TABLE OF
CONTENTS
6. waste management implications.. 6-1
6.1 Introduction.. 6-1
6.2 Environmental Legislation, Standards and
Guidelines.. 6-1
6.3 Assessment Methodology.. 6-3
6.4 Identification and Evaluation of Potential Impacts.. 6-4
6.5 Mitigation Measures.. 6-7
6.6 Evaluation of Residual Impacts.. 6-10
6.7 Environmental Audit. 6-10
6.8 Conclusion.. 6-11
List of
Tables
Table 6.1 Summary
of Estimated Quantities of C&D Materials Generated during Construction of
the Project
Table 6.2 Summary of Waste Handling Procedures and Disposal Routes
6.
waste management
implications
6.1.1.1
This section identifies the
types of wastes that are likely to be generated during the construction and
operation of the Sai O Trunk Sewer SPS and evaluates the potential
environmental impacts that may result from the handling, transport
and disposal of these wastes. Mitigation measures and good site practices
regarding waste handling, storage, collection and disposal have been
recommended with reference to the criteria and guidelines as stated in the
requirements given in Section 3.4.4 and Appendix E of the EIA
Study Brief, as well as Annexes 7 and 15 of the Technical Memorandum on Environmental Impact
Assessment (EIAO-TM) and relevant
waste legislation and guidelines.
6.2.1
General
6.2.1.2
The following legislation also
covers the handling, treatment and disposal of wastes in the Hong
Kong Special Administrative Region (HKSAR):
l
Waste Disposal Ordinance (Cap. 354);
l
Waste Disposal (Chemical Waste) (General)
Regulation (Cap. 354C);
l
Waste Disposal (Charges for Disposal of
Construction Waste) Regulation (Cap. 354N);
l
Land (Miscellaneous Provisions) Ordinance (Cap.
28); and
l Public
Health and Municipal Services Ordinance (Cap. 132) - Public Cleansing and
Prevention of Nuisances Regulation.
6.2.2.1
The Waste Disposal Ordinance (WDO) (Cap. 354) prohibits any
unauthorised disposal of waste.
Construction waste defined under Cap. 354N of the WDO, refers to a substance, matter or thing which is generated from
construction works. It includes all
abandoned materials, whether processed or stockpiled or not, before being
abandoned, but does not include sludge, screenings or matter removed or
generated from desludging, desilting or dredging works. Under the WDO,
waste can be disposed of only at designated waste disposal facilities licensed
by EPD.
6.2.3
Waste Disposal (Chemical Waste)
(General) Regulation
6.2.3.1
Under the WDO, the Chemical Waste (General) Regulation
(Cap.354C) provides regulations for chemical waste control, and administers
the possession, storage, collection, transport and disposal of chemical
wastes. EPD has also issued three
statutory guidelines: A Guide to the
Chemical Waste Control Scheme (2016) to introduce and explain the
legislative controls over the management of chemical waste in Hong Kong; A Guide to the Registration of Chemical
Waste Producers (2016) to introduce the registration provisions of the
Waste Disposal (Chemical Waste)(General) Regulation (the Regulation) and the
procedure for identifying chemical waste generation; and the Code of Practice on the Packaging, Labelling
and Storage of Chemical Wastes (1992), which details how the chemical waste
producers should comply with the regulations on chemical wastes.
6.2.4
Waste Disposal (Charges for
Disposal of Construction Waste) Regulation
6.2.4.1
Under the Waste Disposal (Charges for Disposal of Construction Waste) Regulation
enacted in January 2006, construction waste delivered to a landfill for disposal
must not contain more than 50% by weight of inert material. Construction waste delivered to a sorting
facility for disposal must contain more than 50% by weight of inert material,
and construction waste delivered to a Public Fill Reception Facilities (PFRF)
for disposal must consist entirely of inert material.
6.2.5
Land (Miscellaneous Provisions)
Ordinance
6.2.5.1
The inert portion of
construction and demolition (C&D) materials (including rocks, soil, broken
concrete, building debris, etc.) may be taken to public filling facilities
including public filling area, public filling barging points and stockpiling
areas. These facilities usually form
part of land reclamation schemes and are operated by Civil Engineering & Development
Department (CEDD). The Land (Miscellaneous
Provisions) Ordinance requires that individuals or companies who deliver
public fill to the public filling facilities are required to obtain Dumping
Licences. The licences are issued by
CEDD under delegated authority from the Director of Lands.
6.2.6
Public Health and Municipal
Services Ordinance
6.2.6.1
The
Public Cleansing and Prevention of
Nuisances Regulation (Cap. 132BK) under the Public Health and Municipal
Services Ordinance provides control on dumping of litter in public
places.
6.2.7
Other Relevant Guidelines
6.2.7.1
Other relevant circulars /
guidelines are applicable to waste management practices for the Project
include:
l Code of
Practice on the Packaging, Labelling and Storage of Chemical Wastes (1992),
EPD;
l A Guide to
the Chemical Waste Control Scheme;
l A Guide to
the Registration of Chemical Waste Producers;
l Environment,
Transport and Works Bureau Technical Circular (Works) [ETWB TC(W)] No. 19/2005
‘Environmental Management on Construction Site’;
l Development
Bureau Technical Circular (Works) [DEVB TC(W)] No.06/2010 ‘Trip Ticket System
for Disposal of C&D Materials’;
l DEVB TC(W)
No. 2/2011 ‘Encouraging the Use of Recycled and other Green Materials in Public
Works Projects’;
l DEVB TC(W)
No. 9/2011 ‘Enhanced Control Measures for Management of Public Fill’;
l DEVB TC(W)
No. 08/2010 ‘Enhanced Specification for Site Cleanliness and Tidiness’;
l Works Branch
Technical Circular (WBTC) No. 2/93 ‘Public Dumps’;
l WBTC No.
2/93B ‘Public Filling Facilities’;
l WBTC No.
16/96 ‘Wet Soil in Public Dumps’;
l
WBTC No. 12/2000 ‘Fill Management’;
l WBTC Nos.
25/99, 25/99A and 25/99C, ‘Incorporation of Information on Construction and
Demolition Material Management in Public Works Subcommittee Papers’;
l Project
Administration Handbook (PAH) for Civil Engineering Works, Section 4.1.3 of Chapter
4; and
l CEDD TC No.
03/2015, Management of Construction and Demolition Materials.
6.2.7.2
The current policy related to
the dumping of C&D materials is documented in the WBTC No. 2/93 ‘Public Dumps’.
C&D materials that are wholly inert, namely public fill, should not
be disposed of to landfill, but taken to public filling areas for reuse.
6.2.7.3
The ETWB TC(W) No. 19/2005 on
Environmental Management on Construction Site includes procedures on waste
management requiring contractors to reduce the C&D materials to be disposed
of during the course of construction, The Project
Administrative Handbook for Civil Engineering Works, Section 4.1.3 “Management
of Construction and Demolition Material Including Rock” published by CEDD to
enhance the management of C&D materials and to minimise their generation at
source. The enhancement measures include
drawing up a Construction and Demolition Material Management Plan (C&DMMP)
at an early design stage to minimise C&D materials generation and encourage
proper management of such materials.
Projects generating less than 50,000 m3 C&D materials or
importing less than 50,000 m3 of fill material are exempted from the
C&DMMP. Under
ETWB TC(W) No. 19/2005, the
Contractor is required to prepare and implement an Environmental Management
Plan (EMP) and the Waste Management Plan (WMP) becomes part of the EMP.
6.2.7.4
Under DEVB TCW No. 6/2010
‘Trip Ticket System for Disposal of Construction and Demolition Materials’,
for all contracts that are expected to generate inert C&D materials
requiring disposal from site, the project office shall write to the Public Fill
Committee (PFC) through Secretary of the PFC to request a designated disposal
ground for incorporation into the tender documents. For contracts where the
estimated amount of non-inert C&D materials requiring disposal at landfill
facilities equals to or exceeds 50 m3, the project office shall seek
confirmation from the DEP in terms of the availability of landfill facilities
for disposal of such materials and the DEP will designate landfill facilities,
if available, for the contracts. For contracts where the estimated amount of
non-inert C&D materials to be generated from the contract is less than 50 m3,
the project office is not required to apply to DEP for designated landfill
facilities but it should still specify in the tender documents of the
appropriate landfill facilities for disposal.
6.3.1.1
The assessment of waste
management impacts arising from the construction and operation activities of
the proposed Sai O Trunk Sewer SPS, has been undertaken in accordance with the
EIA Study Brief and criteria given in Annexes 7 and 15 of the EIAO-TM and includes the following
tasks:
l
Identification of the construction and
operation activities of the Project which could give rise to waste arising;
l
Estimation of types and quantities of waste
generated;
l
Examination of opportunities for waste reduction
and re-use (both on-site and off-site) and the required disposal options for
each waste;
l
Evaluation of potential impacts caused by
improper handling, collection, transportation and re-use / disposal of wastes
with respect to potential hazards, air and odour emissions, noise, wastewater
discharges, ecology and public transport.
6.4.1.1
The construction activities of
the Project would generate a variety of wastes, which could be categorised into
several types based on their composition and disposal methods. The identified waste types are described in
the following sections and summarised in Table 6.1.
C&D Materials
6.4.1.2
C&D materials would be
generated from the excavation works and the construction of the proposed Sai O
Trunk Sewer SPS, with an estimated total quantity of approximately 7,350
m³. The C&D materials would comprise
inert C&D materials (or public fill like soil, rock and concrete, etc.), with
an estimated quantity of approximately 6,390 m³, and non-inert C&D
materials (or C&D waste like timber, paper, etc.) generated during
dismantling of formwork, estimated to be approximately 960 m³. The non-inert C&D materials would be
reused and recycled as much as possible before disposal of at landfill. It is the Contractor’s responsibility to
separate the inert and non-inert C&D materials on site. The closest landfill to the Site is North
East New Territories (NENT) Landfill.
DSD shall enquire with the EPD on the availability of landfill and
acceptability of the waste.
6.4.1.3
The inert C&D materials
should be reused on-site as far as possible to minimise the net amount of inert
C&D materials generated from the Project.
It is expected that approximately 1,500 m³ of inert C&D materials,
mainly soil, could be reused on-site as backfill materials. A summary of the C&D materials estimates
during construction phase is shown in Table 6.1 below.
6.4.1.4
The actual quantities of
C&D materials to be generated would be provided in the site WMP to be
developed by the Contractor. However, it
is expected that an estimated volume of inert C&D materials to be disposed
of would be 4,890 m³. The final
destinations of the inert C&D materials would be Tuen Mun Area 38 Fill
Bank.
Table 6.1 Summary of Estimated Quantities of C&D Materials
Generated during Construction of the Project
|
Type of C&D Materials
|
Volume, m³
|
|
Inert
C&D Materials
|
Backfilling
(on site reuse) of Inert C&D Materials
|
1,500
|
|
Inert
C&D Materials to be Disposed of at Tuen Mun Area 38 Fill Bank
|
4,890
|
|
Sub-total Volume, m3
|
6,390
|
|
Non-inert
C&D Materials to be Disposed of at NENT Landfill*
|
960
|
|
Total
Volume of C&D Materials, m3
|
7,350
|
Note:
* The non-inert C&D materials would be reused
and recycled as much as possible before disposal of at landfill.
6.4.1.5
With the implementation of
proper management for C&D materials and good site practices, no
unacceptable environmental impacts (including potential hazard, air and odour
emissions, noise, wastewater discharges and ecology) and public transport
impact due to handling and disposal of C&D materials arising from the
Project are anticipated.
Chemical Waste
6.4.1.6
The maintenance and servicing
of construction plant and vehicles may possibly generate some chemical wastes,
for instance, oil / grease, cleaning fluids, solvents, lubrication oil and
fuel.
6.4.1.7
Since the construction
activities would be carried out in close proximity to watercourses and drainage
systems and residential dwellings, 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 (Cap. 354C).
6.4.1.8
Materials classified as
chemical waste shall require special handling and storage arrangements by the
Contractor. All chemical waste shall be
collected by a licensed collector and be disposed at a licensed chemical waste
treatment and disposal facility such as Chemical Waste Treatment Centre (CWTC)
at Tsing Yi. Unused chemical or those
with remaining functional capacity would be reused and recycled on site or by
licensed companies whenever possible. It
is difficult to quantify the amount of chemical waste that would arise from the
construction activities since it would depend on the Contractor’s on-site
maintenance requirements and the amount of plant utilised. In view of the small project scale, it is
anticipated that the quantity of chemical waste would be limited (a few hundred
litres per month). Mitigation and
control requirements for chemical wastes are detailed in Section 6.5.1.10. Provided that the handling,
storage and disposal of chemical wastes are to be in accordance with these
requirements, adverse environmental impacts (including potential hazard, air
and odour emissions, noise, wastewater discharges and ecology) or public
transport impact would not be expected.
General Refuse
6.4.1.9
General refuse comprises
general site wastes, such as packaging and container waste from materials and
equipment used on the site, and refuse generated by workforce. It is estimated that around 15 workers would
be working on site per day during construction phase. Based on a generation rate of 0.65 kg per
worker per day, the daily arising of general refuse during the construction
period would be about 9.75 kg. Although
the quantity of general refuse is expected to be small, improper collection and
removal of general refuse would give rise to hygiene problems and adverse
environmental impacts to local residents, e.g. odour impacts, and contamination
of the nearby watercourses if being blown around by wind, flushed or leached
into the waterbodies.
6.4.1.10 The general refuse will be collected on-site on a regular basis,
separately from C&D materials by an appropriate waste collector to be
employed by the Contractor. Prior to
disposal off-site, such refuse will be temporarily put in suitably covered
storage areas / bins where they will have to be regularly cleaned and
maintained to avoid attracting vermin and pests. With proper on-site handling and storage as
well as regular disposal of the wastes, no unacceptable environmental impact
(including potential hazard, air and odour emissions, noise, wastewater
discharges and ecology) or public transport impact is anticipated. Recommendations of mitigation measures for
managing general refuse are presented in
Section 6.5.1.11.
Waste Transportation and Disposal Routes
6.4.1.11 During the construction phase, there would be up to about two truck
trips per day to transfer the inert C&D materials and up to about one truck
trip to transfer the non-inert C&D materials and general refuse to the
respective disposal outlets as shown in Table 6.2. For
inert C&D materials that would be disposed of at Tuen Mun Area 38 Fill
Bank, the major roads that the truck would pass through include Tate's Cairn
Highway, Territories Circular Road and Lung Mun Road. For non-inert C&D materials and general
refuse that would be disposed of at NENT Landfill, the major roads that the
truck would pass through include Tate's Cairn Highway, Territories Circular
Road and Po Shek Wu Road. For chemical
waste, it would be collected by licenced chemical waste collectors for disposal
of at CWTC. The waste collection
frequency and transportation routes would be reviewed and subject to the actual
operation of the construction activities.
Considering the minor scale of the construction activities, no barging
point or conveyor system would be necessary.
6.4.2.1
The major waste types to be
generated would be the screenings from the operation of the proposed Sai O
Trunk Sewer SPS. Sewage would pass
through the mechanical screens for prevention of shutting down of pumping
system due to pump damage by large objects.
Based on the record from existing Ha Tsuen Pumping Station (average flow
of 60,000 m3/day generated approximately 17 m3 of
screenings per month), it is estimated that the volume of screenings to be
generated from the proposed Sai O Trunk Sewer SPS (20,600 m3/day)
would be around 5.8 m3 per month.
Even though the quantity of screenings to be generated would be limited
and would be collected on a regular basis (Section
6.5.2 refers), improper handling of the screenings may give rise to odour
nuisance, pollution to the nearby waterbodies, and hygiene problems. With the mitigation and control requirements
in Section 6.5.2, adverse environmental impacts (including potential hazard, air and
odour emissions, noise, wastewater discharges and ecology) or public transport
impact would not be anticipated.
6.4.2.2
Chemical wastes such as waste
lubricating oil, used solvents and spent chemicals would also be generated
during the maintenance activities of the SPS.
The amount of chemical waste that would arise from the maintenance
activities is difficult to be quantified at this stage as it would be dependent
on the maintenance requirements and the quantity of equipment utilized.
Nevertheless, it is expected that the quantity of chemical wastes to be
generated from the maintenance activities would be limited and in the order of
a few cubic meters per month. With the mitigation and
control requirements presented in Section
6.5.1.10, potential environmental impacts (including potential hazard, air
and odour emissions, noise, wastewater discharges and ecology) or public
transport impact arising from the handling, storage and disposal of a small
amount of chemical waste generated from the operation activities would be
negligible.
6.4.2.3
Since the proposed SPS will be
unmanned, no general refuse would be generated during the operational phase.
6.5.1.1
The waste management hierarchy
has been applied in the assessment and development of mitigation measures for
waste which aims at evaluating the desirability of waste management methods and
includes the followings in descending preference:
l
Avoidance and reduction of waste generation;
l
Reuse of materials as far as practicable;
l
Recovery and recycling of residual materials
where possible; and
l
Treatment and disposal according to relevant
laws, guidelines and good practices.
6.5.1.2
Good site practices and waste
reduction measures to achieve avoidance and minimization of waste generation in
the hierarchy are recommended as follow.
Good Site Practices
6.5.1.3
Adverse impacts would not arise
in the construction site, provided that good site practices are strictly
followed. Recommendations for good site
practices during the construction phase include:
l Nomination of approved personnel, such as a site manager, to be
responsible for implementation of good site practices, arrangements for waste
collection and effective disposal to an appropriate facility;
l Training of site personnel in site cleanliness, concepts of waste
reduction, reuse and recycling, proper waste management and chemical waste
handling procedures;
l Provision of sufficient waste reception / disposal points, and regular
collection of waste;
l Adoption of appropriate measures to minimise windblown litter and dust during transportation of waste by either
covering trucks or by transporting wastes in enclosed containers;
l Provision of regular cleaning and maintenance programme for drainage systems, sumps and oil interceptors;
l Adoption of a recording system for the amount of wastes generated, recycled and disposed (including the disposal
sites); and
l Preparation of WMP, as a part of the EMP in accordance with ETWB TC(W)
No. 19/2005 "Environmental Management on Construction Sites" for
submission to the Architect/Engineer for approval.
Waste Reduction
Measures
6.5.1.4
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 are discussed as follow:
l 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;
l 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;
l Recycle any unused chemicals or those with remaining functional
capacity;
l Maximise the use of reusable steel formwork to reduce the amount of C&D
materials;
l Adopt proper storage and site practices to minimise the potential for damage to, or contamination of construction
materials;
l Plan the delivery and stock of construction materials carefully to minimise the amount of waste generated; and
l Minimise over ordering and wastage through careful planning
during purchasing of construction materials.
6.5.1.5
In addition to the above good
site practices and waste reduction measures, specific mitigation measures are
recommended below for the identified waste arising to minimise environmental
impacts during the handling, transportation and disposal of these wastes.
C&D Materials
6.5.1.6
Careful design, planning
together with good site management can reduce over-ordering and generation of
C&D materials such as concrete, mortar and cement grouts. Formwork should be designed to minimise the
use of standard wooden panels, so that high reuse levels can be achieved. Alternatives such as steel formwork or
plastic facing should be considered to increase the potential for reuse.
6.5.1.7
To minimise off-site disposal
of inert C&D materials, the excavated inert materials with suitable
characteristics / size should be reused on-site as fill material as far as
practicable. The surplus inert C&D materials
would be transported and disposed of at public filing area for use as filling
material by other projects. Prior to disposal of non-inert C&D materials,
wood, steel and other metals should also be separated for reuse and / or
recycle where practicable so as to minimise the quantity of waste to be
disposed of at landfill.
6.5.1.8
Suitable areas should be
designated within the works site boundaries for temporary stockpiling of
C&D materials. Within stockpile
areas, the following measures should be taken to control potential
environmental impacts or nuisance:
l
cover material during heavy rainfall;
l
locate stockpiles to minimise potential visual
impacts; and
l
minimise land intake of stockpile areas as far
as possible.
6.5.1.9
In order to monitor the
disposal of C&D materials at the designated public fill reception facility
and landfill and to control fly-tipping, a trip-ticket system should be
included. One may make reference to DEVB TC(W) No.06/2010 for details. When disposing inert C&D materials at a
public filling reception facility, the material shall only consist of soil,
rock, concrete, brick, cement plaster / mortar, inert building debris,
aggregates and asphalt. The material
shall be free from marine mud, household refuse, plastic, metals, industrial
and chemical waste, animal and vegetable matter, and other material considered
to be unsuitable by the Filling Supervisor.
Chemical Wastes
General Refuse
6.5.2.1
The main type of wastes
generated during operational phase would be screenings from the SPS, which
would be similar in nature to general refuse.
The screenings filtered by the mechanical raked bar screen would be collected
into container and removed with covered container or sealed plastic bag
regularly (around every three days). A
reputable waste collector should be employed by the operators to remove the
screenings from the SPS, on a regularly basis to minimise odour, pest and
litter impacts.
6.5.2.2
For the chemical wastes
generated during operational phase, the mitigation measures are the same as
those in Section 6.5.1.10 for construction
phase.
6.5.2.3
Table 6.2
provides a summary of the various types of wastes likely to be generated during
the construction and operational phases of the Project, together with the
recommended handling and disposal methods.
Table 6.2 Summary of Waste Handling Procedures and Disposal Routes
|
Waste Type
|
Handling
|
Disposal
|
|
Construction
|
|
Inert C&D
materials
|
Ÿ Segregation from non-inert C&D
materials
Ÿ Reuse on-site as far as practicable
|
Ÿ
Public filling area (Tuen Mun Area 38 Fill Bank)
|
|
Non-inert C&D materials
|
Ÿ Segregation from inert C&D
materials
Ÿ Reusable materials should be separated
and recycled as far as practicable
|
Ÿ
Strategic landfill (NENT)
|
|
Chemical wastes
|
Ÿ Unused chemical would be recycled
on-site or off-site disposal by licensed collectors.
Ÿ Store on-site within suitably designed
containers
|
Ÿ
CWTC or other licensed facilities
|
|
General refuse
|
Ÿ Provide on-site refuse collection
facilities
Ÿ Provide on-site clearly labelled
recycling bins for segregation of aluminium and plastic wastes, and
wastepaper
|
Ÿ
Employ a reputable waste collector for collection and final disposal
of general refuse to Strategic landfill (NENT)
Ÿ
Employ reliable waste recycling agents to collect the segregated
recyclable wastes
|
|
Operation
|
|
Screenings, silt
and debris
|
Ÿ Off-site disposal required
|
Strategic
landfill (NENT)
|
|
Chemical wastes
|
Ÿ Off-site disposal by licensed collectors
|
CWTC or other
licensed facilities
|
6.6.1.1
With the implementation of the
recommended mitigation measures for the handling, transportation and disposal
of the identified waste arising, residual impacts would not be expected during
the construction and operation of the proposed Project.
6.8
Conclusion
6.8.1.1
During construction phase,
waste types generated from the Project are likely to include C&D materials
(from excavation, demolition of existing structures and site formation),
chemical wastes from maintenance of construction plant and equipment, and
general refuse from workforce. In view
of the nature and limited scale of the Project, the quantity of waste arisings
would not be substantial. However, improper handling, collection,
transportation and re-use / disposal of the wastes would likely give rise to
hygiene problems and adverse environmental impacts, e.g. odour nuisance to
local residents, and contamination of the nearby watercourses. Provided that
these wastes are handled, transported and disposed of according to the
recommended good site practices and measures, no adverse environmental impacts
(including potential hazard, air and odour emissions, noise, wastewater
discharges and ecology) would be anticipated during the construction phase.
6.8.1.2
The main waste types generated
from the operation of the Project would be screenings. Small quantities of chemical wastes are also
anticipated. With implementation of the
recommended mitigation measures, adverse environmental impacts would not be
anticipated during operational phase.