7.1 This section identifies the types of solid 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 wastes. The major solid waste would be construction and demolition (C&D) material generated from excavation and tunnelling works for station and tunnel construction. Waste arisings in the future, as with current operations on the existing Island Line, would be mainly general refuse generated from the staff and public at the stations. Mitigation measures and good site practices, including waste handling, storage and disposal, are recommended with reference to the applicable waste legislation and guidelines.
7.2 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 Process (EIAO-TM), respectively.
7.3 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
·
Waste
Disposal (Charges for Disposal of Construction Waste) Regulation (Cap. 354N)
7.4 The Waste Disposal Ordinance (WDO) prohibits the unauthorised disposal of wastes. Construction waste is defined 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 only at designated waste disposal facilities.
7.5 Under the WDO, the Chemical Waste (General) Regulation 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.
7.6 The Public Cleansing and Prevention of Nuisances Regulation provides control on illegal tipping of wastes on unauthorised (unlicensed) sites.
7.7 The current policy related to the disposal of C&D material is documented in the Works Branch Technical Circular No. 2/93, ‘Public Dumps’. C&D materials that are wholly inert, namely public fill, should not be disposed of to landfill, but taken to public filling reception facilities (PFRFs), which usually form part of reclamation schemes. The Land (Miscellaneous Provisions) Ordinance requires that dumping licences be obtained by individuals or companies who deliver public fill to PFRFs. The Civil Engineering & Development Department (CEDD) issues the licences under delegated powers from the Director of Lands.
7.8 Under the Waste Disposal (Charges for Disposal of Construction Waste) Regulation, enacted in January 2006, 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 PFRF for disposal must consist entirely of inert material. In accordance with the Environment, Transport and Works Bureau (ETWB) TCW No. 31/2004 “Trip Ticket System for Disposal of Construction and Demolition Materials” for all contracts that are expected to generate inert C&D materials (e.g. soil, broken rock, broken concrete and building debris, etc) requiring disposal from the site, the project office shall write to the Public Fill Committee (PFC) through Secretary of the PFC to request a designated disposal ground for incorporation into the tender documents. For contracts where the estimated amount of non-inert C&D materials requiring disposal at landfill facilities equal or exceed 50m3, the project office shall seek confirmation from the Director of Environmental Protection (DEP) as to whether landfill facilities will be available for disposal such materials. The DEP will designate landfill facilities, if available, for the contract. Where the estimated amount of non-inert C&D materials to be generated from the contract is less than 50m3, the project office is not required to apply to DEP for designated landfill facilities. However, the project office should still specify in the tender documents appropriate landfill facilities (e.g. SENT Landfill at Tseung Kwan O, NENT Landfill at Ta Kwu Ling and WENT Landfill at Nim Wan).
7.9 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 and operation phases of the Project follow those presented in Annex 15 of the EIAO-TM and include the following:
§
Estimation
of the types and quantities of the wastes to be 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.
§
Assessment
of impacts on the capacity of waste collection, transfer and disposal
facilities.
7.10 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:
§
Construction
and demolition (C&D) materials
§
General
refuse
§
Chemical
waste
7.11 Each type of waste arising is described below, together with an evaluation of the potential environmental impacts associated with generation, handling, storage and transport of the waste.
Construction and
Demolition Material
7.12
C&D material would be generated from the
construction activities of the WIL, with an estimated total volume of
approximately 818,300 m3 (estimated within 10% error). The C&D material would comprise
approximately 60% rock. A breakdown of the C&D material generated from the
various works items of the Project is given in Table 7.1. The Project
would generate about 502,100 m3 of rock material from the tunnelling
works, shaft/adit construction, the cavern construction for UNI Station and SYP
Station, open cut for KET Station and the construction
of the temporary magazine cavern at
7.13
The C&D material should be reused
on-site as far as possible to minimize the net amount of C&D material
generated from the Project. Given that
the construction works for the Project would mainly involve excavation and
tunnelling works, it is expected that only a limited amount of C&D material
(approximately 7% or 56,000 m3) could be reused on-site for deposition
and compaction and as backfill material (e.g. for the construction shafts and
cut and cover station at KET). It is
proposed that the material stockpiling area at KET Abattoir site would be
available for stockpiling the material to be reused on site. However, the
status of this stockpiling area is still under review with Lands Department and
would yet to be confirmed. The volume of surplus C&D material requiring
disposal off-site is thus approximately 762,300 m3. The surplus
rock material generated could be reused as rock fill by other projects either
in the
7.14
About one third of the rock
will be volcanic which would not be suitable to be used as concrete aggregates
for construction purposes because of concerns about alkali/silica
reactions. Approximately
7.15
The surplus rock and other inert C&D
material would be disposed of at the Government’s PFRFs, for beneficial use by
other projects in the HKSAR, or further disposed of in the Mainland for use by
other suitable projects in the Mainland.
Government advises that disposal of material to PFRFs should be
considered as the last resort with the preferred approach to reuse the material
within the Project or in other projects. Proponent should also explore appropriate
contracts either in Mainland
7.16 To handle and dispose of the large quantity of surplus C&D material off-site from the works areas with least environmental impacts to the local community, barging points for the Project would be erected at the KET Abattoir Site and Western District Public Cargo Working Area (PCWA). The rock debris from tunnels at the west of KET Station, the KET Turnback tunnels and KET Station with its associated adits would be transported a short distance by trucks to the barging point erected at the KET Abattoir Site. The rock debris from tunnels between the east of KET Station and west of SYP Station, and the UNI and SYP Stations with their associated caverns, adits and vent shafts would reach ground level via a construction shaft at KET Praya, and then be transported by a conveyor system across Shing Sai Road and along the edge of the PCWA access road to the barging point at the Western District PCWA. All rock removed from the conveyor system would be crushed below ground prior to being loaded onto the conveyor. To further minimize the environmental impacts due to dust and noise, the conveyor belt system would be fully enclosed. The barging points would also be equipped with water spray to suppress dust generation. The rock debris from the underground magazine site and tunnels at east of SYP Station would be transported by trucks to the Chai Wan Public Fill Barging Point.
7.17 Assuming that the barging point at Western District PCWA is procured under the main Civil Construction Contract 704, the programme demonstrates that the readiness of the barging point for operation would match the commencement of tunnel and cavern excavation at UNI. The C&D material for KET Praya Access and UNI Hill Road construction shafts would be transported to Chai Wan Public Fill Barging Point before availability of the barging point at Western District PCWA (September 2010).
7.18
The barges, loaded with inert C&D
material, would transport the material to the designated PFRFs at Tuen Mun
and/or Tseung Kwan O or to sites in
7.19 The proposed Project would generate about 10,000 m3 of C&D waste which is to be disposed of at the designated landfill site, mainly comprising vegetation cleared from the proposed works areas. Metals should be separated from the C&D waste for recycling as far as possible, in particular steel which has re-sale value.
7.20 Since the construction activities for the KET Station would be located near the harbour front, improper management of C&D materials may introduce debris and pollutants to the harbour waters, and mitigation measures, including adoption of good site practices, would be required for control of impacts. Recommended good site practices are described in Section 7.30.
Table 7.1 Summary
of C&D Material Volumes
|
|
C&D material (Total) |
Rock
excavated |
Artificial
hard material (AHM) |
Material
other than rock & AHM |
Material
Reused as Backfill |
Disposal |
|
m3 |
m3 |
m3 |
m3 |
m3 |
m3 |
|
|
KET
Station and Adits |
147,300 |
10,400 |
3,600 |
133,300 |
39,100 |
108,200 |
|
UNI
Station Cavern |
77,000 |
77,000 |
- |
- |
- |
77,000 |
|
UNI
Station Adits and Vent Shafts |
173,400 |
121,000 |
800 |
51,600 |
6,100 |
167,300 |
|
SYP
Station Cavern |
83,500 |
83,500 |
- |
- |
- |
83,500 |
|
SYP
Station Adits and Vent Shafts |
121,900 |
78,000 |
900 |
43,100 |
10,800 |
111,100 |
|
SHW to
SYP East & West Bound Tunnel |
49,200 |
18,800 |
- |
30,400 |
- |
49,200 |
|
SYP to
UNI Tunnels |
42,100 |
42,100 |
- |
- |
- |
42,100 |
|
UNI to
KET Tunnels |
46,900 |
46,000 |
- |
800 |
- |
46,900 |
|
KET
Turnback Tunnels |
28,200 |
24,000 |
- |
4,300 |
- |
28,200 |
|
Miscellaneous |
2,500 |
1,300 |
- |
1,300 |
- |
2,500 |
|
Concrete
Debris from demolition works of existing buildings / features |
46,300 |
- |
46,300 |
- |
- |
46,300 |
|
Total |
818,300 |
502,100 |
51,600 |
264,800 |
56,000 |
762,300 |
Note: The delivery programme of the C&D material to each barging point
at KET Abattoir site, Western District PCWA and Chai Wan Public Fill Barging
Point will be provided in the Waste Management Plan, which will be prepared by
the Contractor before the commencement of the construction works.
Table 7.2 Summary
of Frequency of Barge Movements and Routings
|
Barging Point |
KET Abattoir Site |
Western District
PCWA |
|
Main
Activities: Spoil removal |
||
|
Period |
Approximately
from mid 2009 to early 2013. |
Approximately
from mid 2010 to early 2013. |
|
Frequency of
Barge Movements and Routing |
Average 1,000 cum/day. Max. 2,000 cum/day.
Assume 8 barges per day. 4 barges per day travelling to/from |
Average 700 cum/day. Max. 1,400 cum/day.
Assume 4 barges per day. 2 barges per day travelling to/from |
|
Main
Activities: Materials delivery |
||
|
Period |
Approximately
from early 2009 to early 2013 |
Approximately
from mid 2010 to early 2013. |
|
Frequency of
Barge Movements and Routings |
Assume 8 barges per day. 4 barges per day
travelling to/from |
Assume 6 barges per day. 3 barges per day
travelling to/from |
General Refuse
7.21
The construction workforce would generate refuse comprising food scraps,
waste paper, empty containers, etc. Such
refuse should be properly managed so intentional or accidental release to the
surrounding environment does not occur.
Disposal of refuse at sites other than approved waste transfer or
disposal facilities shall be prohibited.
Effective collection of site wastes would be required to prevent waste
materials being blown around by wind, flushed or leached into the marine
environment, or creating an odour nuisance or pest and vermin problem. Waste
storage areas should be well maintained and cleaned regularly. With the implementation of good waste
management practices at the site, adverse environmental impacts are not
expected to arise from the storage, handling and transportation of workforce
wastes. The maximum number of
construction workers to be employed is estimated to be about 1,530
workers. Based on a generation rate of
Chemical Waste
7.22 The maintenance and servicing of construction plant and equipment may generate some chemical wastes such as 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 difficult to quantify the amount of chemical waste that would arise from the construction activities since it would be dependent on the Contractor’s 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 and in the order of a few cubic metres per month. The amount of chemical waste to be generated would be quantified in the site Waste Management Plan to be prepared by the Contractor.
7.23 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.
7.24 Materials classified as chemical wastes would require special handling and storage arrangements before removal for appropriate treatment at the approved Chemical Waste Treatment Centre (CWTC). Wherever possible opportunities should be taken to reuse and recycle materials. Mitigation and control requirements for chemical wastes are detailed in Section 7.37. Provided that the handling, storage and disposal of chemical wastes are in accordance with these requirements, adverse environmental impacts are not expected to result.
7.25 During the operation phase, the identified waste types that would be generated at the stations include:
§
General
refuse
§
Industrial waste
§
Chemical
waste
General Refuse and
Industrial Waste
7.26 General refuse would arise from the staff and public and any commercial operators at the stations. Waste would include food, paper, wood, plastic, office waste, etc.
7.27 Maintenance activities of the stations and tracks would generate industrial waste including scrap materials from rail and carriage maintenance, used fluorescent tubes, used welding rods, cleansing materials and discarded electronic equipment.
7.28 A reputable waste collector should be employed to remove general refuse and industrial waste from the stations, separately from chemical wastes, on a daily basis to minimise potential odour, pest and litter impacts.
Chemical Waste
7.29 Chemical wastes may be generated within the stations, such as paints, lubricants and used batteries. These wastes 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) Regulation. The requirements stated in the Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes should be followed in the handling of these chemical wastes, as described in Section 7.37. Chemical wastes should be collected by a licensed collector and transported to a licensed facility for treatment and disposal. Provided that the handling, storage and disposal of chemical wastes are in accordance with these requirements, adverse environmental impacts are not expected to result.
Good Site Practices
7.30 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 waste 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
§
Separation
of chemical wastes for special handling and appropriate treatment at the CWTC.
Waste Reduction Measures
7.31 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:
§
Sort
C&D waste from demolition of existing facilities to recover recyclable
portions such as metals
§
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 providing separate labelled bins to enable this
waste to be segregated from other general refuse generated by the workforce
§
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
§
A
recording system for the amount of wastes generated, recycled and disposed
(including disposal sites) should be proposed
§
Training
should be provided to workers about the concepts of site cleanliness and
appropriate waste management procedures, including waste reduction, reuse and
recycle.
7.32 A Waste Management Plan should be prepared by the Contractor prior to the commencement of construction work to provide an overall framework for waste management and reduction. The WMP shall be certified by the ET Leader and verified by the IEC.
7.33 In addition to the above measures, specific mitigation measures are recommended below for the identified waste arisings to minimise environmental impacts during handling, transportation and disposal of these wastes.
Construction and
Demolition Material
7.34
In order to minimise impacts resulting from
collection and transportation of C&D material for off-site disposal, the
excavated materials arising from station and tunnel construction should be reused
on-site as backfilling material (e.g. for the construction shafts and cut and
cover station at KET and for landscaping works as far as practicable. Surplus rock generated from the tunnelling
works, shafts/adits construction and the stations cavern construction should be
reused in reclamation and site formation projects either in the Mainland or
7.35
Material delivered to PFRFs should be of size less than 250mm or other
sizes as agreed with the Secretary of the PFC.
General Refuse
7.36 General refuse should be stored in enclosed bins or compaction units separate from C&D material and chemical wastes. A reputable waste collector should be employed by the contractor to remove general refuse from the site, separately from C&D material and chemical wastes. Preferably an enclosed and covered area should be provided to reduce the occurrence of 'wind blown' light material.
Chemical Wastes
7.37 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 approved CWTC, or another licensed facility, in accordance with the Waste Disposal (Chemical Waste) (General) Regulation.
7.38 Table 7.3 provides a summary of the various waste types likely to be generated during the construction activities for the Project, together with the recommended handling and disposal methods.
Table 7.3 Summary
of Waste Handling Procedures and Disposal Routes
|
Waste Material Type |
Generated from works item |
Total Quantity Generated |
Quantity
to be disposed off-site |
Disposal |
Handling |
|
C&D Material |
Construction of underground Magazine site;
shafts/adits, tunnels, caverns for UNI
Station and SYP Station, open cut for KET Station and demolition of existing
buildings / features |
818,300 m3 |
762,300 m3 |
Surplus inert C&D material to be reused
in other projects or in Mainland, or delivered to PFRFs for beneficial uses. |
Segregate rock to avoid contamination from
other wastes. Covered conveyor belt to transfer inert
C&D material to barging point at Western District PCWA. Trucks to transfer inert C&D material
to barging point at KET Abattoir Site and Chai Wan Public Fill Barging Point |
|
C&D Waste |
Site clearance at works areas |
|
10,000 m3 |
To be disposed of
to the designated landfill site |
|
|
General Refuse |
Waste paper, discarded containers, etc.
generated from workforce |
|
|
Refuse transfer
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 plant and equipment |
Few cubic metres per month (preliminary estimate) |
Few cubic metres per month (preliminary estimate) |
Chemical Waste Treatment Centre |
Recycle by licensed companies. Stored on-site within suitably designed
containers |
General Refuse and
Industrial Waste
7.39
A reputable waste collector should be
employed to remove general refuse and industrial wastes from the stations on a
daily basis to minimise odour, pest and litter impacts.
Chemical Waste
7.40
The requirements
given in the Code of Practice on the
Packaging, Labelling and Storage of Chemical Wastes should be followed,
where applicable, in handling of these chemical wastes. A trip-ticket system should be operated in
accordance with the Waste Disposal
(Chemical Waste) (General) Regulation to monitor all movements of chemical
wastes which would be collected by a licensed collector to a licensed facility
for final treatment and disposal. The
details of mitigation measures are as described in Section 7.37.
7.41 With the implementation of the recommended mitigation measures for the handling, transportation and disposal of the identified waste arisings, residual impacts are not expected for both construction and operation phases.
7.42 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 shall form the basis of the site Waste Management Plan to be developed by the Contractor in the construction stage.
7.43 Waste types generated by the construction activities are likely to include C&D material (from site clearance, demolition, excavation and tunnelling works), general refuse from the workforce, and chemical waste from the maintenance of construction plant and equipment. Provided that these wastes are handled, transported and disposed of using approved methods and that the recommended good site practices are strictly followed, adverse environmental impacts are not expected during the construction phase.
7.44 The main waste types to be generated during the operation phase would be general refuse from the public, staff and any commercial operators at the stations, industrial waste from maintenance activities and chemical wastes from operational activities at the stations. The handling, collection, transportation and disposal practices of the identified waste arisings would follow the existing arrangements currently in operation at the stations on the existing Island Line.