This Section
identifies the potential wastes arising from the demolition of the CCPP and
potential environmental impacts associated with the handling and disposal of
the waste. The assessment was undertaken
in accordance with the criteria presented in Annexes 7 and 15 of the EIAO-TM, which are summarised as
follows:
·
Evaluate
opportunities to reduce, reuse and recycle waste;
·
Estimate
the types and quantities of the wastes to be generated; and
·
Assess
the secondary environmental impacts due to the management of waste with respect
to potential hazards, air and odour emissions, noise, wastewater discharges and
traffic.
5.2
Legislation
Requirements and Evaluation Criteria
The following legislation covers, or has
some bearing upon, the handling, treatment and disposal of wastes in
·
Waste Disposal Ordinance (Cap 354);
·
Waste Disposal (Chemical Waste) (General)
Regulation (Cap 354C);
·
Land (Miscellaneous Provisions) Ordinance
(Cap 28);
·
Public Health and Municipal Services
Ordinance (Cap 132) - Public Cleansing and Prevention of Nuisances Regulation;
·
Waste
Disposal (Charges for Disposal of Construction Waste) Regulation (Cap 354N)
5.2.1
Waste Disposal Ordinance (Cap 354)
The Waste
Disposal Ordinance (WDO) prohibits the unauthorised disposal of wastes,
with waste defined as any substance or article, which is abandoned. Under the WDO, wastes can only be disposed of at a licensed site. A breach of these regulations can lead
to the imposition of a fine and/or a prison sentence. The WDO
also provides for the issuing of licences for the collection and transport
of wastes. Licences are not,
however, currently issued for the collection and transport of construction
waste or trade waste.
The Waste Disposal (Charges for Disposal of
Construction Waste) Regulation defined construction waste as any substance,
matters or things that is generated from construction work and abandoned,
whether or not it has been processed or stockpiled before being abandoned, but
does not include any sludge, screening or matter removed in or generated from
any de-sludging, de-silting or dredging works.
The Construction
Waste Disposal Charging Scheme came into operation on 1 December 2005. Processing of account applications by
the EPD started on the same day. A
contractor who undertakes construction work with value of HK$1 million or above
is required to open a billing account solely for the contract. Charging for the disposal of
construction waste started on 20 January 2006.
Depending on the percentage of inert materials in the material, construction
waste can be disposed of at public fill reception facilities, landfills and
outlying islands transfer facilities, where differing disposal costs would be
applied. The scheme encourages
waste reduction so that the contractor or Project Proponent can minimise their
costs. Table 5.2a summarises the Government’s construction waste disposal
facilities, the types of waste accepted and disposal the associated costs.
Table 5.2a Government
Waste Disposal Facilities for Construction Waste
|
Government Waste Disposal Facilities |
Type of Construction Waste Accepted |
Charge Per Tonne |
|
Public
fill reception facilities |
Consisting
entirely of inert construction waste |
$27 |
|
Sorting
facilities |
Containing
more than 50% by weight of inert construction waste |
$100 |
|
Landfills
|
Containing
not more than 50% by weight of inert construction waste |
$125 |
|
Outlying |
Containing
any percentage of inert construction waste |
$125 |
5.2.2
Waste Disposal (Chemical Waste) (General)
Regulation
Chemical waste as defined under the Waste Disposal (Chemical Waste) (General)
Regulation includes any substance being scrap material, or unwanted
substances specified under Schedule 1
of the Regulation, if such a
substance or chemical occurs in such a form, quantity or concentration so as to
cause pollution or constitute a danger to health or risk of pollution to the
environment.
Chemical waste
producers shall register with the EPD.
Any person who contravenes this requirement commits an offence and is
liable to a fine and imprisonment.
Producers of chemical wastes must treat their wastes, utilising on-site
plant licensed by the EPD or have a licensed collector take the wastes to a
licensed facility. For each
consignment of wastes, the waste producer, collector and disposer of the wastes
must sign all relevant parts of a computerised trip ticket. The system is designed to allow the
transfer of wastes to be traced from cradle-to-grave.
The Regulation
prescribes the storage facilities to be provided on site including labelling
and warning signs. To minimise the
risks of pollution and danger to human health or life, the waste producer is
required to prepare and make available written procedures to be observed in the
case of emergencies due to spillage, leakage or accidents arising from the
storage of chemical wastes. He/she
must also provide employees with training in such procedures.
5.2.3
Land (Miscellaneous Provisions) Ordinance
(Cap 28)
The inert portion of construction waste ([1])
(also called public fill) may
be taken to public fill reception facilities. Public fill reception facilities are
operated by the Civil Engineering and Development Department (CEDD). The Land
(Miscellaneous Provisions) Ordinance requires that individuals or companies
who deliver public fill to the public fill reception facilities obtain Dumping
Licences. The licences are issued
by the CEDD under delegated authority from the Director of Lands.
Individual licences and windscreen
stickers are issued for each vehicle involved. Under the licence conditions, public
fill reception facilities will only accept inert earth, soil, sand, rock,
boulder, rubble, brick, tile, concrete, asphalt, masonry or used bentonite. In
addition, in accordance with paragraph 11 of ETWB-TC (Works) No. 31/2004,
Public Fill Committee will advise on the acceptance criteria (eg no mixing of construction waste, nominal size of the
materials less than 250mm, etc. The
material should, however, be free from marine mud, household refuse, plastic,
metal, industrial and chemical wastes, animal and vegetable matter and any
other materials considered unsuitable by the public fill reception facility.
5.2.4
Public Cleansing and Prevention of
Nuisances Regulation
This Regulation provides further control on the
illegal dumping of wastes on unauthorised (unlicensed) sites. The illegal dumping of wastes can lead
to a fine and/or imprisonment.
5.2.5
Landfill Disposal Criteria for
Contaminated Soil
No contaminated soil will be generated due
to the demolition of the CCPP (see Section
4). If the residues generated
from the cleaning of the Co-Combustion unit have to be disposed of at the
designated landfill, the residues have to meet the landfill disposal criteria. The criteria are set primarily in terms
of Toxicity Characteristic Leaching Procedure (TCLP) limits and are summarised
in Table 5.2b.
Table 5.2b Landfill
Disposal Criteria
|
Parameter |
TCLP Limit (ppm or mg L-1) |
|
Cadmium |
10 |
|
Chromium |
50 |
|
Copper |
250 |
|
Nickel |
250 |
|
Lead |
50 |
|
Zinc |
250 |
|
Mercury |
1 |
|
Tin |
250 |
|
Silver |
50 |
|
Antimony |
150 |
|
Arsenic |
50 |
|
Beryllium |
10 |
|
Thallium |
50 |
|
Vanadium |
250 |
|
Selenium |
1 |
|
Barium |
1,000 |
|
Note: (a)
Soil
samples should be stored at 0 – 4oC. The allowable storage time
for mercury in soil samples is 8 days while the storage time for the rest of
the parameters in soil samples can be up to 6 months. Soil samples, if stored beyond the
allowable storage time, are not considered representative of the actual site
conditions. |
|
5.2.6
Other Relevant Guidelines
Other
'guideline' documents, which detail how the project proponent or contractor
should comply with the local regulations, are as follows:
·
Waste Disposal Plan for Hong Kong (December 1989), Planning, Environment
and Lands Branch Government Secretariat,
·
Environmental Guidelines for Planning In
Hong Kong (1990), Hong
Kong Planning Standards and Guidelines, Hong Kong Government;
·
New Disposal Arrangements for Construction
Waste (1992), EPD &
CED,
·
Code of Practice on the Packaging,
Labelling and Storage of Chemical Wastes (1992), EPD,
·
Works Branch Technical Circular (WBTC) No.
32/92, The Use of Tropical Hard Wood on Construction Site; Works Branch,
·
WBTC No. 2/93, Public Dumps. Works Branch,
·
WBTC No. 2/93B, Public Filling Facilities, Works Bureau,
·
Waste Reduction Framework Plan, 1998 to
2007, Planning,
Environment and Lands Bureau, Government Secretariat, 5 November 1998;
·
WBTC Nos. 25/99, 25/99A and
25/99C, Incorporation of Information on Construction and Demolition Material
Management in Public Works Sub-committee Papers; Works Bureau,
·
WBTC No. 12/2000, Fill Management; Works Bureau,
·
ETWB TCW No. 33/2002, Management of
Construction and Demolition Material Including Rock; Environment,
Transport and Works Bureau,
·
ETWB TCW No. 31/2004, Trip Ticket System
for Disposal of Construction & Demolition Materials, Environment, Transport and Works Bureau,
Hong Kong SAR Government; and
·
ETWB TCW No. 19/2005, Environmental
Management on Construction Sites, Environment, Transport and Works Bureau,
All equipments and building/structures of
the CCPP are made from asbestos-free materials and therefore no asbestos containing
materials are expected to be arisen from the decommissioning and demolition
works. During the pilot
demonstration, all MSW delivered to the site was treated and no MSW is
currently stored on-site. However,
the following wastes will be generated from the demolition and cleaning of the
CCPP or need to be handled during the decommissioning of the Project:
·
Bottom
ash and fly ash collected during the operation of the CCPP;
·
Lining
of the Co-Combustion unit, such as refractory bricks of the rotary kiln;
·
Scrap
metals from dismantling of the MRRF building and Co-combustion unit;
·
Reinforced
concrete from demolition of the concrete structures (fire services water tank
and pump house), and foundation;
·
Asphaltic
concrete from site pavement;
·
Chemical
waste;
·
Sewage;
and
·
General
waste.
The potential environmental impacts
associated with handling, storage, transport and disposal of these wastes are
assessed in the following section.
The potential environmental impacts associated
with the handling and disposal of waste arising from the demolition of the CCPP
were assessed in accordance with the criteria presented in Annexes 7 and 15 of the EIAO-TM
and summarised as follows:
·
Estimation
of the types, quantities and timing of the wastes to be generated based on
sequence and duration of the decommissioning and demolition activities;
·
Evaluation
of different opportunities for reducing waste generation and reuse/recycling
on-site or off-site;
·
Estimation
of types and quantities of waste required to be disposed of and description of
the disposal options; and
·
Assessment
of the secondary environmental impacts due to the management of the waste with
respect to potential hazards, air and odour emissions, noise, wastewater
discharges and traffic.
5.5
Waste Management
Assessment
5.5.1
Co-Combustion Residues
Bottom ash (residues from the rotary kiln)
and fly ash (residues from dust collector) were generated during the
commissioning and operation of the CCPP.
After decommissioning of the CCPP, the residues were collected and
placed in sealed bags with labels.
The bags are currently stored at the reception hall of the MRRF
building. Table 5.5a summarises the quantities of bottom ash and fly ash
stored on-site.
Table 5.5a Inventory
of Bottom Ash and Fly Ash
|
Phases |
Bottom Ash |
Fly Ash (a) |
||
|
Weight (tonnes) |
No. of bags |
Weight (tonnes) |
No. of bags |
|
|
Load Commissioning 1 |
3.06 |
5 |
12.43 |
0 (b) |
|
Load Commissioning 2 |
6.27 |
9 |
33.53 |
12 |
|
Operation |
60.65 |
89 |
83.43 |
123 |
|
Total |
70.0 |
103 |
129.4 |
135 |
|
Notes: (a)
Fly
ash mixed with the residues collected from the gas cooler. (b)
Less than 1 bag of fly ash was collected during load
commissioning 1. |
||||
Laboratory Analysis Results
The quality of the residues is analysed in
order to assess the opportunity for on-site use as a raw material for the
cement production and to determine if further treatment will be required if the
residues are to be disposed of at landfill. Bottom and fly ash samples were taken
for laboratory analysis by ALS Technichem (HK) Pty
Limited (a laboratory accredited under the Hong Kong Laboratory Accreditation
Scheme (HKOLAS)) (see Figure 5.5a). Twenty-five (25) bags of residues were
selected randomly from each ash category and about 500 grams of ash were taken
from each bag. Five samples were
combined to form one composite sample so that 5 composite samples of bottom ash
and 5 composite samples of fly ash were collected for laboratory analysis. Toxicity Characteristic Leaching
Procedure (TCLP) tests were carried out for the composite samples in order to
determine whether the samples comply with the landfill disposal criteria. Heavy metals, dioxins/furans
(polychlorinated dibenzodioxins (PCDD)/ dibenzofurans (PCDF)) and polychlorinated biphenyls (PCBs)
contents of the ashes were also analysed.
Table 5.5b and 5.5c summarise the analysis results of
the samples.
The results
indicate that the residues contain a trace amount of dioxins (in part per
trillion (ppt) level or 1x 10-12) and very
low heavy metal concentrations. The
TCLP results for both fly ash and bottom ash show that the heavy metal
concentrations are well below the respective limits of the landfill disposal
criteria (the concentrations of most of the parameters are below the detection
limits). No treatment (e.g.
stabilisation or fixation) will be required if the residues are to be disposed
of at landfill. An advance agreement
should be obtained from the Landfill Authority (EPD) for disposal of the
residues at landfill.
Table 5.5b TCLP
Test Results of Co-Combustion Residues
|
Parameter |
Analytical Method |
Assessment Criteria (a) (mg L-1) |
Limit of Reporting (mg L-1) |
Fly Ash Composite Sample (mg L-1) |
Bottom Ash Composite Sample (mg L-1) |
||||||||
|
1-5 |
6-10 |
11-15 |
16-20 |
21-25 |
1-5 |
6-10 |
11-15 |
16-20 |
21-25 |
||||
|
TCLP Test |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
·
Antimony
|
USEPA Method
1311, 3050B or 6010C |
150 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
|
·
Arsenic
|
50 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
|
|
·
Barium
|
1,000 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
|
|
·
Beryllium
|
10 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
|
|
·
Cadmium
|
10 |
0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
|
|
·
Chromium
|
50 |
1 |
1 |
< 1 |
< 1 |
< 1 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
|
|
·
Copper |
250 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
|
|
·
Lead
|
50 |
1 |
< 1 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
1 |
< 1 |
< 1 |
< 1 |
|
|
·
Mercury
|
1 |
0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
|
|
·
Nickel
|
250 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
|
|
·
Selenium
|
1 |
0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
|
|
·
Silver
|
50 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
|
|
·
Thallium
|
50 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
|
|
·
Tin
|
250 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
|
|
·
Vanadium
|
250 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
|
|
·
Zinc
|
250 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
|
|
Notes: (a)
Assessment
criteria are based on Landfill Disposal Criteria for Contaminated Soil (TCLP
limits). (b)
Soil
samples should be stored at 0 – 4 oC.
The allowable storage time for mercury in soil samples is 8 days while the
storage time for the rest of the parameters in soil samples can be up to 6
months. Soil samples, if stored
beyond the allowable storage time, are not considered representative of the
actual site conditions. |
|||||||||||||
Table 5.5c Dioxins
and Heavy Metal Concentrations in Co-Combustion Residues
|
Parameter |
Analytical Method |
|
Limit of Reporting (mg kg-1) |
Fly Ash Composite Sample (mg kg-1) |
Bottom Ash Composite Sample (mg kg-1) |
||||||||
|
1-5 |
6-10 |
11-15 |
16-20 |
21-25 |
1-5 |
6-10 |
11-15 |
16-20 |
21-25 |
||||
|
Dioxins Concentration |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
PCDD/F (I-TEQ) |
USEPA Method 8290 or equivalent |
|
See Note (a)
(b) |
5 x 10-6 |
- |
5.1x10-6 |
- |
3.6x10-6 |
5.3x10-6 |
- |
4.9x 10-6 |
- |
5.6 x 10-6 |
|
Dioxin-like PCBs |
USEPA Method 1668 |
|
See Note (a)
(b) |
1.2x10-6 |
- |
1.3x10-6 |
- |
1.1x10-6 |
1.0x10-6 |
- |
1.3x 10-6 |
- |
1.1 x 10-6 |
|
Heavy Metal Analysis |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
· Antimony |
USEPA Method 6020A/7000 ICPMS |
|
1 |
9 |
7 |
11 |
4 |
11 |
34 |
41 |
42 |
65 |
42 |
|
· Arsenic |
|
1 |
< 1 |
< 1 |
1 |
2 |
2 |
2 |
4 |
5 |
6 |
4 |
|
|
· Barium |
|
0.5 |
176 |
94.1 |
166 |
43.4 |
203 |
1180 |
1480 |
1280 |
1250 |
942 |
|
|
· Cadmium |
|
0.2 |
8.6 |
5.5 |
8.7 |
2.8 |
6.4 |
2.8 |
0.9 |
2.0 |
2.2 |
0.8 |
|
|
· Trivalent Chromium |
|
1 |
22 |
23 |
21 |
10 |
20 |
91 |
136 |
148 |
1110 |
195 |
|
|
· Hexavalent Chromium |
|
1 |
37 |
32 |
35 |
10 |
46 |
< 1 |
3 |
3 |
6 |
5 |
|
|
· Cobalt |
|
0.5 |
2.2 |
1.7 |
2.6 |
1.6 |
2.2 |
8.9 |
12.6 |
9.4 |
16.4 |
7.4 |
|
|
· Copper |
|
1 |
71 |
56 |
79 |
24 |
76 |
1620 |
1380 |
2400 |
1470 |
1720 |
|
|
· Lead |
|
1 |
303 |
309 |
176 |
155 |
258 |
352 |
158 |
1970 |
1310 |
113 |
|
|
· Manganese |
|
0.5 |
134 |
217 |
210 |
256 |
110 |
668 |
970 |
752 |
1050 |
842 |
|
|
· Mercury |
|
0.05 |
0.36 |
0.31 |
0.23 |
0.14 |
0.51 |
< 0.05 |
< 0.05 |
< 0.05 |
< 0.05 |
< 0.05 |
|
|
· Molybdenum |
|
1 |
4 |
2 |
4 |
3 |
4 |
11 |
15 |
8 |
35 |
9 |
|
|
· Nickel |
|
1 |
7 |
8 |
11 |
4 |
9 |
104 |
70 |
113 |
672 |
69 |
|
|
· Tin |
|
0.5 |
55.7 |
27.3 |
56.9 |
13.0 |
32.6 |
268 |
202 |
2300 |
330 |
280 |
|
|
· Zinc |
|
|
1 |
236 |
164 |
306 |
95 |
201 |
3970 |
2310 |
3490 |
3040 |
3360 |
|
· Thallium |
|
|
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
|
· Vanadium |
|
1 |
3 |
4 |
3 |
2 |
4 |
14 |
19 |
6 |
8 |
7 |
|
|
Notes: (a)
The
testing of PCDD/F and dioxin-PCBs consist of a range of testing for elements
in the groups and their isomers with different limits of detection and
quantification. Details of limits
of detection and limit of quantification can be found in the testing report
attached in Annex B. (b)
Three
fly ash samples and three bottom ash samples were taken for PCDD/F and PCBs
testing. The results presented in
the table are the highest concentrations. |
|||||||||||||
Reuse
of the Residues for Cement Production
GIC has
commissioned the Hong Kong University of Science and Technology (HKUST) to
assess the feasibility of using fly ash and bottom ash as the raw material for
production of cement clinker of the GICP.
The physical properties and chemical composition of the residues were
analysed. The results show that the
characteristics ([2])
of the both residues are
similar to those of the typical clinker raw materials (including pulverised fly
ash and bottom ash from coal fired power station, iron/copper slag). The ingredients of both residues show
the normal chemical substances associated with cement clinker raw feed
materials (ie calcium carbonate/calcium oxide/calcium salts, alumina, and iron/copper
slag). The residues contain very
low levels of heavy metals and extremely low levels of (in the order of part
per trillion) dioxins (see Table 5.5c). The heavy metals will be encapsulated in
the cement clinker at high temperature and the trace dioxins will be destroyed
in the precalciner at about 1,040oC and in
the cement kiln at about 1,400oC. The reuse of the residues for the cement
clinker production will not cause adverse impacts on the gaseous emissions of
the cement plant and the cement quality.
It is therefore considered that the residues could be used as an
alternative feedstock for the clinker production.
Table
5.5d presents the key parameters related to the
assessment of the suitability of the residues to be used for cement clinker
production.
Table 5.5d Comparison
of the Characteristics of GIC Cement Raw Materials and the Co-Combustion
Residues
|
GIC Cement Raw Materials |
Bottom Ash |
Fly Ash |
|
Powderly |
Powderly |
Powderly |
|
Al, Ca and Fe are the
major components of cement. The raw materials for
production of Portland cement clinker should have a levels of Al (>25,000 mg/kg) , Ca (>300,000 mg/kg) and Fe |
Contain high levels of Al (> 25,000 mg/kg), Ca (> 300,000 mg/kg),
and Fe which are
comparable with those of the cement raw materials |
Contain high levels of Al ( > 25,000 mg/kg), Ca
and Fe which are comparable with those of the cement raw materials |
|
Calcium oxide is the essential component of the raw materials for cement manufacturing. It represents about
80% (w/w) of the raw materials feed to the kiln |
Calcium oxide is
presented as the highest metal component, representing 80% w/w of the raw material feed to a Portland cement clinker
kiln. Laboratory trial and test results showed that the quality of cement produced
with bottom ash as
part of the raw materials is identical to that of GIC cement. |
Calcium oxide
is presented as the highest metal component, representing 80% w/w of the raw material
feed to a Portland
cement clinker kiln. In addition,
it has a high calcium carbonate/ calcium oxide content |
|
|
Bottom ash
contains very low levels of
heavy metals and extremely
low levels (pg/kg) of dioxins, which has no adverse impacts
on the air emissions of the cement plant |
Fly ash
contains very low levels of
heavy metals and extremely
low levels (pg/kg) of dioxins, which has no adverse impacts
on the air emissions of the cement plant |
In order to maintain the same quality of cement
clinker, a feed loading rate of 0.5% w/w of Co-Combustion residues to other raw
materials will be used. Based on
the current production rate of the cement plant, the residues will be added to the raw materials ([3])
at a rate of 1.25 tonnes per hour
prior to milling. Under this
loading rate, it will take about 56 hours and 104 hours to reuse all the bottom
ash and fly ash, respectively.
With respect to the short duration (7
days) that the residues will be processed at the cement plant, it is anticipated
that the potential air quality impact will be minimal and is transient.
It is
recommended that the Co-Combustion residues to be reused as a raw material for
the cement production at the GICP as it will avoid the need to dispose the
residues at landfill.
Disposal of the residues at landfill should be considered as a last
resort. As the TCLP tests indicate
that the residues comply with the landfill disposal criteria, no further
treatment will be required for landfill disposal. However, an advance agreement should be
obtained from the Landfill Authority (EPD) for the disposal of residues at
landfill.
5.5.2
Inner Lining Materials from the Thermal
Treatment Facilities
The refractory
bricks of the rotary kiln and the castable lining of
the secondary combustion chamber and duct works will be removed. The materials will be placed in sealed bags and disposed of at a designated landfill. The internal wall of the kiln, secondary
combustion chamber and duct works will be properly cleaned with wet
cloths. The cleaning materials will
be collected and placed in sealed plastic bags and disposed of at a designated
landfill. All these materials are
asbestos free. Table 5.5e presents the estimated quantities of the refractory
bricks and lining materials to be removed.
Table 5.5e Refractory Bricks
and Castable Lining to be Removed during Cleaning
Process
|
Items |
Description |
Weight (tonnes) |
|
Refractory bricks / castable
lining |
Refractory bricks and castable lining of the C-Combustion unit |
345 |
|
Dust collector and duct works |
Residual dust inside the Co-Combustion unit |
5.5 |
|
Others |
Materials used for cleaning process (eg wiping cloths) |
0.5 |
|
Total |
|
351 |
Samples have been taken from the
refractory bricks and castable lining of the
Co-Combustion unit and analysed by a HKOLAS Laboratory for TCLP and
dioxins. The sampling locations of
refractory bricks and castable lining are listed in Table 5.5f and shown in Figure
5.5b.
Table 5.5f Refractory
Bricks and Castable Lining Sampling Locations
|
Location Number |
Description |
|
1 |
Rotary Kiln |
|
2 |
Rotary Kiln |
|
3 |
Rotary Kiln |
|
4 |
Secondary Combustion Chamber |
|
5 |
Gas Chamber 1 |
|
6 |
Gas Chamber 2 |
|
7 |
Cyclone 1 |
|
8 |
Cyclone 2 |
|
9 |
Ash outlet from cyclones |
|
10 |
Duct to gas cooler |
|
Dioxin Sample A |
Mixture of sample 1, 2 and 3 |
|
Dioxin Sample B |
Sample 4 |
|
Dioxin Sample C |
Mixture of sample 7 and 8 |
The residues inside the Co-Combustion
equipment will be used as part of the raw materials for the cement
production. Disposal of the
residues at landfill will be the last resort. The laboratory analysis results are
presented in Table 5.5g and Table 5.5h. The TCLP tests show that the
concentrations of various metals in the leachate of
the refractory kiln bricks and castable lining
samples are well below the landfill
disposal criteria for contaminated soil (the concentration of most of the heavy
metals in the leachate is below the detection
limits). It is therefore considered
that the materials could be disposed of at a designated landfill without
further treatment (eg stabilisation or
fixation). An agreement should be
obtained from the Landfill Authority (EPD) for the disposal of the residues at
landfill.
Table 5.5g TCLP
Test Results of the Castable Lining/ Refractory Brick
Samples
|
Parameter |
Analytical Method |
Assessment Criteria (a) |
Limit of Reporting (mg L-1) |
Sampling location (Refer to Figure 5.5b) |
|||||||||
|
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
||||
|
|
|
|
|
Concentration (mg L-1) |
|||||||||
|
TCLP Test |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
·
Antimony
|
USEPA Method
1311, 3050B or 6010C |
150 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
|
·
Arsenic
|
50 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
|
|
·
Barium
|
1000 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
|
|
·
Beryllium
|
10 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
|
|
·
Cadmium
|
10 |
0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
|
|
·
Chromium
|
50 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
4 |
< 1 |
|
|
·
Copper |
250 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
|
|
·
Lead
|
50 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
1 |
< 1 |
< 1 |
< 1 |
|
|
·
Mercury
|
1 |
0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
|
|
·
Nickel
|
250 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
|
|
·
Selenium
|
1 |
0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
< 0.2 |
|
|
·
Silver
|
50 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
|
|
·
Thallium
|
50 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
|
|
·
Tin
|
250 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
|
|
·
Vanadium
|
250 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
|
|
·
Zinc
|
250 |
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
|
|
Notes: (a)
Assessment
criteria are based on Landfill Disposal Criteria for Contaminated Soil (TCLP
limits). (b)
Soil
samples should be stored at 0 – 4 oC.
The allowable storage time for mercury in soil samples is 8 days while the
storage time for the rest of the parameters in soil samples can be up to 6
months. Soil samples, if stored
beyond the allowable storage time, are not considered representative of the
actual site conditions. |
|||||||||||||
Table 5.5h Heavy
Metal and Dioxins Concentrations in the Castable
Lining/ Refractory Bricks Samples
|
Parameter |
Analytical Method |
|
Limit of Reporting (mg kg-1) |
Sampling location (Refer to Figure 5.5b) |
|||||||||
|
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
||||
|
Concentration
(mg kg-1) |
|||||||||||||
|
Dioxins Concentration |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Dioxins (I-TEQ) |
USEPA Method 1613 |
|
See Note (a) |
1.6x10-6
(b) |
|
|
1.7x10-6
(b) |
|
|
1.3x10-6
(b) |
|
|
|
|
Heavy Metal Analysis |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
·
Antimony
|
USEPA Method 6020A/7000 ICPMS |
|
1 |
1 |
< 1 |
3 |
< 1 |
2 |
< 1 |
< 1 |
< 1 |
3 |
< 1 |
|
·
Arsenic
|
|
1 |
5 |
4 |
4 |
< 1 |
12 |
3 |
2 |
2 |
6 |
3 |
|
|
·
Barium
|
|
0.5 |
38 |
18 |
141 |
33 |
43 |
37 |
36 |
67 |
137 |
29 |
|
|
·
Cadmium
|
|
0.2 |
0.3 |
0.3 |
1.6 |
< 0.2 |
0.7 |
0.3 |
0.3 |
< 0.2 |
4.1 |
< 0.2 |
|
|
·
Trivalent
Chromium |
|
1 |
8 |
3 |
14 |
2 |
12 |
21 |
26 |
35 |
315 |
39 |
|
|
·
Hexavalent Chromium |
|
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
1 |
14 |
4 |
128 |
6 |
|
|
·
Cobalt |
|
0.5 |
< 1 |
2 |
3 |
< 1 |
< 1 |
2 |
< 1 |
2 |
10 |
1 |
|
|
·
Copper
|
|
1 |
25 |
4 |
18 |
5 |
5 |
15 |
6 |
19 |
41 |
18 |
|
|
·
Lead
|
|
1 |
13 |
9 |
67 |
72 |
63 |
22 |
34 |
94 |
200 |
13 |
|
|
·
Manganese
|
|
0.5 |
47 |
26 |
72 |
33 |
53 |
49 |
37 |
83 |
600 |
66 |
|
|
·
Mercury
|
|
0.05 |
< 0.05 |
< 0.05 |
< 0.05 |
< 0.05 |
< 0.05 |
< 0.05 |
< 0.05 |
< 0.05 |
< 0.05 |
< 0.05 |
|
|
·
Molybdenum |
|
1 |
< 1 |
< 1 |
< 1 |
< 1 |
3 |
1 |
< 1 |
1 |
13 |
2 |
|
|
·
Nickel
|
|
1 |
11 |
3 |
7 |
< 1 |
< 1 |
7 |
4 |
15 |
310 |
6 |
|
|
·
Tin
|
|
0.5 |
10 |
< 1 |
14 |
< 1 |
6 |
3 |
2 |
2 |
11 |
3 |
|
|
·
Zinc
|
|
|
1 |
77 |
3 |
72 |
37 |
24 |
236 |
9 |
18 |
77 |
14 |
|
·
Thallium
|
|
|
1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
|
·
Vanadium
|
|
1 |
32 |
28 |
48 |
82 |
57 |
79 |
80 |
77 |
23 |
62 |
|
|
Notes: (a)
The
testing of PCDD/F consists of a range of testing for elements in the groups
and their isomers with different limits of detection and quantification. Details of limits of detection and
limit of quantification can be found in the testing report attached in Annex B. (b)
Dioxins
Sample A is a composite sample of samples 1, 2 & 3; dioxins sample B is
from sample 4; dioxins sample C is a composite sample of samples 7 &
8. The results presented in the
table are the maximum concentrations of the samples. |
|||||||||||||
5.5.3
Reuse and Recycling of the MRRF Equipment
and Scrap Metals
Most of the plant and equipment of the
MRRF (including magnetic separator, eddy current separator, etc) are still in
good serviceable conditions and will be sold to other MRRF operators or second
hand equipment vendors. The
other components will be dismantled and sold as scrap metals.
The steel frame structure of the MRRF
building will be demolished. The
steel beams and column will be cut to manageable size to facilitate
transportation. This together with
the metal claddings and scrap metals from the MRRF equipment will be sold to
scrap metal recyclers.
After cleaning, the metals recovered from
dismantling of the Co-Combustion unit (including the rotary kiln, secondary
combustion chamber, duct works, gas cooler and dust collector) will be sold to
recyclers (about 369 tonnes).
Table
5.5i summarises the
equipment of the MRRF to be reused and quantities of scrap metal to be
recycled.
Table 5.5i Equipments
to be Reused and Quantities of Scrap Metal to be Recycled
|
System |
Description |
Estimated Weight (tonnes) |
|
|
Equipment to be reused |
Scrap metals to be
recycled |
||
|
MRRF |
Trommel |
2 |
|
|
|
Ballistic
separator |
14 |
|
|
|
Magnetic
separator |
5 |
|
|
|
Aluminium
separator |
2 |
|
|
|
Belt
conveyor |
31 |
|
|
|
Steel
structure |
|
70 |
|
|
|
|
|
|
Co-Combustion
Unit |
Rotary kiln
|
|
88 |
|
Feed
chamber for rotary kiln |
|
12 |
|
|
Secondary
combustion chamber |
|
100 |
|
|
Precalciner |
|
141 |
|
|
Cyclone |
|
71 |
|
|
Flue gas
ducting |
|
41 |
|
|
Discharge
ducting |
|
18 |
|
|
Tipping
valve |
|
6 |
|
|
Gas cooler |
|
12 |
|
|
Dust
collectors |
|
19 |
|
|
Fans with
motor |
8 |
|
|
|
Ash storage
tank |
|
5 |
|
|
Bucket
elevator |
|
4 |
|
|
Urea water
tank |
|
4 |
|
|
Bottom ash
drag chain conveyor |
|
3 |
|
|
Steel
structure |
|
120 |
|
|
Total |
|
62 |
369 (a) |
|
Note: (a)
Total weight of the equipment (714 tonnes) minus 345 tonnes of refractory lining. |
|||
5.5.4
Construction and Demolition Materials
The public fill (consisting of concrete
and asphaltic concrete) will be generated from the demolition of the site
pavement, fire services water storage tank and pump house, and foundation and
sub-structures of the MRRF building and Co-Combustion unit. Table
5.5j presents the quantities of public fill to be generated from the
demolition works and need to be disposed of at the public fill reception
facilities (eg Tuen Mun Area 38).
Table 5.5j Quantities
of Public Fill to be Generated from the Demolition Works
|
C&D Materials |
Sources |
In Situ Volume (m3) |
Bulk Volume to be
disposed of (m3) |
|
Reinforced Concrete |
Foundation of MRRF building
and the Co-Combustion unit |
950 |
1,330 |
|
|
Fire water pump house |
18 |
25.2 |
|
|
Fire water tank |
46 |
64.4 |
|
Asphaltic concrete |
Surface layout of pavement |
276 |
386.4 |
|
Total |
1,290 |
1,806 |
|
|
Note: (a)
A
bulking factor of 1.4 is applied. |
|||
No soil will be removed from the Project
Site due to the demolition works.
The handling and
temporary storage of such a small volume of public fill on-site will not cause
adverse environmental impact. It is
estimated that about 269 truck trips (assuming a payload of 6.7 m3
per truck) will be required to transport all public fill to the Tuen Mun Area 38 Fill Bank and a
maximum of 10 truck trips per day will be generated. This small traffic flow will not cause
adverse traffic impact to the local road network, and noise and air quality
impacts. The disposal of a small
quantity of public fill to the Tuen Mun Area 38 Fill Bank will not cause adverse operation
impact to the fill bank. An advance
agreement should be obtained from the Public Fill Committee (PFC) for the
disposal of the anticipated amount of public fill at the designated public
filling facilities.
5.5.5
Chemical Waste
Chemical waste, as defined under the Waste Disposal (Chemical Waste) (General)
Regulation, includes any substance being scrap material, or unwanted
substances specified under Schedule 1
of the Regulation. A complete list
of such substances is provided under the Regulation.
The remainder of unused reagents for the
operation of the CCPP will be removed before demolition works. The unused reagents will be recycled by
the suppliers or reused on-site as far as possible. As the last resort, the leftover
reagents will be disposed of at chemical waste to the Chemical Waste Treatment
Centre (CWTC) at Tsing Yi. Table
5.5k summarises the unused reagents
to be recycled or reused on-site.
Table 5.5k Management
of Unused Reagents for the CCPP
|
Chemicals |
Per packing unit |
Quantity |
Total |
Disposal (D)/ Recycled by suppliers (R)/Reuse (RU)
|
|
Unused raw chemicals |
||||
|
· Activated carbon |
25 kg |
23 |
575 kg |
R |
|
· Urea |
50 kg |
56 |
2,800 kg |
R |
|
· Ecolo (a) |
25 L |
10 |
250 L |
R |
|
Chemical leftover in
bins/tanks |
||||
|
· Activated carbon (b) |
- |
- |
30 kg |
RU |
|
Note: (a)
Ecolo is a deodourising
solution used for the (b)
The
activated carbon does not mix with any other chemicals. Due to it small
quantity, it will be reused on-site by mixing with the coal and used as fuel
for combustion in the cement plant.
|
||||
In addition, a small amount of chemical
waste (in the order of one hundred litres, mainly consist of used lubricant
oil for plant and vehicles) will
be generated from maintenance of demolition plant and equipment. These may include, but need not be
limited to the following:
·
Used
batteries or spent acid/alkali from their maintenance;
·
Used
engine oils, hydraulic fluids and waste fuel;
·
Spent
mineral oils/cleaning fluids from mechanical machinery; and
·
Spent
solvents, some of which may be halogenated, from equipment cleaning activities.
Chemical wastes may pose environmental,
health and safety hazards if not stored and disposed of in an appropriate
manner as outlined in the Waste Disposal
(Chemical Waste) (General) Regulation and the Code of Practice on the Packaging, Labelling and Storage of Chemical Wastes. These hazards may include:
·
Toxic
effects to workers;
·
Adverse
effects on air, water and land from spills; and
·
Fire
hazards.
GIC has been registered with the EPD as
chemical waste producer. The
chemical waste will be collected in appropriate containers and be removed by a
licensed chemical waste collector periodically for disposal at the CWTC.
With the implementation of the control
measures stipulated in the EPD’s Code of Practice on the Packaging, Labelling and Storage of Chemical
Wastes, the handling, collection and disposal of the chemical waste
generated from the demolition of the CCPP will not cause adverse environmental
impacts.
5.5.6
Sewage
Sewage will arise from the demolition
staff and should be managed properly to avoid any adverse water quality impact,
odour and potential health risks to the workforce by attracting pests and other
disease vectors.
It is estimated that about 14 construction
workers will be working on site at the peak of the construction programme. With a sewage generation rate of 0.15 m3
per worker per day, about 2.1 m3 of sewage will be generated per
day.
The workers will use the existing sanitary
facilities at the GICP. GIC
confirmed that the existing wastewater treatment will have sufficient capacity
to handle the anticipated flow generated from the demolition staff. No adverse water quality and odour
impact are anticipated due to handling and disposal of the sewage generated
from the demolition staff.
5.5.7
General Waste
The demolition staff would generate
general refuse comprising food waste, paper, empty containers, etc. It is estimated that the quantity of
general refuse to be generated from the demolition staff (up to 14 workers at
any one time) will be minimal (about 9.1 kg per day assuming a waste generation
of 0.65 kg per worker). This waste
will be stored in covered waste container and be disposed of together with the
general refuse arising from the operation of the GICP. The recyclables (eg
paper and aluminium cans) will be separately collected and recycled as far as
practicable. It is not
anticipated that the handling and disposal of the anticipated quantity of
general refuse to be generated from the demolition staff will cause adverse
environmental impacts and operation impact to the landfill.
5.5.8
Summary of Waste Arising from the
Demolition Works
Table
5.5l summarises the waste
arising from the Project. Majority
of the materials/waste arising from the demolition works will be reused or
recycled (including the equipment of the MRRF, unused reagents, etc). Public fill will be disposed of at the Tuen Mun Area 38 Fill Bank,
chemical waste will be disposed of at the CWTC and the general refuse will be
disposed of at the WENT Landfill.
It is intended that the Co-Combustion residues (including fly ash and
bottom ash) will be reused on-site for the production of cement. Alternatively, the residues will be
disposed of at a landfill designated by the EPD. The refractory lining and materials (cloths) arising from cleaning
of the Co-Combustion unit will
also be disposed of at a landfill designated by the EPD.
Table 5.5l Management
of Waste Arising from the Demolition Works
|
Type |
Estimated Quantity |
Disposal/ Treatment Method |
|
Co-Combustion residues (fly ash and
bottom ash) |
200 tonnes |
Reuse on-site for cement production or
disposal of at a designated landfill should be considered as the last resort
|
|
Kiln refractory bricks / castable lining of the Co-Combustion unit |
345 tonnes |
Disposal of at a designated landfill
should be considered as the last resort |
|
Residue inside the equipments |
5.5 tonnes |
Reuse on-site for cement production or
disposal of at a designated landfill should be considered as the last resort |
|
Waste (cloths) arising from cleaning of
the Co-Combustion unit |
0.5 tonne |
Dispose of at a designated landfill |
|
Equipments of the MRRF |
124 tonnes |
Sell to MRRF operators or second hand
equipment vendors |
|
Scrap metals |
369 tonnes |
Sell to recyclers |
|
Unused reagents ·
Activated
carbon ·
Urea
solution ·
Deodourising solution |
575 kg 2,800 kg 250 litres |
To be returned to the suppliers for
reuse |
|
Leftover reagent ·
Activated
carbon |
30 kg |
Re-use on site by mixing with coal and
used it as fuel for combustion in the cement plant |
|
Public fill (including reinforced
Concrete and asphalt) |
1,806 m3 |
Dispose to Tuen
Mun Area 38 Fill Bank |
|
Chemical waste
(mainly the lubricant oil from vehicle maintenance) |
About 100
litres |
Dispose of at
the CWTC |
|
Sewage |
2.1 m3 d-1 |
On-site wastewater treatment plant |
|
General Waste |
9.1 kg d-1 |
Dispose together with other general refuse
arising from the GICP to landfill |
5.6
Mitigation Measures
This section recommends the mitigation
measures and good site practices to avoid or reduce potential adverse environmental
impacts associated with handling, collection and disposal of waste arising from
the demolition of the CCPP.
The Contractor must ensure that all the
necessary permits or licences required under the Waste Disposal Ordinance are obtained for the demolition works.
5.6.1
Waste Management Hierarchy
The various waste management options are
categorised in terms of preference from an environmental viewpoint. The options considered to be most preferable
have the least environmental impacts and are more sustainable in the long
term. The hierarchy is as follows:
·
Avoidance
and reduction;
·
Reuse
of materials;
·
Recovery
and recycling; and
·
Treatment
and disposal.
The above hierarchy has been used to evaluate
and select waste management options.
The aim has been to reduce waste generation and reduce waste handling
and disposal costs.
GIC will ensure that their contractors
will implement the good site practices and mitigation measures recommended in this
EIA Study and those given below. A
Waste Management Plan (WMP) should be prepared by the main contractor taking
account of the recommendations of this EIA Report and with reference to the
requirements of ETWB TCW No. 19/2005.
The Plan should be submitted to GIC for approval prior to the
commencement of the demolition works.
Nomination of approved personnel to be
responsible for good site practices, arrangements for collection and effective
disposal to an appropriate facility of all wastes generated at the site;
·
Training
of site personnel in proper waste management and chemical handling procedures;
·
Provision
of sufficient waste disposal bags and containers and regular collection for
disposal;
·
Appropriate
measures to reduce windblown litter and dust transportation of waste by either
covering load with tarpaulin sheet or by transporting wastes in enclosed
containers;
·
Separation
of chemical wastes for special handling and appropriate treatment at the CWTC;
·
Regular
cleaning and maintenance programme for drainage systems, sumps and oil
interceptors (if used); and
·
A
recording system for the amount of wastes generated, reused on site, recycled
and disposed.
5.6.2
Waste Reduction Measures
Good management and control can prevent generation
of significant amount 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:
·
Segregation
and storage of different types of waste in different containers, skips or
stockpiles to enhance reuse or recycling of material and their proper disposal;
·
Encourage
collection and recycling of aluminium cans and waste paper during demolition
works with separate labelled bins provided to segregate these recyclables from
other general refuse generated by the workforce; and
·
Unused
reagents will be recycled as far as possible.
·
The
Co-Combustion residues should be reused on-site for cement production in order
to avoid the disposal of these wastes at the landfill.
5.6.3
Handling and Disposal of Chemical Waste
GIC is a registered chemical waste
producer and will liaise with EPD to determine the need to update the list of
chemical wastes to be handled during the demolition works.
Chemical waste will be handled in
accordance with the Code of Practice on
the Packaging, Handling and Storage of Chemical Wastes. The containers to be used for storage of
chemical wastes will:
·
Be
suitable for the substance they are holding, resistant to corrosion, maintained
in a good condition, and securely closed;
·
Have
a capacity of less than 450 L unless the specifications have been approved by
the EPD; and
·
Display
a label in English and Chinese in accordance with instructions prescribed in
Schedule 2 of the Regulations.
The storage area for chemical wastes will:
·
Be
clearly labelled and used solely for the storage of chemical waste;
·
Be
enclosed on at least 3 sides;
·
Have
an impermeable floor and bunding, of capacity to
accommodate 110% of the volume of the largest container or 20% by volume of the
chemical waste stored in that area, whichever is the greatest;
·
Have
adequate ventilation;
·
Be
covered to prevent rainfall entering (water collected within the bund must be
tested and disposed of as chemical waste, if necessary); and
·
Be
arranged so that incompatible materials are appropriately separated.
Chemical waste will be disposed of:
·
Via a
licensed waste collector; and
·
To a
facility licensed to receive chemical waste, such as the CWTC which also offers
a chemical waste collection service and can supply the necessary storage
containers.
5.6.4
General Waste
General refuse will be stored in enclosed
bins separately from construction and chemical wastes. Recycling bins will be provided at
strategic locations to facilitate recovery of aluminium can and waste paper
from the site. Materials recovered
will be sold for recycling
5.7
Evaluation of
Residual Impacts
With the implementation of the recommended
mitigation measures, no adverse residual impacts are anticipated from the
demolition of the CCPP.
5.8
Environmental
Monitoring and Audit
It is recommended that monthly site audits
of the waste management practices be carried out during the Project to determine
if wastes are being managed in accordance with the good site practices
described in this EIA Report. The
audits should examine all aspects of waste management including waste storage,
recycling, transport and disposal.
The decommissioning and demolition of the
CCPP will generate a variety of wastes (including Co-Combustion residues,
public fill, chemical waste, general refuse, sewage) and recyclables (MRRF
Equipment, scrap metals, unused reagents, etc). The waste management implications and
environmental impacts associated with the handling, storage and disposal of
these wastes have been assessed.
The physical properties and chemical analysis results show that the
characteristics of the Co-Combustion residues are similar to those of the
typical clinker raw materials (including pulverised fly ash and bottom ash from
coal fired power station, iron/copper slag). The residues contain very low levels of heavy metals and extremely
low levels of (in the order of part per trillion) dioxins, which will not have
adverse impacts on the gaseous emissions and the cement quality. The residues should be used as an alternative feedstock for the
cement clinker production.
With the proposed loading rate of 0.5% w/w
of the Co-Combustion residue to
other raw materials for cement clinker production, it will not adversely affect
the environmental performance of the cement plant. It will take about 7 days for the cement
plant to consume all the residues.
There is no concern of long-term environmental impacts associated with
the proposed residue reuse option.
This will avoid the disposal of residues at landfill.
As a last resort, the residues will be
disposed of at a landfill designated by the EPD. The TCLP tests indicate that the concentrations
of heavy metals in the leachate arising from the
residues are well below the respective limits for landfill disposal. The residues can therefore be disposed
of at the designated landfill without further treatment. An advance agreement should be obtained
from the Landfill Authority (EPD) for the disposal of the residues at landfill.
The refractory
bricks and lining of the Co-Combustion unit and waste generated from cleaning
of the Co-Combustion unit will be placed in sealed PE bags and disposed of at a
landfill designated by the EPD.
The MRRF equipment is still in good
serviceable condition and will be sold to other MRRF operators or second hand
equipment vendors. Scrap metals
will be recycled.
Due the small scale of the CCPP, the
quantities of public fill, chemical waste, general refuse, sewage to be
generated will be small. With the
implementation of the recommended mitigation measures in this EIA Report, the
handling and disposal of these wastes will not cause adverse environmental and
traffic impacts.