7. CONSTRUCTION WASTE management
7.1.1
This
construction waste assessment examines the type, quantity, quality and timing
of potential sources of waste that will arise during the construction phase of
the Project. It identifies potential environmental impacts associated with
their handling and disposal. Options for avoidance, minimization, reuse,
recycling, treatment, storage, collection, transport and disposal of such
wastes are examined.
7.1.2
Where
unacceptable impacts are identified, appropriate mitigation measures and good
site practices are recommended. Disposal options will be outlined for each type
of waste, and the responsibilities for disposal or recycling discussed.
7.1.3 The main objectives of the waste assessment are to:
(i)
identify
the sources, volumes, quality and timing of wastes arising from the
construction activities;
(ii)
recommend
construction waste management requirements in terms of minimisation through
project design, construction method, and site location, identification of reuse
and recycling opportunities and the responsible party for each step of the
waste management process; and
(iii)
recommend
disposal sites and routes for different types of wastes unsuitable for reuse or
recycling.
7.1.4 The recommendations will be carried out in accordance with the current requirements for waste management.
7.1.5 No waste will be generated during the operational phase.
7.2
Relevant Legislation, Policies, Standards and Criteria
Legislation, Circulars, Guidelines
related to Waste Management
7.2.1
The
following legislation relates to the handling, treatment and disposal of wastes
and will be used in assessing potential impacts:
·
Environmental Impact Assessment
Ordinance (Cap. 499)
·
Waste Disposal Ordinance (Cap. 354)
·
Waste Disposal (Chemical Waste) (General)
Regulation
·
Waste Disposal (Charges for Disposal of
Construction Waste) Regulation
·
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)
·
Technical Memorandum on Environmental
Impact Assessment Process
7.2.2 The following documents, circulars and guidelines which relate to waste management and disposal will also be referred to during this study:
·
Technical Memorandum on Environmental Impact Assessment
Process (EIAO-TM) - Annex 7 - Criteria for Evaluating Waste Management
Implications and Annex 15 - Guidelines for Assessment of Waste Management
Implications
·
Code of Practice on the Packaging, Labelling and Storage of
Chemical Wastes, EPD (1992)
·
WBTC No. 2/93 - Public Dumps
·
WBTC No. 2/93B - Public Filling Facilities
·
WBTC No. 16/96 - Wet Soil in Public Dumps
·
WBTC No. 4/98 & 4/98A - Use of Public Fill in Reclamation
and Earth Filling Projects
·
WBTC No. 25/99, 25/99A & C - Incorporation of Information
on Construction and Demolition Material Management in Public Works Subcommittee
Papers
·
WBTC No. 12/2000 - Fill Management
·
WBTC No. 19/2001 - Metallic Site Hoardings and Signboards
·
WBTC No. 12/2002 - Specifications Facilitating the Use of
Recycled Aggregates
·
ETWB TCW No. 33/2002 - Management of Construction and
Demolition Material including Rock
·
ETWB TCW No. 34/2002 - Management of Dredged/Excavated
Sediment
·
ETWB TCW No. 24/2004 - Specifications Facilitating the Use of
Concrete Paving Units Made of Recycled Aggregates
·
ETWB TCW No. 31/2004 - Trip-ticket System for Disposal of
Construction & Demolition Material
·
ETWB TCW No. 19/2005 - Environmental Management on
Construction Sites
7.3.1 Reference has been made to the methodology laid out in the EIAO-TM (Annexes 7 and 15). The principal legislation regulating waste is the Waste Disposal Ordinance (WDO) (Cap. 354).
7.4
Sources and Types of Waste arising from the Project
7.4.1
The proposed water main works
include the following construction activities:
· site clearance and demolition of temporary structures to form works area;
· laying of submarine water main using HDD;
·
laying
of land-based water main; and
·
reinstatement
works.
7.4.2
Construction activities will
result in the generation of a variety of Construction and Demolition (C&D)
materials. The C&D materials are usually mixed consisting of inert
components (public fill) such as soil, rock, concrete, brick, and bentonite
slurry, etc and non-inert components (C&D waste) comprising metal, timber,
paper, plastic and general garbage. Chemical and municipal wastes may also
arise as a result of construction activities. The likely waste generated from
the construction of the Project can be classified into the following main
categories:
· site clearance / demolition materials;
· excavated materials;
· bentonite slurry;
· chemical waste; and
·
general works waste.
7.4.3 With the adoption of HDD as the preferred method of laying the submarine water main, marine sediment will not be required to be dredged or disposed.
7.5
Impact Assessment and Evaluation
Introduction
7.5.1
Handling and disposal of the
above mentioned wastes may cause environmental impacts and nuisance if it is
not properly managed.
Site Clearance / Demolition Materials
7.5.2 Site clearance and demolition works will be required for the works in Cheung Chau, thus generating unwanted material during construction. No site clearance and demolition works are necessary for the works at Lantau.
7.5.3 The proposed works site at Cheung Chau will utilize the existing works compound at Tai Kwai Wan and large scale site formation will not be required. A few temporary structures within the works compound will need to be demolished. Site clearance / demolition works will involve the removal of vegetation (mainly grasses and shrubs) and some trees, demolition of temporary structures topsoil. In addition, existing road surface for the land-based main will have to be broken up thus generating broken concrete. These will all be generated from the works in Cheung Chau.
7.5.4 Site clearance / demolition will generate concrete rubble, plastics, metals, glass, asphalts, wood, vegetation and refuse. As these materials are likely to be in a deteriorating condition, the potential for reuse of such materials on site is very limited.
7.5.5
The proposed launching site and
works area at Cheung Chau is located on a headland at Tai Kwai Wan. Historic
aerial photographs (1945: Figure
6.3.5 and 1963: Figure
6.3.7 in Chapter 6) indicate
the site is a natural coast and vegetated. The 1980 survey map (sheet no.
14-NW-19B) also indicates that the headland is undeveloped up to the early 80s.
The site has remained undeveloped until around 1985 when it was formed with
rock fill to its current profile (Figures
6.3.6 and 6.3.8)
with parts of the site used as contractor’s temporary works compound. According
to
7.5.6 The estimated quantities of C&D materials generated during site clearance / demolition works will be about 40 m3 of inert public fill and about 100 m3 of C&D waste.
Excavated Materials
7.5.7 The majority of C&D materials generated from the Project will arise during the drilling of the submarine water main alignment. Since the drilling works will be conducted within bedrock layer, it is expected that most of this material will be crushed rocks with some fine materials. Such excavated material will initially be mixed with drilling fluid (e.g. bentonite) but will be separated on site before reuse or disposal. Excavated material will also be generated during excavation of trenches for the land-based main at Cheung Chau.
7.5.8 Approximately 920 m3 of excavated materials consisting mostly of crushed rocks and approximately 370 m3 of other inert fill will be generated during the works at Cheung Chau.
7.5.9 The excavated material will be collected at the proposed launching site in Cheung Chau, where the drilling fluid treatment and recycling facilities will be located. The storage and disposal of the excavated material will be handled in Cheung Chau only. No excavated material will be stored in Lantau.
7.5.10 The potential for reuse of suitable excavated material should be explored during the early stages of the Project.
Bentonite Slurry
7.5.11 Drilling fluid is used in HDD mainly to cool and lubricate the bit and drill string, transport cuttings to surface and stabilize the borehole. The most common type of drilling fluid is bentonite mixed with water to form a viscous, shear thinning material often referred to as bentonite slurry.
7.5.12 Bentonite slurry is normally recycled and reused during the drilling process. Inadvertent release of bentonite slurry or improper disposal may lead to contamination of the nearby water bodies. The storage, treatment and recycling of the bentonite slurry (drilling fluid) will only be conducted at the proposed launching site in Cheung Chau.
7.5.13 The estimated quantity of bentonite will be about 980 m3.
Chemical Waste
7.5.14
Wastes classified as chemical
waste are listed in the Waste Disposal (Chemical Waste) (General) Regulation.
Where the construction processes produce chemical waste, the Contractor must
register with
· scrap batteries or spent acid/alkali from their maintenance;
· used engine oils, hydraulic fluids and waste fuel;
· spent mineral oils/cleaning fluids from mechanical machinery; and
· spent solvents/solutions from equipment cleaning activities.
7.5.15 Chemical wastes pose serious environmental and health and safety hazards if not stored and disposed of in an appropriate manner as outlined in the Chemical Waste Regulation. These hazards include:
· toxic effects to works;
· adverse effects on water quality from spills; and
· fire hazards.
7.5.16 Chemical waste will only be stored and handled at the proposed launching site at Cheung Chau.
7.5.17 The amount of chemical waste cannot be accurately predicted at this stage since it largely depends on the Contractor’s housekeeping. The amount is anticipated to be small and it is recommended that the Contractors should implement good housekeeping measures to minimise the amount of chemical waste generated. The amount of chemical waste to be generated will be quantified in the monthly Waste Flow Table to be prepared by the Contractor.
General Works Waste
7.5.18 The following wastes will be generated during general construction activities:
· concrete waste;
· wooden materials; and
· municipal waste.
Concrete Waste
7.5.19 Of the volume of concrete supplied, it is expected that only a very small percentage of the concrete used will be lost to waste. It will be generated mainly during reinstatement of the road surface after laying of land-based water main in Cheung Chau.
Wooden Materials
7.5.20 Different kinds of wooden materials are essential to the construction project, such as wooden boards used as falsework and formwork for concrete structures, erection of site boundaries, as well as bamboo for scaffolding. Wooden materials are important and valuable resources.
7.5.21 Site fencing may be necessary to separate the construction works from the public and to reduce construction nuisance such as noise to nearby sensitive receivers. In this case metal fencing or building panels to provide site fencing should be used. Attention should be paid to WBTC No. 19/2001 – “Metallic Site Hoardings and Signboards” to reduce the amount of timber used on construction sites.
Municipal Waste
7.5.22 Municipal waste will be generated by the site staff and construction workers during the construction period. This includes food scraps, waste papers, plastic containers, packaging materials, etc. The amount of municipal waste that may be produced is dependent on size of workforce at site.
7.5.23 The storage of general refuse has the potential to give rise to a variety of adverse environmental impacts. These include odour if putrescible food waste is not collected frequently, water quality impacts if waste enters water bodies and visual impact from windblown litter. The refuse may attract pests and vermin if the storage areas are not well maintained and cleaned regularly. In addition, disposal of waste at sites other than approved waste transfer or disposal facilities can also lead to environmental impacts.
7.5.24 Handling and disposal of general refuse should cope with the presence of peak workforce during the construction period. Provided that the refuse is stored and transported in accordance with proper practices and disposed at approved disposal facilities, potential environmental impact is not expected.
7.5.25 The amount of general works waste is estimated to be about 120 m3.
7.5.26 A summary of the main C&D materials and wastes expected to arise from the Project and the estimated quantities for each type of C&D materials is presented in Tables 7.1 and 7.2 respectively.
Types of C&D
Materials and Wastes Generated by the Project
|
Area |
Major Activities |
Waste Type |
|
Temporary and permanent works area (mainly in Cheung Chau) |
Site clearance and demolition of structures and road surfaces |
Vegetation, garbage, topsoil, broken concrete and other inert
materials |
|
Temporary and permanent works area at launching site in Cheung Chau |
Drilling
works, pipe installation |
Rocks, fines and spent bentonite |
|
Temporary and permanent works area at land-based main along |
Excavation,
laying of land-based water main |
Broken concrete,
soil, rocks and other inert materials |
|
All |
General site activities |
Chemical waste, concrete waste, scrap metal, wood and general refuse |
The Estimated Quantities of C&D Materials and C&D
Waste Arising from the Project
|
Types of
C&D Materials |
Estimated Quantities* (m3) |
|
Bentonite (see Note 1) |
980 |
|
Inert Fill (see Note 2) |
410 |
|
Rocks (see Note 2) |
920 |
|
Chemical Waste (see Note 3) |
Minimum amount |
|
C&D Waste (see Note 4) |
220 |
|
Approximate timing * :
early 2012 – early 2014 |
|
Notes:
* Tentative construction programme of early
2012 – early 2014 may be subject to further changes. The estimated quantities
are based on preliminary design of the proposed works and the best available
ground investigation data. The waste arising will largely depend on the
contractor works programme and activities. The contractor will be required to
provide detailed estimation of all the C&D materials and waste generated
on-site using the Monthly / Yearly Summary Waste Flow Table as required under
ETWB TCW No. 19/2005.
1
Bentonite should be recycled and reused during the drilling process.
Any spent bentonite unsuitable for reuse should be suitably dewatered for
disposal at public fill reception facilities.
2
Topsoil, rocks and suitable materials should be stockpiled
for later reuse in this or other projects subject to approval by relevant
parties in accordance with the ETWB TCW No. 31/2004. The amount of materials
that can be reused in this Project will be examined further during the detailed
design stage.
3
The amount of chemical waste will be dependent on the
contractor’s on-site maintenance programme and the number of equipment and
vehicles used on-site. Chemical waste should be collected by licensed
contractor and properly disposed of at approved chemical waste treatment
facilities (e.g. the Chemical Waste Treatment Centre at Tsing Yi). Chemical
waste will be generated throughout the construction period.
4
The amount of general works waste will depend on the
contractor’s operating procedures and housekeeping practices as well as the
size of the workforce on-site. All such wastes should be sorted, reused and
recycled before disposal at designated outlets. General works waste will be
generated throughout the construction period.
7.5.27 Out of the total 1,330 m3 of inert public fill (including rocks) generated, it is anticipated that about 31% (about 410 m3) can be reuse on-site.
General
7.6.1
The
HKSAR Government's construction and demolition waste management policy follows
the same hierarchy as for other wastes, i.e. in order of desirability:
avoidance, minimisation, recycling, treatment and safe disposal of waste. During the construction period the Contractor, Engineer and
environmental specialists (Environmental Team, Independent Environmental Check)
should work closely together with a view to reduce the volumes of materials requiring
removal and final disposal.
7.6.2
Upon appointment, the main
Contractor of each construction contract should prepare and implement an
Environmental Management Plan (EMP) in accordance with ETWB TCW No. 19/2005 –
“Environmental Management on Construction Sites” which should describe the
arrangements for avoidance, reduction, reuse, recovery, recycling, storage,
collection, treatment and disposal of different categories of waste to be
generated from the construction activities. The EMP should incorporate site
specific factors, such as the designation of areas for segregation and
temporary storage of reusable and recyclable materials. The waste management
plan now becomes part of the EMP. The EMP should be submitted to the Engineer
for approval. The Contractor should implement the waste management practices in
the EMP throughout the construction stage of the Project. The EMP should be
reviewed regularly and updated (preferably monthly) by the Contractor. The EMP
should take into account the recommended mitigation measures in the approved
EIA report.
7.6.3
The Contractor should refer to
the Construction and Demolition Material Management Plan (C&DMMP) to be
conducted during the design stage of this Project to facilitate him in the
preparation of the EMP. The C&DMMP should be endorsed by WSD’s Vetting
Committee and approved by the Public Fill Committee (PFC). WSD’s Vetting
Committee will monitor the implementation of the C&DMMP and report to
Public Fill Committee in accordance with ETWB TCW No. 33/2002 during construction.
7.6.4
The Contractor should nominate
an appropriate person, such as site agent or environmental officer, to be
responsible for good site practices, arrangement for collection and effective
disposal of all wastes generated at the site to an approved facility. Training
of construction staff should be undertaken by the Contractor about the concept
of site cleanliness and appropriate waste management procedures. The Contractor
should develop and provide toolbox talk for on-site sorting of C&D materials
to enhance worker’s awareness in handling, sorting, reuse and recycling of
C&D materials. Requirements for staff training should be included in the
EMP.
7.6.5
Good planning and site
management practices should be employed to eliminate over ordering or mixing of
construction materials to reduce wastage. Proper storage and site practices
will minimise the damage or contamination of construction materials. Regular
cleaning and maintenance of the waste storage area should be provided.
7.6.6
Where waste generation is unavoidable,
the potential for recycling or reuse should be rigorously explored. If waste
cannot be recycled, disposal routes described in the EMP should be followed. A
recording system for the amount of wastes generated, recycled and disposed
(including the disposal sites) should be implemented. In order to monitor the
disposal of C&D material and solid wastes at public fill reception
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.
7.6.7
Imported soft fill and rocks,
if required, should be sourced from CEDD’s fill bank, other projects or other
approved sources instead of using new materials. Approval from the Engineer and
all other relevant parties should be obtained by the Contractor before
importation of the fill materials.
7.6.8
The main staging area of the
works should be located at the proposed launching site in Cheung Chau. Storage
of equipment, materials, chemical waste and general refuse as well as the
drilling fluid recycling system should also be located in Cheung Chau.
\On-site Sorting, Reuse and Recycling
7.6.9
All waste materials should be
segregated into categories covering:
· excavated materials suitable for public filling facilities;
· remaining C&D waste for landfill;
· spent bentonite for public filling facilities;
· chemical waste; and
· general refuse for landfill.
7.6.10
Proper segregation and disposal
of construction waste should be implemented. Separate containers should be
provided for inert and non-inert wastes.
7.6.11
The
reuse of excavated materials within this Project should be adopted as far as
practicable. The opportunity of reusing the material in other projects in
Cheung Chau should also be explored.
7.6.12
Sorting is important to recover
materials for reuse and recycling. Specific areas should be allocated for
on-site sorting of C&D materials and to provide a temporary storage area
for those sorted materials such as metals, concrete, timber, plastics, glass,
excavated spoil, bricks / tiles and waste paper. If the area is limited, all
C&D materials should at least be sorted on-site into inert and non-inert
components. Non-inert materials (C&D waste) such as bamboo, timber,
vegetation, packaging waste and other organic materials should be reused and
recycled wherever possible and disposed of to designated landfill only as a
last resort. Inert materials (public fill) such as concrete, rock, clay, brick,
soil, asphalt and the like should be separated and reused in this or other
projects (subject to approval by the relevant parties in accordance with the
ETWB TCW No. 31/2004) before disposed of at public fill reception facilities
operated by Civil Engineering and Development Department (CEDD). Steel and
other metals should be recovered from demolition waste stream and recycled.
7.6.13
The reuse of inert materials
such as soil, rock and broken concrete should be maximised. Waste should be separated into fine, soft and
hard materials. With the use of a
crusher coarse material can be crushed to make it
suitable for use as fill material where fill is required in the works. This minimises the use of imported material
and maximises use of the C&D material produced.
7.6.14
Prior to export of material
from the site, the potential for it to be reused should be assessed. Most C&D material can easily be reused
with minimum processing. Waste
separation methods should be followed to ensure that C&D waste is separated
at source. Suitable soft materials
should be used for landscaping and grading of embankments. Fine material should
be separated out and used as topsoil.
7.6.15
The feasibility of using
recycled aggregates in lieu of virgin materials should be rigorously considered
during the detailed design and construction phases as stipulated in WBTC No.
12/2002 and ETWB TCW No. 24/2004. In general, recycled aggregates are suitable
for use as fill materials in earthworks, road sub-base formation, and drainage
works. Recycled aggregates can also be used in concrete (up to Grade 35) for
mass concrete walls and other minor structures such as planter boxes, toe wall
planters and pavement, etc.
Site Clearance / Demolition Materials
Excavated Materials
7.6.16
All C&D materials should be
sorted on-site into inert and non-inert components by the Contractor. Non inert
materials (C&D waste) such as wood, glass and plastic should be reused and
recycled before disposal to a designated landfill as a last resort (currently
assume to be the WENT Landfill) via the Cheung Chau Refuse Transfer Station.
Inert materials (public fill) should be reused on-site or in other projects approved
by relevant parties in accordance with the ETWB TCW No. 31/2004 before disposed
of at public fill reception facilities. Steel and other metals if any should be
recovered from C&D materials and recycled.
7.6.17
Good quality reusable topsoil should
be stockpiled for later landscaping works. Stockpiles should be less than 2 m
in height, formed to a safe angle of repose and hydroseeded or covered with
tarpaulin to prevent erosion during the rainy season and to minimise dust
generation.
7.6.18
Control measures for temporary
stockpiles on-site should be taken in order to minimize the noise, generation
of dust, pollution of water and visual impact. These measures include:
· surface of stockpiled soil should be regularly wetted with water especially during dry season;
· disturbance of stockpiled soil should be minimized;
· stockpiled soil should be properly covered with tarpaulin especially when heavy rain storms are predicted;
· stockpiling areas should be enclosed where space is available;
· stockpiling location should be away from the water bodies; and
· an independent surface water drainage system equipped with silt traps should be installed at the stockpiling area.
7.6.19
The identification of final
disposal sites for C&D materials generated by the construction works will
be considered during the detailed design stage of the Project when the volume
and types of C&D materials can be more accurately estimated. The Public
Fill Committee of CEDD should be consulted on designated outlets (e.g. public
fill reception facility) for public fill, whilst
7.6.20
In order to avoid dust or odour
impacts, any vehicles leaving a works area carrying C&D waste or public
fill should have their load covered up before leaving the construction site.
7.6.21
C&D materials should be
disposed of at designated public fill reception facilities or landfills. Reuse
of public fill materials at other construction projects is subject to the
approval of the relevant project proponents, Engineer and/or other relevant
authorities, such as LandsD, PlanD, etc. Furthermore, unauthorized disposal of
C&D materials in particular on private agricultural land is prohibited and
may be subject to relevant enforcement and regulating actions. The Contractor
shall refer and strictly follow the trip-ticket system for the disposal of
C&D materials as stipulated in the ETWB TCW No. 31/2004.
Bentonite Slurry
7.6.22
Bentonite slurry used in the drilling
works should be treated and recycled at the works area in Cheung Chau. Any
bentonite that is not suitable for recycling should be suitably dewatered
before disposed of at public fill reception facilities.
Chemical Waste
7.6.23
Where the construction processes
produce chemical waste, the Contractor must register with EPD as a chemical
waste producer. Wastes classified as chemical wastes are listed in the Waste
Disposal (Chemical Waste) (General) Regulation. These wastes are subject to
stringent disposal routes. EPD requires information on the particulars of the
waste generation processes including the types of waste produced, their
location, quantities and generation rates. A nominated contact person must be
registered with EPD. An updated list of licensed chemical waste collector can
be obtained from EPD.
7.6.24
Storage,
handling, transport and disposal of chemical waste should be arranged in
accordance with the Code of Practice on the Packaging, Labelling and Storage of
Chemical Wastes published by EPD, and should be collected by a licensed
chemical waste collector.
7.6.25
Suitable containers should be
used for specific types of chemical wastes, containers should be properly
labelled (English and Chinese in accordance with instructions prescribed in
Schedule 2 of the Regulations), resistance to corrosion, safely stored and
securely closed. Stored volume should not be kept more than 450 liters unless
the specification has been approved by the
7.6.26
Hard standing, impermeable
surfaces draining via oil interceptors should be provided in works area
compounds. Interceptors should be regularly emptied to prevent release of oils
and grease into the surface water drainage system after accidental spillages.
The interceptor should have a bypass to prevent flushing during periods of
heavy rain. Oil and fuel bunkers should be bunded and/or enclosed on three sides
to prevent discharge due to accidental spillages or breaches of tanks. Bunding
should be of sufficient capacity to accommodate 110% of the volume of the
largest container or 20% of the total volume of waste, whichever is largest.
Waste collected from any grease traps should be collected and disposed of by a
licensed contractor.
7.6.27
Lubricants, waste oils and
other chemical wastes are likely to be generated during the maintenance of
vehicles and mechanical equipment. Used lubricants should be collected and stored
in individual containers which are fully labelled in English and Chinese and
stored in a designated secure place. If possible, such waste should be sent to
oil recycling companies, and the empty oil drums collected by appropriate
companies for reuse or refill.
7.6.28
The registered chemical waste
producer (i.e. the contractor) has to arrange for the chemical waste to be
collected by licensed collectors. The licensed collector should regularly take
chemical waste to a licensed chemical waste treatment facility (such as the
Chemical Waste Treatment Centre in Tsing Yi). A trip ticket system operates to
control the movement of chemical wastes.
7.6.29
No lubricants, oils, solvents
or paint products should be allowed to discharge into water courses, either by
direct discharge, or as contaminants carried in surface water runoff from the
construction site.
7.6.30
Chemical waste should be stored
in the works compound at Cheung Chau, no chemical waste should be stored in the
works site at Lantau.
7.6.31
The Contractor should prepare
an Emergency Contingency Plan (spill response plan) for the Project to contain
and remove accidental spillage of drilling fluids, chemicals and all hazardous
materials on-site including fuels at short notice and to prevent or to minimize
the quantities of contaminants from entering the nearby water bodies and
affecting the sensitive habitats. Details of the requirements are presented in Chapter 3.
General Works Waste
Concrete Waste
7.6.32
Dry concrete waste (considered as
public fill) should be sorted out from the other wastes and recycled for reuse
or sorted out for disposal at designated public fill reception facilities.
Wooden Materials
7.6.33
All wooden materials used
on-site should be kept separate from other wastes to avoid damage and to
facilitate reuse. Timber which cannot be reused should be sorted out from other
waste and stored separately from all inert waste before being disposed of to
landfill.
7.6.34
Reusable steel or concrete
panel shutters, fencing and hoarding and signboard should be used as a
preferred alternative to items made of wood, to minimise wastage of wood.
Attention should be paid to WBTC No. 19/2001 – “Metallic Site Hoardings and
Signboards” to reduce the amount of timber used on construction sites. Metallic
alternatives to timber are readily available and should be used rather than new
timber. Precast concrete units should be adopted wherever feasible to minimize
the use of timber formwork.
7.6.35
Only waste material need to be taken
to a landfill. It should be separated from recyclable wood and steel materials.
As for all waste types these materials should be reused on-site or other
approved sites before disposal is considered as an option. Disposal to landfill should only be considered
as a final option. Contractors are
responsible for storage of re-useable materials on-site.
Municipal Waste
7.6.36
General refuse generated
on-site should be stored in enclosed bins or skips and collected separately
from other construction and chemical wastes and disposed of at designated
landfill. A temporary refuse collection point should be set up by the
Contractor at the works area in Cheung Chau to facilitate the collection of
refuse by licensed waste collector. The removal of waste from the site should
be arranged on a daily or at least on every second day by the Contractor to
minimise any potential odour impacts, minimise the presence of pests, vermin
and other scavengers and prevent unsightly accumulation of waste.
7.6.37
For
the works within
7.6.38
The recyclable component of the
municipal waste generated by the workforce, such as aluminium cans, paper and
cleansed plastic containers should be separated from other waste. Provision and
collection of recycling bins for different types of recyclable waste should be
set up by the Contractor and should be located at Cheung Chau. The Contractor
should also be responsible for arranging recycling companies to collect these
materials.
7.6.39
The burning of refuse on-site is
prohibited under the Air Pollution Control Ordinance (APCO) (Cap. 311).
7.6.40
A summary of the estimated
C&D materials and waste and their disposal routes are tabulated in Table
7.3. The preliminary disposal programme breakdown is shown in Table
7.4.
Summary of the Quantities and Disposal Routes of
C&D Materials and Waste Arising from the Project
|
C&D Materials and Waste
Types |
Estimated Quantities
generated* |
Estimated Quantities for
Reuse* |
Estimated Quantities for
Disposal* |
Disposal Routes (see note 5) |
|
Site
Clearance / Demolition Materials -
Inert
fill -
C&D
waste |
140 m3
(see note 1) -
40 m3 -
100 m3 |
Nil (see
note 1) |
140 m3
(see note 1) |
Inert fill Bentonite Chemical
waste C&D
waste |
|
Excavated
Materials -
Inert
fill -
Rocks |
1,330 m3
(see note 2) -
410 m3 -
920 m3 |
410 m3
(see note 2) -
290 m3 -
120 m3 |
920 m3
(see note 2) -
120 m3 -
800 m3 |
|
|
Bentonite |
980 m3 |
Nil |
980 m3 |
|
|
Chemical
Waste |
Minimum
amount (see note 3) |
Minimum
amount (see note 3) |
Minimum
amount (see note 3) |
|
|
General Works
Waste (C&D waste) |
120 m3
(see note 4) |
Nil (see
note 4) |
120 m3
(see note 4) |
Notes:
* The estimated quantities are based on the
preliminary design of the proposed channel works and the best available ground
investigation data. The waste arising will largely depends on the contractor
works programme and activities. The contractor will be required to provide
detailed estimation of all the C&D materials and waste generated on-site
using a Monthly / Yearly Waste Flow Table as required under ETWB TCW No.
19/2005.
1
From clearance of vegetation, demolition of hard paved slab,
road surfaces and temporary structures.
2
Topsoil, rocks and suitable materials will be stockpiled for
later reuse in this or other projects subject to approval by the relevant
parties in accordance with ETWB TCW No. 31/2004. The amount of materials that
can be reuse in this Project will be examined further during the detailed
design and construction phases.
3
The amount of chemical waste will be dependent on the
contractor’s on-site maintenance programme and the number of equipment and
vehicles used on-site. Chemical waste should be collected by licensed
contractor and properly disposed of at approved chemical waste treatment
facilities (e.g. the Chemical Waste Treatment Centre at Tsing Yi).
4
The amount of general works waste will depend on the
contractor’s operating procedures and housekeeping practices as well as the
size of the workforce on-site. All such wastes will be sorted, reused and
recycled before disposal at designated outlets.
5
All suitable materials will be reuse and recycle before
disposal. Reuse of C&D materials at other projects is subject to approval
by the relevant parties in accordance with ETWB TCW No. 31/2004. Final disposal
outlets subject to final agreement with Public Fill Committee of CEDD for
public fill reception facilities and
Preliminary Disposal Programme of the C&D
Materials
|
Reuse / Disposal
Arrangement |
Approximate Quantity of
C&D materials (m3) |
|
2012 |
|
|
Reuse of inert public fill |
50 |
|
Disposal of inert public fill to
public fill reception facilities |
720 |
|
Disposal to landfill |
100 |
|
2013 |
|
|
Reuse of inert public fill |
180 |
|
Disposal of inert public fill to
public fill reception facilities |
200 |
|
Disposal of bentonite to public
fill reception facilities |
980 |
|
Disposal to landfill |
80 |
|
2014 |
|
|
Reuse of inert public fill |
180 |
|
Disposal of inert public fill to
public fill reception facilities |
0 |
|
Disposal to landfill |
40 |
Notes:
The exact programme and quantities
of the disposal works will depend on the Contractor’s programme after the
contracts are awarded.
7.7
Evaluation of Residual Impacts
7.7.1
With the implementation of
proper waste management practices for storage, handling, transportation and
disposal of waste arisings, no residual impacts are expected during the
construction phase of the Project.
7.8.1
Auditing should be carried out
periodically to determine if waste is being managed in accordance with
prescribed waste management procedures and the EMP. The audits should examine
all aspects of waste management including waste generation, storage, recycling,
treatment, transportation, and disposal. The general site inspections including
waste management issues will be undertaken weekly by the Environmental Team to
check all construction activities for compliance with all appropriate
environmental protection and pollution control measures, including those set up
in the EMP. Meanwhile, waste management audit will also be carried out as part of
the monthly audit by the Independent Environmental Checker.
7.9.1
Construction and demolition
materials will inevitably be produced during the construction phase of the
Project. Waste generated during construction works includes site clearance /
demolition materials, excavated materials, used bentonite, chemical waste and
general works waste. Waste types, quantities and timing have been estimated and
mitigation measures have been proposed in terms of the
avoidance-minimisation-reuse-recycling-disposal hierarchy.
7.9.2
Potential for reuse of inert
construction & demolition material (public fill) within the Project (or
within Cheung Chau) will be explored throughout the course of the Project in an
effort to minimise off-site disposal.
7.9.3
Provided that there is strict
control of construction and demolition materials generated from construction
works and that all arisings are stored, handled, transported and disposed of in
accordance with the recommended mitigation measures, potential impact is not
expected. The recommended mitigation measures can be enforced by incorporating
them into the waste management requirements as part of the Environmental
Management Plan. Environmental audit would be necessary to ensure the
implementation of proper waste management practices during construction.