7.1.1
This section identifies the types of
construction- and operation-related wastes that are likely to be generated by
the Project and evaluates the potential environmental impacts that may result
from handling, transport and disposal of the waste.
7.1.2
The main environmental concern regarding
waste arises from the construction and demolition material from earthworks for
the proposed reprovisioning works at Sha Tin WTW. Mitigation measures and good site practices,
including waste handling, storage and disposal have been recommended with
reference to the applicable waste legislation and guidelines.
7.2
Environmental
Legislation, Plans, Standards and Guidelines
7.2.1
The criteria and guidelines for assessing
waste management implications are outlined in Annex 7 and Annex 15,
respectively, of the Technical Memorandum on Environmental Impact Assessment
Process (TM-EIA).
7.2.2
The following legislation, which has been
used in assessing potential impacts, relates to the handling, treatment and
disposal of wastes in the Hong Kong SAR:
§
Waste Disposal Ordinance (Cap. 354);
§
Waste Disposal (Chemical Waste) (General)
Regulation (Cap. 354);
§
Waste Disposal (Charges for Disposal of
Construction Waste) Regulation (Cap. 354N).
§
Land (Miscellaneous Provisions) Ordinance (Cap.
28);
§
Public Health and Municipal Services
Ordinance (Cap. 132) - Public Cleansing and Prevention of Nuisances Regulation.
7.2.3
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/ civil engineering materials, but does not
include animal waste. Under the WDO,
wastes can be disposed of only at sites licensed by the Environmental
Protection Department (EPD).
7.2.4
Issued under the WDO, the Chemical Waste
(General) Regulation 1992 administers the possession, storage, collection,
transport and disposal of chemical wastes.
The EPD has also issued a ‘guideline’ document, the Code of Practice
on the Packaging, Labelling and Storage of Chemical Wastes (1992), which
details how the Contractor should comply with the regulations on chemical
wastes.
7.2.5
The Public Cleansing and Prevention of
Nuisances Regulation provides control on illegal tipping of wastes on
unauthorised (unlicensed) sites.
7.2.6
The current policy related to the dumping of
C&D material[1] is documented in the Works
Branch Technical Circular (WBTC) 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 that usually form part of reclamation
schemes. The Land (Miscellaneous
Provisions) Ordinance requires that dumping licences be obtained by
individuals or companies who deliver public fill to public filling areas. The licences are issued by Civil Engineering and
Development Department (CEDD) under delegated powers from the Director of
Lands.
7.2.7
In addition to the WBTC, EPD and CEDD have
produced a leaflet titled ‘New Disposal Arrangements for Construction Waste’
(1992) and together with the approved Construction
Waste Disposal Charging Scheme (2005)
by the Legislative Council that C&D material with less than 50% by weight
of inert material will be accepted at landfill.
If the C&D material contains more than 50% inert
material, the waste must be sorted with inert material sent to a public filling
area and the non-inert material (that is, C&D waste) sent to landfill for
final disposal.
7.2.8
Measures have been introduced under Paragraph 4.1.3 of Chapter 4 of
the Project Administration Handbook for Civil Engineering Works to enhance
the management of C&D material including rock, and to minimize its
generation at source. The enhancement
measures include:
(i)
Drawing up a Construction and Demolition
Material Management Plan (C&DMMP) at an early design stage to minimize
C&D material generation;
(ii)
Vetting of the C&DMMP prior to upgrading
of the project to Category A in the Public Works Programme; and
(iii)
Providing the contractor with information
from the C&DMMP in order to help the contractor prepare the Waste
Management Plan (WMP) and to minimize C&D material generation during
construction.
7.2.9
Technical circular ETWB TCW No. 19/2005
introduces additional measures to enhance waste management on construction
sites. The circular sets out the policy
and procedures requiring contractors to prepare and implement an enhanced WMP
to encourage on-site sorting of C&D material and to minimize generation of
C&D material during the course of construction.
7.2.10
The finalized C&DMMP has been endorsed by the WSD Vetting
Committee on C&DMMP in its meeting on 12 November 2012. The C&DMMP is attached in Appendix 7.1.
Consents on the endorsed C&DMMP and EIA report were obtained from the Public
Filling Committee (PFC) on 3 January 2013,
26 August 2013 and 30 September 2014. The relevant memos from PFC are
given in Appendix
7.2.
7.2.11
Under the regulation of WDO, the Waste
Disposal (Chemical Waste) (General) Regulation provides regulations for
chemical waste control, and administers the possession, storage, collection,
transport and disposal of chemical wastes. EPD has also issued a ‘guideline’
document, the Code of Practice on the Packaging, Labelling and Storage of
Chemical Wastes (1992), which details how the Contractor should comply with the
regulations on chemical wastes.
7.3.1
The methods for assessing potential waste
management impacts during the construction and operation phases follow those
presented in Annex 15 of the TM-EIA and include the following:
§
Estimation of the types and quantities of the
wastes generated;
§
Examination of opportunities for waste
reduction and re-use (both on-site and off-site) and the required disposal
options for each type of waste;
§
Assessment of potential environmental impacts
from the transport/ management of solid waste with respect to potential
hazards, air and odour emissions, noise, wastewater discharges; and
§
Identification of impacts on the capacity of
waste collection, transfer and disposal facilities.
7.4
Identification of Potential Environmental
Impacts
7.4.1
The construction activities to be carried out
for the proposed Project would generate a variety of wastes that can be divided
into distinct categories based on their composition and ultimate method of
disposal. The identified waste types
are:
§
Construction and demolition (C&D)
material.
§
General refuse.
§
Chemical waste.
7.4.2
Sludge would be the major waste generated
during operation of the water treatment process. Other types of wastes such as chemical
waste, and general refuse would also be generated during operation of the
Project.
7.5
Prediction
& Evaluation of Environmental Impacts
7.5.1
The nature of each type of waste arising is
described below, together with an evaluation of the potential environmental
impacts associated with the waste.
7.5.2
Construction and demolition (C&D)
materials would be generated from demolition works of the existing facilities
of the South Works, construction of the new common facilities for the North and
the South Works, the slope excavation works for the reprovision of the South
Works and construction works of new access roads for both construction and
operation of the plant. This C&D
material would comprise both inert and non-inert components, such as soil, artificial
hard materials (AHM) (broken concrete, etc.), rocks, wood and metals. The Engineer has estimated the volume of surplus
C&D materials to be approximately 242,050 m3 of inert material
(i.e. public fill) and approximately 9,980 m3 of non-inert material
(i.e. C&D waste). There is no
sediment requiring marine disposal.
7.5.3
The C&D material would be sorted on-site
and the inert portion would be stored in different containers, skips or
stockpiles to re-use on-site as far as possible to minimise the net amount of
C&D material generated from this Project. Surplus excavated material would therefore
require to be exported off-site. The Project Proponent shall notify CEDD for
the estimated spoil volumes to be generated and liaise and agree with the PFC
for the disposal of surplus inert C&D materials during the detailed design phase
of the Project. A summary of inert C&D materials generated during
construction phase is shown in Table 7.1. The
potential environmental impacts arising from the handling and disposal of this
inert C&D material, such as air and odour emissions, noise and potential
hazard, would be negligible. Appropriate
measures should be taken to minimise potential adverse impacts from dust during
the transportation of C&D material.
Table
7.1 Summary of Inert C&D Material Quantities Generated
Works
Area |
Granitic
Rock (Grade III or below)) (m3) |
Soft
Material |
Artificial
Hard Materials (m3) |
Total
Volume (m3) |
Sha Tin WTW |
27,490 |
190,940 |
30,670 |
249,100 |
7.5.4
The estimated volumes of inert and non-inert C&D material generated from the
construction of the Project are presented in Table
7.2 below, together with the estimated volumes of inert
C&D material to be disposed to public filling area. The timing of these construction activities
is shown in Table 7.3.
Table 7.2 Summary of
Inert and non-inert C&D Material Volumes Generated
from Construction Activities (In Bulk Volumes)
Construction
Activity |
Inert C&D material (m3) |
Reusable inert C&D material (m3) |
Inert C&D material to be disposed to
public filling area (m3) |
Non-inert
C&D material (m3) |
Demolition of
existing facilities of the South Works |
151,950 |
7,050 |
144,900 |
2,500 |
Construction of New
Facilities for both the North and the South Works |
0 |
0 |
0 |
7,480 |
Cut-Back of the
Existing Man-Made Slope |
91,630 |
0 |
91,630 |
0 |
Cut-Back of
Existing Slope for Construction of New Access Roads |
5,520 |
0 |
5,520 |
0 |
Total |
249,100 |
7,050 |
242,050 |
9,980 |
Table 7.3 Anticipated
Timing of Wastes Arising/ Generation from Construction Activities and Disposal
Construction
Activity |
Anticipated Timing |
Demolition of existing
facilities of the South Works |
November 2016 – April
2018 August 2019
– January 2020 May 2020
– October 2020 |
Construction of New
Facilities for both the North and the South Works |
August 2016 – April
2021 |
Cut-Back of the
Existing Man-Made Slope |
November 2016 –
October 2017 |
Cut-Back of
Existing Slope for Construction of New Access Roads |
March 2016 – October
2016 |
Disposal of Surplus
C&D Materials |
Jul 2016 – Dec 2017
(Granitic Rock (Grade III or below)) Jan 2016
– Dec 2017 (Soft Material) Jul 2016
– Dec 2020 (Artificial Hard Material) Jul 2017
– Apr 2021 (Non-inert C&D Material) |
7.5.5
It is anticipated that any fill materials
required will be sourced from the excavated materials stockpiled at the
temporary stockpiling areas, whenever it is suitable. Hence, no
imported fill will be required.
7.5.6
Non-inert C&D materials generated would
be reused and recycled as much as possible before disposal of at
landfills. It is the Contractor’s
responsibility to separate the inert and non-inert C&D materials on site.
7.5.7
The Contractor would quantify in the site
Waste Management Plan the amount of C&D material expected to be generated.
7.5.8
Throughout construction, the workforce would
generate refuse comprising food scraps, waste paper, empty containers,
etc. Escape of such refuse from the site
should not be allowed to occur.
7.5.9
Effective collection and removal of site
wastes will be required to prevent waste materials being blown around by wind,
flushed or leached into the aquatic environment, and to prevent odour nuisance. The work sites may also attract pests and
vermin if the waste storage area is not well maintained and cleaned
regularly. Disposal of refuse must be at
approved waste transfer or disposal facilities.
With the implementation of good waste management practices at the site,
adverse environmental impacts would not be expected to arise from the storage,
handling and transportation of refuse.
7.5.10
The maintenance and servicing of construction
plant and equipment may possibly generate some chemical wastes, for instance,
cleaning fluids, solvents, lubrication oil and fuel. Maintenance of vehicles may also involve the
use of a variety of chemicals, oil and lubricants.
7.5.11
Building demolition may possibly generate
asbestos waste as the existing building insulation materials likely contain
asbestos. Asbestos waste is categorized as chemical waste under the Waste
Disposal (Chemical Waste) Regulation. The Project Proponent should conduct an
asbestos investigation by a registered asbestos consultant prior to demolition
of existing building structure. The investigation should reveal the presence,
quantity and location of Asbestos Containing Materials (ACM). Asbestos waste
will be handled in accordance with the Code of Practice on the Handling,
Transportation and Disposal of Asbestos Waste issued by EPD.
7.5.12
Chemical wastes arising during the
construction phase may pose environmental, health and safety hazards if not
stored and disposed of in an appropriate manner as stipulated in the Waste
Disposal (Chemical Waste) (General) Regulations. The potential hazards include:
§
Toxic effects on the workforce.
§
Adverse impacts on water quality and aquatic
biota from spills.
§
Fire hazards.
7.5.13
Materials classified as chemical wastes will
require special handling and storage arrangements before removal for
appropriate treatment at the Chemical Waste Treatment Facility at Tsing
Yi. Wherever possible opportunities
should be taken to reuse and recycle materials.
Mitigation and control requirements for chemical wastes are detailed
below. Provided that the handling,
storage and disposal of chemical wastes are in accordance with these
requirements, adverse environmental impacts are not expected to result.
Uncertainties
in Prediction & Evaluation of Environmental Impacts
7.5.14
It is difficult to quantify the amount of general
refuse and chemical waste that will arise from the construction activities
since it would be highly dependent on the Contractor’s on-site maintenance
requirements and the number of plant utilised. However, as a worst case, it is
estimated that a factor of 0.65 kg per worker per day of general refuse will be
generated. The total quantity of waste generated would thus be estimated 128.7 kg
per day, assuming the size of the work force would be a maximum of 198 resident
site staff (RSS) and construction workers. Also it is anticipated that the
quantity of chemical waste, such as lubricating oil and solvent produced from
plant maintenance, would be small and in the order of a few cubic metres per
month. The amount of chemical waste to be generated would be quantified in the
site Waste Management Plan to be prepared by the Contractor.
Operation
Phase
7.5.15
Sludge arising from the water treatment
process would be the major waste during the operation of the Project. The monthly volume of thickened sludge
generated in the existing
Sha Tin WTW
was approximately 14,000 m3, and it should be subject to change with
different raw water quality. The
sludge would be thickened on–site and then transported through the twin sludge
transfer pipeline underneath Shing Mun River to the Sha Tin Sewage Treatment
Works (STW) for disposal.
7.5.16
The total volume of thickened sludge
generated from the existing Sha Tin WTW was approximately 465 m3/day
and relates to an average output of about 730 million litres per day (MLD). Taking into account the full capacity of the
WTW after completion of the reprovisioning works with total output of 1,227 MLD, a total volume of thickened
sludge would be approximately
782 m3/day. It is anticipated
that the amount of thickened sludge to be generated from the proposed water
treatment process would not be significantly different from that produced under
the current process. The routing of
sludge disposal would also follow the existing approach that thickened sludge
is transported to Sha Tin STW for disposal based on the best available
information at the time of writing this EIA report. It is anticipated that the handling and
disposal of the sludge generated from the proposed water treatment process
would not induce unacceptable impacts compared to the treatment process of the
existing WTW.
7.5.17
Apart from sludge, other wastes such as chemical waste, general refuse, etc. that will be generated
from the operation of the Project are considered to have no adverse or minimal
environmental impacts.
7.6
Mitigation
of Adverse Environmental Impacts
7.6.1
Appropriate waste handling, transportation
and disposal methods for all waste arisings generated during the construction
works for the Project should be implemented to ensure that construction wastes
do not enter the nearby streams or drainage channel.
7.6.2
It is anticipated that adverse impacts would
not arise on the construction site, provided that good site practices are
strictly followed. Recommendations for
good site practices during the construction activities include:
§
Nomination of approved personnel, such as a
site manager, to be responsible for good site practices, and making
arrangements for collection of all wastes generated at the site and effective
disposal to an appropriate facility.
§
Training of site personnel in proper waste
management and chemical waste handling procedures.
§
Provision of sufficient waste reception/
disposal points, of a suitable vermin-proof design that minimises windblown
litter.
§
Arrangement for regular collection of waste
for transport off-site and final disposal.
§
Appropriate measures to minimise windblown
litter and dust during transportation of waste by either covering trucks or by
transporting wastes in enclosed containers.
§
Regular cleaning and maintenance programme
for drainage systems, sumps and oil interceptors.
§
A recording system for the amount of wastes
generated, recycled and disposed (including the disposal sites) should be
proposed.
§
A Waste Management Plan should be prepared
and should be submitted to the Engineer for approval. One may make reference to ETWB TCW No. 19/2005
for details.
7.6.3
In order to monitor the disposal of C&D
material at landfills and public filling areas, as appropriate, and to control
fly tipping, a trip-ticket system should be included as one of the contractual
requirements to be implemented by an Environmental Team undertaking the
Environmental Monitoring and Audit work.
One may make reference to DEVB TCW No.6/2010 for
details.
7.6.4
Good management and control of construction
site activities/ processes can minimise the generation of waste. Waste reduction is best achieved at the
planning and design stage, as well as by ensuring the implementation of good
site practices. Recommendations to
achieve waste reduction include:
§
Segregate and store different types of
construction related waste in different containers, skips or stockpiles to
enhance reuse or recycling of materials and their proper disposal.
§
Provide separate labelled bins to segregate
recyclable waste such as aluminium cans from other general refuse generated by
the work force, and to encourage collection by individual collectors.
§
Any unused chemicals or those with remaining
functional capacity shall be recycled.
§
Maximising the use of reusable steel formwork
to reduce the amount of C&D material.
§
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.
§
Adopt proper storage and site practices to
minimise the potential for damage to, or contamination of, construction
materials.
§
Plan the delivery and stock of construction
materials carefully to minimise the amount of waste generated.
§
Minimize over ordering of concrete, mortars
and cement grout by doing careful check before ordering.
7.6.5
In addition to the above measures, other
specific mitigation measures are recommended below to minimise environmental
impacts during handling, transportation and disposal of wastes.
7.6.6
The C&D material generated from demolition
works of existing facilities of the South Works, construction works of new
facilities for the North and the South Works, slope excavation works and
construction works of new access roads should be sorted on-site into inert
C&D material (that is, public fill) and C&D waste. To minimise the impact resulting from
collection and transportation of C&D material for off-site disposal, any
excavated material should be reused on-site as backfilling material as far as
practicable. C&D waste, such as wood, plastic, steel and other metals
should be reused or recycled and, as a last resort, disposed of to landfill. A suitable area should be designated within
the site for temporary stockpiling of C&D material and to facilitate the
sorting process. Within the stockpile
areas, the following measures should be taken to control potential
environmental impacts or nuisance:
§
Covering material during heavy rainfall;
§
Locating stockpiles to minimise potential
visual impacts; and
§
Minimising land intake of stockpile areas as
far as possible.
7.6.7
For the disposal of any surplus inert C&D
materials, the Project Proponent have notified CEDD of the estimated spoil
volumes to be generated, and liaised and agreed with the PFC. The finalized
C&DMMP has been endorsed
by the WSD Vetting Committee on C&DMM in its meeting on 12 November 2012. Consents
on the endorsed C&DMMP and EIA report were obtained from the PFC on 3
January 2013, 26 August 2013 and 30 September 2014. No construction work is
allowed until consensus has been made on the overall management and disposal
arrangements be endorsed by the relevant authorities such as PFC and EPD.
7.6.8
General refuse should be stored in enclosed
bins or compaction units separate from C&D material. A reputable waste collector should be
employed by the contractor to remove general refuse from the site, separately
from C&D material. An enclosed and
covered area is preferred to reduce the occurrence of 'wind blown' light material.
7.6.9
All storage of asbestos waste should be
carried out properly in a secure place isolated from other substances so as to
prevent any possible release of asbestos fibres into the atmosphere and
contamination of other substances. The storage area should bear warning panels
to alert people of the presence of asbestos waste.
7.6.10
A licensed asbestos waste collector will be
appointed to collect the asbestos waste and deliver to the designated landfill
for disposal. The Project Proponent should notify EPD in advance for disposal
of asbestos waste. After processing the notification, EPD will issue specific
instructions and directions for disposal. The waste producer must strictly
follow these directions.
7.6.11
If chemical wastes were to be produced at the
construction site, the Contractor would be required to register with the EPD as
a Chemical Waste Producer, and to follow the guidelines stated in the Code of
Practice on the Packaging, Labelling and Storage of Chemical Wastes. Good quality containers compatible with the
chemical wastes should be used, and incompatible chemicals should be stored
separately. Appropriate labels should be
securely attached on each chemical waste container indicating the corresponding
chemical characteristics of the waste, such as explosive, flammable, oxidizing,
irritant, toxic, harmful, corrosive, etc.
The Contractor shall use a licensed collector to transport the chemical
wastes. The licensed collector shall
deliver the waste to the Chemical Waste Treatment Centre at Tsing Yi, or other
licenced facility, in accordance with the Waste Disposal (Chemical Waste)
(General) Regulation.
7.6.12
Table 7.4 provides
a summary of the various waste types likely to be generated during the construction
works for the Project, together with the recommended handling and disposal
methods.
Table
7.4 Waste
Arising, Waste Handling Procedures and Disposal Routes
Waste Material Type |
Generated from |
Materials Generated |
Total Quantity Generated |
Disposal |
Handling Methods / Reuse |
C&D Materials |
Excavation, Demolition Works, Cut-back of the existing
man-made slope, Construction of
new common facilities for the North and South Works and Construction of new
access roads |
Inert C&D materials – Rock, Soft Materials and Artificial
Hard Materials |
249,100 m3 |
Suitable material to be reused on site or to be disposed
to public filling areas |
Segregation
from non-inert C&D materials during stockpiling and transportation Stockpile
area (if required) should be well managed with covers and water spraying
system |
Non-inert C&D materials – Timber, Papers &
Plastics |
9,980 m3 |
To be disposed to landfill |
Segregation
from inert C&D materials during stockpiling and transportation Reusable
materials should be separated and recycled as far as practicable |
||
General Refuse |
Workforce - maximum of 198 RSS |
Food waste, plastic, aluminium cans, waste papers etc. |
Assumed 128.7kg per day |
Refuse station for compaction and containerisation and
then to landfill |
Provide
on-site collection points together with recycling bins Collected
by licensed collectors |
Chemical Waste |
Maintenance and servicing of construction plant,
equipment and vehicle Building demolition |
Oils and grease hydraulic fluids, paints, solvents,
cleaners etc. Asbestos Containing Materials |
Few cubic metres per month |
Chemical Waste Treatment Centre Designated landfill to be determined by EPD |
Store in
compatible containers in designated area on site To be
collected and recycled by licensed collectors All storage of asbestos waste should be
carried out properly in a secure place isolated from other substance and bear
warning panels to alert people of the presence of asbestos waste |
7.7
Evaluation
of Residual Environmental Impacts
7.7.1
With the implementation of the recommended
mitigation measures for the handling, transportation and disposal of the
identified waste arising, adverse residual impact is not expected to occur
during the construction and operation of the proposed Project.
7.8
EM&A
Requirements
7.8.1
It will be the contractor’s responsibility to
ensure that any wastes produced during the construction of the Project are
handled, stored and disposed of in accordance with good waste management
practices and relevant regulations and other legislative requirements. The recommended mitigation measures should
form the basis of the site Waste Management Plan to be developed by the
Contractor in the construction stage.
7.9
Conclusion
7.9.1
Waste types generated by the construction
activities are likely to include inert and non-inert C&D materials from
demolition works of existing facilities of the South Works, construction works
of new facilities for the North and the South Works, slope excavation works and
construction works of new access roads, general refuse from the workforce and
chemical wastes from the maintenance of construction vehicles and
equipment. Provided that these
identified wastes would be handled, transported and disposed of using the
recommended methods and that good site practices would be strictly followed,
adverse environmental impacts are not expected.
7.9.2
The waste management assessment has
recommended good waste management practices to ensure that adverse
environmental impacts are prevented. The
assessment concluded that no unacceptable environmental impacts would result
from the storage, handling, collection, transport and disposal of wastes
arising from the construction and operation of the project.
~ End of Section 7 ~
[1] “C&D material” contains a mixture of
inert and non-inert material. The inert
portion is the “public fill” and the non-inert portion is the “C&D waste”.