6.1.1.1
This section identifies
the types of waste that are likely to be generated during the construction and
operation phases of the proposed Yuen Long South Effluent Polishing Plant
(YLSEPP) development (the Project) and evaluates the potential environmental impacts
that may be resulted from the handling, transport and disposal of wastes.
6.1.1.2
Mitigation measures and
good site practices regarding the waste handling, storage, collection and
disposal are recommended with reference to relevant waste legislation and guidelines.
6.2.1
General
6.2.1.1
The criteria and
guidelines for evaluating and assessing waste management implications are
outlined in Annex 7 and 15 of the Technical Memorandum on Environmental Impact
Assessment (EIAO-TM), respectively.
6.2.1.2
The following
legislation relates to the handling, treatment and disposal of wastes in the
Hong Kong Special Administrative Region (SAR):
·
Waste Disposal Ordinance (Cap. 354);
·
Waste Disposal (Chemical Waste)
(General) Regulation (Cap. 354C);
·
Waste Disposal (Charges for
Disposal of Construction Waste) Regulation (Cap. 354N);
·
Land (Miscellaneous Provisions)
Ordinance (Cap. 28); and
·
Public Health and Municipal Services Ordinance
(Cap. 132BK) – Public Cleansing and Prevention Nuisances Regulation.
Waste Disposal Ordinance (Cap. 354)
6.2.1.3
The Waste Disposal
Ordinance (WDO) prohibits the unauthorised disposal of wastes. Under WDO, waste
can be disposed of only at designated waste disposal facilities licensed by the
Environmental Protection Department (EPD).
Waste Disposal (Chemical Waste) (General) Regulation (Cap. 354C)
6.2.1.4
Issued under the WDO,
the Chemical Waste (General) Regulation administers the possession, storage,
collection, transport and disposal of chemical wastes. EPD has also issued
three guidelines detailing how the Contractor should comply with the
regulations on chemical wastes, namely A Guide to the Chemical Waste Control
Scheme (2016), A Guide to the Registration of Chemical Waste Producers (2016)
and Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes
(1992).
Waste Disposal (Charges for Disposal of
Construction Waste) Regulation (Cap. 354N)
6.2.1.5
Construction waste is
defined as any substance, matter or thing that is generated and abandoned from
construction works regardless if it has been processed or stockpiled before
being abandoned, excluding sludge, screenings or any matter removed or
generated from desludging, desilting or dredging works. 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 Facility (PFRF) for
disposal must consist entirely of inert material.
Land (Miscellaneous Provisions)
Ordinance (Cap. 28)
6.2.1.6
The inert portion of
Construction and Demolition (C&D) materials (including rocks, soil, broken
concrete, building debris etc.) may be taken to PFRFs. PFRFs 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
PFRFs are required to obtain Dumping Licences. The licences are issued by CEDD
under delegated authority from the Director of Lands.
Public Health and Municipal Services Ordinance – Public
Cleansing and Prevention of Nuisances Regulation (Cap. 132BK)
6.2.1.7
The Public Cleansing
and Prevention of Nuisances Regulation provides control on illegal dumping of
wastes on unauthorised/ unlicensed sites. The illegal dumping of wastes can
lead to a fine and/or imprisonment.
6.2.2
Other Relevant Environmental
Guidelines
6.2.2.1
Other environmental
relevant circulars/ guidelines applicable to waste management practices for
this Project include:
· Works
Branch Technical Circular (WBTC) No. 2/93 Public Dumps;
· WBTC No. 2/93B Public
Filling Facilities;
· WBTC No. 12/2000 Fill
Management;
· WBTC No. 19/2001 Metallic
Site Hoardings and Signboards;
· WBTC No. 12/2002
Specifications Facilitating the Use of Recycled Aggregates;
· Environment, Transport
and Works Bureau Technical Circular (Works) (ETWB TCW) No. 19/2005
Environmental Management on Construction Sites;
· Development Bureau
Technical Circular (Works) (DEVB TCW) No. 06/2010 Trip-ticket System for
Disposal of Construction and Demolition Material;
· DEVB TCW No. 08/2010
Enhanced Specification for Site Cleanliness and Tidiness;
· DEVB TCW No. 09/2011
Enhanced Control measures for Management of Public Fill;
· Hong Kong Planning
Standards and Guidelines, 2016 (PlanD);
· Code of Practice on the
Packaging, Labelling and Storage of Chemical Wastes (EPD);
· A Guide to the Chemical
Waste Control Scheme (EPD); and
· Section 4.1.3 of Chapter
4 of the Project Administration Handbook (PAH) for Civil Engineering Works,
Management of Construction/ Demolition Materials including Rocks.
6.2.2.2
The WBTC No. 2/93
‘Public Dumps’ documents the current policy related to the disposal of C&D
materials. C&D materials that are wholly inert, i.e.
public fill, should be taken to PFRFs for reuse instead of being disposed of at
landfill.
6.2.2.3
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.
6.2.2.4
Further measures have
been introduced under Paragraph 4.1.3 of Chapter 4 of the PAH for Civil
Engineering Works to enhance the management of C&D materials, and to
minimize its generation at source. The enhancement measures include:
· Drawing
up a Construction and Demolition Materials Management Plan (C&DMMP) at an
early design stage to minimize C&D materials generation and to encourage
proper management of such materials;
· Vetting of the C&DMMP
prior to upgrading of the project to Category A in the Public Works Programme;
and
· Providing the Contractor
with information from the C&DMMP in order to facilitate the preparation of
Waste Management Plan (WMP) and to minimize C&D materials generation during
construction.
6.2.2.5
The ETWB TCW No.
19/2005 Environmental Management on Construction Sites introduces additional
measures to enhance waste management on construction sites. The circular sets
out the policies and procedures that require the Contractors to prepare and
implement an Environmental Management Plan (EMP), which includes the WMP to
encourage on-site sorting of C&D materials and to minimize generation of
C&D materials during the course of construction.
6.3.1.1
The Project site is
located at southern end of Kung Um Road to the north of Tai Lam Country Park
and within a rural area currently occupied mainly by brownfield operations. The
Project site also falls within the YLS DA.
6.4.1.1
The assessment of the
potential waste management implications during the construction and operation
phases of the proposed YLSEPP has been conducted in accordance with Annexes 7 and
15 of the EIAO-TM, including the following tasks:
· Estimation
of the types and quantities of the wastes generated;
· Evaluation of
opportunities for waste reduction and re-use;
· Identification of
disposal options for each type of wastes;
· Assessment of potential
environmental impacts arising from the wastes
management with respect of potential hazards, air and odour emissions, noise,
wastewater discharge, and public transport; and
· Assessment of the impacts
caused by handling, collection, transportation and re-use / disposal of wastes.
6.4.1.2
Prior to considering
the disposal options for various types of waste, opportunities for reducing
waste generation, on-site or off-site reuse and recycling have been evaluated.
Measures which can be taken in the planning and design phases (e.g. by modifying the design approach) and in the
construction phase for maximizing waste reduction have been separately
considered. Practices to promote segregation of waste materials are
additionally considered for advancing the waste management efficiency.
6.4.1.3
After considering all
the opportunities for reducing waste generation and maximizing reuse, the types
and quantities of the waste required to be disposed of have been estimated and
the disposal options for each type of waste have been described. The disposal
method recommended for each type of waste has been taken into
account the result of the assessment. The impacts caused by handling
(including stockpiling, labelling, packaging and storage), collection and
reuse/ disposal of waste have been addressed and appropriate mitigation
measures have been proposed.
6.5.1
Construction
Phase
6.5.1.1
The construction
activities to be carried out for the Project include land excavation, backfilling,
foundation works and installation of new facilities. The types of waste
associated with these activities include:
· C&D
materials;
· Chemical waste; and
· General refuse.
Construction and demolition (C&D)
materials
6.5.1.2
C&D materials would
be generated mainly from the excavation and construction works for the proposed
YLSEPP. The C&D materials would
comprise both inert C&D materials (i.e. public
fill including soil, rock, concrete etc.) and non-inert C&D materials (i.e.
C&D waste including vegetation, timber, paper, plastics etc.). Based on the
latest layout, it was estimated that the total quantity of C&D materials
generated would be 289,000 m3. A summary of the C&D materials
estimates during construction phase is shown in Table 6.1.
6.5.1.3
The inert C&D
materials should be reused on-site as far as possible to minimize the net
amount of inert C&D materials generated from the Project. The amount of inert materials generated during construction
phase is expected to be around 268,100 m3. Such inert C&D
materials would be reused on-sites as much as possible before disposal to the public
filling area or other construction sites with potential fill demand. Around 52,900
m3 of inert C&D materials, mainly soil, could be reused on-site
as backfill materials.
6.5.1.4
The non-inert C&D
materials would be reused and recycled on site as much as possible before
disposal at landfill. For example, the timber and bamboo materials used as
formwork for concreting and temporary scaffolding would be reused to reduce the
generation of waste. The amount of non-inert materials generated during
construction phase is expected to be around 20,900 m3. It is the
Contractor’s responsibility to separate the inert and non-insert C&D
materials on site. Drainage Services Department (DSD) shall enquire EPD on the
availability of landfill and acceptability of the waste.
Table 6.1 Estimated Quantities of C&D Materials
during Construction Phase
|
Type
of C&D Materials
|
Total
Quantity (m3)
|
Reused in the
Project (m3)
|
Delivered to PFRF
or Reused in other projects (m3)
|
Delivered
to Landfill (m3)
|
|
Non-inert C&D Material
|
20,900
|
0
|
0
|
20,900
|
|
Inert C&D Materials (Soft Material
Fill)
|
255,100
|
52,900
|
202,200
|
0
|
|
Inert C&D Materials (Broken
concrete)
|
7,900
|
0
|
7,900
|
0
|
|
Rock (Grade III or above)
|
5,100
|
0
|
5,100
|
0
|
|
Total
|
289,000
|
52,900
|
215,200
|
20,900
|
Note: Quantities of C&D materials are
round up to nearest hundred.
6.5.1.5
The non-inert C&D
materials would be disposed of at landfill while surplus inert C&D
materials (general fill) will be transported to public filling area. With the
implementation measures recommended in Section 6.6.1, no adverse environmental impacts (including potential hazard, air and
odour emissions, noise, wastewater discharge and ecology) and public transport
impact caused by handling, storage, transport and disposal of C&D materials
are expected.
Chemical Waste
6.5.1.6
The maintenance and
servicing of construction plant, equipment and vehicles may generate a
negligibly small amount of chemical wastes such as
waste oil / grease, spent solvent / detergents, empty fuel / lubricant drums,
used oil filter and scrap batteries.
6.5.1.7
Considering the Project
site falls within the YLS DA, construction activities under this Project would
be undertaken remotely from the existing village houses. Nevertheless, chemical
wastes arising during construction phase may still 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).
6.5.1.8
It is difficult to
quantify the amount of chemical waste that would arise from the construction
activities as it would be highly dependent on the Contractor’s on-site
maintenance activities and the quantity of plant and equipment utilized. It is
anticipated that the quantity of chemical waste, such as cleaning fluids,
lubrication oil and solvent produced from plant maintenance, would be small and
in the order of a few cubic meters per month. The amount of chemical waste to
be generated would be quantified in the WMP to be prepared by the Contractors.
6.5.1.9
The contractor must
register with EPD as a chemical waste producer if any chemical waste would be
generated during construction phase. 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. Mitigation and control requirements for chemical
wastes are detailed in Section 6.6.1. Provided that the handling, storage and disposal of chemical wastes
are in accordance with these requirements and the Code of Practice on
Packaging, Labelling and Storage of Chemical Wastes published by EPD, adverse
environmental impacts (including potential hazard, air and odour emissions,
noise, wastewater discharge and ecology) and public transport impact will be
negligible.
General Refuse
6.5.1.10
General refuse
comprising general site wastes, such as packaging and container waste from
materials and equipment used on the site, food scraps, waste
paper, empty containers etc. would be generated by workforce during
construction phase. 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.
6.5.1.11
The maximum number of
construction workers to be working on site at any one time was estimated to be
about 400. Based on a generation rate of 0.65kg per workers per day,
approximately 260 kg of general refuse would be generated daily during the
construction period. It is expected that the general refuse and non-inert C&D
materials from construction sites would be disposed of at landfill. Given the
quantity of general refuse to be disposed of at landfill would be small, no
adverse impact on the operation of landfill would be anticipated.
6.5.1.12
In order to minimize
the final disposal quantities of general refuse, provision of sufficient number
of recycling bins for the collection of different types of recyclable waste
(including paper, aluminium cans, plastic and glass bottles) and sufficient
number of general refuse bins for the collection of non-recyclable waste is
recommended. The Contractor should implement an education programme for workers
on avoiding, reducing, reusing and recycling of general refuse.
6.5.1.13
The general refuse
would 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 off-site disposal, 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 would be anticipated. Recommendations of mitigation
measures for managing general refuse are presented in Section 6.6.1.
6.5.2
Operational
Phase
6.5.2.1
Wastes arising from the
operation of the Project would include:
· Screenings
and grits;
· Dewatered sludge;
· Chemical waste; and
· General refuse.
Screenings and Grits
6.5.2.2
Screenings and grits
would be generated at the inlet works with preliminary treatment during
operation phase of the YLSEPP. The estimated total volume of screenings and
grits to be generated would be up to 4 m3 per day. The screenings
and grits would be compacted and properly stored in a covered container prior
being disposed of at landfill on a daily basis. The transportation and disposal
of the screenings and grits would be managed and controlled by a reputable
waste collector employed by the operators to reduce the potential pest, odour
and litter impacts.
Dewatered Sludge
6.5.2.3
The
pre-treated food waste reception area at YLSEPP would receive approximately 100
wet tonnes of organic waste per day for co-digestion with sludge generated from
sewage treatment. The incoming organic waste (around 15% dry solid content) will
be transported to YLSEPP via fully enclosed trucks and stored in a food waste
bunker with a 2-day storage capacity. The organic waste will be pumped to the Food
Waste Preparation Tank and diluted with YLSEPP’s effluent water to around 5%
dry solid content. The diluted organic waste will then be routed to the
anaerobic digester for co-digestion with the sewage sludge and subsequently
sent to the digested sludge storage tanks for storage. In view of the design
capacity of the food waste bunker and design configuration of the digesters (i.e. 3 duty and 1 standby) with a target sludge retention
time of minimum 20 days for each digester, no adverse environmental impact
would be anticipated from the incoming organic waste arrangement during maintenance
or breakdown of the digesters.
6.5.2.4
The co-digested sludge
generated from YLSEPP containing sewage sludge and organic waste would be
dewatered to a dry solid content satisfying EPD’s requirement before disposal
to EPD’s Sludge Treatment Facility (STF) at Tuen Mun.
The estimated amount of dewatered sludge generated by YLSEPP is approximately
64.6 wet tonnes per day (i.e. the contribution to the dewatered
sludge from sewage sludge and organic waste are approximately 40.3 wet tonne
per day and 24.3 wet tonne per day, respectively). The dewatered sludge would be stored properly in covered containers
within the YLSEPP to avoid odour nuisance prior to being delivered to the STF
for disposal. It was estimated that around 6 containers per day would be
required to transport the dewatered sludge for disposal at STF via Nim Wan Road.
6.5.2.5
Provided that the
recommended mitigation measures in Section
6.6.2 are properly implemented, adverse environmental impacts from the
storage, handling, transport and disposal of the organic waste and dewatered
sludge would not be anticipated.
Chemical
Waste
6.5.2.6
Small quantities of
chemical wastes such as spent UV lamps, paints, lubricants and used batteries
would also be generated during maintenance activities and may pose
environmental, health and safety hazards if improperly handled. Measures
stipulated in the Waste Disposal (Chemical Waste) (General) Regulation and the
Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes
would be strictly followed for the handling and disposal of chemical waste.
6.5.2.7
The operator must
register with EPD as a chemical waste producer if any chemical waste would be
generated from the operation. Chemical waste should be collected periodically
in drum-type containers by licensed chemical waste collectors and disposed of
at the CWTC at Tsing Yi. The quantities of chemical waste generated from the
operation phase is considered as minimal (e.g. a few
cubic metres per month would be anticipated). With proper storage, handling and
disposal of this waste, no adverse environmental impact would be anticipated.
General Refuse
6.5.2.8
During operation phase,
general refuse, including food waste, paper, wood, plastic, office wastes etc.,
would be generated by staff, visitors, and office activities. As a worst case scenario, the total number of personnel present
on-site is estimated to be not more than 150 per day. Based on a generation rate of 0.65 kg per personnel
per day, appropriately 97.5 kg of general refuse would be generated daily
during the operation period. Plastics,
papers and other recyclable wastes should be separated from general refuse and
recycled as far as possible. The remaining refuse would be collected by
licensed collectors daily or at least on every second day and disposed of at
landfill.
6.5.2.9
The anticipated
potential environmental impacts arisen from the handling, storage and disposal
of waste in operation phase would be insignificant provided that the mitigation
measures stated in Section 6.6.2 are strictly followed.
Waste Management Hierarchy
6.6.1.1
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:
·
Avoidance and reduction of waste generation;
·
Reuse of materials as far as practicable;
·
Recovery and recycling of residual materials where possible; and
·
Treatment and disposal according to relevant laws, guidelines and good
practices.
6.6.1.2
Based on the waste
management hierarchy, waste reduction measures are recommended as follows to
reduce impacts and costs arisen from the Project. Recommendations of good site
practices and waste reduction measures would be stated in order to achieve
avoidance and minimization of waste generation in the hierarchy. EMP and
trip-ticket system are recommended for monitoring management of waste.
Good Site Practices
6.6.1.3
It is anticipated that
adverse impacts would not arise at the construction site, provided that good
site practices are strictly followed. Recommendations of good site practices
during construction phase include:
·
Nomination of an 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; and
·
Preparation of a WMP in accordance with ETWB TCW No. 19/2005 and submit
to the Engineer for approval.
6.6.1.4
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 monitoring and auditing work. One may refer
to DEVB TCW No.6/2010 for details.
Waste Reduction Measures
6.6.1.5
Good management and
control of construction site activities/ processes can minimize 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 materials;
·
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 at 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
minimize the amount of surplus waste generated;
·
Adopt pre-cast construction method instead of cast-in-situ method for
construction of concrete structures as much as possible;
·
Minimise over ordering of concrete, mortars and cement grout by doing
careful check before ordering; and
·
Provide training to workers on the importance of appropriate waste
management procedures, including waste reduction, reuse and recycling.
6.6.1.6
In addition to the
above measures, other specific mitigation measures are recommended below to
minimize environmental impacts during handling, transportation and disposal of
wastes.
Storage, Collection and Transportation of
Waste
6.6.1.7
Storage of materials on
site may induce adverse environmental impacts if not properly managed,
recommendations to minimize the impacts include:
·
Waste, such as soil, should be handled and stored well
to ensure secure containment, thus minimizing the potential of pollution;
·
Maintain and clean storage areas routinely;
·
Stockpiling area should be provided with covers and water spraying
system to prevent materials from wind-blown or being washed away; and
·
Different locations should be designated to stockpile each material to
enhance reuse.
6.6.1.8
Licensed waste haulers
should be employed for the collection and transportation of waste generated.
The following measures should be enforced to minimize the potential adverse
impacts:
·
Remove waste in a timely manner;
·
Waste collectors should only collect wastes prescribed by their
permits;
·
Impacts during transportation, such as dust and odour, should be
mitigated by the use of covered trucks or in enclosed containers;
·
Obtain relevant waste disposal permits from the appropriate
authorities;
·
Dispose of waste at licensed waste disposal facilities; and
·
Maintain records of quantities of waste generated, recycled and
disposed.
6.6.1.9
Land transport would be
used for transportation of excavated and stockpile materials. It is expected
there would be a maximum of 120 vehicle trips per day for transporting waste
during construction phase. The identified disposal outlets for the disposal of
various types of wastes are summarised in Table 6.2. No barging points or conveyor systems would be established for the
Project. The transportation routings may change subject to the actual traffic
conditions of the roads. Nevertheless, with the implementation of appropriate
mitigation measures (e.g. using water-tight containers
and covered trucks), no adverse environmental impacts would be expected due to
the transportation of waste.
Table 6.2 Summary of Waste Disposal
|
Disposal
Outlet
|
Type
of Waste
|
|
Construction Phase
|
|
Landfill
|
Non-inert C&D Materials
and General Refuse
|
|
Public Filling Area
|
Surplus Inert C&D
Materials
|
|
CWTC
|
Chemical Waste
|
|
Operation Phase
|
|
Landfill
|
Screenings, Grits and
General Refuse
|
|
STF
|
Sludge
|
|
CWTC
|
Chemical Waste
|
6.6.1.10
In order to monitor the
disposal of C&D materials at PFRFs and landfills and to control
fly-tipping, a trip-ticket system should be established in accordance with DEVB
TCW No. 6/2010. A recording system for the amount of waste generated, recycled
and disposed, including the disposal sites, should also be set up. Warning
signs should be put up to remind the designated disposal sites. CCTV should be
installed at the vehicular entrance and exit of the site as additional measures
to prevent fly-tipping.
6.6.1.11
In addition to the
above general measures, other specific mitigation measures on handling the
C&D materials and materials generated from excavation and construction
works for the proposed YLSEPP are recommended below, which should form the
basis of the WMP to be prepared by the Contractor during construction phase.
Construction and Demolition Material
6.6.1.12
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 maximize 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.
6.6.1.13
In order to minimize
the impacts resulting from collection and transportation of C&D materials
for off-site disposal, the excavated materials arising from foundation works
should be reused on-site as backfilling materials and for landscaping works as
far as practicable. Other mitigation requirements are listed below:
·
A WMP, which becomes part of the EMP, should
be prepared in accordance with ETWB TCW No.19/2005;
·
A recording system for the amount of wastes
generated, recycled and disposed (including the disposal sites) should be adopted
for easy tracking; and
·
In order to monitor the disposal of C&D materials at public filling
facilities and landfills and to control fly-tipping, a trip-ticket system
should be adopted (refer to DEVB TCW No. 06/2010).
6.6.1.14
It is recommended that
specific areas should be provided by the Contractors for sorting and to provide
temporary storage areas (if required) for the sorted materials. Control
measures for temporary stockpiles on-site should be taken in order to minimize
the noise, generation of dust and pollution of water. These measures include:
·
Surface of stockpiled soil should be
regularly wetted with water especially during dry season;
·
Disturbance of stockpile soil should be minimised;
·
Stockpiled soil should be properly covered with tarpaulin especially when
heavy storms are predicted; and
·
Stockpiling areas should be enclosed where space is available.
6.6.1.15
The Contactor should
prepare and implement an EMP in accordance with ETWB TCW No. 19/2005, which
describes the arrangements for avoidance, reuse, recovery, recycling, storage,
collection, treatment and disposal of different categories of waste to be
generated from construction activities. Such a management plan should
incorporate site-specific factors, such as the designation of areas for
segregation and temporary storage of reusable and recyclable materials. The EMP
should be submitted to the Engineer for approval. The Contractor should
implement waste management practices in the EMP throughout the construction
stage of the Project. The EMP should be reviewed regularly and updated by the
Contractor, preferably on a monthly basis.
6.6.1.16
All surplus C&D
materials arising from or in connection with construction works should become
the property of the Contractor when it is removed unless otherwise stated. The
Contractor would be responsible for devising a system to work for on-site
sorting of C&D materials and promptly removing all sorted and process
materials arising from the construction activities to minimize temporary
stockpiling on-site. The system should be included in the EMP identifying the
source of generation, estimated quantity, arrangement for on-site sorting,
collection, temporary storage areas and frequency of collection by recycling
Contractors or frequency of removal off-site. A Construction and Demolition Material
Management Plan (C&DMMP) should be prepared and submitted together with EIA
Report for PFC’s approval as required under Section 4.1.3 of the PAH.
Chemical Waste
General Refuse
6.6.1.18
Recycling of waste paper, aluminium cans and plastic bottles should be
encouraged, it is recommended to place clearly labelled recycling bins at
designated locations with convenient access. Other general refuse should be
separated from chemical and industrial waste by providing separated bins or
skips for storage to maximize the recyclable volume. A reputable licensed waste
collector should be employed to remove general refuse on a daily basis to
minimize odour, pest and litter impacts.
6.6.2.1
The major waste arising
from the operation of YLSEPP would be screenings and grits collected from the
inlet works and the dewatered sludge generated by YLSEPP.
6.6.2.2
The below good
housekeeping practices for the proposed YLSEPP should be followed to further
ameliorate any odour impact from handling, collection, transportation and
disposal of screenings, grits and sludge:
·
Screens should be cleaned regularly to remove
any accumulated organic debris;
·
Screening and grit transfer systems should be flushed regularly with
water to remove organic debris and grit;
·
Grit and screened materials should be transferred to closed containers;
·
Scum and grease collection wells and troughs should be emptied and
flushed regularly to prevent putrefaction of accumulated organics;
·
Skim and remove floating solids and grease from primary clarifiers
regularly;
·
Frequent sludge withdrawal from tanks is necessary to prevent the
production of gases;
·
Organic waste should be transported to YLSEPP by fully enclosed trucks
to avoid odour nuisance;
·
Organic waste should be stored in closed containers at the reception
area;
·
During the unavailability of digesters (e.g.
maintenance or co-digestion period), the diluted organic waste should remain
inside the Diluted Food Waste Preparation Tank under continuously mixed
condition;
·
Sludge should be transported to the STF by water-tight containers to
avoid H2S/odour emission and ingress of water into the containers
which would lower the sludge dryness during transportation;
·
Sludge cake should be transferred to closed containers;
·
Sludge containers should be flushed with water regularly; and
·
Sludge trucks and containers should be washed thoroughly before leaving
the YLSEPP to avoid any odour nuisance during transportation.
6.6.2.3
The screenings and
grits would be collected and disposed of at landfill regularly by a reputable
waste collector while the dewatered sludge would be disposed of at STF in Tuen Mun to reduce the potential pest, odour and litter
impacts. In addition, all wastewater generated from the sludge dewatering
process and all contaminated water from the cleaning operations recommended for
odour control will be diverted to the proposed YLSEPP for proper treatment.
6.6.2.4
The chemical waste
generated during operational phase would follow the same handling procedures
and disposal method presented in Section
6.6.1.17.
6.6.2.5
A summary of the
estimated various types of waste during construction and operational phases and
their disposal routes are presented in Table 6.3.