The existing
ERM-Hong
Kong, Ltd (ERM) has been commissioned by the Environmental Protection
Department (EPD) to undertake the South
East New Territories (SENT) Landfill Extension – Feasibility Study (the
“Assignment”) under Agreement No. CE 10/2005(EP). As part of the Assignment, an
Environmental Impact Assessment (EIA) Study has been prepared in accordance
with EIA Study Brief (No.
ESB-119/2004) issued under the Environmental
Impact Assessment Ordinance (EIAO).
The EIA Report addresses potential
environmental impacts associated with the construction, operation, restoration
and aftercare of the Extension ( “the Project”). This Executive
Summary summarises the key findings of the EIA.
The Government is therefore actively
promoting initiatives to reduce waste generation and promote waste
recycling. When comparing the waste
statistics for 2006 with those of previous years, the amount of MSW disposed of
at the three strategic landfills (WENT, NENT and SENT) dropped by 1% against an
economic growth of 6.8% in 2006.
Equally encouraging is the increase in the recovery rate of domestic
waste from 16% in 2005 to 20% in 2006.
At the same time, the overall recovery of MSW has also increased from
43% in 2005 (2.59 million tonnes) to 45% in 2006 (2.84 million tonnes), three
years ahead of the target stated in the Policy Framework. There are however areas of concern. Even though the amount of MSW landfilled was reduced by 1% in 2006, there is still a long
way to go in achieving the Policy Framework’s target of reducing the total MSW landfilled to less than 25%. In addition, despite EPD’s
efforts in waste reduction and recovery, the amount of MSW generated remains on
an increasing trend. This is likely
to be the result of growth in commercial, industrial and tourism-related
activities in 2006 which has led to an increase of about 4% in commercial and
industrial waste generation. Therefore, despite the progress achieved for
source separation and waste recycling, it is important to press ahead with the
other initiatives in the Policy Framework such as Producer Responsibility
Schemes (PRSs), MSW charging, integrated waste
management facilities (IWMF) and landfill extensions.
At the same time, the Government is also
looking into building modern large scale integrated waste management facilities
that would employ thermal treatment as a core technology as it is clearly not
sustainable to continue to rely on landfilling alone
for the disposal of untreated MSW.
The IWMF are planned to be commissioned in the mid 2010s, assuming that
good progress is made. As mentioned
in the Policy Framework, landfills will still be required as the final
repositories for non-recyclable waste, inert waste and waste residues after
treatment. Taking into account the
waste reduction and treatment initiatives in the Policy Framework,, it has been
estimated that the demand for landfill space from 2006 to 2025 is around 200
million tonnes, while the remaining landfill capacity, at the end of 2004 was
90 million tonnes. The provision of
sufficient landfill space by extending the capacity of the three existing
landfills is an important and integral part of the waste management strategy in
In addition to the need for landfill
capacity on a territory-wide basis, there is a need to meet the regional demand
for waste disposal outlets. The
three landfills are at strategic locations in Hong Kong and the extension of
all three is necessary to maintain the overall waste disposal plan which is
based on bulk waste transfer to avoid excessive number of waste collection
vehicles travelling in the urban areas ([1]).
Due to its close proximity to the urban areas, the SENT Landfill is the
most highly used waste disposal facility amongst the three landfills, particularly
by private waste collectors for commercial, industrial as well as construction
wastes. It receives about 6,200
tonnes of municipal, construction and special wastes every day. If the SENT Landfill is closed, waste
will have to be diverted to the NENT and WENT Landfills. This will require vehicles collecting
waste from the catchments of the SENT Landfill to travel an additional hundred
thousand kilometres per day in total through the built-up areas to the remotely
located NENT and WENT Landfills, thus resulting in additional environmental
impacts such as increased traffic movements, vehicular emissions and noise
impacts on many more sensitive receivers en-route. To reduce these impacts, we would need a
succession plan by developing new waste transfer and/or handling facilities in
the south-east region of the territory, such as new handling facility for
construction waste (ie the Construction Waste
Handling Facility (CWHF)) and refuse transfer station for MSW (ie the South-East Kowloon Material Recovery and Transfer
Station (SEKTS)). As the planning
(including the site search), feasibility study, statutory environmental impact
assessment process, tendering and contract arrangement, detailed design,
construction and commissioning of these facilities would take equally long time
as the landfill extension scheme, it further strengthens the importance of
maximising the capacity of Extension where feasible in order to minimize those
impacts as far as we could manage.
Projecting the time at which these new facilities
will be available is very uncertain as the site for the CWHF will unlikely be
available in the early 2010s and the site selection for the SEKTS has not yet
been started. It will be a long
planning and public consultation process to secure suitable waterfront sites at
the Tseung Kwan O and South East Kowloon areas which
are acceptable to the public for the development of these waste transfer/handlling facilities, but without compromising the overall
planning and development of these two areas. In addition, the funding for developing
these facilities has not been secured.
Under an optimistic set of conditions to form a target programme at the
present stage, they could possibly be in place by 2017. With SENT expected to be full by 2012,
at least six years of additional void space is necessary. It is important to extend the lifespan
of the SENT Landfill so that the Government can have time to plan and develop
these new waste handling facilities.
The Project is classified as a Designated
Project under Schedule 2, Category G.1 and Q.1 of the EIAO and therefore the construction, operation, restoration and
aftercare of the Extension will require an Environmental Permit.
The objectives of the EIA Study are to
provide information on the nature and extent of environmental impacts arising
from the Extension; to recommend appropriate mitigation measures to control the
potential environmental impacts so that it complies with the requirements of
the Technical Memorandum on Environmental
Impact Assessment Process of the EIAO (EIAO-TM); and to confirm the
environmental acceptability of the Extension. Key environmental issues identified in
the EIA Study Brief include air quality, noise, water quality, waste management,
landfill gas hazards, ecology and landscape and visual impacts.
The EIA was conducted in accordance with
the guideline on assessment methodologies provided in the EIAO-TM. The general approach
for the assessment includes description of baseline environmental conditions
for the impact assessment, identification and evaluation of potential impacts
and recommendation of mitigation measures and an environmental monitoring
programme. The assessments in this
EIA Study are conducted using well-proven and internationally accepted methods
based on reasonable worst-case conditions.
EPD identified 15 hectares of land in TKO
Area 137 together with an adjoining narrow strip of land within the Clear Water
Bay Country Park (CWBCP) as a potential site for the extension of the SENT
Landfill. Figures 2.1a to 2.1e show the
five extension options identified and examined under the Assignment. The key information of each extension
option is summarised in Table 2.1a.
Table 2.1a Key
Information of Extension Options
|
Options |
Characteristics |
Net Void Space (million m3) |
Encroachment into CWBCP (hectares) |
Estimated Construction Cost (HK$ per tonne of
waste) |
Additional Lifespan (years) |
||||
|
Option |
·
Stand-alone landfill ·
No sharing of Infrastructure |
1.3 |
0 |
350 |
<1 |
|
|||
|
Option 1b |
·
Stand-alone landfill ·
Sharing of infrastructure with
existing landfill |
1.6 |
0 |
200 |
<1 |
|
|||
|
Option 2 |
·
Piggy-back landfill ·
Sharing of infrastructure with
existing landfill |
10 |
0 |
80 |
4 |
|
|||
|
Option |
·
Piggy-back landfill ·
Sharing of infrastructure with
existing landfill |
15 |
3 |
60 |
5 |
|
|||
|
Option 3b |
·
Piggy-back landfill ·
Sharing of infrastructure with
existing landfill |
17 |
5 |
50 |
6 |
|
|||
|
Note: Construction cost of existing strategic landfill
is about HK$60 per tonne. |
|
||||||||
Five criteria were used to evaluate the
five extension options:
·
Landfill
capacity offered;
·
Efficiency
of use of land;
·
Cost
effectiveness;
·
Level
of encroachment into
·
Potential
environmental impacts.
Engineering measures and additional landtake in TKO Area 137 have also been considered to
maximise the void space while not encroaching the CWBCP.
The stand-alone options (Options 1a and 1b)
provide very low void capacity, equivalent to an extended lifetime for the SENT
Landfill of less than one year. The
piggyback options (Options 2, 3a and 3b) provide significantly higher void
capacity. Option 3b provides the
highest void capacity of all options evaluated and provides sufficient time for
the new generation of waste management facilities to come into operation.
All options make use of the 15 hectares of
land in TKO Area 137 that adjoins the southern end of the existing SENT
Landfill. Options
The stand-alone options have the highest
unit capital cost (per tonne of waste).
Option 3b has the lowest capital cost and is thus the most cost
effective option.
Options 1a, 1b and 2 will not encroach into
the CWBCP and hence will have no direct impact on the CWBCP. Options 3a and 3b will make temporary
encroachments of approximately 3 ha and 5 ha respectively. These options will therefore have a
direct impact on the habitat of CWBCP and wildlife within the country
park. It is noted that the
potential encroachment area is a cliff face dominated by shrubland
and grassland. At present, there
are no hiking trails or formal footpaths in the area. The area can only be accessed from the
existing SENT Landfill or the fill bank in TKO Area 137 and has not been used
for recreational and educational purposes.
The 9-month ecological baseline survey identified that the affected
habitats within CWBCP comprise shrubland and
grassland that is not of high ecological value. While some wildlife species of
conservation interest (including birds, butterflies, bats and reptiles) were
recorded within the direct impact area, all of these species were found to be highly
mobile and were found to have access to an abundant number of similar habitats
close by and within the CWBCP area.
Due to their smaller scale, Options 1a and
1b will have lower environmental impacts at local level when compared with the
other options. However, their shorter
lifespan may mean that diversion of waste collection vehicles to other
landfills will be required for a longer period, thus generating more
environmental impacts at a territorial level. Conversely, the larger scale Options 2
and 3a will have greater environmental impacts at the local scale but, due to
their longer lifespan, lower environmental impacts at territorial level. With careful design and good site
management and progressive restoration, local environmental impacts can be
mitigated. Option 3b, as the
largest extension option, will generate greater environmental impacts at the
local scale than the other four and will impact upon the natural habitats
within the CWBCP. Impacts on the
CWBCP can be mitigated by compensatory planting and appropriate afteruse development of the encroached area to enhance
educational and recreational value.
Engineering
measures that would increase void space but avoid the extension encroaching
into the CWBCP were considered.
These included building a retaining wall or earth bunds around the waste
mound. To make these measures
effective, the retaining wall or earth bund would need to be over 40m tall.
Such measures would have considerable cost implications and the earth bund
itself may consume a significant portion of landfill voidspace. The standalone feature would also be
difficult to integrate with the surrounding landscape and visually difficult to
accept. Such engineering measures
were therefore not put forward for further consideration.
An option to increase the amount of land
that is used within TKO Area 137 has been investigated, to investigate whether
encroachment into the CWBCP could be avoided. To develop an extension of capacity equivalent
to that in Option 3b without encroachment into the CWBCP would require
approximately double the size of the identified site in TKO Area 137 to be
used. Due to high demand of land in
TKO Area 137, additional allocation of land is not feasible. Also, to extend the SENT Landfill
further south adjacent to the CWBCP can only provide limited additional void
space.
With
reference to Clause 3.3.2 of the Study Brief, consideration was given to avoid
or minimize the encroachment onto the CWBCP and the disturbance to the
ecosystems in the adjacent areas including the CWBCP. Hence, Options 1a, 1b and 2, which do
not encroach upon the CWBCP are considered first.
Of
the five options examined, Options 1a and 1b would have the least impacts on
CWBCP and the sensitive receivers in the vicinity in terms of both construction
and operation. However, the
additional landfill void capacity provided by these options is very small,
making them inefficient in terms of cost and use of available land. The lifespan of these options is also
short and thus will result in longer period where waste collection vehicles
move waste to the more remote landfills, in turn resulting in more
environmental impacts at territorial level. These options are thus not
recommended.
Option 2’s void capacity is 6 times than that of Option 1b
and will not require additional land within the CWBCP. However, the void capacity will only be
10 Mm3 (ie still well below the target
void capacity), and the construction cost will be more expensive than that of
the existing strategic landfills.
Compared with Options 3a and 3b, the void space provided by Option 2 is
50% less than these encroachment options.
To maximise utilisation of the existing landfills, some diversion of the
waste collection vehicles to the other two landfills will be required, hence
will still creating environmental impacts at a territorial level. Option 2 would have similar local
environmental impacts to Options 3a and 3b, except that no natural habitat
would be impacted directly.
Visually, Option 2 does not blend with the surrounding environment as
well as Options 3a and 3b. Use of
engineering measures to increase voidspace whilst
avoiding encroachment was found to be expensive and likely to result in an
adverse visual impact. The
resulting gain in void space is small.
As
Options 1a, 1b and 2 cannot provide sufficient landfill voidspace
to help meet demand in Hong Kong for the next 20 years, Option 3a and 3b, which
require temporary encroachment into the CWBCP were considered further.
Options
3a and 3b will both have direct impacts on the CWBCP. In terms of maximising void capacity,
making the most effective use of available land and achieving the highest cost
effectiveness, Option 3b performs the best. The local environment impacts, similar to those
associated with Option 2, can be mitigated by careful design and good site
practices. The
temporary encroachment area is primarily a cliff face without any hiking trail
and proper access. It is unlikely
that public enjoyment of CWBCP would be affected. In terms of impacts on natural habitats,
the encroachment area is of low to moderate ecological value with flora and
fauna commonly found within the CWBCP.
When the temporary
encroached area is restored together with the fully restored landfill in the
vicinity after the completion of landfill operation, it is anticipated that the
restored Extension could be enriched to enable a higher amenity value for
public enjoyment.
It
is understood that there is a public need for both landfill space and country
park. The loss of void space as a
result of not maximising the use of this Extension Site will be reprovided at other landfills, as a result of reduction of
landfill space in other landfills as well as an overall shortfall of landfill
space in Hong Kong within the next 20 years and the environmental impacts
caused by longer journey to these landfills. When balancing all of the above
considerations, Option 3b, giving the largest void space and lifespan while
able to control environmental impacts to more acceptable levels with proper
design and mitigation, is recommended as the preferred option for detailed EIA.
It is recommended that the Extension Site
at TKO Area 137 and the existing SENT Landfill Infrastructure Area will be
formed by filling, instead of excavation in the SENT Landfill Infrastructure
Area and the TKO Area 137. This
method will ensure smaller amount of excavated material to be generated and
avoid the base of the landfill intercepting groundwater level, which is
relatively shallow in TKO Area 137.
The construction methods identified for
the slope formation work, their respective environmental benefits and dis-benefits have been examined. Blasting techniques are preferred over
non-explosive methods. Though
blasting is associated with relatively higher magnitude of environmental
impacts, these are very short lived and can be mitigated. In contrast, impacts associated with
non-explosive methods or open excavation (including continual use of noisy
hydraulic breakers) would be longer lived and are therefore not preferred. Blasting would also be more cost
effective and help ensure the timely completion of the works.
Similarly, alternative methods for
constructing the two small drainage tunnels have been examined. Tunnel boring is preferred over
blasting. Both options have similar
environmental impacts, most of which will be confined within the tunnel. Tunnel boring, however, has higher
productivity and a better controlled excavation profile while blasting brings
with it potential safety concerns over the use of explosives in a confined
space in close proximity to potential sources of landfill gas.
The sequence of constructing the Extension
is:
1)
construction
of a new infrastructure area which will also be designed to treat leachate and landfill gas from the existing SENT Landfill;
2)
demolition
of the infrastructure at the existing SENT Landfill; and
3)
formation and lining of the entire base of the landfill,
including the slope formation, prior to commencement of waste placement.
This works sequence will ensure uninterrupted
operation of the existing SENT Landfill, a smooth transition of operations to
the extension and safe operation during landfilling.
The Extension will be developed in
Phases. Within each Phase, it is
proposed that filling should start on the western side (ie
the side closest to
A layout plan of the preferred extension option
is shown in Figure 3.1a. The Extension is a “piggyback” landfill
occupying the existing SENT Landfill infrastructure area, 15 hectares of TKO
Area 137 and approximately 5 hectares of the CWBCP. The infrastructure area will be located
at the southern end of the Project Site.
The Extension covers an area of around 50
hectares (including the area required for site infrastructure). Discounting the void space required for
engineering works, daily and intermediate cover, the total net void capacity
for waste is around 17 Mm3.
The lifespan of the Extension is estimated to be around six years, with
operations starting in 2013 ([2]).
The design of the Extension includes:
·
A
landfill liner and cap – these are made of impermeable materials and are
designed to contain waste, leachate and landfill gas
within the waste boundary.
·
A
landfill gas management system – this comprises a number of landfill gas collector
wells and pipelines to gather the landfill gas and a landfill gas treatment
facility. Together, these elements
will control landfill gas
build-up and prevent migration of landfill gas off the site and into the
surrounding area.
·
A leachate management system – this comprises a number of leachate collection and extraction points, pipelines and a
treatment plant. This system will
control the leachate level within the landfill and
ensure that treated leachate complies with the
effluent discharge standard set for the Extension.
·
A
surface water management system – this comprises surface water cut off channels
constructed around the perimeter of the landfill site and drainage
tunnels. These features will
prevent surface water from upland areas from entering the Extension and will
also prevent contaminated runoff of the Extension from discharging to the
surrounding area.
·
A
groundwater management system – this comprises a specially designed drainage
layer below the liner at the base of the landfill. This layer is designed to collect and
transport groundwater away from the liner to the collection sumps at the
boundary of the Extension.
·
Odour
management and control system – key features comprise enclosing all the leachate storage and treatment tanks ([3]), applying deodorizers or odour
suppression agents at the active tipping face and at the western site boundary,
minimising the sizes of the active tipping face and special waste trench,
provision of mobile cover for the special waste trench, covering the non-active
tipping face with impermeable liner, prompt covering of MSW with soil or
selected inert materials, enclosing the weighbridge area, provision of vehicle
washing facility and progressive restoration of areas reaching the finished
profile.
·
Site
infrastructure – this includes waste reception facilities (eg
weighbridge, reception kiosk); vehicle wash facilities; offices and visitor
centre; a laboratory; maintenance workshops; a storage area; the landfill gas
treatment facility and leachate treatment plant described
above.
The key dates of the implementation
programme are shown in Table 3.2a.
Table 3.2a Key
Dates of Implementation Programme
|
Key Stage of the Project |
Indicative Date |
|
Start
construction |
2011 |
|
Commissioning
of new infrastructure facilities |
2011 |
|
Demolition
of existing infrastructure facilities |
2012 |
|
Stop
taking waste at the existing SENT Landfill |
2012 |
|
Start
waste intake at the Extension |
2013 |
|
Stop taking
waste at the Extension |
2018 |
|
End of
aftercare for the Extension |
2048 |
The potential environmental impacts
associated with the Project are summarised in the following sections.
Potential dust nuisance from construction
activities and gaseous emissions from plant have been evaluated. With the implementation of the
recommended dust control measures and good construction site practices, it is
not anticipated that the construction of the Extension will cause adverse dust
and air quality impacts.
The concentrations of gaseous emissions
predicted to be generated by the landfill gas treatment facility, the leachate treatment plant and the LFG generator are within
the relevant Air Quality Objectives (AQOs),
international chronic and acute reference guidelines and health risk guidelines
at air sensitive receivers (ASRs) taking into account other gaseous emissions
within 500m from the Extension site boundary and the general background contributions. The volatile organic compounds (VOCs) emissions from the Extension are predicted to be low
at the site boundary and that levels are within the respective trigger
levels. It is therefore not
envisaged that the operation of the Extension will cause adverse air quality
impact to the identified ASRs with respect to potential VOCs
emissions from the landfill.
The design of the
Extension has incorporated a stringent odour
management and control system (see Section
3.1). Good site practices and housekeeping would be
stipulated in the operation contract.
With the exceptions of those ASRs in the
immediate vicinity of the boundary of the Extension, no exceedances
of the odour criterion were predicted with the implementation of the odour
management and control system.
Residual impacts were predicted in a small area zoned for industrial
development covering part of TKO Area 137 and
The frequency of the exceedances
at
During the aftercare phase, air emission
sources are primarily associated with the landfill gas management facility and
the LFG generator. The Extension
will be sealed with a capping system (including an impermeable liner) and the
entrapped landfill gas will be extracted for utilisation or flaring. The vent
gas produced in the enclosed tanks will be either diverted to the flares or to
an air scrubber. The scrubbed vent gas will be used as part
of the air intake for the aeration system of the SBR tank. The odour sources will be limited to the
sequential batch reactor tanks of the leachate
treatment plant. As the emission
strength and scale of the Extension operation during this phase are
significantly reduced compared to the operation and restoration phases, no
adverse odour impact is anticipated.
The impact from gaseous emissions from the landfill gas treatment
facility and the LFG generator is predicted to be within the AQO criteria,
reference acute and chronic concentrations and health risk guidelines at any of
the identified ASRs. It is
therefore concluded that the aftercare of the Extension will not cause adverse
air quality impacts to the identified ASRs.
The requirements of regular monitoring of
dust, odour, ambient VOCs, ammonia and hydrogen sulphide,
and gaseous emissions from stacks have been recommended and detailed in the EM&A Manual.
The predicted construction noise levels at
identified noise sensitive receivers (NSRs) are well
below the noise criteria specified in the EIAO-TM. Hence,
no adverse construction noise impact is anticipated.
The predicted operation noise levels due to the Extension,
including the fixed plant items, at the representative NSRs
are within the noise criteria mentioned in relevant TMs.
Following the closure of the landfill, noise impact during the aftercare
phase is anticipated to be negligible.
The road traffic noise at NSRs
due to
While no adverse noise impacts are
expected during the operation and restoration phases of the Extension, it is
recommended that good site practices be implemented to further minimise any
noise impact.
With the implementation of the mitigation
measures set out in the EIA and good construction site practices, there will be
no adverse impacts on water quality.
A surface water drainage system will be
constructed around the active tipping area to prevent stormwater
from entering the landfill and get contaminated, and vice versa prevent
contaminated rainwater from discharging off the site. Contaminated runoff will be collected by
this system and treated with leachate. A comprehensive leachate
containment system will be installed to contain leachate
generated from the landfill.
Construction quality control and assurance procedures will be
implemented to ensure that joints are properly sealed and to avoid damage to
the impermeable liner during construction of this system.
The hydrogeological
assessment concludes that, while the landfill cap remains intact and leachate control is maintained, there will be no adverse
impacts on groundwater quality.
Even in the very long term (on a timescale of several hundred years),
when the landfill cap degrades and the active leachate
control can no longer perform their full function, the potential impacts on
groundwater quality are predicted to be slight. Under such conditions, the quality of
groundwater discharges to
Leachate and sewage collected from the Extension
will be treated at the on-site leachate treatment
plant. Effluent will be discharged
to the public sewer for conveying to the Government treatment works for further
treatment. Treated effluent
entering the sewer will comply with the effluent discharge standards set out in
the Technical Memorandum Standards for Effluents Discharged into Drainage
and Sewerage Systems, Inland and Inshore Waters. There will be no adverse water quality
impact.
The waste arisings
during the construction, operation, restoration and aftercare phases include
excavated material, construction and demolition material, general refuse from
daily operations, chemical waste from maintenance of plant and equipment and
sludge from the leachate treatment plant. The quantity, quality and timing of
these waste arisings have been identified. With good site practices, the potential
environmental impacts associated with the storage, handling, collection,
transport and disposal of the identified waste arisings
from the Extension will be within acceptable limits set out in the EIAO-TM. No adverse waste management impacts are
anticipated.
The potential hazards associated with
sub-surface migration of landfill gas from the existing SENT Landfill to the
Extension and from the Extension to the adjacent existing and future
developments have been assessed.
Both the existing SENT Landfill and the Extension are considered as a
“medium” source. Comprehensive and
proven landfill gas control measures have been installed in the existing SENT
Landfill and will be installed in the Extension. The source-pathway-target analysis shows
that landfill gas risk posed by the SENT Landfill and the Extension is medium
to high during both construction and operation phases within the Extension Site. Whereas the risk posed by the Extension to
the adjacent developments ranges from very low to low depending on the nature
and location of the these developments.
In general, underground rooms or voids
should be avoided as far as practicable in the design of the infrastructure
area of the Extension. Other
precautionary and protection measures during construction, design, operation
and restoration phases of the Extension have been recommended. It is expected that with the proposed
precautionary measures in place, the potential risk of landfill gas migration
to the respective targets will be minimal.
Regular monitoring of landfill gas in perimeter landfill gas monitoring
wells and service voids along the Extension Site boundary will be undertaken to
ensure that no unacceptable off-site migration of landfill gas occurs.
The terrestrial and aquatic ecological
resources recorded within the Study Area (including the Extension Site and the
500m buffer area) include plantation, shrubland,
grassland, developed area, seasonal stream and subtidal
habitats, as well as associated wildlife.
Of these habitats, shrubland has a moderate
ecological value, whilst other habitats are of low or low to moderate
ecological value. The ecological
value of the developed area is negligible.
The majority of
the proposed Extension will be located in habitats which have already disturbed
or developed including the existing SENT Landfill and the fill bank in TKO Area
137. The proposed Extension will
encroach into a small strip (approximately 5 ha) of the CWBCP, comprising shrubland and grassland habitats of low to moderate
ecological value. The potential impacts on these natural
habitats within the CWBCP are considered to be low to moderate. With the implementation of the
recommended mitigation measures, no adverse residual impact is expected. There are no marine works involved and
no marine habitats and species will be affected.
A survey recorded 11 wildlife species of
conservation interest (including birds, butterflies, bat and reptile) at the
Extension Site. As these species are highly mobile
and as there is a large extent of similar habitat in the vicinity of the
Extension, the impacts on wildlife are considered to be minimal.
The EIA sets out mitigation measures to
reduce ecological impacts. These
include the adoption of surface water, groundwater, leachate
and landfill gas management systems, good construction practices and provision
of compensatory planting. These
measures will reduce potential disturbance to the surrounding environment and
will also help provide a habitat of higher ecological value than that of the
existing site.
With mitigation measures in place, the
landscape impacts would range from “insubstantial” to “substantial” at
landscape resources during construction phase. The landscape impacts will be reduced to
“insubstantial to moderate” during the operation and restoration phases and
further reduced to “insubstantial to slight” at year 10 of the aftercare phase
when the restored landscape is fully mature. There will be “Slight positive”
landscape impacts on the reclaimed TKO Area 137.
Most of the sensitive residential
receivers are relatively distant from the Extension. With mitigation measures in place, the
visual impacts to the sensitive residential receivers would range from
“Insubstantial” to “slight” at the visual sensitive receivers during
construction phase and slightly worsen to “Insubstantial to moderate” during
the operation and restoration phases as the volume and height of the landfill
gradually increase. During the
aftercare phase, the impact will be reduced to “Insubstantial to slight” on day
1 of the aftercare phase, when landfilling operations
have ceased; and further reduced to “Insubstantial” as the landscape
restoration gradually matures.
Environmental monitoring and audit
requirements have been identified and recommended to implement to ensure the
effectiveness of the recommended mitigation measures. These requirements are specified in the EM&A Manual. The monitoring requirements cover the
area of dust, organic emissions, odour, gaseous emissions, surface water,
groundwater, leachate and
landfill gas. Regular site audits
throughout the construction, operation, restoration and aftercare of the
Extension have also been recommended.
The environmental impact assessment
(covering air quality, noise, water quality, waste management, landfill gas
hazards, ecology and landscape and visual impacts) has concluded that no
unacceptable environmental impacts are envisaged as a result of the
construction, operation, restoration and aftercare of the Extension, provided
that the recommended mitigation measures are implemented. It is predicted that there will be
residual odour impact on air sensitive receivers in the immediate vicinity of
the Extension Site boundary. Taking account of
the nature of the developments affected, the number of people impacted, the
transient nature, low frequency and magnitude of the exceedances,
the residual impacts are considered acceptable.
Recommendations for an environmental
monitoring and audit programme have been prepared to ensure the effectiveness
of the recommended mitigation measures.
·
the daily quantity of
MSW could not be handled by one or two landfills simply because of the strain
that would be placed on the surrounding road network and on the landfill sites
themselves;
·
the increases in MSW were
projected for the western and north-eastern
·
there would continue
to be a need for a final disposal facility in reasonable proximity to
The
existing 3 strategic landfills were therefore located at the western,
north-eastern and south-eastern
