The Need and
Justification for the Project
To Upgrade
Control on Air Emissions
2.1
The
existing Cape Collinson Crematorium has started operation since 1962. Cremator
Nos. 1-10 were replaced in 1995 and Nos. 11-12 were commissioned in 2001. The
Eastern District Council Members have raised concerns on air emissions of the
existing cremators. To minimize adverse impact on the environment, timely
replacement of the existing cremators will lead to improvement in control of
air emissions.
2.2
The
existing cremators are approaching the end of serviceable life and further
restoration work is considered not cost-effective or sustainable. Replacement
of all the existing cremators at the same site will be cost-effective and sustainable
while minimizing the potential impact on the environment from continued use of
the old cremators.
2.3
The
new cremators are designed to be capable of meeting EPD’s latest requirements
described in “A Guidance Note on the Best Practicable Means for Incinerators
(Crematoria)” BPM12/2(06).
To Meet Increasing Public Demand
for Cremation Services
2.4
At
present, the Government provides all the crematorium facilities that are open
for public use. The number of cremation sessions has been rising steadily in
the past three decades and the existing cremators in the territory are
operating at almost their full capacities. In 2008, out of the total number of
deaths of 41,530 in
2.5
The
old cremators at Cape Collinson Crematorium should be replaced in the public
interest and the capacity of the crematorium facilities should be expanded to
meet the increasing demand.
2.6
The
current
2.7
In
addition, new cremation technology will be deployed to enhance the handling
capacity of cremators and to improve the control on air emissions from the
cremators.
2.8
It
is envisaged that by 2012 upon commissioning of the four new cremators at Cape
Collinson Crematorium (under Phase 1 development) together with the six
cremators to be re-provisioned at Wo Hop Shek Crematorium, the annual cremation
capacity will be about 42,000 sessions. This capacity will just be adequate to
meet the expected cremation demand at that time.
2.9
Improvement
in waiting time overall is expected upon the completion of the remaining six
cremators at Cape Collinson Crematorium (under Phase 2 development) in 2014. By
then, the total annual cremation capacity will be increased to about 51,000
sessions and the waiting time can probably be shortened by one to two days from
the current 15 days at maximum.
2.10
If
the existing cremators are not replaced and upgraded in time, or if sufficient
numbers of additional cremators are not provided for commissioning by 2012 and
2014, a considerable number of applications for cremation sessions will unlikely
be met within the present pledge of 15 days. Extended waiting time for the
bereaved family will not be acceptable to the community. In addition, it is
envisaged that the air quality in the vicinity of Cape Collinson Crematorium
cannot be improved and the public concern on air emission cannot be addressed
unless and until the new cremation facilities are in place.
Consideration of Alternative Options
New Sites in More Remote Areas
2.11
Alternative
project sites within
2.12
There
will be environmental dis-benefits arising from crematorium developments in new
sites. Some of these dis-benefits may include newly-introduced traffic noise,
visual impact of a new facility, air emissions, environmental impact due to
tree felling, site formation works, construction traffic movements and
associated vehicular pollution and noise. Yet, these dis-benefits are either
transitional or, when suitably mitigated, should not undermine the development
potential of these sites.
2.13
Nonetheless,
it will take many years to develop adequate supporting transport network and
infrastructural facilities in these areas before they are suitable for
development. Depending on the land use zoning, it will also take time to
resolve the non-compatibility of crematorium development with the planning
intention of these areas, assuming that they have not previously been zoned for
crematoria. As such, new sites in remote areas may not readily meet the current
and increasing demand for cremation service.
Alternative Site in Tuen Mun
2.14
The
unallocated government land in Tuen Mun Area 46 is zoned for crematorium and
columbarium (C&C) development and is the only remaining zoned land that is
not yet developed to its planning intention.
2.15
Parts
of the site are currently leased to a private operator as a golf driving range
and to Environmental Protection Department (EPD) as a works area and site
office. The latter lease will expire by 2009. As local support for carrying out
C&C developments on this site is still lacking, it is expected that the
development scale, delivery schedule and mode of operation for any C&C
development at this potential site can only be considered at a later stage. As
such, the site is regarded as a potential site for planning of cremation in the
long run but not at the present stage.
Alternative
Extension at Other Existing Crematorium Sites
2.16
All
the eight cremators at Kwai Chung and Fu Shan Crematoria were replaced by more
efficient ones in 2003 and 2004 respectively. Six re-provisioned cremators at
Diamond Hill Crematorium were commissioned in 2007 and six new cremators at Wo
Hop Shek Crematorium will be reprovided by 2012. All the existing crematoria are
either developed to the maximum site utilization or that further extension will
be hindered by physical constraints.
Very limited expansion may be possible at certain sites but will not be
sufficient to meet the rising demand for cremation services.
Redevelopment of the Existing
2.17
Even
if other suitable new sites over the territory can be identified, it is not
expected that new crematorium facilities in these areas can be developed within
a short time. By contrast, the existing Cape Collinson Crematorium site is a
developed site with the necessary transport network and infrastructure and, is primarily
on government land. The proposed project at the existing site can start at the
earliest opportunity, thereby meeting the primary objective of upgrading the
cremation service as soon as possible.
2.18
As
described above, the development of new crematorium facility at a new or remote
site will carry environmental dis-benefits. By comparison, the impact of such
dis-benefits is relatively less significant for development of the existing
Cape Collinson Crematorium and will result in additional environmental
benefits.
2.19
Human
activities already exist at the current site in
2.20
The
upgrading of the existing Cape Collinson Crematorium will not result in a new
source of air emissions into the area, as the site has been used for cremation
since 1962. The existing cremators can only meet old emission standards,
whereas new cremators will meet the more stringent new standards. Therefore, the
project will result in an environmental benefit in terms of improved control of
air emissions. The air quality assessment indicates there is no unacceptable
impact from the new cremation facility.
2.21
The
noise assessment also indicates there is no adverse noise impact from upgrading
the existing Cape Collinson Crematorium.
2.22
The
existing cremators should henceforth be upgraded as early as possible to
address the local concerns on air quality, and to meet the rising public demand
for cremation service.
2.23
In-situ
development to redevelop the existing Cape Collinson Crematorium site to
accommodate the re-provisioned / new cremators under the Project is proposed.
Alternative
Extension Options
2.24
In
addition to the proposed redevelopment arrangement at the existing crematorium
site, other possible alternative extension options for the Project have been
explored. These include extension to adjacent sites near the Cape Collinson
Crematorium as shown in Figure 2.1 and
as briefly described below.
2.25
A
site to the west of the existing crematorium building (Site A) is not
considered feasible because it has recently been developed as a garden of
remembrance to facilitate the bereaved families to scatter cremains and is not
available for the Project. There are also a large number of niches surrounding
the site.
2.26
A
site to the east of the existing crematorium (Site B) is also eliminated
because there is insufficient flat area upon which to construct a crematorium.
Besides, the land is covered with a large number of trees and any development
will lead to substantial tree felling.
2.27
The
use of alternative in-situ extension arrangements such as retaining of the
existing crematorium building to minimise the construction impact, setting back
of the building to the south as shown in Figure
2.2, and sinking of the whole building below ground were also explored.
However, this option is not preferred in view of the following:
l
Although
there will be less environmental impact due to less demolition works, retention
of the existing crematorium is not practicable in view of the additional large
building area required to accommodate the air filtration system of the new
cremator design. It is not feasible to incorporate the new facilities within
the existing building envelope.
l
Extension
of the building to the south will result in extensive cutting of natural slope
at the southern portion of the site and undesirable effect on the existing
trees abutting the site.
2.28
The
topography of Cape Collinson Crematorium is rather hilly with majority of the area
already occupied by existing C&C facilities. Levelled sites that are
sufficiently sized for construction of a crematorium with ten cremators, three
service halls and other ancillary facilities are extremely limited. Choice of
sites is further restricted as areas up the hillside lack suitable flat land
which is essential for development of the Project. In the circumstances, the
existing crematorium site with its boundary suitably adjusted is considered the
only feasible and suitable option to enable early implementation of the
Project.
2.29
If
the proposed crematorium is to be operated from two separate sites with the
additional cremators / service halls in a new separate location, operational
efficiency will be adversely affected and there will be inconvenience to the
facility users. Furthermore, more sensitive receivers will be affected due to
the distribution of the facilities in two different sites.
Selection of Preferred Scenario
2.31
Based
on the findings as described above, the preferred scenario is redevelopment of
the existing Cape Collinson Crematorium site by adjustment into its adjoining
area so that the overall site area can accommodate 10 cremators and other
ancillary facilities by 2014. It is selected for the following reasons:
l
It is
the most suitable option for early implementation to meet the rising demand for
cremation service as soon as possible;
l
Human
disturbance already exist in the current site and its vicinity, therefore the
environmental impact of the Project on the local environment is marginal
compared with a new development on a
l
In-situ
redevelopment in the existing site has a much less significant environmental
impact with regard to introducing a new source of air emission and visual
impact of a new crematorium facility to a new site;
l
The
existing cremators can be upgraded using the latest cremation technology as
soon as possible, thereby addressing the local concern and achieving the
environmental benefit of improving the air quality;
l
If the
new crematorium is to be operated in two separate sites with the additional
cremators / service halls in a new separate location, operational efficiency
will be adversely affected and causing inconvenience to the facility users.
More sensitive receivers will be affected due to the distribution of the
facilities in two different sites.
Table 2.1 Environmental Benefits and Dis-benefits of Feasible Extension Options
|
Extension Options |
Environmental Benefits |
Environmental Dis-benefits |
Reasons for Not Selected as Preferred Option |
|
New sites in more remote areas outside Cape Collinson Crematorium |
The development will not be
constrained by existing building structures or establishments. There is more
scope for more flexible planning. |
1 Depending on site location,
potential impact to environment will be imposed on a 2 Vehicular emission and traffic noise brought about by
construction traffic movement during construction phase; 3 Traffic noise and vehicular emissions brought about
by traffic generated during operation phase; 4 New
air emission source into the remote area; 5 Potential visual impact by a new crematorium; and 6 Access road construction, site formation and tree felling
work may be involved. |
It will take
many years to develop adequate supporting transport network and
infrastructural facilities in these areas before they are ready for
development. Depending on the land use zoning, it will also take time to
resolve the non-compatibility of crematorium development proposal with the
planning intention of these areas, assuming that they have not previously
been zoned for crematoria. It will not be able to meet the current and
increasing demand for public cremation service. |
|
Alternative site in Tuen Mun Area 46 |
Same as above. |
1 Potential visual impact by a new crematorium; 2 Vehicular emission and traffic noise brought about by construction
traffic movement during construction phase; 3
Traffic noise and
vehicular emissions brought about by traffic during
operation phase; and 4
New air emission source into
the area. |
Parts of the site are currently on
lease as a private golf driving range and an EPD works site. The latter lease
will expire by 2009. As local support for carrying out crematorium and
columbarium developments on this site is still lacking, it is expected that
the development scale, delivery schedule and mode of operation for any
C&C development at this potential site can only be considered at a later
stage. As such, the site is regarded as a potential site for planning of
cremation in the long run but not at the present stage. |
|
Extension Options |
Environmental Benefits |
Environmental Dis-benefits |
Reasons for Not Selected as Preferred Option |
|
Further
extension in other existing crematoria at Kwai Chung, Fu Shan, Diamond Hill and Wo Hop Shek in addition to the
already implemented / being implemented development plans |
Human activities and activities
relating to the operation of crematoria already exist in these sites. Impact
on the environment arising from further extension will be marginal. |
Air
and noise emissions to these areas brought about by increasing traffic
and cremation emissions will be increased though marginally. |
Most of the existing crematoria have
been developed to the maximum site utilization. Further extension will be
hindered by physical constraints. Very limited expansion may be possible at
certain sites but not sufficient to meet the rising public demand for
cremation service. |
|
Expansion of the existing Cape Collinson Crematorium |
|||
|
Site to the west of the existing crematorium site (Site A) |
Improve local air quality with the replacement of new
cremators with advanced
emission control technology. |
--- |
It has been developed as garden of
remembrance lots and is not available for the project. |
|
Site to
the east of the existing crematorium (Site B) |
Improve local air quality with the replacement of new
cremators with advanced
emission control technology. |
Insufficient flat area and requires
extensive site formation works. Generation of noise
and air quality impacts during construction. |
The site is covered with trees and
substantial tree felling is required for development. |
|
Redevelopment in-situ at the existing |
|||
|
Preferred Option in this EIA Study |
Improve local air quality with the replacement by new
cremators with advanced emission control technology. Environmental assessment
indicates that there will not be adverse air quality and noise
impacts arising from the construction and operation of the new crematorium.
Human disturbance already exist in the Cape Collinson Site, impact of the
proposed new crematorium in the current site on the local environment will be
marginal. |
Some site formation works will be required but environmental impact can
be minimised to acceptable
levels through mitigation measures. |
Not applicable |
|
Alternative in-situ extension arrangements |
|||
|
Retaining of the existing crematorium building |
Less demolition works. |
This will make the
planning of the building inflexible and require a
larger site area. Consequently,
giving rise to a larger extent of construction dust impacts and disturbance
to the existing trees. |
It is not feasible in view of the additional large building
area required to accommodate the air filtration system of the new cremator
design. It is not possible to incorporate the new facilities within the existing building envelope. |
|
Extension Options |
Environmental Benefits |
Environmental Dis-benefits |
Reasons for Not Selected as Preferred Option |
|
Setting back of the building to the south |
--- |
Insufficient flat area and requires
extensive site formation works. Generation of noise
and air quality impacts during construction. |
This requires more extensive cutting of natural slope at the
southern portion of the site and undesirable disturbance to the existing
trees abutting the site. |
|
Sinking of the whole building below ground |
Reduce visual
impact to the surrounding. |
Deep basement construction will impose significant engineering
difficulties and increase overall environmental
impact during construction phase. |
The dis-benefits (in terms of
engineering difficulties and environmental impact) will outweigh the visual
benefits. |
Description of the Existing and
New Crematorium
2.32
The
existing Cape Collinson Crematorium is located at
2.33
In
view of the old design of existing cremators in Cape Collinson Crematorium, the
Project seeks to replace all the existing cremators to meet the current
emission standards stipulated under BPM12/2(06) and to increase the capacity of
the crematorium to meet rising demand on cremation.
2.34
As
there is no other flat area available for the construction of a replacement
crematorium under a single phase, it is only feasible to divide the development
into two phases.
2.35
The
Project Site is the site of the existing Cape Collinson Crematorium which
consists of four service halls with 12 cremators. Site formation work will be
carried out at the beginning of Phase 1 which involves extension of the
existing car park area for the construction of an access road. After the site
formation has been completed, a new crematorium with four cremators and two
service halls will be constructed to the north of the existing crematorium.
During this period, all the 12 cremators in the existing crematorium will still
remain in operation until the satisfactory commissioning of the new cremators
under Phase 1 by 2012. After completion of the Phase 1 works, demolition of the
existing crematorium, construction of another six cremators and one service
hall will then be carried out in Phase 2. The block plans of the proposed
crematorium (Phase 1 and Phase 2) are shown in Figures 2.3 and 2.4
2.36
The
proposed crematorium will be organized into three distinct zones on four
levels, namely basement (cremator plant room and operation & maintenance
supporting facilities), Level 1 (service halls, office and related facilities),
Level 2 (filtration plant, building services and roof garden) and Level 3
(mechanical and electrical plant rooms). The cremator operation areas will be
separated from the public areas by spatial zoning. The floor plans and sections
are shown in Figures 2.5 and
2.6, respectively.
2.37
The
service halls, coach parking spaces and hearse parking spaces are located on
Level 1. The roof garden on Level 2 will provide a peaceful and comfortable
environment for the public and provide immediate and distant views between the
existing
2.38
The
building footprint areas of Phase 1 and Phase 2 will be approximately 1,100m2
and 1,600m2, respectively. The maximum building height would be
about 17m and the chimneys height will be in the range of 24 to 26m above local
ground level.
Construction/Demolition
Programme
2.39
The
Project will be carried out in two phases. The tentative construction programme
for Phase 1 and Phase 2 works are shown in Figure
2.7. Prior to Phase 1 construction works, tree transplanting will be
carried out in advance from January 2010 to June 2010.
Phase
1 (July 2010 to March 2012)
2.40
Four
new cremators, together with the necessary ancillary facilities, will be
provided at the adjoining site to the north of the existing crematorium. The
total installed capacity of four new cremators under Phase 1 will be 680 kg/cycle
(i.e. 170 kg/cycle each). Based on 70 minutes average cycle time, the total
installed capacity of the four new cremators under Phase 1 will be about 583
kg/hour.
2.41
Provision
of a full range of ancillary facilities required for the operation of a
crematorium including:
l
Two
multi-purpose service halls;
l
Ash
storage room and pulverization room with a bone cremulator and dust-proof
cabinets;
l
Dangerous
goods stores;
l
Coach
and parking spaces;
l
Anti-burglary
devices;
l
Anti-bumping
devices inside the cremation room;
l
CCTV
system with recording device at strategic locations for monitoring purpose; and
l
Landscaping.
2.42
As
advised by the Project Proponent, the existing crematorium will still be
operating to serve the public during the testing and commissioning (T&C) of
the four new cremators under Phase 1. However, special arrangement will be made
to control that there will be no more than ten of both existing and new
cremators in operation at any time (i.e. two new cremators and eight existing
cremators) during testing and commissioning period to avoid additional loading
of chimney emissions to the environment. In other words, eight out of 12
existing cremators will be operated concurrently with two new cremators during T&C
period of Phase 1. The T&C period of Phase 1 would not exceed 4 months and
the actual testing of four new cremators would last for about 28 days within
the T&C period. Only two new cremators will be tested at any one time
with 3 cremation cycles or the requisite number of complete cycles to cover a
minimum period of six hours, whichever is the longer duration daily for each
new cremator.
Phase
2 (March 2012 to December 2014)
2.43
After
the satisfactory commissioning of the new cremators under Phase 1, the existing
crematorium as well as the existing underground fuel tank will be demolished
and removed. While the existing electric sub-station will be retained for the
new crematorium, a new transformer room has been proposed at the southwest of
the crematorium (see Figure 1.1). No
overlapping of construction/demolition works between Phase 1 and Phase 2 will
occur. The facilities to be provided under Phase 2 include:
l
Six
new cremators with equivalent provision and specifications in comparison to
those built under Phase 1 ;
l
Three
joss paper burners;
l
One
multi-purpose service hall;
l
Mortuary;
l
Office
accommodation;
l
Clergy
rooms;
l
Coach
and hearse parking spaces;
l
Refuse
storage chamber;
l
Transformer
room;
l
Toilet;
and
l
Landscaping.
2.44
Owing
to physical site constraint, only a temporary office will be provided during
Phase 2 construction. Unclaimed bodies will be handled in mortuaries of other
crematoria. A temporary refuse
collection point will be set up in the vicinity for refuse storage and disposal
in the period.
2.45
The
total installed capacity of six new cremators under Phase 2 will be 1,100 kg/cycle
(i.e. five cremators of 170 kg/cycle each and one cremator of 250 kg/cycle).
Based on 70 minutes average cycle time, the total installed capacity of the six
new cremators under Phase 2 will be about 943 kg/hour.
Construction and
Demolition Methodology
2.46
The
construction and demolition works of the Project will be divided into two
phases, namely Phase 1 and 2. Although the detailed
construction/demolition plan has not yet been formulated at this stage, the
demolition and construction methodology will be based on the following.
Phase 1
Construction Works
2.47
Site formation: As the existing
crematorium will still be operating during the Phase 1 construction period, new
access road will be constructed at the northern side of the site for the future
access to the existing crematorium at the early stage of the construction
works. Upon the completion of the access road construction, new crematorium
with 1-level basement will be constructed at bottom level of around +131.0mPD.
Excavation work of maximum retaining height of about 8.5m is required.
Temporary shoring system with lateral support by means of non-percussive method
such as strutted pipe pile wall will be considered for the excavation works.
2.48
Slope
upgrading/modification works will be carried out on the adjacent slope features
to upgrade the existing slope features to satisfy the currently required safety
standard.
2.49 Substructure and superstructure: Raft foundation system with ground anchor will be constructed for the foundation system of the new building. The new crematorium building in the form of reinforced concrete slabs, beams, walls and columns structures will then be cast by using conventional construction method without requiring any special technique and equipment.
Phase 2
Demolition Works
2.50 According to the general layout plan, the existing crematorium will be demolished and removed. The L-shaped columbarium structure will be retained with local structural strengthening works. The demolition works will be carried out using traditional method without blasting. In view of the anticipated excessive noise nuisance during demolition works, hydraulic concrete crusher will be employed instead of excavator mounted hydraulic breaker. The proposed temporary retaining wall system (i.e. pipe pile wall) along the existing basement wall should be installed and strutted prior to the demolition of the existing semi-basement structure.
Construction
Works
2.51 Site formation: Upon completion of the demolition works, new crematorium with basement will be constructed at level of around +131.0mPD. Excavation work of maximum retaining height of about 8.5m is required. Temporary shoring system with lateral support by means of non-percussive method such as strutted pipe pile wall will be considered for the excavation works.
2.52 New retaining walls will be constructed to cater the level difference between the proposed service hall and existing columbarium block. Slope upgrading/modification works will be carried out on the adjacent slope feature to satisfy the currently required safety standard.
2.53 Substructure and Superstructure: Similar to Phase 1, raft foundation system with ground anchor will be constructed for the foundation system of the new building. The new crematorium building in the form of reinforced concrete slabs, beams, walls and columns structures will then be cast by using conventional construction method without requiring any special technique and equipment.
Environmental Considerations for Construction and Demolition Methods
Construction
Method
2.54 The new crematorium building in the form of reinforced concrete slabs, beams, walls and columns structures will be cast by using conventional bottom-up construction method without requiring any special technique and heavy plants/equipment. The major plants daily involved are the tower cranes, concrete trucks and pump trucks, etc. In view of these low rise traditional reinforced concrete structures, there is no practical alternative construction methods that can avoid the use of aforesaid machinery.
Demolition Method
2.55 Comparing with those applicable demolition methods as stated in Table 4.1 of the latest Code of Practice for Demolition of Buildings 2004, the “Top-Down Method with Hydraulic Crusher Method” had been adopted to demolish the existing building in view of its energy efficiency and noise reduction performance. In addition, the following environmental measures would be adopted through out the site work.
1.
Slightly
lower wrecking efficiency method as “Saw cutting” will be firstly employed to
separate the adjoining building and parts of building to be demolished.
In such case, vibration and dust effect can be kept minimal on the
adjoining building.
2.
Existing
lift shaft, light well and openings on floor may be used to convey debris down
the building floors. Plastic chutes will be used inside the floor
openings and lift wells to minimize noise and confine the falling debris.
3.
To
prevent dust generation during the debris hauling, water spraying shall be
applied during the hauling process.
4.
The
sequence of demolition should be planned to allow the separation and sorting of
building materials. Concrete and/or brick debris should be broken down into
smaller sizes and separated from reinforced steel for disposal.
5.
Concrete
debris may be pulverised into aggregate size and used for road base, temporary
haul roads, fill materials or aggregates for concrete. Old bricks may be
salvaged for reuse as architectural features or other uses.
6.
Broken
concrete may be disposed of at construction and demolition (C&D) materials
recycling facilities for processing into recycled products and aggregates for
beneficial reuse.
7.
In the
event that broken concrete is mixed with some other wastes, broken concrete
should be sorted out on site from the mixture of wastes, before disposal at C&D
materials recycling facilities.
2.56
Cremation is commonly adopted
in
2.57 Cremators of flat-bed type and free-falling type are most commonly used due to their high combustion efficiency. Higher combustion efficiency of new cremators helps decompose organic matters more completely, and hence reduction in air pollutants emissions from the cremation process.
2.58 Free-falling cremators consist of a primary combustion chamber at high level and a mineralization chamber at a lower level. The “cremains” (a portmanteau of “cremated” and “remains”) will fall from the primary combustion chamber to the mineralization chamber (cremains collection chamber). When the cremains are transferred to the mineralization chamber, another coffin can be fed into the primary combustion chamber for cremation. The operations of the primary combustion and mineralization chambers are independent.
2.59 The selection of cremation technology to be adopted will be subject to the tendering process. Notwithstanding this, the new cremators will be designed with equivalent specifications as the recent crematoria projects at Fu Shan and Diamond Hill, with adoption of the latest technology for flue gas filtering and emission monitoring. The new cremators will be fully capable of meeting all the BPM12/2(06) requirements, at full load conditions.
2.60 A total of ten cremators will be provided in the new crematorium. Nine cremators will be of 170 kg/cycle capacity and the remaining one cremator will be of 250 kg/cycle capacity. The total operating capacity of all the cremators will be about 1,780 kg/cycle (i.e. 1,526 kg/hour based on 70 minutes average cycle time) under full load conditions. In contingency condition, say when one cremator has a failure in critical items of equipment, it will be shut down and a contingency plan will be followed. The operating capacity of the new cremators in contingency situation will confine to the capacity of the remaining healthy cremators in operation. As confirmed by the Project Proponent, the design of the new cremators will make reference to the cremators at the new Fu Shan Crematorium and Diamond Hill Crematorium. The flue gas volumetric flow rates of the 170 kg and 250 kg cremators are 2,500m3/hour (at 6.3% oxygen, 15.5% moisture, 200°C) and 4,600m3/hour (at 11% oxygen, 12.7% moisture, 200°C), respectively.
2.61 Based on the findings of a fuel study carried out during the preliminary design stage of cremator installation for the to-be-reprovisioned Wo Hop Shek Crematorium, average air pollutant emissions data of the Kwai Chung Crematorium and Fu Shan Crematorium using ultra-low sulfur diesel (ULSD) and Towngas respectively could meet all the BPM12/2(06) emission requirements. To further reduce emissions of air pollutants from fuel combustion, and thereby to be more environmental-friendly, the Project Proponent has selected Towngas as burning fuel, instead of ULSD. Towngas is made from high quality naphtha which yields a cleaner gas with higher efficiency. The extremely low sulphur content of naphtha reduces the emission of sulphur oxide. The public will benefit from the use of clean gaseous fuel with less pollution effect notwithstanding the higher operating costs.
2.62 Chimneys diameters will be 0.22m for 170kg and 0.30m for 250 kg cremators. The design efflux velocity at full load condition will comply with the minimum requirement of 10m/s as required in BPM12/2(06). Ten chimneys will be located at the eastern side of the project site and the chimneys heights are in the range of 24m to 26m above local ground level. The locations of chimneys and their exact heights are shown in the floor plans (see Figure 2.5).
2.63 The temperature of the combustion gas from the primary combustion zone will be raised to 850°C (after the last injection of combustion air) in a controlled and homogeneous fashion such that even under the most unfavourable conditions at least two seconds residence time in the secondary combustion zone is achieved in the presence of at least 6% oxygen.
2.64 Although the final selection of cremators will be subject to open tendering procedure, the performance and specifications of the new cremators will fully comply with the BPM12/2(06).
Air Pollution Control Technology
2.65 Air pollutants, such as particulate matter, heavy metals, organic gases, acidic gases, dioxins, etc., will be generated by the combustion process within the flue emissions from the new crematorium. Installation of an APC equipment is required to reduce the emissions of such air pollutants to acceptable levels. Applicable APC technologies are described below.
Wet Scrubbing
2.66 Wet scrubbing removes air pollutants in flue gas through dissolution and chemical absorption by scrubbing solution. The solution may be water or other chemical solutions. Common scrubbing solutions include sodium hydroxide, acidified potassium permanganate, hypochlorite and other acidic solutions.
Carbon
Injection
2.67 Carbon injection removes organic air pollutants in flue gas. Fine charcoal powder is injected into the flue gas ducting and organic air pollutants in flue gas are absorbed by the charcoal powder. The fine charcoal powder is then collected with bag filter. This technology is commonly adopted to control the emissions of dioxins and is a dry air pollution control process.
Neutralization
with Chemical
2.68 Neutralization is adopted if the flue gas is highly acidic or alkaline. For acidic gases, neutralization is accomplished by spraying of lime or soda lime solution to the flue gas. Inorganic acids are usually used to neutralize highly alkaline flue gas. Spray nozzle or jet nozzle is usually used to spray neutralizing solution to the flue gas system. This is a dry air pollution control process.
Electrostatic Precipitation
2.69 Electrostatic precipitators are used to collect fine particulate matters in flue gas. The electrostatic precipitator maintains an electric field of several kilowatts to charge up the fine particulates. The charged particulates are collected with the oppositely charged collector plates. Electrostatic precipitators are highly efficient in collecting fine particulates. Collected dust is easily handled and disposed of. This is a dry air pollution control process.
Bag Filters
2.70 Bag filters are commonly adopted to control particulate emissions. Particulate matters are collected with the filter medium. The filter bags may be made of cotton or fabric material. Filter bags will be cleaned up regularly to avoid clogging. This is a dry air pollution control process.
Quenching
2.71 If flue gas is cooled down slowly to about 400°C to 600°C, atoms of carbon, oxygen, hydrogen and chlorine will re-combine to form dioxins, as these are the most thermodynamically favourable chemical species – this is the dioxin “formation window”. Quenching cools down the flue gas suddenly, to shorten the time within the dioxin “formation window” and so avoids the formation of dioxins. Quenching is usually achieved by drawing in a large amount of fresh air or spraying of water.
Flue Gas Cleaning System to be
Adopted in the New Crematorium
2.72 After passing through the heat exchanger, the flue gas will enter the flue gas filtering plant, such that specific pollutants in the gas stream will be trapped. The flue gas filtering plant comprises a cyclone (for separation of large particles and sparks in the flue gas downstream of heat exchanger), a chemical addition system (with calcium hydroxide and furnace coke for neutralizing acidic pollutants such as hydrogen chloride and removing dioxins radicals in flue gas stream), a conditioning rotor (for recycling unused additives) and a flat bag filter (for filtering out fine carbon particulates with compressed air jet).
2.73 To further enhance the environmental performance of new cremators against emission of mercury and residual dioxins, chemo-absorption equipment using non-toxic additives is under design and will be added downstream of the flat bed filter, whenever practicable, to ensure compliance with emission limits as stipulated in BPM12/2(06).
Environmental Considerations for Cremation
System
2.74 The cremation system consists of the cremator, the coffin insertion system, heat recovery system and the downstream waste gas cleaning system. Continuous emission monitoring system are installed to monitor the pollutant level.
2.75 The cremator is designed as a multi-zone cremator, consists of primary and secondary combustion chamber, mineralization chamber and a built-in cremulator with cremain collection chamber. Cremation process can be started as long as the primary chamber and secondary chamber are preheated to 650°C and 850°C, respectively. Electrical interlock is provided such that the charging door can only be opened when the secondary chamber temperature is higher than 850°C (10-min average) and with sufficient negative suction pressure and temperature at the primary chamber to prevent emission of smoke or gases out of the cremator through the charging door into the coffin charging area. To ensure a complete combustion, the secondary chamber is designed to provide a residence time of not less than 2 seconds at 850°C and an average oxygen content of not less than 6%. When the cremation cycle completed, human cremain falls directly into a dust proof cremulator underneath the cremator for separation of metal waste and grinding. The processed cremain is then loaded into the urn inside cremulator. The operation of cremulator is under a negative suction pressure, any leaking of airborne dust which may arise when the cremain is being processed is prevented. It maintains a cleaner and healthier environment. Exposure risk of human cremain for crematorium personnel is also minimized.
2.76 A heat recovery system is located between the cremator and the flue gas cleaning system. This heat recovery system facilitates the use of the thermal energy of the exhaust gas for preheating the combustion air and for external purposes. The heat exchanger of the heat recovery system is designed to provide a fast cooling the flue gas through the temperature range at which dioxins may re-form by de-novo synthesis so that re-formation of dioxins during cooling is minimized.
2.77 Continuous emission monitoring system (CEMS) is provided at the specified locations of the whole cremation lines. The CEMS monitors pollutants level, temperature and oxygen content of the waste gas. Audio and visual alarm will alert the operator in case of any abnormal pollutant emission is identified.
2.78 SCADA system is installed to provide data and signal communication among the cremation plant. EPD and overseas manufacturer can make use of the system to monitor the emissions and the process parameters of the cremator lines. In addition to the monitoring functions, overseas manufacturer is able to carry out remote control functions including fault diagnosis, strategic controlling and downloading of new configuration files or programmes of the cremator lines through the system.
2.79 After due consideration of the siting, layout, cremation/air pollution control technology, cremators design, construction and demolition schedule as discussed in the previous sections, the proposed Project will have the following key environmental and social benefits:
l
The
Project will be able to address the increasing cremation demand without
construction of additional cremators as the efficiency of the new cremators is
much improved;
l
The
existing cremators can be upgraded within the shortest possible time to address
local concern on air emissions;
l
Installation
of new cremators of improved design and APC technologies would improve the air
quality in the vicinity of the
l
Towngas
has been selected as burning fuel for the new cremators instead of ultra low
sulphur diesel (ULSD) which has been using for existing cremators, will further
reduce emissions of air pollutants from fuel combustion, thereby to be more
environmentally-friendly;
l
Spatial
utilization in the Project site will be improved;
l
The
Project will be able to address the increasing cremation demand efficiently by
avoiding the long lead time required to get a piece of vacant and earmarked
land for adding a new crematorium in the relevant statutory plan;
l
Food,
Environment and Hygiene Committee (FEHC) under the Eastern District Council at
its meeting in 2008 supported the reprovisioning plan by emphasizing the need
for timely replacement of the crematorium to improve air emission quality.
Interactions with Other Projects
2.80 According to the currently available information, there will be no concurrent projects to be constructed and operated in the vicinity of the Project.