Table 4.1 Air Pollutant Emission Limited as Stipulated in the Existing BPM 12/2
and the Target Emission Levels of the New Crematorium
Air Pollutants |
Unit |
Emission Limit of Existing BPM 12/2 |
Target Emission Levels of the New Crematorium |
Particulate matters |
mg/m3 |
100 |
100 |
Hydrogen chloride |
mg/m3 |
100 |
100 |
Carbon monoxide |
mg/m3 |
100 |
100 |
Total organic carbon |
mg/m3 |
20 |
20 |
Mercury |
mg/m3 |
- |
0.2 (a) |
Sulphur dioxide |
mg/m3 |
- |
180 (a) |
Nitrogen Oxides (NOx as NO2) |
mg/m3 |
- |
380 (NOx) (a) |
Dioxins |
ng I-TEQ/m3 |
1.0 |
1.0 |
Note : The emission limits are corrected to 273 K, 101.325 kPa, dry and oxygen 11%
(a) Crematorium Operation and Emissions, Cemetery and Funeral Services Information Sheet, Ministry of Public Safety and Solicitor General, British Columbia, Canada
Other major design requirements of the new cremators as stipulated by BPM 12/2 aresummarized as follows:
l Cremators shall have a secondary combustion chamber. Sufficient secondary air shall be supplied to cremators in order to maintain good combustion efficiency;
l The combustion temperature of the secondary combustion chamber shall be maintained at least 850°C (at all time) and the residence of gas shall not be less than 2 seconds;
l The oxygen level of flue gas shall be greater than 6%;
l The current requirement of linear efflux velocity at chimney is not less than 7 m/s. However, a more stringent requirement linear efflux velocity not less than 15 m/s would be adopted for the new cremators.
The above design requirements of the new cremators would enhance combustion efficiency, hence to reduce emission of air pollutants. Further the dispersion of air pollutant emissions would be much improved by emission through high chimneys.
Table 4.2 Background Air Pollutant Levels Adopted for Air Quality Assessment
Pollutant |
Unit |
Background Concentration |
RSP |
µg/m3 |
60 (1) |
CO |
µg/m3 |
1,051 (2) |
SO2 |
µg/m3 |
21 (1) |
NO2 |
µg/m3 |
59 (1) |
Hg |
µg/m3 |
0.00022 (3) |
Dioxin |
pg I-TEQ/m3 |
0.055 (2) |
Note: (1) Guidelines on Assessing the 'TOTAL' Air Quality Impacts, HKEPD
(2) Annual air pollutant concentrations in Tsuen Wan, Air Quality in Hong Kong 2001, HKEPD
(3) Annual Hg concentration in Tsuen Wan, Air Quality in Hong Kong, 2000, HKEPD
ASR ID |
Air Sensitive Receiver |
Building Height (no. of floor) |
Distance from Crematorium (m) |
Angle, From North (Degree) |
Elevation, mP.D. |
A1 |
The Salvation Army William Booth Secondary School |
6 |
316 |
322 |
84.1 |
A2 |
Tak Oi Secondary School |
6 |
422 |
313 |
85.2 |
A3 |
Po Leung Kuk No. 1 W. H. Cheung Collage |
6 |
272 |
315 |
87.4 |
A4 |
Heep Woh College |
6 |
369 |
305 |
83.5 |
A5 |
Tsz Wan Shan Catholic Primary School |
8 |
381 |
290 |
85.6 |
A6 |
Po Leung Kok Celine Ho Yam Ho Tong College |
8 |
406 |
270 |
85.6 |
A7 |
St. Patrick Catholic Primary School |
8 |
313 |
261 |
85.6 |
A8 |
Po Leung Kok Grandmont Primary School |
8 |
237 |
270 |
85.6 |
A9 |
(New school under construction) |
8 |
234 |
292 |
85.6 |
A10 |
Fu Yan Hse |
20 |
188 |
160 |
61.0 |
A11 |
Fu Lai Hse |
20 |
291 |
165 |
61.0 |
A12 |
Fu Shun Hse |
22 |
234 |
145 |
61.0 |
A13 |
S.K.H. Kei Sum Primary School |
6 |
313 |
136 |
61.0 |
A14 |
King Pik Hse (Blk B) |
33 |
406 |
140 |
64.4 |
A15 |
Blk E, King Shan Court |
33 |
453 |
153 |
61.5 |
A16 |
The HK Sea Cadet Corp Centre |
2 |
150 |
140 |
62.2 |
A17 |
Staff Quarter for Diamond Hill Crematorium |
2 |
78 |
120 |
60.4 |
A18 |
Grand View Garden (Blk 1) |
39 |
297 |
180 |
39.7 |
A19 |
Grand View Garden (Blk 6) |
28 |
422 |
192 |
39.7 |
A20 |
Grand View Garden (Blk 3) |
35 |
391 |
175 |
38.3 |
A21 |
Hong Kong School For The Deaf |
3 |
406 |
195 |
37.8 |
A22 |
Chi Lin Nunnery |
3 |
438 |
200 |
31.4 |
A23 |
Park over the Diamond Hill No. 2 Fresh Water Reservoir (under planning) |
0 |
156 |
210 |
84.0 |
A24 |
Diamond Hill Funeral Parlour |
4 |
156 |
315 |
79.0 |
The locations of the ASRs are shown in Figure 4.1.
Table 4.4 Tentative Work Schedule of the Project
Duration |
Description |
Activity Concerned |
9/2004 – 2/2006 |
Phase I Building works for new cremators and service halls |
Site formation, demolition of the existing CLP substation, building works, installation major E&M components |
3/2006 – 5/2006 |
Commissioning and operation of new cremators |
Testing and Commissioning Operation |
10/2006 – 11/2007 |
Phase II Decommissioning of the Existing Crematorium and construction of the remaining facilities for the New Crematorium |
Demolition of the Existing Crematorium, building works for the remaining facilities |
Table 4.5 Dust Emission Factors Adopted for the Air Quality Assessment of the Phase I Construction Works
Activities |
Dust Emission Factors (1) |
Dust Emission Rates for Air Dispersion Modelling |
General construction activities |
2.69 Mg/hectare/month (Section 13.2.3)(1) |
2.076 x 10-4 g/m2/s |
Wind erosion of open site |
0.85 Mg/hectare/year (Table 11.9.4)(1) |
2.695 x 10-6 g/m2/s |
Note: (1) Compilation of Air Pollutant Emission Factors, USEPA AP-42, 5th Edition, January 1995
a. The TST meteorological station is located in busy urban area, which is surrounded by high-rise buildings. The geographical conditions are similar to the Diamond Hill Crematorium, which is also surrounded by many buildings including schools, high-rise residential blocks and other buildings. On the other hand, the Kai Tak anemometer station is located at the end of the ex-airport runway and there is an open area with no hill and building. The topography of the Kai Tak Station is not similar to the Crematorium;
b. The distances between the Crematorium and TST and the Kai Tak Station are similar, just 5.3 km and 4.8 km respectively, there is no significant difference in distance.
c. The meteorological data recorded at the TST Hong Kong Observatory Headquarters are more complete and representative for a facility located in Kowloon urban area, as compared with Kai Tak anemometer station.
- Respirable suspended particulates (RSP)
- Hydrogen chloride (HCl)
- Carbon monoxide (CO)
- Total organic compounds (TOC)
- Sulphur dioxide (SO2)
- Nitrogen dioxide (NO2)
- Mercury (Hg)
- Dioxins
In addition, the impact of odour and excessive cancer risk due to the operation of the New Crematorium would be assessed.
Table 4.6 Acceptable Air Quality Criteria of the Air Quality Impact Assessment
Air Pollutant |
Unit |
Air Quality Acceptable Criteria |
||
1-hour average |
24-hour average |
Annual Average |
||
Total suspended particulates |
mg/m3 |
500 (1) |
260 (2) |
80 (2) |
Respirable suspended particulates |
mg/m3 |
(not established) |
180 (2) |
55 (2) |
Hydrogen chloride |
mg/m3 |
2,100 (3) |
(not established) |
20 (4) |
Carbon monoxide |
mg/m3 |
30,000 (2) |
10,000 (2) (8-hr average) |
(not established) |
Sulphur dioxide |
mg/m3 |
800 (2) |
350 (2) |
80 (2) |
Nitrogen dioxide |
mg/m3 |
300 (2) |
150 (2) |
80 (2) |
Mercury |
mg/m3 |
1.8 (3) |
(not established) |
1 (5) |
Dioxins (2378 TCDD equivalent) |
pg I-TEQ/m3 |
(not established) |
(not established) |
1 (6) |
Note : The air pollutant concentrations are corrected to 25°C and 101.325 kPa
Reference : (1) Technical Memorandum of Environmental Impact Assessment Ordinance, HKEPD
(2) Hong Kong Air Quality Objective
(3) Reference Exposure Limits, Office of Environmental Health Hazard Assessment, California, USA
(4) Integrated Risk Information System, USEPA
(5) WHO Air Quality Guideline, World Health Organization, 1999
(6) Primary Ambient Air Quality Standard for Dioxin, Department of Environmental Protection, State of Connecticut, USA, http://dep.state.ct.us/air2/regs/mainregs.htm
Air pollutant emission rate = emission standard x flue gas emission rate
Table 4.7 Calculation of Emission Rates of Air Pollutants
Parameter |
Emission Rate Guideline mg/m3 |
Emission rate, g/s |
|
170 kg cremator |
250 kg cremator |
||
Particulates (regarded as 100% RSP) |
100 (3) |
0.04994 |
0.06439 |
Hydrogen chloride |
100 (3) |
0.04994 |
0.06439 |
Carbon monoxide |
100 (3) |
0.04994 |
0.06439 |
TOC |
20 (3) |
0.00999 |
0.01288 |
SO2 |
180 (4) |
0.08990 |
0.1159 |
NO2 |
380 (4) |
0.03796 |
0.04894 |
Mercury |
0.2 (4) |
0.0000999 |
0.0001288 |
Dioxins (expressed as 2,3,7,8-TCDD equivalent) |
1 ng I-TEQ/m3 (3) |
0.4994 x 10-9 |
0.6439 x 10-9 |
Notes : (1) Note : The emission limits are corrected to 273 K, 101.325 kPa, dry and oxygen 11%
(2) Volumetric flow rates of 1,798 and 2,318 m3/hour at reference conditions are adopted for 170 kg and 250 kg cremators respectively
(3) Emission limits as stipulated in the current BPM standard.
(4) 20% of nitrogen oxides are assumed to be present as NO2 in this study. The emission limits for SO2, NOx and mercury of 180 mg/m3, 380 mg/m3 and 0.2 mg/m3 are adopted from the Ministry of Public Safety & Solicitor General, British Columbia, Canada – Crematorium Operations and Emissions (Canada).
Table 4.8 Calculation of Emission Rates of Odour
Parameter |
Average Odour Conc. Of Flue Gas (OU)(1) |
Emission rate, (OU-m3/s) (2) |
|
170 kg cremator |
250 kg cremator |
||
Odour |
325 |
142.2 |
261.6 |
Note: (1)Measurement Report of the Odour Emissions from the Kwai Chung Crematorium in January 2003, HKPU
(2) The emission rates are calculated based on the conditions of odour analysis at laboratory, i.e. 298 K and 1 atmospheric pressure which are the same as the testing condition of the odour measurement was carried out at laboratory. The flue gas volumetric flow rates were calculated as 1575.4 m3/hour for 170 kg cremators and 2898.5 m3/hour for 250 kg cremators respectively
Stability Class |
Conversion Factor from 15-minute to 3-minute average |
Conversion Factor from 3-minute to 5-second average |
Overall Conversion Factor from 15-minute to 5-second average |
Class A,B |
2.23 |
10 |
22.3 |
Class C |
1.70 |
5 |
8.5 |
Class D |
1.38 |
5 |
6.9 |
Class E,F |
1.31 |
5 |
6.55 |
Table 4.9 Data Input for ISCST Analysis – Phase I Construction Work
Item |
Descriptions |
Area of the Phase I site |
40 m x 55 m (Southern half of the site) |
No. of working hours |
7:00 – 19:00, Monday to Saturday |
Emission factor |
2.69 Mg/hectare/month 0.85 Mg/hectare/year |
Dust emission rate |
2.076 x 10-4 g/m2/s (general construction activities) 2.695 x 10-6 g/m2/s (wind erosion) |
Source of meteorological data |
Duration : Whole year of 2000, hourly data Meteorological station : HK Observatory in TST Height of anemometer : 42.0 mA.G. |
Surface roughness |
0.5 m |
Table 4.10Fugitive Dust Impact to the ASRs at 1.5 m above ground due to the Phase I Construction Work
ASR ID |
Fugitive Dust Impact, mg/m3 (Unmitigated) |
Fugitive Dust Impact, mg/m3 (Mitigated) |
||
1-hr TSP |
24-hr TSP |
1-hr TSP |
24-hr TSP |
|
Air Quality Acceptable Criteria |
500 |
260 |
500 |
260 |
A1 |
291 |
139 |
120 |
99 |
A2 |
206 |
121 |
110 |
99 |
A3 |
346 |
151 |
126 |
99 |
A4 |
260 |
133 |
116 |
99 |
A5 |
241 |
130 |
114 |
100 |
A6 |
227 |
126 |
112 |
99 |
A7 |
289 |
139 |
119 |
100 |
A8 |
395 |
162 |
131 |
102 |
A9 |
424 |
168 |
134 |
102 |
A10 |
482 |
181 |
141 |
102 |
A11 |
299 |
141 |
120 |
100 |
A12 |
382 |
159 |
130 |
102 |
A13 |
281 |
137 |
118 |
100 |
A14 |
219 |
124 |
112 |
100 |
A15 |
199 |
120 |
109 |
99 |
A16 |
629 |
212 |
157 |
106 |
A17 |
1260 |
348 |
228 |
112 |
A18 |
291 |
139 |
119 |
100 |
A19 |
210 |
122 |
111 |
99 |
A20 |
225 |
125 |
112 |
99 |
A21 |
218 |
126 |
111 |
99 |
A22 |
205 |
121 |
110 |
99 |
A23 |
600 |
206 |
154 |
103 |
A24 |
723 |
232 |
168 |
102 |
Notes : (1) TSP background level of 98 mg/m3 was included
(2) Based on the air dispersion modelling results, the maximum TSP levels are found at 1.5 m above ground at each of the ASR.
Table 4.11 Data Input for ISCST3 Modelling Work
No. of Cremator |
170 kg Cremator x 4 |
250 kg cremator x 2 |
Efflux velocity |
15 m/s |
|
Stack exit diameter |
0.22 m |
0.30 m |
Exit temperature of flue gas |
120 oC |
|
Elevation (mP.D.) |
72.5 m |
|
Stack height |
28.5m (101 m.P.D.) |
|
Fuel of Cremators |
Light Diesel |
Table 4.12Maximum Air Quality Impact at the 24 ASRs
Air Pollutant
|
RSP (mg/m3) |
Carbon monoxide (mg/m3) |
Hydrogen Chloride (mg/m3) |
Nitrogen Dioxide (mg/m3) |
TOC (mg/m3) |
|||||||||||||
Averaging Period |
24-hour |
1-hour |
8-hour |
1-hour |
Annual |
1-hour |
24- hour |
1-hour |
24-hour |
|||||||||
Acceptable Criteria
ASR |
180 |
30,000 |
10,000 |
2,100 |
20 |
300 |
150 |
-- |
-- |
|||||||||
Conc |
mA.G. |
Conc |
mA.G. |
Conc |
mA.G. |
Conc |
mA.G. |
Conc |
mA.G. |
Conc |
mA.G. |
Conc |
mA.G. |
Conc |
mA.G. |
Conc |
mA.G. |
|
A1 |
64 |
1.5 |
1091 |
1.5 |
1059 |
1.5 |
40 |
1.5 |
0.1 |
1.5 |
89 |
1.5 |
62 |
1.5 |
8.0 |
1.5 |
0.88 |
1.5 |
A2 |
62 |
1.5 |
1074 |
1.5 |
1056 |
1.5 |
23 |
1.5 |
0.0 |
1.5 |
77 |
1.5 |
61 |
1.5 |
4.7 |
1.5 |
0.45 |
1.5 |
A3 |
65 |
1.5 |
1102 |
1.5 |
1061 |
1.5 |
51 |
1.5 |
0.1 |
1.5 |
98 |
1.5 |
63 |
1.5 |
10.3 |
1.5 |
1.05 |
1.5 |
A4 |
63 |
1.5 |
1082 |
1.5 |
1058 |
1.5 |
31 |
1.5 |
0.1 |
1.5 |
83 |
1.5 |
61 |
1.5 |
6.3 |
1.5 |
0.52 |
1.5 |
A5 |
62 |
1.5 |
1081 |
1.5 |
1057 |
1.5 |
30 |
1.5 |
0.2 |
1.5 |
82 |
1.5 |
61 |
1.5 |
6.2 |
1.5 |
0.41 |
1.5 |
A6 |
64 |
1.5 |
1095 |
25.5 |
1058 |
1.5 |
44 |
25.5 |
0.7 |
1.5 |
93 |
25.5 |
62 |
1.5 |
9.1 |
25.5 |
0.77 |
1.5 |
A7 |
68 |
19.5 |
1117 |
25.5 |
1066 |
25.5 |
66 |
25.5 |
1.3 |
1.5 |
109 |
25.5 |
65 |
1.5 |
13.5 |
25.5 |
1.64 |
25.5 |
A8 |
68 |
1.5 |
1145 |
25.5 |
1068 |
1.5 |
94 |
25.5 |
1.9 |
1.5 |
130 |
25.5 |
65 |
1.5 |
19.3 |
25.5 |
1.66 |
25.5 |
A9 |
65 |
1.5 |
1107 |
1.5 |
1065 |
1.5 |
56 |
1.5 |
0.5 |
1.5 |
102 |
1.5 |
63 |
1.5 |
11.6 |
1.5 |
1.01 |
1.5 |
A10 |
71 |
58.5 |
1218 |
61.5 |
1079 |
61.5 |
167 |
61.5 |
0.7 |
55.5 |
186 |
61.5 |
67 |
58.5 |
33.3 |
61.5 |
2.14 |
58.5 |
A11 |
68 |
61.5 |
1133 |
61.5 |
1065 |
61.5 |
82 |
61.5 |
0.3 |
55.5 |
121 |
61.5 |
65 |
61.5 |
16.3 |
61.5 |
1.56 |
61.5 |
A12 |
68 |
58.5 |
1164 |
61.5 |
1071 |
55.5 |
113 |
61.5 |
0.4 |
55.5 |
145 |
61.5 |
65 |
58.5 |
22.6 |
61.5 |
1.55 |
58.5 |
A13 |
62 |
19.5 |
1075 |
19.5 |
1057 |
19.5 |
24 |
19.5 |
0.1 |
19.5 |
77 |
19.5 |
61 |
19.5 |
5.0 |
19.5 |
0.42 |
19.5 |
A14 |
62 |
55.5 |
1097 |
55.5 |
1057 |
55.5 |
47 |
55.5 |
0.1 |
49.5 |
94 |
55.5 |
61 |
55.5 |
9.3 |
55.5 |
0.45 |
55.5 |
A15 |
63 |
61.5 |
1082 |
55.5 |
1058 |
1.5 |
31 |
55.5 |
0.2 |
49.5 |
83 |
61.5 |
61 |
61.5 |
6.2 |
55.5 |
0.61 |
49.5 |
A16 |
64 |
7.5 |
1074 |
7.5 |
1064 |
7.5 |
23 |
7.5 |
0.2 |
7.5 |
77 |
7.5 |
62 |
7.5 |
4.8 |
7.5 |
0.90 |
7.5 |
A17 |
61 |
7.5 |
1059 |
7.5 |
1063 |
7.5 |
8 |
7.5 |
0.0 |
7.5 |
65 |
7.5 |
59 |
7.5 |
1.8 |
7.5 |
0.12 |
7.5 |
A18 |
64 |
79.5 |
1130 |
79.5 |
1062 |
79.5 |
79 |
79.5 |
0.2 |
79.5 |
119 |
79.5 |
62 |
79.5 |
15.8 |
79.5 |
0.90 |
79.5 |
A19 |
63 |
79.5 |
1095 |
79.5 |
1059 |
79.5 |
44 |
79.5 |
0.1 |
79.5 |
92 |
79.5 |
61 |
79.5 |
8.8 |
79.5 |
0.52 |
79.5 |
A20 |
63 |
79.5 |
1101 |
79.5 |
1058 |
79.5 |
50 |
79.5 |
0.2 |
79.5 |
97 |
79.5 |
61 |
79.5 |
10.0 |
79.5 |
0.56 |
79.5 |
A21 |
62 |
13.5 |
1062 |
13.5 |
1055 |
13.5 |
11 |
13.5 |
0.1 |
13.5 |
68 |
13.5 |
60 |
13.5 |
2.3 |
13.5 |
0.39 |
13.5 |
A22 |
62 |
1.5 |
1061 |
13.5 |
1054 |
13.5 |
10 |
13.5 |
0.1 |
13.5 |
67 |
13.5 |
60 |
1.5 |
2.0 |
13.5 |
0.31 |
1.5 |
A23 |
68 |
1.5 |
1122 |
1.5 |
1072 |
1.5 |
71 |
1.5 |
0.7 |
1.5 |
113 |
1.5 |
65 |
1.5 |
15.0 |
1.5 |
1.76 |
1.5 |
A24 |
68 |
13.5 |
1116 |
13.5 |
1065 |
13.5 |
65 |
13.5 |
0.2 |
13.5 |
108 |
13.5 |
65 |
13.5 |
13.7 |
13.5 |
1.61 |
13.5 |
Note: (1) Assuming the particulate emissions from the chimney are all RSP
(2) The background level of RSP (60 mg/m3), carbon monoxide (1,051 mg/m3) and NO2 (59 mg/m3) were included
Table 4.12Maximum Air Quality Impact at the 24 ASRs (Con’t)
Air Pollutant
|
Sulphur Dioxide (mg/m3) |
Mercury (mg/m3)
|
Dioxins (pg I-TEQ/m3) |
Excess cancer risk (per 1,000,000) |
|||||||||
Averaging Period |
1-hour |
24-hour |
1-hour |
Annual |
Annual |
||||||||
Acceptable Criteria ASR (Elevation, m) |
800 |
350 |
1.8 |
1.0 |
1.0 |
100 |
|
||||||
Conc |
mA.G. |
Conc |
mA.G. |
Conc |
mA.G. |
Conc |
mA.G. |
Conc |
mA.G. |
Risk Level |
mA.G. |
|
|
A1 |
92 |
1.5 |
29 |
1.5 |
0.08 |
1.5 |
0.000 |
1.5 |
0.056 |
1.5 |
0.02 |
1.5 |
|
A2 |
63 |
1.5 |
25 |
1.5 |
0.05 |
1.5 |
0.000 |
1.5 |
0.055 |
1.5 |
0.01 |
1.5 |
|
A3 |
120 |
13.5 |
30 |
1.5 |
0.11 |
1.5 |
0.000 |
1.5 |
0.056 |
1.5 |
0.03 |
1.5 |
|
A4 |
77 |
1.5 |
26 |
1.5 |
0.07 |
1.5 |
0.000 |
1.5 |
0.056 |
1.5 |
0.03 |
1.5 |
|
A5 |
76 |
1.5 |
25 |
1.5 |
0.06 |
1.5 |
0.001 |
1.5 |
0.057 |
1.5 |
0.09 |
1.5 |
|
A6 |
101 |
25.5 |
28 |
1.5 |
0.09 |
25.5 |
0.002 |
1.5 |
0.062 |
1.5 |
0.28 |
1.5 |
|
A7 |
139 |
25.5 |
36 |
25.5 |
0.14 |
25.5 |
0.003 |
1.5 |
0.068 |
1.5 |
0.51 |
1.5 |
|
A8 |
189 |
25.5 |
36 |
25.5 |
0.20 |
25.5 |
0.004 |
1.5 |
0.074 |
1.5 |
0.72 |
1.5 |
|
A9 |
122 |
1.5 |
30 |
1.5 |
0.12 |
1.5 |
0.001 |
1.5 |
0.060 |
1.5 |
0.20 |
1.5 |
|
A10 |
322 |
61.5 |
40 |
58.5 |
0.35 |
61.5 |
0.002 |
55.5 |
0.062 |
55.5 |
0.25 |
55.5 |
|
A11 |
168 |
61.5 |
35 |
61.5 |
0.17 |
61.5 |
0.001 |
55.5 |
0.058 |
55.5 |
0.11 |
55.5 |
|
A12 |
225 |
61.5 |
35 |
58.5 |
0.24 |
61.5 |
0.001 |
55.5 |
0.059 |
55.5 |
0.14 |
55.5 |
|
A13 |
64 |
19.5 |
25 |
19.5 |
0.05 |
19.5 |
0.000 |
19.5 |
0.056 |
19.5 |
0.05 |
19.5 |
|
A14 |
105 |
55.5 |
25 |
55.5 |
0.10 |
55.5 |
0.000 |
49.5 |
0.056 |
49.5 |
0.05 |
49.5 |
|
A15 |
77 |
55.5 |
27 |
61.5 |
0.07 |
55.5 |
0.003 |
49.5 |
0.057 |
49.5 |
0.06 |
49.5 |
|
A16 |
63 |
7.5 |
29 |
7.5 |
0.05 |
7.5 |
0.001 |
7.5 |
0.057 |
7.5 |
0.09 |
7.5 |
|
A17 |
35 |
7.5 |
22 |
7.5 |
0.02 |
7.5 |
0.000 |
7.5 |
0.055 |
7.5 |
0.01 |
7.5 |
|
A18 |
162 |
79.5 |
29 |
79.5 |
0.16 |
79.5 |
0.005 |
79.5 |
0.057 |
79.5 |
0.09 |
79.5 |
|
A19 |
100 |
79.5 |
26 |
79.5 |
0.09 |
79.5 |
0.003 |
79.5 |
0.056 |
79.5 |
0.05 |
79.5 |
|
A20 |
111 |
79.5 |
26 |
79.5 |
0.10 |
79.5 |
0.003 |
79.5 |
0.057 |
79.5 |
0.06 |
79.5 |
|
A21 |
42 |
13.5 |
24 |
13.5 |
0.02 |
13.5 |
0.000 |
13.5 |
0.056 |
13.5 |
0.04 |
13.5 |
|
A22 |
39 |
13.5 |
24 |
1.5 |
0.02 |
13.5 |
0.000 |
13.5 |
0.056 |
13.5 |
0.03 |
13.5 |
|
A23 |
148 |
1.5 |
36 |
1.5 |
0.15 |
1.5 |
0.002 |
1.5 |
0.062 |
1.5 |
0.28 |
1.5 |
|
A24 |
138 |
13.5 |
35 |
13.5 |
0.14 |
13.5 |
0.001 |
13.5 |
0.057 |
13.5 |
0.06 |
13.5 |
|
Note: (1) The background level of SO2 (21 mg/m3), Hg (0.00022mg/m3) and dioxins (0.055 pg I-TEQ/m3) were included
Table 4.13Increased Risk to Lifetime Exposureof 70 years to Dioxins
|
Cancer Risk |
Maximum annual dioxins level at air sensitive receiver A8 |
0.074 – 0.055 = 0.019 pg I-TEQ/m3 |
Maximum excess cancer risk (A8) |
0.019 x 38 x 10-6 0.72 x 10-6 |
Cancer risk impact |
Not significant |
Annual emission of dioxins |
= |
Emission concentration x volumetric flow rate x 10 hours x 365 days |
|
= |
1.0 ng/m3 x (1,798 m3/hr x 4 + 2,318 m3/hr x 2) x 10 hours x 365 days
|
|
= |
43.2 mg I-TEQ/year |
Table 4.14Data Input for ISCST3 Modelling Work for Odour Assessment
No. of Cremator |
170 kg Cremator x 4 |
250 kg cremator x 2 |
Efflux velocity |
15 m/s |
|
Stack exit diameter |
0.22 m |
0.30 m |
Odour emission rate |
142.2 OU-m3/sec |
261.6 OU-m3/sec |
Atmosphere stability class |
Class A,B Class C Class D Class E,F |
|
Ambient temperature of at ASRs |
25 oC |
|
Elevation (mP.D.) |
72.5 m |
|
Stack height |
28.5 m (101 mP.D.) |
Table 4.15Results of the Odour Assessment at Different Atmospheric Stability Classes
Atmosphere Stability Class |
ASR with Max Odour Impact |
15-minute Average Odour (OU) |
Multiplying Factor |
5-second Average Odour (OU) |
Class A,B |
A23 (1.5 m) |
0.12060 |
22.3 |
2.69 |
Class C |
A23 (1.5 m) |
0.11446 |
8.5 |
0.97 |
Class D |
A10 (55.5 m) |
0.22362 |
6.9 |
1.54 |
Class E,F |
A10 (61.5 m) |
0.55358 |
6.55 |
3.63 |
Air Quality Acceptable Criteria – 5-second Average Odour Exposure |
5 |
|||
Maximum 5-second Average Odour Exposure |
3.63 |
Table 4.16Maximum 5-second Odour Exposure at ASRs Under Stability Class E,F
ASR |
1-hour Average Odour (OU) |
Multiplying Factor |
5-second Average Odour (OU) |
Air Quality Acceptable Criterion (EIAO TM Annex 4) |
5 OU over 5 seconds |
||
A1 (19.5 m) |
0.0573 |
6.55 |
0.38 |
A2 (19.5 m) |
0.0010 |
0.01 |
|
A3 (19.5 m) |
0.0069 |
0.05 |
|
A4 (19.5 m) |
0.0001 |
0.00 |
|
A5 (25.5 m) |
0.0477 |
0.31 |
|
A6 (25.5 m) |
0.1465 |
0.96 |
|
A7 (25.5 m) |
0.2160 |
1.41 |
|
A8 (25.5 m) |
0.3063 |
2.01 |
|
A9 (25.5 m) |
0.0629 |
0.41 |
|
A10 (61.5 m) |
0.5536 |
3.63 |
|
A11 (61.5 m) |
0.2714 |
1.78 |
|
A12 (61.5 m) |
0.3762 |
2.46 |
|
A13 (19.5m) |
0.0386 |
0.25 |
|
A14 (55.5 m) |
0.1546 |
1.01 |
|
A15 (61.5 m) |
0.1040 |
0.68 |
|
A16 ( (7.5 m) |
0.0001 |
0.00 |
|
A17 (7.5 m) |
0.0000 |
0.00 |
|
A18 (79.5 m) |
0.2599 |
1.70 |
|
A19 (79.5 m) |
0.1447 |
0.95 |
|
A20 (85.5 m) |
0.1665 |
1.09 |
|
A21 (7.5 m) |
0.0026 |
0.02 |
|
A22 (13.5 m) |
0.0019 |
0.01 |
|
A23 (1.5 m) |
0.0257 |
0.17 |
|
A24 (13.5 m) |
0.0022 |
0.01 |
Note: (1) Figures in brackets are the levels of ASR above ground
l FEHD will limit the use of joss paper burners. Joss paper burners will be only allowed for the use of memorial ceremonies upon request by the relatives. Other usage of joss paper burners will not be allowed;
l Guidance will be provided to the users to advise them to minimize the quantity of burning material;
l FEHD staff will advise the users to ensure better combustion of the joss paper in order to reduce smoke emission.
It is anticipated that the emission of air pollutants would be much improved by administrative management measures to reduce the usage of joss paper burners to minimal and to improve the combustion efficiency. Whenever necessary, FEHD will advice users to reduce the quantity of burning materials through proper education channels.
Comparison of the Environmental Performance with the Existing Crematorium
(a) Approach 1 - Actual measurement of air pollutant emissions (including dioxins) from the existing cremators;
(b) Approach 2 - Making reference to air pollutant emissions measurement results for other operating cremators with similar design, either locally or in overseas countries; or
(c) Approach 3 - Qualitative comparison by assessing the extent of air quality improvement that will be brought about by replacing the existing cremators with new ones.
Both Approach 1 and Approach 2 can give quantitative estimates of air pollutant emissions from the existing cremators, although strictly speaking Approach 2 is only an indication of the possible emission levels from existing cremators because there is no actual emission measurement done for the existing cremators. In comparison, Approach 3 cannot provide any quantitative estimates of air pollutant emissions from existing cremators.
Approach 1 - actual measurement of air pollutant emissions
- The design of the Existing Crematorium Chimney is 10 m above ground, there is an ejector fan installed inside the chimney to exhaust flue gas and no sampling facility is available to carry out stack sampling work. The existing stack for the cremators in the Existing Crematorium in Diamond Hill is not suitable for carrying out air pollutant emission sampling work because (1) there is an ejector fan in the stack which disturbs the air flow pattern, (2) there is not sufficient straight run of the stack to even out the air flow, (3) sampling could only be done along one axis instead of perpendicular axes as required in stack measurement. In conclusion, the design and facility of the Existing Crematorium failed to provide representative stack emission data.
- To overcome these constraints, it is necessary to extend the stack sufficiently long to achieve uniform air flow free of the influence of the ejector fan and to conduct the stack sampling on a temporarily erected sampling platform above the roof. Unfortunately, the existing roof could not support the additional loading of the temporary platform and so it is necessary to construct an extensive steel portal across the crematorium hall with truss supports from the ground and the truss supports will be massive concrete blocks. It is expected that this will take about six months to design the temporary structure and process the application. Furthermore, the sampling work and laboratory analysis of the collected samples will take another two months. This will affect the master programme of the Project significantly.
- Furthermore, the massive concrete support for the temporary structure for stack sampling work will obstruct the only access road to the Existing Crematorium. FEHD/Arch SD confirmed that temporary blocking of the access road, and hence temporary closure of the Crematorium, is needed to construct the structure and conduct the stack sampling. It is estimated that the Existing Crematorium has to be closed for at least four weeks to facilitate the stack sampling work. This will seriously affect the operation of the Crematorium and the normal provision of cremation service to the public will be accordingly affected.
Approach 2 – Making reference to air pollutant emission results for other operating cremators with similar design
- The cremators in the Existing Crematorium in Diamond Hill are diesel-fired cremators while the cremators in Fu Shan Crematorium are gas-fired;
- Four of the cremators in the Existing Crematorium in Diamond Hill are designed with single combustion chamber only while the cremators in Fu Shan Creamtorium and Cape Collinson Crematorium are designed with both primary and secondary combustion chambers.
Approach 3 – Qualitative comparison
Table 4.17 Comparison of Existing and New Cremators
|
Existing Cremators |
Future New Cremators
|
|
Cremator Design |
Combustion chambers |
Primary chamber only |
Primary and secondary chambers
|
Combustion temperature |
Around 800 oC |
At least 850 oC for 2 seconds in secondary combustion chamber to ensure complete combustion
|
|
Monitoring of sufficient combustion air in combustion zone
|
Not provided |
Continuous monitoring by oxygen and carbon monoxide sensors in secondary chamber |
|
Air Pollutant Emission and Monitoring |
Air pollution control system |
Nil |
Adequate air pollution control system including cyclone, bag filter with lime and activated carbon injection will be installed to treat the flue gas before dispersion to the atmosphere. Alternative air pollution control system with equivalent performance may be installed subject to final selection in the open tender process
|
Air pollutant emission monitoring
|
Smoke density meter to monitor smoke emission only |
Smoke density at the chimney will be continuously monitored. In addition, regular stack monitoring will be conducted according to the future Specified Process Licence |
|
Compliance with BPM emission limits
|
Not applicable |
Must comply with stipulated emission limits for various air pollutants including dioxin |
|
Cremator Management Practices |
Environmental management programme |
Nil |
Will be established and implemented to control the operation and maintenance practice of the crematorium in order to achieve better environmental performance
|
The above table clearly demonstrates that the future new cremators are of better design and equipped with adequate air pollution control system. They will also fully comply with all the requirements of the BPM 12/2. On the other hand, complaint of dark smoke emission and odour associated with the existing cremators are received occasionally. This shows that the existing cremators are not performing ideally in environmental perspective. Obviously, when the existing cremators are replaced by the new cremators in future, there would be substantial improvement in the air quality in the district and we expect there will not be dark smoke and odour emissions from the cremators.
Table 4.18Data Input for ISCST3 Analysis – Phase II Construction Work
Item |
Descriptions |
Area of the Phase II site |
65 m x 75 m (Northern half of the site) |
No. of working hours |
7:00 – 19:00, Monday to Saturday |
Emission factor |
2.69 Mg/hectare/month (Section 13.2.3) 0.85 Mg/hectare/year (Table 11.9.4) |
Dust emission rate |
2.076 x 10-4 g/m2/s (general construction activities) 2.695 x 10-6 g/m2/s (wind erosion) |
Source of meteorological data |
Duration : Whole year of 2000, hourly data Meteorological station : HK Observatory in TST Height of anemometer : 42.0 m A.G. |
Surface roughness |
0.5 m |
Table 4.19Fugitive Dust Impact to the ASRs at 1.5 mA.G. due to Phase II Construction Work
ASR ID |
Fugitive Dust Impact, mg/m3 (Unmitigated) |
Fugitive Dust Impact, mg/m3 (Mitigated) |
||
1-hr TSP |
24-hr TSP |
1-hr TSP |
24-hr TSP |
|
Air Quality Acceptable Guideline |
500 |
260 |
500 |
260 |
A1 |
529 |
121 |
146 |
101 |
A2 |
413 |
113 |
133 |
100 |
A3 |
743 |
134 |
170 |
103 |
A4 |
463 |
119 |
139 |
101 |
A5 |
424 |
133 |
134 |
102 |
A6 |
357 |
126 |
127 |
101 |
A7 |
457 |
156 |
138 |
105 |
A8 |
650 |
181 |
160 |
108 |
A9 |
775 |
164 |
174 |
106 |
A10 |
585 |
147 |
152 |
124 |
A11 |
387 |
126 |
130 |
102 |
A12 |
517 |
143 |
145 |
103 |
A13 |
405 |
129 |
132 |
102 |
A14 |
314 |
119 |
122 |
101 |
A15 |
278 |
113 |
118 |
100 |
A16 |
755 |
174 |
171 |
107 |
A17 |
1245 |
264 |
226 |
118 |
A18 |
389 |
126 |
130 |
101 |
A19 |
288 |
112 |
119 |
100 |
A20 |
309 |
115 |
121 |
100 |
A21 |
300 |
114 |
120 |
100 |
A22 |
276 |
112 |
118 |
100 |
A23 |
688 |
153 |
164 |
105 |
A24 |
1542 |
307 |
259 |
123 |
Notes : (1) TSP background level of 98 mg/m3 was included
(2) Based on the air dispersion modelling results, the maximum TSP levels are found on the ground level (1.5 m) at each of the ASR.
o Enclosure of the work area
o Containment and sealing for the asbestos containing waste
o Provision of personal decontamination facility
o Use of personal respiratory/protection equipment
o Use of vacuum cleaner equipped with high-efficiency air particulate (HEPA) filter for cleaning up the work area
o Carrying out air quality monitoring during the asbestos abatement work
o A registered asbestos contractor to carry out the work;
o A registered asbestos supervisor to supervise the work;
o A registered asbestos laboratory to monitor the air quality, and
o A registered asbestos consultant to supervise and certify the asbestos abatement work.
Site Management When Handling Asbestos Containing Materials
- if there is sensitive receptor around the area, conduct environmental air monitoring at this off-site sensitive receptors
- Submit to EPD a completion report, include photos and air monitoring results, immediately after completion of asbestos abatement work for each work zone
1. Erect a site barrier with the height of no less than 2.4 m at the construction site boundary to enclose the work area;
2. Apply frequent water spraying to ensure the surface of the construction site sufficiently wet to reduce fugitive dust due to wind erosion and transportation on unpaved haul road;
3. Cover up stockpiles of fill material and dusty material;
4. Install a vehicle-cleaning system at the main entrance of the construction site to clean up the vehicles before leaving the site.
a. Commissioning test of the new cremators would be carried out one by one, with no more than 2 new cremators undergoing commissioning test at the same time;
b. The total number of operating cremators, including both new and existing cremators, would not be more than 6.
An operational log book would be maintained to record the operational time of each of the new and existing cremators.
(a) The new cremators will be fired by light diesel with sulphur content less than 0.5% by weight and viscosity of less than 6 centistokes at 40 oC or better. Arch SD had considered whether to use gas-fired or diesel-fired cremators. In view of the advanced cremator design and the installation of air pollution control system to treat the flue gas from the cremators, it is expected that emissions from the diesel-fired cremators can comply with the BPM requirement and there would be no excessive dark smoke emissions. FEHD therefore decided to use diesel-fired cremators instead of gas-fired cremators.
(c) Overview of Fugitive Dust Emissions, May 2000 - Section 3, by Mary Hewitt Daly and Jennifer Franco,http://www.pirnie.com/docs/resources_pubs_air_may00_6.html
(d) Summary of Minimum Dust Control Parameter, Mine Safety and Health Administration, Pittsburgh Safety and Health Technology Centre, http://www.msha.gov/S&HINFO/TECHRPT/DUST/MINPAR.pdf