7.1.1
This Section
identifies the potential waste arising from the construction and operation of
the Project and assesses the potential environmental impacts associated with
waste handling and disposal. The main
issues include the following:
·
Handling and disposal of construction and demolition
(C&D) materials
arising from nullah modification, excavation and construction works;
and
·
Management of chemical waste, general refuse and
floating refuse.
7.1.2
Waste avoidance, minimisation,
reuse and recycling, storage, collection, transport and disposal schemes have
been examined and appropriate measures for waste reduction and management have
been proposed.
7.1.3
This Section
also identifies and assesses any potential land contamination issues arising
from the Project and to propose remediation measures if necessary.
7.2.1
The following discussion on legislative
requirements and evaluation criteria applies to both the construction and
operation phases of the Project. The
criteria and guidelines for evaluating potential waste management implications
are laid out in Annexes 7 and 15 of the EIAO-TM under the EIAO (Cap
499). The following legislation
covers, or has some bearing upon the handling, treatment and disposal of the
wastes generated from the construction and operation of the Project.
·
Waste
Disposal Ordinance (Cap.354);
·
Waste
Disposal (Chemical Waste) (General) Regulation (Cap 354C);
·
Land
(Miscellaneous Provisions) Ordinance (Cap.28); and
·
Public
Health and Municipal Services Ordinance (Cap.132) – Public Cleansing and
Prevention of Nuisances Regulation.
Waste Disposal Ordinance (Cap 354)
7.2.2
The Waste
Disposal Ordinance (WDO)
prohibits the unauthorised disposal of wastes, with
waste defined as any substance or article, which is abandoned. 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,
wasted building, civil engineering materials, but does not include animal
waste.
7.2.3
Under the WDO,
wastes can only be disposed of at a licensed site. The WDO
provides for the issuing of licences for the
collection and transport of general wastes.
Licences are, however, not currently issued
for the collection and transport of construction waste or trade waste. For general waste there is no charge and this will need to be disposed of in a licensed
facility.
7.2.4
The Waste
Disposal (Charges for Disposal of Construction Waste) Regulation defined
construction waste as any substance, matters or things that is generated from
construction work and abandoned, whether or not it has
been processed or stockpiled before being abandoned. It does not include any sludge, screening or
matter removed in or generated from any desludging, desilting or dredging
works.
7.2.5
The Construction
Waste Disposal Charging Scheme entered into
operation on 1 December 2005. Starting
from 1 December 2005, the main contractor who undertakes construction work
under a contract with value of HK$1 million or above is required to open a
billing account solely for the contract for waste disposal. Application shall be made within 21 days
after the contract is awarded.
7.2.6
Depending on the percentage of inert materials
in the construction waste, inert construction waste can be disposed of at
public fill reception facilities.
However, mixed construction waste can be disposed of at construction
waste sorting facilities, landfills and Outlying Islands Transfer Facilities
which have different disposal costs. The
scheme encourages reducing, reusing and sorting of construction waste such that
the waste producer can reduce their disposal fee. Table 7.1 summarises the government construction waste disposal
facilities, types of waste accepted and disposal cost.
Table 7.1 Government
Facilities for Disposal of C&D Materials
|
Government
Waste Disposal Facilities
|
Type
of Construction Waste Accepted
|
Charge
(HK$/Tonne)
|
|
Public fill reception facilities
|
Consisting entirely of
inert construction waste++
|
$71
|
|
Sorting facilities
|
Containing more than 50% by weight of
inert construction waste++
|
$175
|
|
Landfills@
|
Containing not more than 50% by weight
of inert construction waste++
|
$200
|
|
Transfer Facilities@
|
Containing any percentage of
inert construction waste++
|
$200
|
|
# Except for the Outlying Islands
Transfer Facilities, the minimum charge load is 1 tonne, i.e. if a load of
waste weighs 1 tonne or less, it will be charged as 1 tonne. A load of waste
weighing more than 1 tonne will be charged at 0.1 tonne increment. For
Outlying Islands Transfer Facilities, the charge is $20 per 0.1 tonne and the
minimum charge load is 0.1 tonne.
++ Inert construction waste means rock,
rubble, boulder, earth, soil, sand, concrete, asphalt, brick, tile, masonry
or used bentonite.
@ If a load of waste contains
construction waste and other waste, that load will be regarded as consisting
entirely of construction waste for the purpose of calculating the applicable
charge.
|
Waste Disposal (Chemical Waste) (General) Regulation (Cap 354C)
7.2.7
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 Regulation, if the specified substance or chemical occurs in such a
form, quantity or concentration so as to cause pollution or constitute a danger
to health or risk of pollution to the environment.
7.2.8
A person should not produce, or cause to be
produced, chemical wastes without registration with the Environmental
Protection Department (EPD). Chemical
wastes must either be treated using on-site facility licensed by EPD or be collected
by a licensed collector for off-site treatment at a licensed facility. Under EPD Regulation, the waste producer,
collector and disposal facility must sign all relevant parts of a computerised trip ticket for each consignment of
waste. The computerized system is
designed to allow the transfer of wastes to be traced from cradle-to-grave.
7.2.9
The EPD Regulation prescribes storage facilities
to be provided on-site which include labelling and warning signs. To reduce the risks of pollution and danger to
human health or life, the waste producer is required to prepare and make
available written emergency procedures for spillage, leakage or accidents
arising from the storage of chemical wastes. They must also provide their employees with
training on such procedures.
Land (Miscellaneous Provisions) Ordinance (Cap 28)
7.2.10
The inert portion of C&D materials (also
called public fill) may be taken to public fill reception facilities. Public fill reception facilities usually form
part of land reclamation schemes and are operated by the Civil Engineering and
Development Department (CEDD) and others.
The Land (Miscellaneous Provisions) Ordinance requires that individuals or
companies who deliver public fill to the public fill reception facilities to
obtain Dumping Licences. The licences are
issued by CEDD under delegated authority from the Director of Lands.
7.2.11
Individual licences
and windscreen stickers are issued for each vehicle involved. Under the licence
conditions, public fill reception facilities will only accept earth, soil,
sand, rubble, brick, tile, rock, boulder, concrete, asphalt, masonry or used
bentonite. In addition, in accordance
with paragraph 11 of DEVB TC(W) No.
6/2010 “Trip Ticket System for Disposal of Construction and Demolition
Materials”, the Public Fill Committee will advise on the acceptance
criteria (e.g. no mixing of construction waste, nominal size of the materials
less than 250mm, etc). The material will, however, be free from
marine mud, household refuse, plastic, metal, industrial and chemical wastes,
animal and vegetable matter and any other materials considered unsuitable by
the public fill reception facility supervisor.
Public Health and Municipal Services Ordinance (Cap 132) – Public
Cleansing and Prevention of Nuisances Regulation
7.2.12
This Regulation provides a further control on
the illegal dumping of wastes on unauthorised (unlicensed)
sites.
Other Relevant Guidance
7.2.13
Other guideline documents which detail how the
Contractor will comply with the WDO and its associated regulations include:
·
Waste Disposal Plan for Hong Kong (December 1989), Planning, Environment
and Lands Branch Government Secretariat, Hong Kong
Government;
·
Chapter 9 - Environment (1999), Hong
Kong Planning Standards and Guidelines, Hong Kong
Government;
·
New Disposal Arrangements for Construction Waste (1992), EPD & CED, Hong Kong SAR
Government;
·
Code of Practice on the Packaging, Labelling and Storage of Chemical
Wastes (1992), EPD, Hong Kong
Government;
·
Works Branch Technical Circular (WBTC) No. 32/92, The Use of Tropical
Hard Wood on Construction Site, Works Branch, Hong
Kong Government;
·
WBTC No. 2/93, Public Dumps, Works
Branch, Hong Kong Government;
·
WBTC No. 2/93B, Public Filling Facilities, Works Branch, Hong Kong
Government;
·
WBTC No. 16/96, Wet Soil in Public Dumps,
Works Branch, Hong Kong Government;
·
WBTC Nos. 4/98 and 4/98A, Use of Public Fill in Reclamation and
Earth Filling Projects, Works Bureau, Hong Kong SAR
Government;
·
WBTC Nos. 25/99, 25/99A and 25/99C,
Incorporation of Information on Construction and Demolition Material Management
in Public Works Sub-committee Papers; Works Bureau, Hong Kong SAR Government;
·
WBTC No. 12/2000, Fill Management; Works
Bureau, Hong Kong SAR Government;
·
WBTC No. 19/2001, Metallic Site Hoardings and Signboards, Works Bureau, Hong Kong SAR Government;
·
WBTC No. 11/2002, Control of Site Crusher, Works Bureau, Hong Kong SAR Government;
·
WBTC No. 12/2002, Specification Facilitating the Use of Recycled
Aggregates. Works Bureau, Hong Kong SAR Government;
·
ETWB TC(W) No. 19/2005 Environmental Management on Construction
Site; Environment, Transport and Works Bureau, Hong Kong SAR Government.
·
DEVB TC(W) No. 6/2010, Trip Ticket for Disposal of Construction and
Demolition Materials;
·
DEVB TC(W) No. 8/2010, Enhanced Specification for Site Cleanliness and
Tidiness;
·
DEVB TC(W) No.2/2011, Encouraging the Use of Recycled and Other
Green Materials in Public Works Projects;
·
DEVB TC(W) No. 9/2011, Enhanced Control Measures for Management of
Public Fill; and
·
Hong Kong Blueprint for Sustainable Use of Resources 2013-2022, Environment Bureau, May 2013;
·
Project Administration Handbook for Civil Engineering Works (2014
Edition) – Section 4.1.3 relating to construction
and demolition materials.
7.3.1
The potential environmental impacts associated with
the handling and disposal of waste arising from the construction and operation
of the Project were assessed in accordance with the criteria presented in Annexes 7 and 15 of EIAO-TM and summarised as follows:
·
Estimation of the types and
quantities of the wastes to be generated based on information provided by the
Engineering Design Team and the relevant research and studies on waste
arisings;
·
Assessment of the secondary
environmental impacts due to the management of waste with respect to potential
hazards, air and odour emissions, noise, wastewater discharges and traffic; and
·
Assessment of the potential
impacts on the capacity of waste collection, transfer and disposal facilities.
Introduction
7.4.1
The proposed improvement works include the
following construction activities:
·
Excavation of the nullah;
·
Construction of DWFI system;
·
Laying of rising mains; and
·
Construction
of DWF pumping station
7.4.2
Construction activities will result in the
generation of a variety of C&D materials. The C&D materials are usually mixed
consisting of inert components (public fill) such as soil, rock, concrete,
brick, and asphalt etc and non-inert components
(C&D waste) comprising metal, timber, paper, plastic and general refuse. Chemical waste may also arise as a result of
construction activities. Floating refuse
may arise from litter at upstream and floating refuse from Shan Pui River through
tidal water during heavy rain. The likely waste generated from the proposed construction
works can be classified into the following categories:
·
C&D materials;
·
Chemical waste;
·
General refuse; and
·
Floating refuse
7.4.3
River sediment will not be excavated for the
construction of the Project as excavation works will be confined to the level
above the river sediment layer (i.e. only concrete, soil and rock which were
used as filled materials for the YLTN will be excavated).
7.4.4
During operation period, only a small amount of silt
material and debris will be generated from the maintenance of the DWFI and nullah,
while small amount of screenings and chemical waste will be generated from the
routine operation and maintenance of the DWF pumping station.
7.4.5
Handling and disposal of the above
mentioned wastes may cause environmental impacts and nuisance if it is not
properly managed.
Construction Phase
Excavated Waste Materials
7.5.1
The majority of C&D
materials generated from the Project will arise during the construction of the DWFI
system, rising mains and DWF pumping station. It is expected that most of this material will
be broken pieces of concrete, soil and rock from ground breaking and excavation
works. A preliminary estimate of the C&D
materials generated, reused and disposed during construction is shown in Table 7.2.
7.5.2
Most of the C&D materials are inert and
approximately 29% of the materials can potentially be reused on-site. For example, the generated soil can be
stockpiled for later reuse for backfilling.
7.5.3
However, there is limited potential to reuse the
excavated concrete. The surplus inert
C&D materials will be disposed at Tuen Mun Area
38 Fill Bank via New Territories Circular Road.
It is estimated that a total of 2 truck trips per day will be required
to dispose these materials off-site (). In addition, it is estimated that
approximately 700 m3 of C&D wastes will be generated and disposed
of at WENT Landfill via Nim Wan Road.
7.5.4
With proper implementation of good site
practices and mitigation measures, no unacceptable environmental impacts are anticipated
from management of the C&D materials generated.
Table 7.2 Estimated
Quantities of C&D Materials generated, reused and disposed during
Construction
Scope
of Works
|
C&D
Material (Excavated Materials) Arisings (m3)
|
Reuse
On-site (m3) (see Note 1)
|
Surplus
C&D Materials (m3) for Off-site Disposal
|
C&D
Waste (m3)
|
Chemical
Wastes
|
General
Refuse
|
Floating Refuse
|
|
Construction
of DWFI System
|
11,550
|
2,310
|
9,240
|
500
|
50 litres per month
(See Note 2)
|
32.5 kg per day (See Note 3)
|
(See Note 4)
|
|
Construction
of Rising Mains
|
2,000
|
1,774
|
226
|
100
|
|
Construction
of DWF Pumping Station
|
1,702
|
340
|
1,362
|
100
|
|
Total
|
15,252
|
4,424
|
10,828
|
700
|
|
Notes:
1
Suitable
rock should be reused as backfilling materials.
2
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. Chemical waste will be generated throughout
the construction period.
3
The
amount of general refuse will dependent 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 refuse will be generated throughout
the construction period.
4
With proper waste management and education,
floating refuse arising from the construction activities is not anticipated.
For floating refuse not generated from the Project (i.e. litter at upstream
and floating refuse from Shan Pui River through tidal water), the quantity is
not estimated under this EIA. However, any floating refuse trapped within the
Project Area will be collected by contractor and disposed to landfill.
5
All
C&D waste should be sorted, reused and recycled as far as possible before
disposal at designated landfill.
|
Chemical Waste
7.5.5
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 EPD as a chemical waste producer.
Chemical waste should be collected by
licensed contractor and properly disposed of at approved chemical waste treatment
facilities.
7.5.6
Variety of chemicals would be used for carrying
out construction activities. These
chemicals may include paints, petroleum products, spent lubricants, grease,
mineral oil, solvent and other chemicals used during construction activities. Accidental spillages of chemicals in the
works area may contaminate the top soils on exposed ground/earth. The contaminated soil particles may be washed
away by construction site runoff causes water pollution.
7.5.7
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 workers;
·
Adverse effects on water
quality from spills; and
·
Fire hazards.
7.5.8
The amount of chemical waste cannot be
accurately predicted at this stage since it largely depends on the contractor’s
housekeeping measure. The amount is
anticipated to be small (about 50 litres per month) and
it is recommended that good housekeeping measures should be implemented to
reduce the amount of chemical waste generated. The chemical wastes will be
collected by licensed collector for the disposal of at licensed treatment
facilities (e.g. Chemical Waste Treatment Centre (CWTC) at Tsing Yi) in accordance
with relevant regulation and guideline.
7.5.9
With the incorporation of suitable arrangements
for the storage, handling, transportation and disposal of chemical wastes under
the requirements stated in the Code of
Practice on the Packaging, Labelling and Storage of Chemical Waste, no unacceptable
environmental impacts and hazards will result from the handling, transportation
and disposal of chemical waste arising from the Project.
General Refuse
7.5.10
The presence of a construction site with workers
and associated site office will result in the generation of general refuse
(mainly consist of food waste, aluminium cans and
waste paper) which requires off-site disposal.
The storage of general refuse has the potential to give rise to adverse
environmental impacts. These include odour if the waste is not collected frequently, windblown
litter, water quality impacts if waste enters water bodies, and visual impact.
7.5.11
Assuming up to 50 construction workers will be
working on site at any one time, with a general refuse generation rate of 0.65
kg per worker per day (),
the amount of general refuse to be generated will be about 32.5 kg per
day. An adequate number of waste
containers will be provided to avoid spillage of waste.
7.5.12
Recyclable materials such as paper and aluminium cans will be separated and delivered to the local
recyclers. An adequate number of waste
containers will be provided to avoid spillage of waste. The non-recyclable waste will be collected and
disposed of at the landfill on a regular basis.
With respect to the small quantity of general refuse to be transferred,
it is not anticipated that it will cause unacceptable operational impacts to
these facilities.
Floating Refuse
7.5.13
The litter from the upstream may come down along
the nullah to the Project Area. During heavy rain, the inflatable rubber dam
may be deflated and floating refuse in Shan Pui River may be subsequently washed
up onto the Project Area through tidal water. During construction phase, the
construction workforce may also generate floating refuse (e.g. waste paper and
empty containers) while working along the nullah. With proper waste management
and training to workers, floating refuse arising from the construction
activities is not anticipated. Any floating refuse trapped within the Project
Area will be collected by contractor and disposed of to landfill.
Operational Phase
7.5.14
During the operation phase, catch pits will be
provided to collect the silt material and debris in order to avoid blockage of
the drainage system and minimize the amount of silt material and debris flowing
to the YLTN. In addition, maintenance
works will be carried out to remove the silt material and debris inside the
drainage channels/pipes and the broken pieces of the damaged part of the drainage
channels/pipes. Such waste will be
removed by manual means and disposed of to landfill after the clearance
works. No unacceptable environmental
impacts are thus anticipated.
7.5.15
Mechanical screens will be installed at the
inlet chamber of the DWF pumping station. Small amount of screenings will be
generated. The screenings will be properly packed and handled within the
pumping station structure to avoid odour and hygiene
nuisance. The screenings will then be transported to landfill for disposal.
Routine maintenance of the pumping station will generate a very small amount of
chemical waste. The chemical wastes will be collected by licensed collector for
the disposal of at licensed treatment facilities (e.g. Chemical Waste Treatment
Centre (CWTC) at Tsing Yi) in accordance with relevant regulation and guideline.
No unacceptable environmental impacts are thus anticipated.
Construction Phase
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.
7.6.2
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 workers’ awareness in handling, sorting, reuse and
recycling of C&D materials. Requirements
for staff training should be included in the contractor’s Environmental
Management Plan (EMP).
7.6.3
Good planning and site management practice 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.
7.6.4
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
filling facilities and landfills and to control fly-tipping, a trip-ticket
system should be included. One may make reference to DEVB
TC(W) No. 6/2010 for details.
7.6.5
Regular cleaning and maintenance of the waste
storage area should be provided.
On-site Sorting, Reuse and Recycling
7.6.6
All waste materials should be segregated into
categories covering:
·
Inert C&D materials
suitable for reuse on-site;
·
Inert C&D materials
suitable for public fill reception facilities;
·
Recyclable C&D waste for
recycling;
·
Remaining C&D waste for
landfill;
·
Chemical waste; and
·
General refuse for landfill.
7.6.7
Proper segregation and disposal of construction
waste should be implemented. Separate containers should be provided for inert
and non-inert wastes.
7.6.8
Sorting is important to recover materials for
reuse and recycling. Specific area
should be allocated for on-site sorting of C&D materials and to provide a
temporary storage area for those sorted materials. If 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 the designated landfill only as a last
resort. Inert materials (public fill)
such as concrete, stone, 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 DEVB TC(W) No. 6/2010) before
disposed of at a public filling facility operated by CEDD. Steel and other metals should be recovered
from demolition waste stream and recycled.
7.6.9
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 materials can be crushed to make it suitable for
use as fill materials where fill is required in the works. This minimises the
use of imported materials and maximizes the use of the C&D materials
produced.
Excavated Materials
7.6.10
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.
7.6.11
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 filling area) for public fill, whilst
EPD should be consulted on landfills
for C&D waste. Disposal of C&D
waste to landfill must not have more than 50% (by weight) inert material. The C&D waste delivered for landfill
disposal should contain no free water and the liquid content should not exceed
70% by weight.
7.6.12
In order to avoid dust or odour
impacts, any vehicle leaving a works area carrying C&D waste or public fill
should have their load covered up before leaving the construction site.
7.6.13
C&D materials should be disposed of at
designated public fill reception facilities or landfills. Disposal of these materials for the use at
other construction projects is subject to the approval of the Engineer and/or other
relevant reception authorities. 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
disposal of public fill and C&D waste will be controlled through trip-ticket
system in accordance with DEVB TC(W) No.
6/2010.
Chemical Waste
7.6.14
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.
7.6.15
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.
7.6.16
Suitable containers should be used for specific
types of chemical wastes. The containers should be properly labelled (in English
and Chinese in accordance with instructions prescribed in Schedule 2 of the
Regulations), resistance to corrosion, stored safely and closely secured. Stored volume should not be kept more than 450
liters unless the specification has been approved by the EPD.
Storage area should be enclosed by three
sides by a wall, partition of fence that is at least 2 m height or height of
tallest container with adequate ventilation and space.
7.6.17
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.
7.6.18
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.
7.6.19
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.
7.6.20
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.
General Works Waste
Concrete Waste
7.6.21
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 filling facilities.
Wooden Materials
7.6.22
All wooden materials used on-site should be kept
separately from other wastes to avoid damage and to facilitate reuse. Timber which cannot be reused should be sorted
out from other wastes and stored separately from all inert wastes before being
disposed of to landfill.
7.6.23
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.
7.6.24
Only waste material is needed 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.
General Refuse
7.6.25
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 to facilitate the collection of refuse by licensed
contractors. The chemical wastes will be
collected by licensed collector for the disposal of at licensed treatment
facilities (e.g. Chemical Waste Treatment Centre (CWTC) at Tsing Yi) in
accordance with relevant regulation and guideline. 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.
7.6.26
The recyclable components of the general 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. The contractor should also be responsible for
arranging recycling companies to collect these materials.
Floating Refuse
7.6.27
Any floating refuse trapped within the Project
Area shall be collected by contractor and disposed of to landfill.
Operation
Phase
7.6.28
The silt materials and debris collected during
maintenance should be properly packed and transported to the designated
landfill for disposal as soon as possible. All chemical waste should be
properly stored, labelled and removed by licensed waste collectors in
accordance with Waste Disposal (Chemical Waste) (General) Regulation.
Introduction
7.7.1
This Section
identifies and assesses land lots and sites within the Project boundary which,
due to their past or present land uses, are potentially contaminated sites.
Relevant Legislation, Policies, Standards and Criteria
7.7.2
The following requirements and guidelines are
relevant to assessment of land contamination.
·
Section 3.1 of Annex 19 of EIAO-TM under the EIAO;
·
Guidance Note for Contaminated Land Assessment and Remediation
(August 2007);
·
Guidance Manual for Use of Risk-Based Remediation Goals for Contaminated
Land Management (December 2007); and
·
Practice Guide for Investigation and Remediation of Contaminated
Land (August 2011).
Assessment Methodology
7.7.3
According to the Practice Guide, site appraisal
shall precede to determine the need for site investigation, and to provide the
information to support a contamination assessment, which the findings will
subsequently determine if site remediation is required.
7.7.4
The site appraisal consists of the following:
·
desk-top review of existing and
historical survey maps;
·
interpretation of existing and
historical aerial photographs;
·
review of land use record,
permitted uses of existing private lots;
·
site walkover to verify the
collected information; and
·
review the relevant government
records (i.e. Dangerous Goods storage, spillage / leakage of chemicals,
chemical wastes producers) of the Project Site.
7.7.5
The site walkover was undertaken to identify any
physical clues of contamination, such as presence of industrial related
building structures, chemical drums, chemical or oil stains, unnatural colours / odours and abandoned
piping / mechanical components.
Site Appraisal Findings
Past Land Uses
7.7.6
A review of historical aerial photos (from 1964
– 2011) was undertaken to identify the past land uses within the project area (Annex
7A). Based on the historic
photos, the land use in the area was formerly fishponds, agricultural lands,
roads and village areas. With the development of Yuen Long New Town, the works
areas were developed in stages into roads, footpaths and the Yuen Long Nullah. Some sites were not developed and were left
vacant most of the time. Although the
proposed DWF pumping station is located at Tung Tau Industrial Area, it is located in a small strip of land between a road and the
nullah and was not developed into industrial uses. According to the aerial
photos, there was no presence of building structures that would indicate
possible industrial activities in the proposed works area. A summary of the
review is provided in
7.7.7
Table 7.3.
Table 7.3 Review
of Historical Aerial Photographs
|
Aerial Photo Reference
|
Year
|
Observed Land Use
|
|
DWFI & Rising Main
|
DWF pumping station at Tung
Tau Industrial Area
|
|
Annex 7A_1
|
1963
|
YL
Industrial Estate not yet developed, YLTN under construction, upstream of
nullah mainly agricultural land, downstream portion mainly fishponds
|
Vacant land
next to Yuen Long creek with fishponds nearby
|
|
Annex 7A_2
|
1973
|
YL
Industrial Estate not yet developed, YLTN largely formed
|
Vacant land
and road with fishponds nearby, Tung Tau Industrial Area not yet developed
|
|
Annex 7A_3
|
1982
|
Works in
progress at YL Industrial Estate, road, footpath, channel bed
|
Vacant land,
works in progress at Tung Tau Industrial Area
|
|
Annex 7A_4
|
1993
|
Road,
footpath, channel bed, YL Industrial Estate largely in operation
|
Vacant land
|
|
Annex 7A_5
|
2003
|
Road,
footpath, channel bed
|
Vacant land
|
|
Annex 7A_6
|
2012
|
Road,
footpath, channel bed
|
Vacant land
|
|
Annex 7A_7
|
2018
|
Road, footpath,
channel bed
|
Vacant land
|
Present Land Uses
7.7.8
Site walkover was undertaken in December 2018 to
verify existing land uses and to identify potential sources and signs of
contamination, such as presence of industrial activities, chemicals, oil and
hazardous waste handling and storage locations, bulk storage tanks, sumps,
pipelines, staining, decolouration, abnormal odours, distressed vegetation, etc.
7.7.9
The walkover confirmed the area for constructing
the DWFI and rising mains consist mainly of concrete channel bed, roads and
footpaths. The proposed DWF pumping station is currently vacant. No polluting
activities / sources were observed within the project site areas during the
walkover. The proposed works will not encroach upon any petrol filling
stations, car repair / dismantling workshops, industrial premises or other
major polluting areas. All the project site areas are currently located in
government land. Representative photos showing the existing site conditions are
presented in Annex 7B.
Spillage / Leakage Records
7.7.10
Fire
Services Department (FSD) and EPD have been enquired on any dangerous goods
license and possible incident on spillage, leakage of chemicals or dangerous
goods at the Project Area. Reply from FSD and EPD indicate that there has been
no dangerous goods license since Year 1990 and no records of any incidents of
spillage/leakage of chemical waste or dangerous goods with the Project Area in
the past 3 years. The relevant correspondences are provided in Annex 7C.
7.7.11
The
EPD’s Chemical Waste Producer Register was inspected in June 2019 and no record
of chemical producer was identified within the Works Area.
Summary of Findings
7.7.12
The proposed works will be constructed on
existing vacant lands, carriageways, footpaths and the YLTN channel bed. No signs of suspected land contamination due
to past and present land uses were identified from review of historical aerial
photos and during site walkover.
7.8.1
With the implementation of the recommended
mitigation measures, no unacceptable residual impacts are anticipated from the
construction and operation of the Project.
Construction Phase
7.9.1
To facilitate monitoring and control over the
contractors’ performance on waste management, a waste monitoring and audit programme will be implemented throughout the construction
phase and a Waste Management Plan (WMP) will be prepared and implemented by the
contractor in accordance with ETWB TC(W)
No. 19/2005. The aims of the
monitoring and audit programme are:
·
To review the WMP, which will
form part of the EMP in accordance with ETWB
TC(W) No. 19/2005, including the quantities and types of C&D materials
generated, reused and disposed of off-site; the amount of fill materials
exported from/imported to the site and the quantity of timber used in temporary
works construction for each process/activity;
·
To monitor the implementation
and achievement of the WMP on site to assess its effectiveness; and
·
To monitor the follow-up
actions on deficiencies identified.
7.9.2
Site inspections will be undertaken each week. Particular attention will be given to the
contractor’s provision of sufficient spaces, adequacy
of resources and facilities for on-site sorting and temporary storage of
C&D materials. The C&D materials
to be disposed of from the site will be visually inspected to ensure the
absence of non-inert materials (e.g. general refuse, timber, etc). The waste to
be disposed of at landfills will as practicable contain no observable inert or
reusable/recyclable C&D materials (e.g. soil, broken rock, metal, and
paper/cardboard packaging, etc). Any irregularities observed during the site
inspections will be raised promptly to the contractor for rectification.
7.9.3
The findings of the waste inspections will be reported
in the monthly Environmental Monitoring and Audit Report.
Operation Phase
7.9.4
No monitoring and audit is
required during operation of the Project.
7.10
Conclusion
7.10.1
Wastes generated by the construction activities
are likely to include C&D materials from the construction works, general
refuse from the workforce and chemical waste from any maintenance of
construction plant and equipment. Provided
that these identified wastes arisen are handled, transported and disposed of
using approved methods and that the recommended good site practices are
strictly followed in terms of the avoidance-minimisation-reuse-recycling-disposal
hierarchy, unacceptable environmental impacts are not anticipated during
construction of the Project.
7.10.2
The recommended measures can be enforced by
incorporating them into the waste management requirements in the WMP as part of
the EMP. Environmental site audit would
be necessary to ensure the implementation of proper waste management practices
during construction.
7.10.3
For the operation phase, only silt material and
debris are expected to be produced by maintenance works of the DWFI system. Such waste will be removed by manual means
and disposed of immediately after the clearance works. Small amount of screenings and chemical waste
will be generated during operation and routine maintenance of the DWF pumping
station. No unacceptable environmental impacts are anticipated with proper
waste management practices.
7.10.4
A review of past and present land uses of the
project site was conducted. Based on desk-top review and site walkover, the
presence of contaminated land is not expected.