR), reporting the chemical and biological screening results and the estimated quantities of sediment under different disposal options, shall then be submitted to DASO team/EPD for agreement under DASO.
6.5.19 To ensure disposal space is allocated for the Project, the Project Proponent should be responsible for obtaining agreement from MFC on the allocation of the disposal site. The contractor(s), on the other hand, should be responsible for the application of the marine dumping permit under DASO from EPD for the sediment disposal.
6.5.20 The excavated sediments is expected to be loaded onto the barge and transported to the designated disposal sites allocated by MFC. The excavated sediment would be disposed of according to its determined disposal options and PNAP No. 252 (ADV-21).
6.5.21 Stockpiling of contaminated sediments should be avoided as far as possible. If temporary stockpiling of contaminated sediments is necessary, the excavated sediment should be covered and the area should be placed within earth bunds or sand bags to prevent leachate from entering the ground, nearby drains and surrounding water bodies. The stockpiles area should be completely paved in order to avoid contamination to underlying soil or groundwater. Separate and clearly defined areas should be provided for stockpiling of contaminated and uncontaminated materials. Leachate, if any, should be collected and discharged according to the WPCO.
6.5.22 In order to minimise the potential odour / dust emissions during excavation and transportation of the sediment, the excavated sediments shall be wetted during excavation / material handling and shall be properly covered when placed on trucks or barges. Loading of the excavated sediment to the barge shall be controlled to avoid splashing and overflowing of the sediment slurry to the surrounding water.
6.5.23 The barge transporting the sediments to the designated disposal sites shall be equipped with tight fitting seals to prevent leakage and shall not be filled to a level that would cause overflow of materials or laden water during loading or transportation. In addition, monitoring of the barge loading shall be conducted to ensure that loss of material does not take place during transportation. Transport barges or vessels shall be equipped with automatic self-monitoring devices as specified by the DEP.
Potential Floating Refuse
6.5.24 Proper management and education would be given to construction site workers such that accidental release or intentional disposal would be avoided. The refuse should be stored in enclosed bin to avoid adverse impacts to the surroundings, including marine environment. Regular checking should also be carried out to ensure that the refuse is stored properly. With the implementation of the measures as mentioned above, no adverse environment impact associated with floating refuse is anticipated.
6.5.25 If chemical waste is produced, the Project Proponent would be required to register with the EPD as a Chemical Waste Producer. The guidelines stated in the Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes should be followed in handling of chemical waste. A trip-ticket system would be adopted by the Project Proponent to monitor disposal of chemical waste.
6.5.26 Appropriate containers with proper labels should be used for storage of chemical wastes. Chemical wastes should be collected and delivered to designated outlet by a licensed collector. Chemical waste shall be disposed of at appropriate facility such as the CWTC by licensed collectors. It is expected quantities of chemical wastes to be generated would be about a few cubic metres per month.
6.5.27 Designated areas will be assigned for proper storage and collection of MSW generated on site. Segregation of MSW will be conducted on site to allow for maximisation of recycling opportunities. It is recommended to place clearly labelled recycling bins at designated locations which could be accessed conveniently. A reputable waste collector should be employed to remove MSW regularly to minimise potential impacts arising from storage and collection of MSW.
6.6 Evaluation of Residual Environmental Impact
6.6.1 With the implementation of the recommended mitigation measures for the handling, transportation and disposal of the identified waste arising, adverse residual impact is not expected to occur during the construction and operation of the Project.
6.7 Environmental Monitoring and Audit Requirement
6.7.1 During the construction period, it is the ContractorĄŠs responsibility to ensure that all waste produced during the construction of the Project are handled, stored and disposed of in accordance with good waste management practices, relevant legislation and waste management guidelines.
6.7.2 Waste materials generated during construction activities, such as C&D materials, are recommended to be audited at regular intervals to ensure that proper storage, transportation and disposal practices are being implemented. This would ensure the waste generated would be properly disposed of. The Contractor would be responsible for the implementation of any mitigation measures to minimise waste or mitigate problems arisen from waste materials.
6.7.3 During operation, with the implementation of good waste management practices, no adverse environmental impact is anticipated, and therefore waste monitoring and audit programme during the operation phase is not required.
6.8 Conclusion
6.8.1 Waste types generated by this Project are likely to include C&D materials, chemical waste from maintenance of construction plant and equipment, general refuse, excavated sediment, and potential floating refuse. Provided that these wastes are handled, transported and disposed of according to the recommended good site practices, adverse environmental impacts are not expected during the construction phase.
6.8.2 The excavated sediment generated from the Project comprises of marine-based and land-based sediment and the total volume is estimated to be 1,050 m3 with approximately 650 m3 being marine-based sediment and 400 m3 being land-based sediment. Marine-based sediment is anticipated to be excavated during the construction of the sea portion of the bridge foundation and is recommended to be disposed of at the designated marine disposal areas according to PNAP No. 252 (ADV-21). Based on the chemical and biological screening results, approximately 590 m3 of marine-based sediment is suitable for Type 1 - Open Sea Disposal and 60 m3 of marine-based sediment is suitable for Type 1 - Open Sea Disposal (Dedicated Sites). Land-based sediment is expected to be generated from the construction of bridge piers and abutment for the land viaduct. The land-based sediment will be treated using S/S technique and will be reused on site (e.g. as backfilling materials). With the implementation of the recommended mitigation measures and in accordance with the requirements of PNAP No. 252 (ADV-21), no adverse environment impacts would be expected from excavation, treatment, transportation and disposal of sediment.
6.8.3 The main waste types generated during the operation of this Project would be chemical waste and MSW from maintenance activities and staff. It is anticipated that no adverse impacts would arise if the mitigation measures were strictly followed.
[1] Highways Department, Environmental Impact Assessment Report for Hong Kong-Zhuhai-Macao
Bridge Hong Kong Boundary Crossing Facilities (Agreement No. CE 14/2008
(HY)) (EPD Register No.: AEIAR-145/2009), 2009.