6
CONSTRUCTION WASTE MANAGEMENT AND DISPOSAL
6.1
Introduction
6.1.1 This section identifies the types of wastes
that are likely to be generated during the construction phase of the CWB &
IECL and evaluates the potential environmental impacts that may result from
these waste arisings. Mitigation
measures and good site practice, including waste handling, storage and
disposal, will be recommended with reference to the applicable waste
legislation and guidelines.
6.2
Environmental Legislation, Policies, Plans, Standards and Criteria
6.2.1 The criteria and guidelines for
assessing waste management implications are outlined in the Annex 7 and Annex
15 of the Technical Memorandum on Environmental Impact Assessment Ordinance
(EIAO-TM), respectively.
6.2.2 The following legislation relates to
the handling, treatment and disposal of wastes in the Hong Kong SAR and will be
used in assessing potential impacts:
·
Waste
Disposal Ordinance (Cap. 354);
·
Waste
Disposal (Chemical Waste) (General) Regulation (Cap. 354);
·
Land
(Miscellaneous Provisions) Ordinance (Cap. 28);
·
Dumping
at Sea Ordinance (Cap. 466); and
·
Public
Health and Municipal Services Ordinance (Cap. 132) - Public Cleansing and
Prevention of Nuisances (Urban Council) and (Regional Council) By-laws.
6.2.3 The following documents, circulars
and guidelines which relate to waste management and disposal in Hong Kong SAR
will also be referred to during this study:
·
Waste
Disposal Plan for
·
Environmental
Guidelines for Planning in
·
New
Disposal Arrangements for Construction Waste (1992), Environmental Protection
Department and Civil Engineering Department;
·
Code
of Practice on the Packaging, Labelling and Storage of Chemical Wastes (1992),
Environmental Protection Department;
·
Waste
Reduction Framework Plan, 1998-2007 (1998), Planning, Environment and Lands
Branch,
·
Works
Branch Technical Circular No. 2/93, Public Dumps;
·
Works
Bureau Technical Circular No. 2/93B, Public Filling Facilities;
·
Works
Branch Technical Circular No. 16/96, Wet Soil in Public Dumps;
·
Works
Bureau Technical Circular No. 4/98 & 4/98A, Use of Public Fill in Reclamation
and Earth Filling Projects;
·
Works
Bureau Technical Circular No. 5/98, On Site Sorting of Construction Waste on
Demolition Sites;
·
Works
Bureau Technical Circular No. 5/99 & 5/99A, Trip-ticket System for Disposal
of Construction and Demolition Material;
·
Works
Bureau Technical Circular No. 19/99, Metallic Site Hoardings and Signboards;
·
Works
Bureau Technical Circular No. 25/99, 25/99A & 25/99B, Incorporation of
Information on Construction and Demolition Material Management in Public Works
Sub-committee Papers;
·
Works
Bureau Technical Circular No. 3/2000, Management of Dredged / Excavated
Sediment;
·
Works
Bureau Technical Circular No. 12/2000, Fill Management; and.
·
Works
Bureau Technical Circular No. 29/2000, Waste Management Plan.
Waste Management
6.2.4
The
Waste Disposal Ordinance (WDO) prohibits the unauthorised disposal of
wastes. Construction waste is not
directly defined in the WDO but is considered to fall within the category of
“trade waste”. Trade waste is defined
as waste from any trade, manufacturer or business, or any waste building, or
civil engineering materials, but does not include animal waste. Under the WDO, wastes can be disposed of at
sites licensed by the EPD.
6.2.5
The Public
Cleansing and Prevention of Nuisance By-Laws provides control on illegal
tipping of wastes on unauthorised (unlicensed) sites.
Chemical Waste
6.2.6
Under
the Waste Disposal (Chemical Waste) (General) Regulations all producers of
chemical waste must register with the EPD and treat their wastes, either
utilising on-site plant licensed by the EPD, or arranging for a licensed
collector to transport the wastes to a licensed facility. The regulation also prescribes the storage
facilities to be provided on site, including labelling and warning signs, and
requires the preparation of written procedures and training to deal with
emergencies such as spillages, leakages or accidents arising from the storage
of chemical wastes.
Construction and Demolition (C&D) Materials
6.2.7
The
current policy related to the dumping of construction and demolition (C&D)
material is documented in the Works Branch Technical Circular No. 2/93, ‘Public
Dump’. Construction and demolition materials that are wholly inert, namely
public fill, should not be disposed of to landfill, but taken to public filling
areas which usually form part of reclamation schemes. The Land (Miscellaneous Provisions) Ordinance requires that
dumping licences are obtained by individual or companies who deliver public
fill to public filling areas. The
licences are issued by the Civil Engineering Department (CED) under delegated
powers from the Director of Lands.
6.2.8
In
addition to the Works Branch Technical Circular, EPD and CED have produced a
leaflet titled ‘New Disposal Arrangements for Construction Waste’ (1992) which
states that C&D material with less than 30% by weight of inert material
(that is, public fill) will be accepted at landfill. If the material contains more than 30% inert material, the waste
must be sorted with suitable material and sent to public filling area and the
non-inert material (that is, C&D waste) sent to landfill for final
disposal.
6.3.1
The
criteria for evaluating the potential construction waste management
implications are set out in Annex 7 of the EIAO-TM. The methods for assessing potential waste management impacts
during construction follow those presented in Annex 15 of the EIAO-TM and
include the following:
·
estimation
of the types and quantities of the wastes generated, and timing of these waste
arisings;
·
assessment
of potential impacts from the management of solid waste with respect to
potential hazards, air and odour emissions, noise, wastewater discharges and
transport;
·
measures for reducing waste generation;
·
possibility of on-site and off-site reuse;
·
adequate area on-site for waste segregation and storage;
·
quantities of wastes to be disposed of off-site;
·
possible disposal options; and
·
impacts
on the capacity of waste collection, transfer and disposal facilities.
6.4
Identification of Environmental Impacts
6.4.1 Activities during the construction
phase of the CWB & IECL will result in the generation of a variety of
wastes that can be divided into distinct categories based on their nature and
the options for their disposal. These
include:
·
construction
and demolition material (including excavated material);
·
excavated
sediment;
·
chemical
waste; and
·
general
refuse.
6.4.2 The definitions for each of these
categories and the nature of their arisings and potential impacts are discussed
below.
6.5
Prediction and Evaluation of Environmental Impacts
Construction
and Demolition (C&D) Material
6.5.1 Excavated material will comprise
primarily public fill and marine sand that has been used as reclamation fill in
the CRIII and WDII. From the Central
Reclamation Phase I (CRI) area, excavated material will be mainly marine sand.
The estimates on the volume of excavated material to be generated from tunnel
works, road formation and foundation earthworks are summarised in Table 6.1.
Table 6.1 Excavated Material from works managed by Highways Department
|
Location |
Volume of Excavated Material (m3) |
Excavated Material to be Reused (m3) |
Excavated Material to be Disposed Off-site (m3) |
Programme |
|
Central Interchange Tunnel Works: ·
Eastbound Tunnel ·
Westbound Tunnel ·
Tunnel modification Road Formation |
43,400 43,400 15,470 19,800 |
4,900 4,900 760 1,900 |
38,500 38,500 14,710 17,900 |
Dec 2005 – Jul
2006 Jul 2006 – Apr
2007 Feb 2007 – Feb
2008 Mar 2007 – Aug 2008 |
|
Sub-total |
122,070 |
12,460 |
109,610 |
|
|
IECL ·
East Portal Area ·
IECL Foundation Earthworks |
54,000 79,100 |
5,170 17,000 |
48,830 62,100 |
May 2008 – Aug
2010 May 2008 – Aug
2010 |
|
Sub-total |
133,100 |
22,170 |
110,930 |
|
|
|
1,000 |
150 |
850 |
Jun 2009 – Oct
2010 |
|
|
1,030 |
150 |
880 |
Jun 2009 – Oct
2010 |
|
East Ventilation and |
2,000 |
200 |
1800 |
Jun 2009 – Oct
2010 |
|
Total |
259,200 |
35,130 |
224,070 |
|
6.5.1
The
estimated total quantity of excavated material from the Central Interchange,
IECL and tunnel buildings is 259,200m3 and out of which 35,130m3
will be reused on-site and 224,070m3 will be required to be disposed
off-site. As the construction works for the CWB & IECL project mainly
comprise highway structural works for the trunk road tunnel and bridges and at grade slip roads the capacity
to receive excavated material on site is limited and only about 14% can be
reused as the backfill material for the foundation, tunnel, road formation and
landscaping works.
6.5.2
It
should be noted that according to current planning the WDII reclamation works
will still be in progress at the time the surplus material from Central
Interchange will need to be disposed off-site. As such, it may be possible that
the surplus material from the Central Interchange identified to be disposed
off-site could be used as fill material in WDII, depending on the programme of
works that will actually take place at that time. Given the likely inert nature of this material, reuse on-site or
in other reclamation works is not likely to have any unacceptable environmental
impact. Potential impacts associated
with the excavated material are related to air quality and dust generation
during excavation, stockpiling and transportation, which have been discussed in
Section 3.
Excavated
Material from Works entrusted to Territory Development Department
6.5.3 The section of tunnel box structure
through CRIII and WDII areas
will be constructed under entrustment to Territory Development Department in
these two respective projects. The estimated quantities of excavated material
are given in Table 6.2.
Table 6.2 Excavated Material from Work Entrusted to Territory Development
Department
|
Location |
Volume of Excavated
Material (m3) |
Volume of Excavated
Material to be Disposed Off-site (m3) |
|
|
Central Reclamation Phase III |
|
|
|
|
Excavated
reclamation fill material from tunnel box construction |
439,000 (1) |
50,000 (1) |
|
|
Wan Chai Development Phase II |
|
|
|
|
Excavated
reclamation fill material from tunnel box construction |
500,000(2) |
170,000(2) |
|
|
Excavated ground
fill material from tunnel construction |
70,000(2) |
|
|
Sources:
(1) Atkins China Ltd.
(May 2001). Central Reclamation Phase
III Comprehensive Feasibility Study for Minimum Option, Draft Final EIA Report
Revision 03.
(2) Maunsell Consultants Asia Ltd.
(May 2001). Wan Chai Development Phase
II Comprehensive Feasibility Study, EIA Report, Advance Final Version Revision
B.
6.5.4 With reference to the CRIII EIA Report, the volume of excavated material from the entrusted tunnel works is about 439,000m3 and out of which 50,000m3 will be required to be disposed off-site. Most of the excavated material will be reused within the CRIII reclamation. However, the 50,000m3 excavated material from the last portion of the tunnel works will need to be disposed off-site because most of the reclamation works within the CRIII areas will have been completed by that time. It should be noted that according to the current planning the WDII reclamation works will still be in progress at the time the surplus excavated material from the CRIII project will need to be disposed off site. As such, it may be possible that the surplus excavated material from the CRIII project identified to be disposed off site could be used as fill material in WDII, depending on the programme of works that will actually take place at that time.
6.5.1 The quantity of excavated material requiring off-site disposal arising from the CWB entrusted tunnel works within the WDII area is about 170,000m3 as indicated in the WDII EIA Report. This quantity was estimated with a view to maximizing the reuse of excavated material as reclamation fill for the WDII project.
6.5.2 The excavated material requiring off-site disposal will be generated from the tunnel sections at reclamation near Wan Chai waterfront, according to various programme constraints arising from the reprovisioning requirements of existing waterfront facilities. Upon completion of land formation, diaphragm wall construction will commence and be followed by excavation for tunnel construction.
6.5.3 According to the construction programme for the WDII project, all the reclamation filling will have been completed when the excavation for the last tunnel sections commences. Therefore, the quantity of excavated material after deducting those for backfilling for the proposed ground level roads will need to be disposed off-site.
C&D
Material from
6.5.4
Construction
and demolition (C&D) material will be generated from new building
construction and will comprise unwanted material generated during construction. C&D material may include:
·
wood
from formwork;
·
material
and equipment wrappings;
·
unusable
cement / grouting mixes; and
·
damaged
or contaminated construction material.
6.5.5 The total quantity of C&D
material generated during the construction phase will be dependent on the
construction methods and site practices adopted, and hence it is difficult to
quantify at this stage. The amount of
C&D material expected to be generated will be quantified in the Waste
Management Plan to be prepared by the Contractor. An estimate of the C&D material likely to be generated from
new building construction has been made based on the gross floor area (GFA) of
the buildings to be constructed (Table 6.3).
The proposed ventilation buildings will be small structures and the volume
of C&D material to be generated is likely to be small.
Table 6.3 Estimated Quantities of
C&D Material from New Building Construction
|
|
GFA (m2) |
C&D Material (m3) |
C&D Material for
Off-site Disposal * |
|
|
Public Fill (m3) |
C&D Waste (m3) |
|||
|
|
3133 |
313 |
251 |
63 |
|
|
2272 |
227 |
182 |
45 |
|
East Ventilation
and |
9815 |
982 |
785 |
196 |
|
Total |
15220 |
1522 |
1218 |
304 |
Note: * Forecast ratio for C&D waste : public
fill is 2 : 8 (Source : Monitoring of Solid Waste in Hong Kong 1997).
6.5.6
The
quantity of C&D material to be produced from the construction of the tunnel
buildings has been estimated based on a C&D material generation rate of 0.1
m3 per 1 m2 of GFA constructed ([1]). A breakdown of the estimated quantities of
public fill and C&D waste is also given in Table 6.3. The C&D material generated from the
construction of the tunnel buildings will require off-site disposal.
6.5.7 Demolition waste will arise from the
site clearance of the existing Island Eastern Corridor, the Rumsey Street
Flyover downramp and the Hing Fat Street Flyover. The volume of waste is not expected to be significant and will comprise
primarily concrete. The demolition
wastes will be taken either to landfill or, where inert and free from
contamination, be reused within the project as far as possible. The breakdown of the estimated quantities of
demolition material is given in Table 6.4.
It is assumed that approximately 95% of the C&D material will be
public fill and the other will be C&D waste.
Table 6.4 Estimated Quantities
of Demolition Material
|
Location |
Quantity
(m3) |
Estimated
breakdown (m3) |
||
|
Public
Fill |
C&D
Waste for Off-site Disposal |
|||
|
Off-site
Disposal |
Reuse
On-site |
|||
|
Existing |
17,500 |
15,794 |
831 |
875 |
|
Existing |
3,500 |
3,159 |
166 |
175 |
|
|
5,700 |
5,144 |
271 |
285 |
|
Total |
26,700 |
24,097 |
1,268 |
1,335 |
Note: The above
quantities include superstructures, substructures (exclude piles) and filling
materials for abutments.
6.5.8 C&D material should be sorted on-site into public fill (that is, the inert portion), which should be reused on-site wherever possible, and C&D waste (that is, the non-inert portion) which may need to be disposed of to landfill. As the majority of demolition material will comprise concrete, however, it is anticipated that this public fill material may not be possible for reuse on-site and will require off-site disposal to public filling areas. The tunnel excavation works undertaken prior to the demolition works will provide large amounts of C&D material which can be reused on-site and thus the surplus demolition material will require off-site disposal due to the limited capacity of the CWB & IECL project to receive material during the late stage of construction works. It is estimated that around 5% of the public fill will be suitable for reuse on-site; a volume of approximately 1,268 m3, and should be broken down to 250 mm in size. The surplus public fill with an estimated volume of approximately 24,097 m3 will require off-site disposal.
6.5.9
If
surplus public fill is to be transported off-site for disposal in public
filling areas, the project initiating office should contact the Secretariat of
the Public Fill Committee (Chief Engineer / Port Works, CED) at the detailed
design stage to check the availability of such sites.
6.5.10
If
construction wastes are generated in large quantities they may hinder building
operations and present a safety hazard if not removed, in addition to causing
potential water quality impacts, as discussed in Section 5. The storage and disposal of C&D
materials have the potential to create similar visual, dust and associated
traffic impacts as the storage and disposal of excavated material.
6.5.11 A summary of the estimated quantity of the C&D material requiring disposal off-site for the whole CWB & IECL project is shown in Table 6.5.
Table
6.5 Summary of the C&D Material requiring disposal off-site
arising from the CWB & IECL Project
|
Location |
Construction
and Demolition Material Requiring
Disposal Off-site |
Total |
|
|
Type of Fill (m3) |
|||
|
Public Fill |
Sand Fill |
||
|
Excavated Material from works entrusted to TDD’s CRIII Project |
- |
50,000 |
50,000 |
|
Excavated Material from works entrusted to TDD’s
WDII Project |
55,000 |
115,000 |
170,000 |
|
Excavated Material from
works for Central
Interchange IECL Tunnel
Buildings |
16,330 110,930 3,530 |
93,280 - - |
109,610 110,930 3,530 |
|
Sub-total |
130,790 |
93,280 |
224,070 |
|
C&D Material from Demolition
of Existing Structures |
1,218 24,097 |
- - |
1,218 24,097 |
|
Sub total |
25,315 |
- |
25,315 |
|
Total |
211,105 |
258,280 |
469,385 |
Notes:
1. The quantities and types of excavated
material are estimated and based on the current reclamation fill proposals and
construction programmes of CRIII, WDII and CWB & IECL Projects. The actual quantities and types may vary
subject to the implementation programmes adopted by contractors during
construction.
2. Part of public fill material from WDII
will be excavated from the existing Wanchai Public Cargo Working Area.
3. Public fill material from the Central
Interchange will be excavated from the area between the existing ground level
(approx. +5.0mPD) to a level of
+2.6mPD based on the as built drawing of CRI project.
4. The reuse of surplus material from the
Central Interchange and CRIII will be maximised in the WDII Reclamation,
however the quantities of these transferred materials should depend on the
detailed programme of works that will actually be taken place during
construction period.
Excavated Sediment
6.5.12
The construction
of the pier foundations for the elevated section of CWB & IECL over the
western side of the Causeway Bay Typhoon Shelter will generate excavated marine
sediment requiring off-site disposal.
Under the reclamation for Wan Chai Development Phase II sediment will be
left in situ at the western corner of
the Causeway Bay Typhoon Shelter and thus the piling works for the pier
foundations will encounter marine sediment.
The estimated volume of excavated sediment is 730 m3. The Phase II marine site investigation works
for the Wan Chai Development Phase II Comprehensive Feasibility Study included
sediment sampling within the western side of the typhoon shelter. An indication of sediment quality may be
made from the sediment testing results for vibrocore MV10 which show that the
sediment is classified as Category H (one or more contaminant levels above the
Upper Chemical Exceedance Level) in accordance with WBTC No. 3/2000. The excavated sediment will therefore require
confined marine disposal. Requirements
for the transportation and disposal of the excavated sediment are given in
Section 6.6.
Chemical
Waste
6.5.13 Chemical waste as defined under the
Waste Disposal (Chemical Waste) (General) Regulation includes any substance being
scrap material, or unwanted substances specified under Schedule 1 of the
Regulations. A complete list of such
substances is provided under the Regulations.
Chemical wastes likely to be generated during the construction will for
the most part arise from the maintenance of plant and equipment. These may include, but need not be limited
to the following:
·
spent
filter cartridges containing heavy metals;
·
scrap
batteries or spent acid / alkali from their maintenance;
·
brake
clutch linings containing asbestos materials;
·
used
hydraulic and lubricating oil;
·
spent
mineral oils / cleaning fluids from mechanical machinery; and
·
spent
solvents / solutions, which may be halogenated, from equipment cleaning
activities.
6.5.14 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 Regulations. These hazards include:
·
toxic
effects to workers;
·
adverse
impacts on water quality from spills and associated adverse impacts on water
sensitive receivers; and
·
fire
hazards.
6.5.15 If chemical wastes do arise during
the construction, they should be stored, transported and disposed of in
accordance with the guidelines detailed in Section 6.6.
General Refuse
6.5.16 The construction works will result
in the generation of a variety of general refuse requiring disposal. These
wastes may include food wastes and packaging, waste paper, and newspapers and
will generally be disposed of to landfill.
Release of general refuse into marine waters should not be permitted as
introduction of these wastes is likely to have detrimental effects on water
sensitive receivers in the area.
6.5.17 The storage of general refuse has
the potential to give rise to a variety of adverse environmental impacts. These include odour if waste is not
collected frequently, windblown litter, water quality impacts if waste enters
water bodies, and visual impact. The
site may also attract pests and vermin if the waste storage area is not well
maintained and cleaned regularly. In
addition, disposal of wastes, at sites other than approved landfills, can also
lead to similar adverse impacts at those sites.
6.6
Recycling, Treatment, Storage and Disposal Options
6.6.1
This
section discusses the options for waste management and highlights the
methodologies available for waste minimisation.
Construction
and Demolition Material
6.6.2
Given
the likely inert nature of the excavated material, this material should be
reused on‑site wherever possible for the CWB and IECL construction
works. However, although the subsequent
construction works may take up part of the excavated material from CWB tunnel
works during early stage of construction, the remaining surplus excavated
material from site clearance of Island Eastern Corridor and demolition the Hing
Fat Street Flyover and Rumsey Street Flyover downramp during the late stage of
construction is unlikely to be reused on-site.
The surplus good quality excavated material may be used for other
reclamation or development projects that have a material deficit. The excavated material from reclaimed areas
may require dewatering prior to disposal.
To enable excavated material to be used for reclamation purposes, it
must be kept separate from other waste material such as wood.
6.6.3
The
surplus material could be used at other development sites available for
receiving fill materials. The Marine
Fill Committee (MFC) manages a “Fill Management Database” containing fill and
surplus data for reclamation and earth-moving projects in Hong Kong. The database is aimed to facilitate the use
of surplus materials and to allow contacts amongst project offices for possible
arrangement of delivery of materials.
The availability of the development sites for receiving fill materials
is, however, determined by the officer responsible for the project.
6.6.4
A
number of measures can be introduced during the construction period relating to
a high standard of design and management that will minimise the generation of
C&D material.
6.6.5
The
design could maximise the use of standard wooden panels in formwork so that the
maximum reuse of panels can be achieved.
The need to cut panels could also be minimised. Alternatives such as the use of steel
formwork or plastic facing could be considered to increase the potential for
reuse. It is important that wood wastes
are stored separately from other C&D wastes to minimise any contamination
that would render the wastes unsuitable for disposal at public filling area.
6.6.6
Careful
planning and good site management could be employed to minimise the over
ordering or mixing of concrete, mortars and cement grouts. In addition, proper storage and site
practices will minimise the damage or contamination of construction materials. Used bentonite slurries should be reused
on-site as far as possible. The
amount of residual used bentonite slurry requiring disposal is estimated to be
about 133,749 m3 (from the
Central Interchange: 9,703m3, from the entrusted tunnel works in
CRIII area: 48,327m3 and
from the entrusted tunnel works in WDII area:
75,720 m3). The residual bentonite slurry should
be mixed with dry excavated material for disposal at the designated public
filling facilities. In accordance with
WBTC No. 16/96, this ‘wet soil’ should be free from marine mud, household
refuse, plastic, metal, industrial and chemical waste, animal and vegetable
matter etc. As a last resort, the
residual bentonite slurry may be disposed of at a marine dumping ground subject
to obtaining a marine dumping licence from EPD on a case-by-case basis.
6.6.7
It
would be advantageous for the Contractor to recycle as much as possible of the
construction waste on‑site in order to reduce the requirement to import
additional materials. Recycling would also reduce the collection,
transportation and disposal of construction waste and any associated charges by
the waste haulier.
6.6.8
On-site
measures may be implemented that promote the proper disposal of wastes once off
site. For example, having separate
skips for inert (rubble, sand, stone, etc) and non‑inert (wood, organics,
etc.) wastes would help ensure that the former are taken to public filling
areas, while the latter are properly disposed of at controlled landfills.
6.6.9
In
order to minimise the impacts of the demolition works, these wastes must be
cleared as quickly as possible after demolition. The demolition and clearance works should therefore be undertaken
simultaneously.
6.6.10 A trip-ticket system should be
implemented in contracts for the proper disposal of C&D material at public
filling facilities or landfills.
Excavated Sediment
6.6.11
In
order to determine the disposal requirements of the excavated sediments,
sediment sampling and testing are required to be carried out at the design
phase of the Project. The basic requirements
and procedures for sediment disposal are specified under the WBTC No.
3/2000. The excavated sediments will be
loaded onto barges and transported to designated disposal sites depending on
their level of contaminants. As
discussed in Section 6.5.17, the marine sediment to be excavated is likely to
be classified as Category H (but biological test not required). In accordance with WBTC No. 3/2000, the
contaminated sediment must be effectively isolated from the environment upon
final disposal and shall be disposed of at the East Sha Chau Contaminated Mud
Pits that is designated for the disposal of contaminated mud in Hong Kong.
Chemical Wastes
6.6.12
Chemical
wastes will arise principally as a result of maintenance activities. It is difficult to quantify the amount of
chemical waste that will arise from the construction activities since it will
be highly dependant on the Contractor's on‑site maintenance requirements
and the number of plant and vehicles utilised.
6.6.13
If
chemical wastes do arise from the construction works then appropriate methods
should be employed for their storage, collection and disposal. The Contractor should contact an approved
operator to collect the wastes for disposal at the Chemical Waste Treatment
Facility, or other licensed facility.
6.6.14
The
Chemical Waste Regulations governing the storage and disposal of chemical
wastes must be followed, in order to ensure that there are no unacceptable
impacts. The volumes of chemical waste
should be kept to a minimum by separation of waste streams and good management
that reduce the potential for contamination.
6.6.15
Containers
used for the storage of chemical wastes should be suitable for the substance
they are holding, resistant to corrosion and maintained in a good condition. The containers should be stored safely and
securely closed.
6.6.16
Chemical
wastes should not be stored in any container with a capacity exceeding 450
litres unless the specifications have been approved by the EPD. Every container of chemical waste should
display a label in English and Chinese in accordance with instructions
prescribed in Schedule 2 of the Regulations.
6.6.17
The
storage area for any containers should not be used for any purpose except for
the storage of chemical wastes and should be fully labelled in accordance with
the Regulations. Chemicals that are
incompatible and could cause fire or explosion if they are mixed should be
segregated in separate areas. The
storage area should be enclosed on at least three sides by a wall, partition or
fence that is at least 2 m in height or the height of the tallest container,
whichever is greater. Adequate ventilation and space for the handling of
containers should be provided, with the area being kept clean and dry.
6.6.18
Liquid
chemical wastes should be stored in an area which has an impermeable floor and
retention structure with the capacity to accommodate 110% of the volume of the
largest container or 20% by volume of the chemical waste stored in that area,
whichever is the greatest. When calculating the available retaining capacity,
the volume occupied by the containers being stored should be taken into
consideration. Bunded areas should be
kept clean and dry, possibly by covering.
If water does collect within the bund, it must be tested before being
disposed. This requirement does not
apply to large, approved below ground containers.
General Refuse
6.6.19
General
refuse generated on‑site should be stored and collected separately from
other construction and chemical wastes.
The Contractor may arrange for the collection and disposal of the refuse
by a reputable waste haulier. 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.
6.6.1
General
refuse should be stored in enclosed bins or compaction units. Recyclable refuse such as paper, cans and
plastic bottles should be separately collected for recycling. Compaction units assist in reducing the
volumes of waste to be transported for disposal. However, the relatively small volumes of wastes generated during
the construction may be insufficient to justify the use of compaction units. Provided appropriate handling, storage, and
disposal procedures and facilities are employed during the construction stage,
no unacceptable impacts resulting from waste generation are anticipated to
occur.
6.7
Mitigation of Adverse Environmental Impacts
6.7.1
The
potential environmental impacts associated with waste arisings from the
construction of the CWB & IECL and the recommended handling, transportation
and disposal options have been discussed in detail in Section 6.6. This section outlines appropriate mitigation
measures to minimise any impact from these construction waste arisings. These measures should be incorporated into
the contract specifications.
Segregation of Wastes
6.7.2
In
order to ensure that all waste is disposed of in an appropriate manner, waste
shall be separated by category on‑site by the Contractor. It is recommended that the waste could be
segregated into the following defined categories and shall then be disposed of
as follows:
·
inert portion of C&D material, that is,
public fill, deemed
suitable for reclamation or land formation shall be re-used on site as far as
possible and the surplus material disposed of at reclamation or public filling
areas;
·
non-inert portion of C&D material, that is,
C&D waste,
deemed unsuitable for reclamation or land formation shall be disposed of at
landfill;
·
chemical waste as defined by Schedule 1 of the Waste
Regulations (Chemical) 1992, shall be
stored in accordance with approved methods defined in the Regulations and the
chemical waste disposed of at the Chemical Waste Treatment Centre located at
Tsing Yi;
·
excavated sediment shall be disposed at the East Sha Chau
contaminated mud pits in accordance with WBTC No. 3/2000; and
·
general refuse shall be disposed of at landfill.
Waste Minimisation
6.7.3
C&D
materials should be recycled or reused wherever possible. The demolition
material arising from the site clearance of existing Island Eastern Corridor,
the Rumsey Street Flyover downramp and Hing Fat Street Flyover should be broken
down to 250 mm in size in order to facilitate reuse and recycling. Steel reinforcement should be removed from
the demolition material prior to disposal and reused or recycled. The waste management strategy to be employed shall be waste
minimisation at source. Where waste
generation is unavoidable then the potential for recycling or reuse shall be
explored and opportunities taken. If
wastes cannot be recycled, then the recommended disposal routes shall be
followed.
6.7.4
Waste
reduction measures shall be introduced at the design stage and carried through
the construction activities, wherever possible, by careful purchasing control,
reuse of formwork and good site management.
6.7.5
Training
and instruction of construction staff shall be given at the site to increase
awareness and draw attention to waste management issues and the need to
minimise waste generation. The training
requirements shall be included in the site Waste Management Plan.
Storage, Collection and Transport of Waste
6.7.6
Reputable
waste hauliers shall be used to collect and transport the wastes to the
appropriate disposal points. The necessary
measures to minimise adverse impacts, such as windblown litter and dust from
the transportation of these wastes, and impacts on water quality during the
storage, handling and transportation of these wastes, shall also be instigated.
6.7.7
It is
recommended that:
·
wastes
shall be handled and stored in a manner which ensures that they are held
securely without loss or leakage thereby minimising the potential for
pollution. Release of these potential
pollutants into marine waters during storage and handling shall not be
permitted as introduction of polluted waters is likely to have detrimental
effects on water quality and water sensitive receivers;
·
only
reputable waste hauliers authorised to collect the specific category of waste
concerned should be employed;
·
removal
of demolition material shall coincide with the demolition work;
·
prior
to disposal of C&D waste, it is recommended that wood, steel and other
metals shall be separated for re-use and / or recycling to minimise the
quantity of waste to be disposed of to landfill;
·
appropriate
measures shall be employed to minimise windblown litter and dust during
transportation by either covering trucks or transporting wastes in enclosed
containers;
·
the
necessary waste disposal permits shall be obtained from the appropriate
authorities, if they are required, in accordance with the Waste Disposal
Ordinance (Cap. 354), Waste Disposal (Chemical Waste) (General) Regulation
(Cap. 354) and the Land Ordinance;
·
collection
of general refuse shall be carried out frequently, preferably daily;
·
waste
shall only be disposed of at licensed sites and the site staff and Contractor
shall develop procedures to ensure that illegal disposal of wastes does not
occur;
·
waste
storage areas shall be well maintained and cleaned regularly;
·
a
recording system for the amount of wastes generated, recycled and disposed of
off-site during the implementation of the project; and
·
in
order to monitor the disposal of public fill and C&D waste at public
filling areas and landfills, and to control fly-tipping, a trip-ticket system
shall be included as one of the contractual requirements and implemented by the
Environmental Team. An Independent
Checker (Environment) should be responsible for auditing the results of the system.
6.7.1
It
will be the responsibility of the Contractor to satisfy the appropriate
authorities that the contamination levels of the marine sediment to be
excavated have been analysed and recorded.
According to the WBTC No. 3/2000, this will involve the submission of a
formal Sediment Quality Report to the DEP, at least 3 months prior to the
construction contract being tendered.
6.7.2
During
transportation and disposal of the excavated marine sediments, the following
measures should be taken to minimise potential impacts on water quality.
·
Bottom
opening of barges shall be fitted with tight fitting seals to prevent leakage
of material. Excess material shall be
cleaned from the decks and exposed fittings of barges and hopper dredgers
before the vessel is moved.
·
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.
6.8
Evaluation of Residual Impacts
6.8.1
With the
implementation of the recommended mitigation measures for the handling,
transportation and disposal of the identified waste arisings, minimal residual
impacts are anticipated during the construction of the CWB & IECL.
6.9
Environmental Audit
6.9.1
It is
recommended that the waste arisings generated during the construction
activities be audited periodically to determine if wastes are being managed in
accordance with approved procedures and the site Waste Management Plan. The Waste Management Plan prepared by the
Contractor has to be submitted to the Engineer for approval on the advice of
the EPD. The audits should look at all
aspects of waste management including waste generation, storage, recycling,
transport and disposal. An appropriate
audit programme would be to undertake a first audit near the commencement of
the construction works, and then to audit quarterly thereafter.
6.10
Conclusion
6.10.1
Provided
that waste arisings from the construction of the CWB & IECL are handled,
transported and disposed of using approved methods as described above, and that
no solid or liquid wastes enter nearby marine waters, no unacceptable
environmental impacts are envisioned.
In most cases, the inert C&D material can be reused within the
project or at reclamation or public filling areas, whilst the non-inert C&D
material will be disposed of to landfill.
6.10.2
The
mitigation measures recommended in this section should be incorporated into
contract specifications to ensure that environmental nuisance does not arise
from the storage, transport and disposal of various types of waste arisings
from the construction of the CWB & IECL.
These recommendations should form the basis of the site Waste Management
Plan to be developed by the Contractor at the detailed design stage.
([1])
Reduction of Construction Waste, Final
Report (March 1993). Hong Kong
Polytechnic University.