4 Air Quality impact Assessment

4.1 Introduction

This section presents an assessment of the potential air quality impacts arising from the construction, operation, restoration and aftercare of the proposed Extension.

During the construction phase, dust nuisance arising from blasting, excavation and filling, slope stabilisation, site formation, stone crushing and vehicle movements on the site is a potential concern. Potential sources of air quality and odour impacts during the operation, restoration and aftercare phases of the Extension will include waste filling activities, the landfill gas (LFG) treatment facility, the new leachate treatment plant (LTP) and the LFG generator.

Representative Air Sensitive Receivers (ASRs) have been identified and an assessment of the potential air quality impacts has been conducted. Adjacent emission sources such as industrial emissions from Tseung Kwan O Industrial Estate (TKOIE), restoration of existing SENT Landfill and the future operations in TKO Area 137 during construction operation/restoration and aftercare phases of the Extension have also been taken into consideration. Mitigation measures have been recommended, where appropriate, to reduce the impacts.

4.2 Legislation Requirement and Evaluation Criteria

4.2.1 Air Pollutants Covered by Hong Kong Air Quality Objectives (HKAQOs)

The principal legislation for the management of air quality in Hong Kong is the Air Pollution Control Ordinance (APCO) (Cap. 311). Under the APCO, the Hong Kong Air Quality Objectives (HKAQOs), which are presented in Table 4.2a, stipulate the statutory limits for air pollutants and the maximum allowable numbers of exceedences over specific periods.

Table 4.2a Hong Kong Air Quality Objectives (mg m^-3) ^(a)

Air Pollutant	Averaging Time
	1 Hour ^(b)	8 Hour ^(c)	24 Hour ^(c)	1 Year ^(d)
Total Suspended Particulates (TSP)	-	-	260	80
Respirable Suspended Particulates (RSP) ^(e)	-	-	180	55
Sulphur Dioxide (SO₂)	800	-	350	80
Nitrogen Dioxide (NO₂)	300	-	150	80
Carbon Monoxide (CO)	30,000	10,000	-	-
Notes: (a) Measured at 298K (25°C) and 101.325 kPa (one atmosphere) (b) Not to be exceeded more than three times per year (c) Not to be exceeded more than once per year (d) Arithmetic means (e) Suspended airborne particulates with a nominal aerodynamic diameter of 10 micrometres or smaller

The Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM) also includes an hourly TSP criterion of 500 mg m^-3 for construction dust impacts and an odour criterion of 5 Odour Units (OUs) for a 5-second averaging period for odour impact assessment.

The criteria outlined in Table 4.2a and in the EIAO-TM were used to assess the potential air quality impacts associated with the Extension.

The measures set out in the Air Pollution Control (Construction Dust) Regulations should be followed to reduce dust impacts from this Project.

If a stone crushing plant of a capacity greater than 5,000 tonnes per year is needed, a licence must be obtained under the Air Pollution Control (Specified Process) Regulation and the control measures set out in the Guidance Note on the Best Practicable Means for Mineral Works (Stone Crushing Plants) (BPM 11/1) should be followed.

Should the fuel consumption rate of a premises/process with chimney emission exceed the specified fuel consumption rates stated in the Air Pollution Control (Furnaces, Ovens and chimneys) (Installation and Alternation) Regulations, an approval of chimney installation/alternation should be obtained from the EPD prior to the operation.

4.2.2 Air Pollutants Not Covered by HKAQOs

For those pollutants not covered by the HKAQOs, health risk criteria recommended in the international guidelines, such as those promulgated by the World Health Organisation (WHO), the United States Environmental Protection Agency (US EPA) and the California Air Resources Board (CARB) have been considered. The criteria/guideline values were selected in the following order of preference:

· WHO;

· US EPA; and

· CARB.

Cancer Health Risk Assessment

Of the non-criteria substances emitted during the operation/restoration and aftercare phases, benzene and vinyl chloride are considered carcinogenic. Table 4.2b shows the Unit Risk Factors (URFs) for the carcinogenic substances considered in this assessment.

Table 4.2b Guideline Unit Risk Factors for Carcinogenic Substances

Substance	Unit Risk Factor (mg m^-3)^-1
Benzene	7.8x10^{-6 (a)}
Vinyl Chloride	8.8x10^{-6 (b)}
Notes: (a) Reference to US EPA – Integrated Risk Information System – On-line data as in October 2007. The URF of benzene is in a range of 2.2x10^-6 – 7.8x10^-6 per mg m^-3. Upper range of URF is adopted for the worst case assessment (http://cfpub.epa.gov/iris/quickview.cfm?substance_nmbr=0276). (b) Reference to US EPA – Integrated Risk Information System – On-line data as in October 2007. The URFs of vinyl chloride are 4.4x10^-6 per mg m^-3for the exposure during adulthood and 8.8x10^-6 per mg m^-3 for the exposure from birth. Higher URF is adopted for the worst case assessment (http://cfpub.epa.gov/iris/quickview.cfm?substance_nmbr=1001).

The risk assessment guidelines for assessing the carcinogenic health risks from exposure to air toxics are summarised in Table 4.2c.

Table 4.2c Risk Assessment Guidelines for the Assessment of Carcinogenic Health Risks

Acceptability of Cancer Risk	Estimated Individual Lifetime Cancer Risk Level
Significant	> 10^-4
Risk should be reduced to As Low As Reasonably Practicable (ALARP)	> 10^-6 – 10^-4
Insignificant	£ 10^-6

Non-Cancer Health Risk Assessment

Benzene and vinyl chloride have the potential to cause chronic and/or acute impacts for long and/or short-term exposures, respectively. The reference chronic and acute concentrations of these pollutants are summarised in Table 4.2d.

Table 4.2d Guideline Values for Chronic and Acute Reference Concentrations

Substance	Chronic Reference Concentration (Annual Average in mg m^-3)	Acute Reference Concentration (Hourly Average in mg m^-3)
Benzene	30 ^(a)	1,300 ^(b)
Vinyl Chloride	100 ^(a)	1.8x10⁵ ^(b)
Notes: (a) US EPA – Integrated Risk Information System – On-line data as in October 2007 (b) California Environmental Protection Agency, Air Resources Board (ARB)/Office of Environmental Health Hazard Assessment (OEHHA) (http://www.oehha.ca.gov/air/acute_rels/allAcRELs.html).

The risk assessment guidelines also recommend criteria to assess the acceptability of chronic and acute non-cancer health risks and these are summarised in Tables 4.2e and 4.2f, respectively.

Table 4.2e Acceptability of Chronic Non-Cancer Health Risks

Acceptability	Assessment Results ^(a)
Chronic non-cancer risks are considered “Insignificant”	AC_A £ RC_c
Chronic non-cancer health risks are considered “Significant”. A more detailed assessment of the control requirements and further mitigation measures are needed.	AC_A > RC_c
Note: (a) AC_A and RC_c represent annual average concentration and chronic reference concentration, respectively.

Table 4.2f Acceptability of Acute Non-cancer Health Risks

Acceptability	Assessment Results ^(a)
Acute non-cancer risks are considered “Insignificant”	AC_HM £ RC_A
Acute non-cancer health risks are considered “Significant”. A more detailed assessment of the control requirements and further mitigation measures are needed.	AC_HM > RC_A
Note: (a) AC_HM and RC_A represent hourly average and acute reference concentrations, respectively.

4.3 Baseline Conditions and Background Air Quality

4.3.1 Baseline Conditions

The proposed Extension is located to the south of the existing SENT Landfill. The TKOIE is located to the north west of the Extension (see Figure 4.4a). The TKO Area 137 Fill Bank currently occupies part of the Extension site and the area south of the Extension. TKO Area 137 has been zoned for industrial activity (Deep Waterfront Industry) according to the Outline Zoning Plan (OZP) No. S/TKO/15 gazetted in November 2004.

No residential dwellings have been identified within 500m of the Extension site boundary. The nearest residential use (LOHAS Park), which is under construction, is located at about 1.8 km from the Extension site boundary.

The existing air quality in the vicinity of the Extension is affected by:

· Emissions from facilities in the TKOIE;

· Dust, odour and stack emissions from the SENT Landfill;

· Dust nuisance from TKO Area 137 Fill Bank;

· Vehicular emissions on Wan Po Road (both to and from the SENT Landfill and TKO Area 137 Fill Bank); and

· Background air quality in the Pearl River Delta.

During the operation of the Extension, the existing SENT Landfill will be closed. A capping system which will comprise (from bottom to top), as soil layer, a non-woven geotextile, an HDPE liner (impermeable liner), a sub-soil drainage layer and a final cover soil layer, will be installed. The LFG and leachate generated from the existing SENT Landfill will be collected by the leachate and LFG collection system and conveyed to the new LTP and LFG treatment facility for treatment. Therefore, no odour will be anticipated to be emitted from the restored area of the existing SENT Landfill.

4.3.2 Background Air Quality

EPD does not operate any Air Quality Monitoring Stations (AQMSs) in the Tseung Kwan O area.

For TSP, RSP, NO₂ and SO₂, the past six years (2001 - 2006) of air pollutant data([1]) recorded at the Kwun Tong AQMS (see Table 4.3a), which is the nearest EPD AQMS to the Extension, have been used to characterise the background air quality for the impact assessment. For CO, the past six years (2001 – 2006) of air pollutant data recorded at the Mongkok AQMS have been used as no CO monitored at Kwun Tong AQMS.

Table 4.3a Background Air Quality

Air Pollutant	Background Concentration (mg m^-3)
Total Suspended Particulates (TSP)	78 ^(a)
Respirable Suspended Particulates (RSP)	57 ^(a)
Nitrogen Dioxide (NO₂)	66 ^(a)
Sulphur Dioxide (SO₂)	18 ^(a)
Carbon Monoxide (CO)	1,294 ^(b)
Benzene	2.1 ^(c)
Vinyl Chloride	5.1 ^(c)
Notes: (a) From six years (2001-2006) annual average data on air pollutant concentrations measured at the EPD Kwun Tong AQMS (http://www.epd-asg.gov.hk/english/report/aqr.php). (b) Since no CO data is recorded at EPD Kwun Tong AQMS, therefore, the CO data recorded at Mongkok AQMS is used. (c) Reference to Table 4.5f. The maximum average benzene and vinyl chloride concentrations measured at the ambient VOC monitoring stations at the existing SENT Landfill for the past 5 years (2002 – 2006) were used.

Ambient benzene and vinyl chloride concentrations are measured at the ambient monitoring stations at the existing SENT Landfill. The locations of the ambient monitoring stations are shown in Figure 4.3a. In accordance with the Environmental Management Plan (EMP) of the existing SENT Landfill, benzene and vinyl chloride levels are measured at quarterly intervals. The measured data of benzene and vinyl chloride at the existing SENT Landfill monitoring stations were used to establish the background concentrations of these pollutants in the Study Area (see Table 4.3a).

As the existing SENT Landfill will be closed during the operation of the Extension, there will be no other similar odour sources identified within 500m of the Extension site boundary. Hence, no background odour is anticipated.

4.4 Air Sensitive Receivers

Table 4.4a and Figure 4.4a show the ASRs or those buildings that may be affected. Representative ASRs were identified in line with the requirements set out in the EIA Study Brief (ESB-199/2004) and Annex 12 of the EIAO-TM. The list includes existing and planned buildings within 500m of the Extension and ASRs along the Wan Po Road and Chiu Shun Road, in accordance with the requirements of Section 3.4.1.2 of the EIA Study Brief. Planned developments were identified with reference to the latest Outline Zoning Plans (No. S/TKO/15 gazetted in November 2004).

For the assessment of construction dust and gaseous emission, the Study Area is defined as 500m from the Extension site boundary.

Table 4.4a Identified Representative Air Sensitive Receivers

ASR	Location	Approx. Distance from Extension Site Boundary (m)	Type of Uses ^(a)	Approx. Max. Height above Ground (m)	Construction Dust ^(d)	Gaseous Emission ^(d)	Odour
A1-1	Proposed C&DM Handling Facility	150	I	30 ^(c)	Ö	Ö	Ö
A1-2 (1)	Planned Industrial Uses in TKO 137 (south of Extension) – 1	10	I	30 ^(c)	Ö	Ö	Ö
A1-2 (2) ^(b)	Planned Industrial Uses in TKO 137 (south of Extension) – 2	200	I	30 ^(c)	Ö	Ö	Ö
A1-3 (1)	Planned Industrial Uses in TKO 137 (south of TVB City) – 1	90	I	30 ^(c)	Ö	Ö	Ö
A1-3 (2) ^(b)	Planned Industrial Uses in TKO 137 (south of TVB City) - 2	200	I	30 ^(c)	Ö	Ö	Ö
A2	TVB City	110	C	30	Ö	Ö	Ö
A3	HAESL	410	I	30	Ö	Ö	Ö
A4	HAECO Component Overhaul Building	470	I	30	Ö	Ö	Ö
A5	Exhibition Services & Logistics Centre	690	I	30	-	-	Ö
A6	Gammon Skanska	950	I	30	-	-	Ö
A7	Yan Hing Machinery Industrial Building	400	I	30	Ö	Ö	Ö
A8	Apple Daily	505	C	30	Ö	Ö	Ö
A9	Mei Ah Industrial Building	530	I	30	-	-	Ö
A10	Asia Netcom	590	C	30	-	-	Ö
A11	Wellcome Storage	580	I	30	-	-	Ö
A12	Avery Dennison Machinery	600	I	30	-	-	Ö
A13	Hitachi	700	I	30	-	-	Ö
A14	Next Media Co. Ltd	740	C	30	-	-	Ö
A15	Varitronix	850	I	30	-	-	Ö
A16	Four Seas Food Processing Co. Ltd	1,060	I	30	-	-	Ö
A17	Committed HSBC Office	1,000	C	30	-	-	Ö
A18	Eastern Pacific Electronics	1,250	I	30	-	-	Ö
A19	Committed Tung Wah Group of Hospital Aided Primary & Secondary School	1,470	E	20	-	-	Ö
A20	LOHAS Park	1,830	R	200	-	-	Ö
A21	Chiaphua-Shinko Centre	1,860	I	30	-	-	Ö
A22	Shaw Film Studios	2,290	C	30	-	-	Ö
A23	Oscar by the Sea	3,160	R	170	-	-	Ö
A24	Tseung Kwan O Sport Ground	3,810	Rec	1.5	-	-	Ö
A25	Tseung Kwan O Town Park	4,050	Rec	1.5	-	-	Ö
A26	Leung Sing Tak Primary School	4,010	E	20	-	-	Ö
A27	Nan Fung Plaza	4,070	R	130	-	-	Ö
A28	St Andrew’s Church	4,160	Church	20	-	-	Ö
A29	Fung Ching Memorial Primary School	4,190	E	20	-	-	Ö
A30	On Ning Garden	4,260	R	120	-	-	Ö
A31	Sheung Ning Playground	4,240	Rec	1.5	-	-	Ö
A32	Tseung Kwan O Swimming Pool	4,530	Rec	1.5	-	-	Ö
A33	La Cite Noble	3,930	R	140	-	-	Ö
A34	Yuk Ming Court	3,980	R	110	-	-	Ö
A35	Ming Tak Estate	4,130	R	110	-	-	Ö
A36	Tin Ha Wan Village	3,950	R	10	-	-	Ö
A37	Tseung Kwan O Hospital	4,260	Hospital	25	-	-	Ö
A38	Ocean Shore Phase I	3,900	R	160	-	-	Ö
A39	Choi Ming Estate, Choi Yiu Court	3,820	R	155	-	-	Ö
A40	Park Central Block 1	3,530	R	185	-	-	Ö
A41	Bauhinia Garden Block 5	3,200	R	165	-	-	Ö
A42	Heng Fa Chuen	3,300	R	70	-	-	Ö
A43	Island Resort	2,400	R	160	-	-	Ö
Notes: (a) I = Industrial premises, R = Residential developments, C = Commercial premises, and Rec = Recreational facilities (b) As the type of industrial uses in the TKO Area 137 is not available (except the C&DM Handling Facility) at the time of the EIA Study, the HKPSG recommended setback distance of 200m from the major odour source (ie the SENT Landfill Extension) is included. The potential air quality impact within and outside the 200m buffer area has been assessed. (c) Planning Department has been consulted with respect to the building height restriction of TKO Area 137. It was agreed that the consultant should assume that the maximum height of the buildings at TKO Area 137 will be 30m. (d) Representative ASRs within 500m from the Extension site boundary will be included in the assessment of the construction dust impact and impact due to gaseous emission.

4.5 Potential Sources of Impacts

4.5.1 Construction Phase

Nuisance from dust generating activities has the potential to arise during construction. The major construction works include blasting, slope stabilization, excavation and filling, site formation, stone crushing and vehicle movements on the site. Blasting, materials handling during slope cutting and site formation, rock crushing and wind erosion of the filled area will be the major dust generating activities during the construction of the Extension. The construction works area is shown in Figure 4.5a.

Blasting will take place for the slope cutting at the area currently occupied by the TKO Area 137 for about 107 days between the third quarter of 2011 and end of 2012. One blast will be made each day. A total of about 320,000 m³ of rock will be generated and approximately 3,000 m³ of rock will be generated per day. It should be noted that all construction works will be ceased during the blasting due to site constraint and safety reason.

Due to limited space at the Extension site, most of the rocks will be exported off-site. A small rock crushing plant will be employed on-site to crush the blasted rocks (about 155,800 m³) into 25mm – 100mm in size and used as leachate drainage stones for the Project and the rest of the blasted rock will be broken down to about 250 mm in size for disposal off-site. During this process, watering will be carried out and no fugitive emission will be generated. Dust will be generated from the rock crushing activities screening and at the conveyor transfer point. With the provision of enclosure for the conveyor belt and watering at the conveyor transfer point, no fugitive dust emission is anticipated. Other dust control measures recommended in the Guidance Note on the Best Practicable Means for Mineral Works (Stone Crushing Plants) (BPM 11/1) will also be implemented at the rock crusher, and hence dust will only be emitted from the crushing and screening processes.

Should the processing capacity of the rock crusher exceeded 5,000 tonnes per day, it will be classified as a Specified Process (SP) and a licence will be required for the operation under the Air Pollution Control (Specified Process) Regulations.

About 770,000 m³ of excavated soil will also be generated during the slope cutting period between the third quarter of 2011 and end of 2012 (around one and a half years). Some of which will be reused for site formation works (about 475,000 m³). Due to limited space at the Extension, a small portion of the surplus soils (10,000 m³) will be stockpiled on-site for subsequent use as daily or intermediate cover materials for the Phase 1 operation of the Extension.

Throughout the construction period, good site practices and dust control measures stipulated in the Air Pollution Control (Construction Dust) Regulations will be implemented to reduce the dust emission as much as possible. The site-specific good site practices and dust control measures are recommended in Section 4.8.1.

4.5.2 Operational/Restoration Phase

Section 3 details the activities that will take place during operation and restoration of the Extension. As the restoration will take place progressively, whilst operations are ongoing on other parts of the site, these two phases have been considered together in the assessment.

The potential sources of air quality and odour impacts arising from the Extension during the operational/restoration phase include:

· Gaseous emissions from the new LFG treatment facility, the thermal oxidizer of the LTP and generator at the new infrastructure area;

· Vehicular emissions from traffic associated with the Extension;

· Fugitive emissions from the active tipping face; and

· Odour emissions arising from Waste Filling Activities and Operation of LTP.

Gaseous Emissions from the LFG Treatment Facility

LFG is a by-product of the waste decomposition process when this takes place under anaerobic conditions. Typically, this comprises methane (CH₄), carbon dioxide (CO₂) and trace amounts of other gases (eg volatile organic compounds (VOCs), hydrogen sulphide (H₂S), etc). The proportions of these compounds vary over the life of the landfill and from landfill to landfill. The quantity also varies from little or none in the early years of operation, rising to a peak during the operational period, before gradually declining over time following restoration of the landfill.

During the operation/restoration phase, the majority of the LFG generated will be collected by the extensive LFG collection system and used on-site (as the first priority) or flared off. The LFG will be pre-treated (removal of moisture) prior to utilization or flaring in order to minimize corrosion to the equipment.

The LFG treatment facility will comprise two flares (each with a maximum capacity of 10,000 m³hr^-1)located at the south-eastern boundary of the site (see Figure 4.5b). During the operation/restoration phase, the LFG collected will mainly be used in the LTP and LFG generator (IMW) to supply power for the facilities in the Infrastructure Area and the remainder will be diverted to the on-site utilization plant or flares at the LFG treatment facility. Based on the outline design of the LTP, the plant will consume a maximum of 3,125 m³ of LFG per hour and the LFG generator will consume about 1,500 m³ of LFG per hour. If not utilized for other beneficial uses, the remaining LFG (a maximum of 15,375 m³hr^-1) will be flared. For the worst case assessment, it is assumed that the LFG flares will be operated at their maximum design capacity (ie 10,000 m³hr^-1each). The combustion temperature of the flares will be about 850°C. At this temperature, methane, VOCs and the trace pollutants (such as H₂S) will be oxidised and destroyed. After flaring, trace amount of nitrogen dioxide (NO₂), carbon monoxide (CO), sulphur dioxide (SO₂) from the oxidation of H₂S, benzene, vinyl chloride and non-methane organic compound (NMOCs) will be emitted and the potential impacts of these air pollutants have been assessed in the following section.

The diameter and height of each flare stack will be 3.8m and 25m above the ground, respectively. The exit flowrate and velocity of the exhaust gas for each flare will be about 499,582 m³hr^-1 and 12.24 m s^-1 at 850°C. Table 4.5a shows the performance standards to which the flares will be operated to maintain a destruction efficiency of at least 99%.

Table 4.5a Designed Performance Standards of the LFG Flare

Parameter	Performance Standards
Emission limit for nitrogen oxides (NO_x)	11.28 mg m^{-3 (a) (b)}
Emission limit for carbon monoxide (CO)	28.19 mg m^{-3 (a) (b)}
Emission limit for sulphur dioxide (SO₂)	1.55mg m^{-3 (a)}
Emission limit for benzene	2.98x10^-3 mg m^{-3 (a) (c)}
Emission limit for vinyl chloride	1.88x10^-3 mg m^{-3 (a) (c)}
No. of flares	2
Stack height	25 m
Stack diameter	3.8 m
Exit temperature ^(d)	850°C
Exhaust gas flowrate	499,582 m³ hr^{-1 (a)}
Exhaust gas velocity	12.24 m s^-1
Notes: (a) Emission limit of air pollutant in exhaust gas. For SO₂, please refer to Annex A1 for detailed calculations. (b) Emission limits were estimated based on the specification of flares operating in the existing SENT Landfill. (c) Emission limits for benzene and vinyl chloride were estimated from the maximum concentrations of benzene and vinyl chloride in raw LFG measured at the inlet of the flare at the existing SENT Landfill. The maximum emissions of vinyl chloride and benzene were 4.4 ppm and 5.6 ppm, respectively. In accordance with the existing SENT Landfill Contract Specification, at least 99% of VOC destruction efficiency should be maintained. The emission limits are estimated based on the emission concentrations in the inlet, LFG flowrate, exhaust flowrate and the VOC removal efficiency. Please refer to Annex A1 for the detailed calculations.

Gaseous Emissions from Thermal Oxidizer of LTP

Leachate will be collected from the Extension and the restored existing SENT Landfill and pumped to the LTP in the new infrastructure area. The LTP will consist of four buffer storage tanks, two ammonia stripping towers and two thermal oxidisers (ie, one duty and one standby), a stripped leachate storage tank, two SBR tanks and a sludge holding tank. Except for the SBRs, all tanks will be enclosed and the air exhaust from the tanks will be diverted to the thermal oxidiser as part of the air intake.

The raw leachate will be stripped in the ammonia stripping towers. The ammonia laden air and the exhaust air of the enclosed tanks will be oxidised and destroyed in the thermal oxidiser (which will operate at 850°C) prior to discharge to the atmosphere. Under this combustion temperature, the ammonia gas will be completely destroyed ([2]).

LFG will be used as a fuel for the thermal oxidiser. The estimated maximum LFG consumption will be 3,125 m³hr^-1 assuming that the LTP is operating at its maximum capacity of 1,500 m³d^-1 ([3]), and 50 m³ of LFG is required for each cubic metre of leachate treated. A worst case assumption has been adopted whereby the emissions of nitrogen oxides (NO_x), sulphur dioxide (SO₂) (product of decomposition of any residual H₂S at high temperature), carbon monoxide (CO), benzene, vinyl chloride and NMOCs are assumed to be same as those for the flares (see Table 4.5a).

The physical parameters and emission data of thermal oxidiser are summarized in Table 4.5b.

Table 4.5b Stack Emissions and Physical Parameters of the Thermal Oxidiser

Parameter	Thermal Oxidiser of the LTP
Emission limit for NO_x	28.4 mg m^{-3 (a)}
Emission limit for CO	70.91 mg m^{-3 (a)}
Emission limit for SO₂	3.9mg m^{-3 (a)}
Emission limit for benzene	7.51x10^-3 mg m^{-3 (a)}
Emission limit for vinyl chloride	4.73x10^-3mg m^{-3 (a)}
No. of Stack	2 (one duty and one standby)
Stack height	9.76 m ^(c)
Stack diameter	1.12 m ^(c)
Exit temperature	171.6 °C ^(c)
Exhaust gas velocity	17.5 m s^{-1 (c)}
Exhaust gas flowrate	62,068 m³ hr^-1
Notes: (a) All emission limits are under its exhaust gas condition. (b) Refer to the detailed calculations presented in Annex A1. (c) With reference to the design of the Thermal Catalytic Units of the existing Bioplant at SENT Landfill.

Gaseous Emissions from LFG Generator

A generator fuelled by LFG will be installed to provide power for on-site plant and equipment. Taking account of the anticipated power requirements of the infrastructure area of the Extension, the capacity of the generator will be about 1MW which is similar to the generator used in the existing SENT Landfill. The physical parameters and emission data of generator, reference to the LFG generator operating in the existing SENT Landfill, are summarized in Table 4.5c.

Table 4.5c Stack Emissions and Physical Parameters of the LFG Generator

Parameter	LFG Generator
Engine power	1MW ^(a)
LFG input to generator	1,500 m³hr^{-1 (a)}
Emission limit for NO_x	0.14 lb mmBTU^{-1 (b)}
Emission limit for CO	0.44 lb mmBTU^{-1 (b)}
Emission limit for SO₂	0.045 lb mmBTU^{-1 (b)}
Emission limit for benzene	2.1x10^-5 lb mmBTU^{-1 (b)}
Emission limit for vinyl chloride	1.6x10^-6 lb mmBTU^{-1 (b)}
No. of Stack	2 (one duty and one standby)
Stack height	28 m
Stack diameter	0.305 m ^(a)
Exit temperature	454°C ^(a)
Exhaust gas velocity	48.6 m s^{-1 (a)}
Notes: (a) Reference to the generator being operated at the existing SENT Landfill. (b) Reference to the Compilation of Air Pollutant Emission Factors, AP-42, 5^th Edition, Table 3.1-1 and 3.1-2b.

Summary: Under normal operations, LFG collected from the Extension will be primarily used as fuel for the LTP and generator. The remainder will be utilised or flared. Table 4.5d summarises the emission data of each facility and the location of these facilities is shown in Figure 4.5b. The detailed calculation is summarized in Annex A1.

Table 4.5d Summary of Gaseous Emission Inventory for the Flares and Thermal Oxidiser During Operation/Restoration Phase ^(a)

Parameter	Flare	Thermal Oxidiser	LFG Generator
No. of emission points	2	1 (one duty and one standby)	1 (one duty and one standby)
Stack height (m)	25	9.76	28
Stack diameter (m)	3.8	1.12	0.305
Exhaust gas velocity (m s^-1)	12.24	17.5	48.6
Exhaust gas flowrate (m³ s^-1)	499,582	62,068	12,780
Exit temperature (°C)	850	171.6	454
Emission limit for NO_x ^(b)	11.28 mg m^-3	28.4 mg m^-3	0.14 lb mmBTU^-1
Emission limit for CO ^(b)	28.19 mg m^-3	70.91 mg m^-3	0.44 lb mmBTU^-1
Emission limit for SO₂^(b)	1.55 mg m^-3	3.90 mg m^-3	0.045 lb mmBTU^-1
Emission limit for benzene^(b)	2.98x10^-3mg m^-3	7.51x10^-3mg m^-3	2.1x10^-5 lb mmBTU^-1
Emission limit for vinyl chloride ^(b)	1.88x10^-3mg m^-3	4.73x10^-3mg m^-3	1.6x10^-6 lb mmBTU^-1
Emission rate for NO₂ (g s^-1)	0.31 ^(c)	0.10 ^(c)	0.11 ^(c)
Emission rate for CO (g s^-1)	3.91	1.22	1.721
Emission rate for SO₂ (g s^-1)	0.22	0.07	0.176
Emission rate for benzene (g s^-1)	4.14x10^-4	1.29x10^-4	8.22x10^-5
Emission rate for vinyl chloride (g s^-1)	2.61x10^-4	8.15x10^-5	6.26x10^-6
Notes: (a) Detailed calculations are summarized in Annex A1. (b) All emission limits are under its exhaust gas condition. (c) Assuming 20% of NO_x is NO₂.

Vehicular Emissions from Traffic Associated with the Extension

The waste arising forecast indicates that a maximum of 134 vehicles per hour([4]) will be generated from the operation of the Extension which will be about 19% on the Wan Po Road south of Chung Wang Street and about 2.4% on the Wan Po Road south of Pak Shing Kok Road as compared to forecasted background traffic in 2018 (refer to Annex B2-3). It is anticipated that this limited increase in traffic flow will not result in adverse air quality impacts at the identified ASRs.

Fugitive Emissions at Landfilling Area in the Extension

The landfill activities during the operation/restoration phase of the Extension will generate fugitive dust and gaseous emissions from (1) the construction of drainage channels and sumps, LFG and leachate extraction wells and collection systems; (2) haul roads; and (3) operation of the construction equipment. Landfill surface emission from the active tipping face is also a potential fugitive emission source.

Fugitive Dust Emissions: Fugitive dust will be emitted from the placement of cover materials, construction of LFG and leachate collection pipes and wells, traffic movements on the unpaved haul roads and traffic movements at the waste reception area. The quantities of soil and rock to be handled for different phases of the Extension are summarized in Table 4.5e.

Table 4.5e Total Soil and Rock Fill Requirements

Phase	Total Fill Requirement (m³)		Fill Requirement Per Day (m³d^-1) ^(a)
	Soil	Rock	Soil	Rock
1	365,600	60,500	1,000	165.8
2	453,100	60,500	1,240	165.8
3	478,700	60,500	1,310	165.8
4	557,900	60,500	1,530	165.8
5	590,800	60,500	1,620	165.8
6	658,800	60,500	1,800	165.8
Total	3,104,900	363,000	-	-
Note: (a) For each phase, no. of day is 365.

The management of fugitive dust at the Extension will be similar to that being implemented at the existing SENT Landfill and will include immediate compaction of the fill area; regular damping down of the surface of the haul road; provision of vehicle washing facility for RCVs at the exit of the Extension (to ensure no significant dust will be brought onto the public road); and regular cleaning of the main access road and waste reception area by road sweeper.

Although the lining of side slopes will be carried out concurrently with the waste tipping operation, no earthworks will be required for the slope lining works. Hence, there will be no cumulative dust impacts for these activities.

At the existing SENT Landfill, the average ambient daily TSP concentration record at the ambient TSP monitoring stations located at the site boundary ([5]) over the past five years (2002-2006) was 89 µg m^-3. There were no exceedances of the daily dust criterion of 260 µg m^-3 due to the operation of the landfill.

As the majority of the Extension site will be covered with impermeable liner, the potential areas from which dust can be generated will be much lower when compared with the existing SENT Landfill operation. Hence, it is anticipated that the potential dust to be generated due to the operation of the Extension will be much lower than that from the operation of the existing SENT Landfill. With the implementation of the dust control measures recommended in Section 4.8.2, it is expected that the TSP concentrations at the Extension site boundary during the operation/restoration phase will be well below the daily dust criterion and there will be no adverse dust impacts to the identified ASRs.

Gaseous Emissions from Construction Plant: Gaseous emissions such as nitrogen dioxide (NO₂) and sulphur dioxide (SO₂) will be generated from the operation of diesel-fuelled construction for the following activities.

· Construction of drainage channels and sumps – transportation of materials, bar bending and cutting as well as concreting;

· Road construction – transportation of materials, grading, road rolling;

· Deposition and compaction of waste – transportation, deposition and compaction of waste;

· Placement and removal of daily covered materials – by excavator, bulldozer, dump truck, vibratory roller and loader; and

· Capping and landscaping (progressive restoration) – by bulldozer, dump truck, vibratory roller, loader and mobile crane.

These plants will be located across the site, depending on need. The nearest representative ASR, TVB City, is located at about 110 m away from the nearest construction site boundary. The total gaseous emissions generated by the plant over the construction site area (ie, 20ha) are small and it will disperse and diluted with the ambient air very rapidly. Therefore, the potential air quality impact associated with operation of the construction plant on the identified ASRs is envisaged to be limited and minor.

Emissions of LFG including VOCs from Landfill Surfaces: The predicted LFG generation rates have been discussed in Section 8.5.1. The LFG management system is designed to collect LFG generated from the Extension as early as possible. Except the active tipping face and the special waste trench, all the areas will be covered by 600mm of soil and an impermeable liner. In addition to the vertical LFG collection wells, a number of horizontal LFG collection wells will be installed above the leachate drainage layer and within the waste mass. The majority of LFG will be captured by the collection system.

The composition of LFG is anticipated to be similar to that from the existing SENT landfill, given that the waste types accepted will be similar.

Samples obtained from the LFG abstraction wells of the existing SENT Landfill contain about 40 to 60% methane, 30 to 45% carbon dioxide and a trace amount of VOCs ([6]). In 2005 and 2006, out of the 39 VOCs ([7]) analysed, only dichlorodifluoromethane, vinyl chloride, dimethyle sulphide, methylene chloride, benzene, heptanes, trichloroethylene, toluene, octanes, tetrachloroethylene, ethylbenzene, xylenes, propyl benzene and dichlorobenzene were detected. For most of these, the measured concentrations were in the range 0.01 and 39.7 µg m^-3.

The ambient concentrations of the 39 VOCs were also monitored on a quarterly basis at the ambient air quality monitoring stations at the site boundary. A summary of the measured concentrations of these 39 VOCs from 2002 to 2006 is presented in Table 4.5f. Benzene, chloroform, dichlorodifluoromethane, ethylbenzene, methylene chloride, propyl benzene, toluene and xylene were measured in most of the samples. However, the concentrations were well below the respective trigger levels. Other VOCs were not detected or measured. Exceedances of the trigger levels for chloroform and propyl benzene were detected in one occasion at the ambient VOC monitoring stations. Investigations were conducted and it was considered that the abnormal readings were caused by off-site sources such as vehicle exhaust.

Table 4.5f VOC Concentrations at Site Boundary and On-site of the Existing SENT Landfill (2002 - 2006)

Pollutant	Trigger Level	Monitored VOC Concentration (µgm^-3)
		VOC/1			VOC/4			VOC/6			VOC/8			On-site
		Min	Max	Average	Min	Max	Average	Min	Max	Average	Min	Max	Average	Min	Max	Average
1,1,1-Trichloroethane	19,000	ND	2.3	1.2	ND	2.9	1.5	ND	5.8	1.7	ND	4.1	1.2	ND	4.1	1.4
1,2-Dibromoethane	40	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	4.4	4.4	ND	ND	ND
1,2-Dichloroethane	400	ND	0.6	0.4	ND	2.1	0.9	ND	1.3	0.7	ND	2.5	1.2	ND	4.4	1.7
Benzene	160	ND	4.4	1.0	<0.5	10.1	1.5	<0.5	25.1	2.1	<0.5	13.1	1.5	<0.5	4	1.2
Butan-2-ol	3,000	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND
Buthanethiol	4	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND
Butyl Benzene	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND
Carbon Disulphide	255	ND	0.9	0.9	ND	41.2	26.0	ND	5.5	5.1	ND	6.7	6.7	ND	6.8	6.3
Carbon Tetrachloride	126	ND	3.5	1.1	ND	0.9	0.7	ND	1.3	0.8	ND	5	1.2	ND	3.8	1.6
Chloroform	98	ND	67	9.5	ND	409.2	36.1	ND	19.1	3.4	ND	30.2	11.0	ND	67	17.2
Decane	1,000	ND	ND	ND	ND	<1	<1	ND	ND	ND	ND	ND	ND	ND	ND	ND
Dichlorobenzene	1500	ND	29	4.1	ND	95	19.3	ND	65	5.6	ND	137	13.8	ND	4	1.5
Dichlorodifluoromethane	49,500	1	37.1	3.7	ND	450	27.1	ND	159.4	11.0	ND	490	25.9	ND	8.1	1.9
Dimethyl Sulphide	11	ND	ND	ND	ND	9.4	5.0	ND	0.7	0.7	ND	ND	0.4	ND	0.2	0.2
Di-n-Propyl Ether	2700	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND
Ethanethiol	1	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND
Ethanol	1,900	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND
Ethyl Butyrate	-	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND
Ethyl Propionate	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND
Ethylbenzene	1,000	ND	160	14.1	ND	268	28.3	ND	562	32.3	ND	182	17.8	ND	160	16.7
Heptane	16,000	ND	21.9	7.2	ND	<1	0.8	ND	34	17.8	ND	49	17.0	ND	47.9	21.6
Limonene	57	ND	5.2	5.2	ND	ND	ND	ND	3.5	3.5	ND	2	2.0	ND	ND	ND
Methane	-	<1	480	31.2	<1	250	48.7	<1	97.9	21.1	<1	436.7	34.4	<1	130	10.2
Methanethiol	-	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND
Methanol	2,600	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND
Methyl Butyrate	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND
Methyl Propionate	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND
Methylene Chloride	3,500	<0.4	557.3	49.5	<0.4	174	28.9	<0.4	104.2	17.1	ND	680.6	97.9	<0.4	2885	197.5
n-Butyl Acetate	1,500	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND
Nonane	24,000	ND	5	1.8	ND	29	7.9	ND	<0.9	<0.9	ND	<0.9	<0.9	ND	26	16.0
Octane	14500	ND	13	4.5	ND	3	1.8	ND	37	25.9	ND	30	12.2	ND	14.5	6.2
Propyl Benzene	196	ND	74.9	11.1	<0.8	605.1	42.3	ND	340	31.0	ND	280	24.0	ND	282	21.9
Propyl Propionate	56,000	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND
Terpenes	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND
Tetrachloroethylene	3,350	ND	94.5	10.1	ND	19.5	6.3	ND	24.5	3.8	ND	11.5	6.1	ND	7.5	2.7
Toluene	1,880	4	124	24.2	<0.5	463	89.6	<0.5	1003	74.2	<0.5	423	55.0	<0.5	264	50.4
Trichloroethylene	5,350	ND	2.2	1.4	ND	6	3.1	ND	4.8	2.8	ND	4.4	2.0	ND	<1.2	<1.2
Undecane	1,300	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND	ND
Vinyl Chloride	78	0.4	0.4	0.4	ND	9.5	4.2	ND	36.5	5.1	ND	4.9	3.5	ND	<0.3	0.3
Xylene	4,350	ND	200	16.7	<0.5	479	50.1	<0.5	941	54.4	<0.5	271	29.8	<0.5	200	22.8
Notes: (a) “ND” means Not Detectable. (b) Bold and underlined figure indicates the exceedance of the trigger level.

As the majority of the Extension site will be covered with an impermeable liner and LFG will be extracted via a comprehensive LFG collection system during the operation phase, it is anticipated that the fugitive LFG emission from the Extension due to waste tipping activities will be significantly reduced relative to the existing SENT Landfill. Taking account of the ambient VOC monitoring results at the existing SENT Landfill, it is expected that the ambient VOC concentrations at the Extension Site boundary will be well below the trigger levels for individual compounds. Further dilution of the VOC concentration is expected due to dispersion off-site. The anticipated VOC concentrations at the identified ASRs will be minimal and will not cause adverse impacts.

Odour Emissions from Waste Filling Activities and Operation of LTP

The restoration of the landfill will take place progressively, whilst operations are ongoing on other parts of the site, therefore, these two phases have been considered together in the assessment.

Potential sources of odour impact during operation/restoration phase included:

· Waste filling area; and

· Operation of the LTP and the LFG treatment facility.

In order to minimize the potential odour emissions during the operational phase of the Extension, a number of odour management and control measures have been incorporated into the outline design. These measures are summarized in Table 4.8a.

Odour Emissions from Waste Filling Area

The Extension is scheduled to commence operation in 2013 and will be designed to receive MSW, special waste ([8]) and construction waste. By that time, the Sludge Treatment Facilities (STF) are scheduled to be in operation ([9]) and sludge from sewage treatment works (STWs) will be diverted to the STF for treatment and disposal.

The operational life of the Extension is expected to be about 6 years. The Extension will be developed in 6 phases (Phases 1 to 6) and each phase will be in operation for approximately 1 year. The ground level of the first phase will be at about +6mPD and the highest level will be at +150 mPD. The Extension will open to receive wastes from 8 am to 11 pm every day.

Waste Reception Area: All incoming and outgoing refuse collection vehicles (RCVs) will be weighed at the enclosed weighbridge office at the waste reception area. All RCVs visiting the Extension are of enclosed-type and expected to comply with relevant regulations and to be properly maintained, therefore, the potential odour emission from RCVs and at the waste reception area are assumed to be minimal.

Active Tipping Face: After weighing, the RCVs will be directed to the active tipping face for unloading. The operation at the active tipping face will be similar to that of the existing SENT Landfill. Two platforms (ie lower and upper platforms) will be used for separate unloading of MSW (at the lower platform) and construction waste (at the upper platform). The construction waste will overlay the MSW. The wastes will be promptly spread by bulldozer and compacted by a landfill compactor to minimize the exposure time of MSW thus minimise the opportunity of odour emission to the atmosphere. The tipping face area will be 30m x 40m ([10]). After 11 pm, the Extension will be closed and the compacted waste will be covered with 300mm of cover soil immediately. Therefore, odour emissions from the active tipping face are expected during the operating hours; however, the emissions will be much reduced thereafter.

Special Waste Trench: A trench will be excavated into the landfill mass for the disposal of waste that needs special handling. The trench will be located at least 50 m from the active tipping face and the waste boundary. The trench will only operate when the waste depth is at least 10m above the base to avoid damage to the leachate collection system. The size of the trench will vary in accordance with the volume of special waste that has been pre-registered for disposal by the special waste producers. With reference to the operational experience at the existing SENT Landfill and the quantity of special waste received, it is expected that the maximum size of the trench will be about 6m x 2.5m. The trench will be open to receive special waste from 9 am to 5 pm everyday. After 5 pm, the trench will be backfilled with inert waste and covered by 600 mm of soil and an impermeable liner to minimise odour emissions. Special waste for trench disposal is normally required to be delivered in sealed bags and no odour will be generated from the bagged waste. However, odour will potentially be emitted from the side walls and the base of the trench itself during operating hours. In order to reduce the odour emission from the trench, the trench will be covered by a movable cover with retractable or suitable opening so that the trench is covered at all times except during waste deposition. The air trapped inside the trench will be extracted and scrubbed by a mobile odour removal unit prior to discharge to the atmosphere. Therefore, the odour emitted from the trench will be minimal. However, for the worst-case assessment in this Study, it is assumed that the trench is open to atmosphere without any odour removal.

Main Haul Road to Active Tipping Face: The MSW will be delivered in RCVs with enclosed compactor body. It is therefore anticipated that the potential odour emission from the RCVs along the haul road of the Extension will be minimal.

Daily Covered Area: At the end of each working day (ie after 11 pm), the active tipping face will be covered with 300 mm of soil and compacted.

Intermediate Cover Area: Except for the active tipping face and the final cover area (see below for details), all other areas of the Extension will be covered with 600mm of soil ([11]) and an impermeable liner in order to minimize rainwater infiltration into the waste and odour emission as well as to enhance LFG extraction. It is therefore anticipated that no odour will be emitted from this area ([12]).

Final Cover Areas: After waste tipping reaches the final levels, a capping system will be installed. The capping system will comprise (from bottom to top) a soil layer, a non-woven geotextile, an HDPE liner (impermeable layer), a sub-soil drainage layer and a final cover soil layer. Permanent gas extraction system will be installed to extract LFG from the waste mass. Planting will also be provided for the final covered area. It is therefore anticipated that no odour will be emitted from this area ([13]).

Operation of Leachate Treatment Plant (LTP)

Leachate collected from the Extension and the existing SENT Landfill will be pumped to the LTP in the new infrastructure area. The LTP will consist of four buffer storage tanks, two ammonia stripping towers, two thermal oxidisers (i.e., one in operation and one standby), a stripped leachate storage tank, two SBR tanks and a sludge holding tank. Except for the SBR tanks, all tanks will be enclosed and the air exhaust from the tanks will be diverted to the thermal oxidiser. The operation temperature of the thermal oxidizer is about 850°C. Odorous gas in the exhaust air (such as ammonia) will be oxidised and destroyed at such high temperature ([14]) in the thermal oxidiser prior to discharge to the atmosphere. The SBR tanks will therefore be the only odour emission source in the LTP.

The dimension of each of the SBR tanks is 20m (width) x 35m (length). The tank height is about 5m. The leachate temperature in the SBR will be maintained at about 40°C throughout the year. The LTP will operate on a 24-hours per day basis.

Operation of LFG Treatment Facility

The LFG treatment facility will be operated on a 24-hours per day basis. The LFG collected from the LFG extraction system will be either diverted to other utilization scheme for beneficial use or flared at the treatment facility. The flaring temperature is about 850°C and odorous compounds such as VOCs or H₂S in the LFG will be oxidised and destroyed at such temperatures. Therefore, no odour emission is expected from the LFG treatment facility.

Summary of Potential Odour Emission Sources

As discussed above, the major potential odour sources will include waste tipping activities at the active tipping face and at the special waste trench as well as the operation of the LTP.

The odour emission sources during the operation/ restoration phase are summarized in Table 4.5g.

Table 4.5g Summary of Odour Emission Sources

Odour Emission Source	Area	Remarks
During Operation Hour (8am – 12 midnight)
Active tipping face for MSW + construction waste	30m x 20m	· From 8am to 11pm. Covering the active tipping face after operation at 11pm to 12 midnight
Active tipping face for construction waste	30m x 20m	· From 8am to 11pm. Covering the active tipping face after operation at 11pm to 12 midnight
Special waste trench	6m x 2.5m (plan area exposed to air) ^(a)	· From 9am to 5pm. Covering the trench at 5pm – 6pm
After Operation Hour (12 midnight – 8am on the next day)
Daily cover area	30m x 40m	12 midnight – 8am (on the next day)
24-hour Operation
SBR tanks of the LTP	20m x 35m (2 nos.)	24 hours
Note: (a) Longer side : 6m (l) x 2m (H); shorter side: 2.5m (l) x 2m (H); bottom: 6m x 2.5m

4.5.3 Aftercare Phase

Upon completion of final filling and capping, the aftercare phase will commence and is estimated to last for up to 30 years. The LFG and leachate management systems as well as the LFG generator will continue to operate during the aftercare phase.

Operation of LTP

It should be noted that once the landfill is restored, the leachate generation rate from the Extension will be significantly reduced and hence the average daily volume of leachate to be treated will be reduced from about 350 m³d^-1 to 23 m³d^-1, ie approximately an 93% reduction). With respect to the small volume of leachate generated, it will be able to reduce the nitrogen levels in the leachate using biological treatment (ie, nitrification and denitrification) so that the effluent will comply with the discharge standards. The operation of the ammonia strippers and thermal oxidisers will not be necessary.

The vent gas from the enclosed leachate storage and treatment tanks will be diverted to an air scrubber or the flares prior to discharge to the atmosphere. The designed odour (including ammonia gas) removal efficiency of the air scrubber will be at least 95%. Therefore, majority of the odorous gas in the vent gas from enclosed tanks will be removed. The scrubbed vent gas will be used as part of the air intake for the aeration system of the SBR tank. If the vent is diverted to the flare(s) as part of the air intake, the odorous gas will be destroyed at high combustion temperature (at 850^oC).

The potential source of odour emission during the aftercare phase will only be the open SBR tanks (please refer to Table 4.6e for the odour emission rate of the SBR tanks).

Operation of LFG Treatment Facility

Together with the final capping system, the permanent LFG extraction system will prevent fugitive emission of LFG from the restored landfill. The LFG abstracted will be utilised or flared. Under a high combustion temperature (850^oC) at the flare, the odorous VOCs in the LFG will be completely oxidised and destroyed.

Conversely, the total LFG generated from the restored SENT Landfill and the Extension will increase (maximum yield of about 17,000 m³ hr^-1). A worst case scenario has been assumed where the two flares will be operated at full load (20,000 m³ hr^-1). The emission inventory of flares is summarized in Table 4.5h. The detailed calculation is summarized in Annex A1.

LFG Generator

LFG generator will continue to provide power supply for the operation of LFG Treatment Facility, LTP and other facilities at the infrastructure area. The emission inventory of the LFG generator is summarized in Table 4.5h and detailed calculations are presented in Annex A1.

Table 4.5h Summary of Gaseous Emission Inventory for the Flares and Generator During Aftercare Phase ^{(a) (b)}

Parameter	Flare	LFG Generator
No. of emission points	2	1 (one duty and one standby)
Stack height (m)	25	28
Stack diameter (m)	3.8	0.305
Exhaust gas velocity (m s^-1)	12.24	48.6
Exhaust gas flowrate (m³ s^-1)	499,582	12,780
Exit temperature (°C)	850	454
Emission limit for NO_x^(c)	11.28 mg m^-3	0.14 lb mmBTU^-1
Emission limit for CO ^(c)	28.19 mg m^-3	0.44 lb mmBTU^-1
Emission limit for SO₂^(c)	1.55 mg m^-3	0.045 lb mmBTU^-1
Emission limit for benzene^(c)	2.98x10^-3mg m^-3	2.1x10^-5 lb mmBTU^-1
Emission limit for vinyl chloride ^(c)	1.88x10^-3mg m^-3	1.6x10^-6 lb mmBTU^-1
Emission rate for NO₂ (g s^-1) ^(d)	0.31	0.11
Emission rate for CO (g s^-1)	3.91	1.721
Emission rate for SO₂ (g s^-1)	0.22	0.176
Emission rate for vinyl chloride (g s^-1)	4.14x10^-4	8.22x10^-5
Emission rate for benzene (g s^-1)	2.61x10^-4	6.26x10^-6
Notes: (a) Detailed calculations are summarized in Annex A1. (b) Reference to Table 4.5d (c) All emission limits are under exhaust gas condition. (d) Assuming 20% of NO_x is NO₂

4.5.4 Cumulative Impacts

According to the EIA Study Brief requirement, major emission sources in the vicinity should be included to assess the cumulative air quality impact.

Construction Phase

The operation of the existing SENT Landfill (last year of operation) and the C&DM Handling Facility in TKO Area 137 are identified as potential concurrent projects during the construction phase of the Extension.

During the last year of the operation of the existing SENT Landfill, most of the landfill area will be capped and restored. Dust will be emitted from the placement of cover materials, traffic movements on the unpaved haul roads and traffic movements at the waste reception area (please refer to Figure 4.5a). As discussed in Section 4.5.3, due generation will be minimised by implementation of dust control measures, including immediate compaction of the fill area; regular damping down of the surface of the haul road; provision of vehicle washing facility for RCVs at the exit of the existing SENT Landfill (to ensure no significant dust will be brought onto the public road); and regular cleaning of the main access road and waste reception area by road sweeper.

The separation distance between the active tipping area of the existing SENT Landfill and the dusty construction work area of the Extension site is about 850m (refer to Figure 4.5a). As the worse wind angles which carry the dust from dusty activity area of Extension and that for dust generated from the active tipping area of the existing SENT Landfill are different, no cumulative dust impacts are anticipated due to the operation of the existing SENT Landfill and the construction of the Extension.

TKO Area 137 is currently planned for Deep Water Front Industrial uses. A Construction and Demolition Material (C&DM) Handling Facility is scheduled to be commissioned in phases in TKO Area 137 (see Figure 3.9b) in 2009. The capacity of the C&DM Handling Facility is about 20,000 tonnes per day. However, the detailed design information is not available at this stage but it is understood that the potential dust impacts associated with the operation of the C&DM Handling Facility will be assessed as part of the feasibility and engineering design of the facility. It is recommended that the cumulative dust impact in the vicinity should be addressed in the environmental study under that study. It is anticipated that the facility will incorporate necessary dust control measures (as stipulated in the Air Pollution Control (Construction Dust) Regulations) in the design of the facility (which may include enclosure of the dusty operations) and good site practices to control dust emissions from the facility. It is expected that no adverse dust impact will result from the operation of the facility.

As of the existing fill bank at TKO Area 137 will be decommissioned by the end of 2008, no cumulative dust impact will be anticipated.

In summary, no cumulative dust impact is anticipated during the construction of the Extension.

Operation/Restoration and Aftercare Phases

Odour Impact

When the Extension commences operation, the existing SENT Landfill will be closed and will not generate odour. No other similar concurrent type of odour source is identified within 500m of the Extension site boundary during the operation/restoration and aftercare phases. Hence, no cumulative landfill odour impact is expected.

Gaseous Emissions from the existing TKO Industrial Estate

Within 500m from the Extension site boundary, emissions from TVB City and HAESL may cause cumulative air quality impact. On-site chimney survey within the 500m area from the Extension site boundary was conducted in January 2008. Interviews were also conducted to validate the stack operation and its emission inventory.

According to the information provided by TVB City and the public information obtained from the EPD Regional Office (East), the major gaseous emission sources identified at TVB City are the emergency generators. As the emergency generators will only operate when CLP’s grid is suspended, the operating time of these generators is very limited and it will not expected to cause cumulative air quality impact within the Study Area.

With reference to the EIA Report of HAECO Aircraft Engine Test Cell Facility at TKO, NO₂, CO and SO₂ are the key air pollutants to be emitted during engine testing. These emission rates and stack characteristics are summarized in Table 4.5i.

Table 4.5i Stack and Emission Characteristics in Study Area ^(a)

Stack ID	No. of Stacks	Efflux Velocity (m s^-1)	Stack Diameter (m)	Stack Height Above Ground (m)	Exit Temp. (°C)	Emission Rate (g s^-1)
						NO₂	CO	SO₂
HAECO / HAESL ^(c)	1	16.4 for NO₂ and SO₂; 12 for CO	14.7	40	52	21.2	23.9	1.92
Notes: (a) Reference to the EIA Report of HAECO Aircraft Engine Test Cell Facility at TKO. (b) It is the equivalent diameter. The stack is in square shape with an area of 13m x 13m.

The above stack characteristic, emission inventory and engine type being tested at HAESL have been confirmed by HAESL.

The emissions of NO₂, CO and SO₂ from HAESL are included to assess the cumulative air quality impact during both the operation/restoration and aftercare phases.

4.6 Assessment Methodology

4.6.1 Construction Phase

Dust will be generated from blasting, materials handling, wind erosion, rock crushing and truck movements on paved haul roads within the site. It should be noted that no construction works will be carried out during blasting due to the site constraint and safety reason. The dust impact from blasting will be assessed individually.

TSP levels at the identified ASRs were predicted using the Fugitive Dust Model (FDM). The 2006 meteorological data obtained from the existing SENT Landfill weather station and TKO weather station operated by the Hong Kong Observatory (HKO) were used for the model runs. Dust emission rates and associated particle size distributions for the assessment were determined in accordance with the Compilation of Air Pollutant Emission Factors, AP-42, 5^th Edition. One blast will be made each day and the construction works would be carried out for 12 hours (from 7am to 7pm) per day and 24 days per month. During night-time (7pm to 7am on next day), only wind erosion of open fill area was considered. Mitigation measures recommended in Section 4.8.1 have been considered in the dust emission rate estimation.

The mitigated TSP emission rates during blasting, rock crushing, materials handling, wind erosion and truck movement on unpaved haul road within the construction site are estimated and summarized in Table 4.6a and detailed calculations are presented in Annex A2.

Table 4.6a Mitigated Dust Emission Rates ^{(a) (b) (c)}

Construction Works	Dust Generating Activities	Dust Emission Rate	Remarks
Slope Cutting	Blasting	1.93 gs^-1	· Blasting area = 1,000 m² (estimated by the engineer) · 1 blast per day during daytime · Total no. of day = 107 days · Emission height = 0,5m
Excavation	Materials Handling	0.0103 gs^-1	· Excavation period = 1.5 year · Total volume of soil excavated = 770,000 m³ · Hourly soil generation rate = 148.5 m³/hr · 50% dust removal efficiency by watering · Working time: between 7am and 7pm · Emission height: 0.5m
	Rock crushing	· Crushing = 0.0098 gs^-1 · Screening = 0.018 gs^-1	· Rock to be crushed per day = 400m³ per day (max.) · Working time: between 7am and 7pm · Emission height = 5m
	Truck movement on unpaved haul road	0.00435 gm^-2s^-1	· Total no. of vehicle trip per hour = 70 (including return trip) · Average truck weight = 21.5 tonnes · 90% dust removal efficiency by watering of main haul road, limiting vehicle speed and paving with aggregate/gravel · Working time: between 7am and 7pm · Emission height: 0.5m
Filling	Materials Handling	0.0054 gs^-1	· Filling period = 1.5 year · Total volume of fill materials = 407,200 m³ · Hourly filling rate = 78.5 m³/hr · 50% dust removal efficiency by watering · Working time: between 7am and 7pm · Emission height: 0.5m
	Truck movement unpaved haul road	0.00156 gm^-1s^-1	· Total no. of vehicle trip per hour = 26 (including return trip) · Average truck weight = 20 tonnes · 90% dust removal efficiency by watering of main haul road, limiting vehicle speed and paving with aggregate/gravel · Only carried out during daytime between 7am and 7pm
	Wind erosion	§ Daytime : 1.35x10^-6 gm^-2s^-1 § Night-time : 2.7x10^-6 gm^-2s^-1	· Total area = about 15 hectare · 50% dust removal efficiency by watering during daytime and no dust reduction at night-time · 24-hour
Notes: (a) Detailed calculations and location of the dust emission sources are presented in Annex A2. (b) Dust emission factors in Compilation of Air Pollutant Emission factors, (AP-42), 5^th Edition by USEPA is used. (c) Dust control measures recommended in Section 4.8.2 have been adopted.

Hourly and daily TSP concentrations were predicted at 1.5m and 10m above ground of the representative ASRs A1 to A4, A7 and A8 which are located within 500m of the Extension site boundary as the dust impact is localized. Daily TSP concentrations predicted from blasting, construction works and night-time wind erosion activities will be directly added to obtain an overall daily TSP concentration at the ASRs. The background TSP concentration, as presented in Table 4.3a, was also used to assess the cumulative TSP concentrations.

4.6.2 Cumulative Gaseous Emissions During Operation/Restoration and Aftercare Phases

An EPD approved air dispersion model, ISCST3, was employed for the assessment. The 2006 meteorological data obtained from the existing SENT Landfill weather station and TKO weather station operated by the Hong Kong Observatory (HKO) were used for the model runs. The “rural” mode was used. Terrain effects within 500m of the Extension site boundary have been included.

The emission rates of NO₂, CO, SO₂, benzene and vinyl chloride from the operation of the LFG treatment facility, LTP and LFG generator during operation/restoration and aftercare phases, presented in Tables 4.5d and 4.5h, respectively, were used for the prediction. The thermal oxidiser, LFG flares and LFG generator will be operated 24 hours per day. It is conservatively assumed that the engine testing at HASEL will be carried on a 24-hour basis. The locations of the LFG treatment facility, LTP, LFG generator and the emission points at HASEL are shown in Figure 4.5b.

The hourly, daily and annual average concentrations of the key air pollutants were predicted at 1.5m to 30m above ground at the representative ASRs A1 to A4, A7 and A8 as the maximum height of these ASRs is 30 m above ground. The worst affected height was identified and isopleths showing the levels of these key air pollutants at 1.5m above ground and the worst affected height were plotted.

Background concentrations presented in Table 4.3a were included in the assessment of the cumulative air quality impact.

4.6.3 Odour Emissions from Waste Filling Activities and Operation of LTP During Operation/Restoration Phase

Selection of Emission Source Locations for Worst Cases

The operation/restoration of the Extension will be divided into six phases starting from the south and filling progressively to the north (see Figures 4.6a-1 and 4.6a-2) in general. Three worst-cases (Cases 1 – 3) in each phase (except Phase 6) have been identified for the odour impact assessment, which have taken into account the worst case odour impacts to existing ASRs in TKOIE (eg TVB City), planned ASRs in the TKO Area 137, and ASRs at higher elevations (eg LOHAS Park (ASR A20)). Odour emission inventory including type of source, source area, source height, duration and the temperature of each worst-case are summarized in Table 4.6b.

Table 4.6b Odour Emission Inventory in Each Worst Case

Source Height	Worst-case Scenario ^(b)	Odour Source	Area	Air Temperature of Odour Emission ^(a)
Phase 1 · 10m above ground Phase 2 · 30m above ground Phase 3 · 50m above ground Phase 4 · 70m above ground Phase 5 · 100m above ground Phase 6 · 130m above ground	In each phase, there will be 3 worst cases ^(b): · Case 1 (southern end of Extension) · Case 2 (western side of Extension close to A1-1) · Case 3 (northern side of the Extension)	During Extension Opening Hours (8am – 12 midnight)
		Active tipping face for MSW + construction waste	· 30m x 20m	30°C
		Active tipping face for construction waste	· 30m x 20m	30°C
		Special waste trench	· 6m x 2.5m (plan area exposed to air)	30°C
		After Extension Opening Hours (12 midnight – 8am on the next day)
		Daily cover area	· 30m x 40m	30°C
		24-hour Operation
		SBR tanks	· 35m x 20m (2 nos.)	30°C
Notes: (a) Reference to the sensitivity analysis summarized in Annex A3. (b) For Phase 6, since the waste tipping area is small, therefore, 2 worst cases are assumed.

Reasonable Worst-case Odour Modelling Parameter

Odour Sampling at SENT Landfill

Odour generated from landfill operation varies from landfill site to landfill site; no general odour emission rates for landfilling activities are available. Odour samples were taken from the existing SENT Landfill for olfactometry analysis by the Odour Research Laboratory of the Hong Kong Polytechnic University to establish a set of odour emission rates for this study.

Sampling Time and Locations: Measurements were taken between 9:00 am and 9:30 pm at four locations (see Table 4.6c). The sampling locations and the ambient temperature during sampling are presented in Table 4.6c.

Table 4.6c Odour Sampling Regime

Location	Sampling ID	Ambient Temperature (°C)
MSW + Construction Waste (S1)	S1-1	30.83
	S1-2	31.45
	S1-3	26.01
	S1-4	23.03
	S1-5	20.85
	S1-6	30.05
MSW + Construction Waste + 300mm Soil Cover (S2)	S2-1	30.97
	S2-2	31.58
	S2-3	26.16
	S2-4	29.55
Special Waste Trench (S3)	S3-1	27.00
	S3-2	26.47
SBR of LTP (S4)	S4-1	26.90

As the existing SENT Landfill receives MSW, construction waste, special wastes as well as dewatered sludge from sewage treatment works (STWs), the sampling locations for S1 and S2 were therefore selected away the existing active tipping face and at the upwind location to avoid potential odour contamination. A new tipping platform was formed at the sampling location and MSW and construction waste were disposed of using the normal practices. The ratio of MSW to construction waste disposed was the same as that predicted for the Extension (ie the ratio of MSW to construction waste is about 1 : 2). For S2, the compacted MSW and construction waste was covered with 300mm of cover soil. The odour samples for S3 and S4 were taken at the base of the special waste trench and at the water surface of the SBR tank of the SENT Bioplant, respectively.

The odour emission from construction waste is very low and on a conservative basis, it is assumed that the odour emission rate from construction waste tipping is the same as that for S2.

It should be noted that the existing SENT Landfill also receives sewage sludge; therefore, the odour emission rate measured at the trench will be much higher than that expected for the Extension. Adopting the measured odour emission rates measured at the existing special waste trench in the assessment is a conservative approach.

Odour Sampling and Analysis Methods: Odour samples were taken using the flux chamber method which is the method recommended by the USEPA ([15]) and is also the most commonly used odour sampling method for large surface emission source such as landfill sites. The flux chamber used is a circular chamber with a diameter of 0.41m and an area of 0.13 m². It was tightly placed on the surface of the odour source and the air inside the chamber was purged with nitrogen gas at a sweeping rate of 5 litres per minute. The odour sample was collected in a Tedlar bag at a rate of 3 litres per minute. Before taking the next sample, the flux chamber was cleaned with distilled water and then flushed with nitrogen for about 10 minutes to remove residual odour in the chamber. The sampling system and the flux chamber are shown in Figure 4.6b.

The odour samples were analysed within 24 hours of the sampling using the olfactometry method by the Odour Research Laboratory of the Hong Kong Polytechnic University. The odour concentration of the samples, measured in Odour Units (OU) per m³, was determined by a Forced-choice Dynamic Olfactometer in accordance with the European Standard Method EN 13725.

Odour emission rate was then calculated using the following equation:

Odour Sampling Results: The measured odour concentrations and calculated odour emission rates of each odour source are summarized in Table 4.6d.

Table 4.6d Odour Sampling Results

Location	Sampling ID	Onsite Ambient Temperature During Sampling (°C)	Measured Odour Concentration (OU/m³)	Odour Emission Rate (OU/m²/s)
MSW + Construction Waste (S1)	S1-1	30.83	1,092	0.70
	S1-2	31.45	1,738	1.11
	S1-3	26.01	1,521	0.98
	S1-4	23.03	1,296	0.83
	S1-5	20.85	264	0.17
	S1-6	30.05	1,579	1.01
MSW + Construction Waste + 300mm Soil Cover (S2)	S2-1	30.97	80	0.051
	S2-2	31.58	160	0.10
	S2-3	26.16	169	0.11
	S2-4	29.55	193	0.12
Special Waste Trench (S3)	S3-1	27.00	10,768	6.90
Special Waste Trench (S3)	S3-2	26.47	16,830	10.79
SBR of LTP (S4)	S4-1	26.90	76	0.049

Definition of a Reasonable Worst-case Odour Modelling Parameters

A sensitivity analysis was undertaken to determine a reasonable worst-case scenario for the odour assessment. Details of the sensitivity analysis can be found in Annex A3. The analysis shows that the reasonable worst-case ambient temperature for estimating the odour emission rate is 30°C. Therefore, the reasonable worst-case odour emission rates at this temperature are summarized in Table 4.6e.

Table 4.6e Reasonable Worst-case Odour Emission Rates Adopted in Odour Impact Assessment

Odour Source	Source Area	Odour Emission Rates at 30°C (OU/m²/s) ^(a)	Total Odour Emission (OU/s)
During Extension Opening Hours (8am – 12 midnight)
Active tipping face for MSW + Construction Waste	30m x 20m	0.94	564
Active tipping face for construction waste	30m x 20m	0.12	72
Special waste trench	6m x 2.5m (plan area exposed to air)	31.74 ^(c)	476
After Extension Opening Hours (12 midnight – 8am on the next day)
Daily cover area ^(b)	30m x 40m	0.12	144
24-hour Operation
SBR tanks	2 number of 35m x 20m	0.049	69
Notes: (a) Reference to Annex A3. (b) Total area of active tipping face. (c) Reference to Annex A3 for the adjustment of the odour emission rate at 30°C.

Air Dispersion Model and Worst-case Odour Modelling Parameters

The AUSPLUME model, developed by the Australian Government (Environmental Protection Agency, Victoria), was employed for the odour impact assessment. The use of the AUSPLUME model has been approved by the EPD.

As discussed in Annex A3, the modelling parameters are summarized in Table 4.6f.

Table 4.6f Worst-case Odour Modelling Parameters

Modelling Parameter	Setting
Surface roughness	· 120 cm
Meteorological data	· 2006 hourly SENT landfill weather data : wind speed, wind direction and air temperature · 2006 HKO TKO weather data : stability class · 2006 HKO King’s Park weather data : mixing height · 90% of data are valid
Terrain effect	· Terrain data within 500m from the Extension site boundary have been included in model · “Egan half height” option is selected
Type of odour source in model	· Area source : active tipping faces for MSW and construction waste, daily cover area at night-time and special waste trench · Point source : SBR tanks (with very low exit velocity of 0.001 m s^-1) as the leachate temperature is slightly higher than ambient

Also, odour management and control measures summarized in Table 4.8a have been considered in the worst-case assessment.

Assessment Height and Presentation of Predicted Results

5-second odour concentrations were modelled at 1.5m, 10m, 20m, 30m, 50m, 70m and 90m ([16]) above ground level at the identified ASRs and the worst affected heights under different worst-case scenarios are also identified in the assessment. Contours of the predicted odour concentrations at the worst affected height within the Study Area (500m from the Extension site boundary) under different scenarios were plotted.

Conversion of Modelled Results From 3-minute Averaging Time to 5-second Averaging Time

Under the EIAO-TM, the odour assessment criterion is defined as 5 OU under a 5-second averaging time. To convert the AUSPLUME output (presented as the maximum 3-minute mean concentration) to a maximum 5-second mean concentration, the approach suggested by the Warren Spring Laboratory (WSL) ([17]) was adopted:

“Typical maximum or peak 5-second average concentrations within any 3-minute period appear to be of the order of 5 times the 3-minute average. During very unstable conditions larger ratios, perhaps 10:1, are more appropriate…..”

It should be noted that the ratios provided in the WSL report refer to peak to mean concentrations for emissions from stacks. Emissions from low-level area sources will fluctuate less and therefore the peak to mean ratios will be lower. The use of the peak to mean ratios provided in the WSL report therefore provides a conservative estimate for the 5-second mean concentrations for area sources.

For stable conditions (stability classes C to F), a factor of 5 was applied whilst for unstable conditions (stability classes A and B) a factor of 10 was applied to the emission rates input in the model run. The modelled results will be the 5-second odour concentrations.

The factored odour emission rates are presented in Table 4.6g. These odour emission rates applied to the three worst-cases described in Table 4.6b. An example showing hourly emission rate file adopted in AUSPLUME model is presented in Annex A4.

Table 4.6g Odour Emission Rates for AUSPLUME Model Run

Modelling Period	Odour Emission Source	Area Size in Model	Air Temperature of Odour Emission	Factored Odour Emission Rate to be used in Model Run to obtain 5-second Results (OU m^-2s^-1) ^(b)
			Air Temperature of Odour Emission	Stability Class A & B ^(c)	Stability Class C to F ^(d)
During Operation (8am – 12 midnight)	Active tipping face for MSW + Construction Waste	30m x 20m	30°C	9.4	4.7
	Active tipping face for construction Waste ^(a)	30m x 20m	30°C	1.2	0.6
	Special Waste Trench	6m x 2.5m (plan area exposed to air)	30°C	317.41	158.7
Night-time (Midnight to 8am on the next day)	Daily Cover Area ^(a)	30m x 40m	30°C	1.2	0.6
24-hour Operation	2 numbers of SBR tanks	20m x 35m (each)	30°C	343 (OU s^-1)	171.5 (OU s^-1)
Notes: (a) The odour emission rates of daily cover area at night and the active tipping face for construction waste during operation are similar due to the odour nature of the ground is the same. (b) Reference to Tables 4.6b and 4.6e for original odour emission at 30°C. (c) A factor of 10 is applied to convert the results from 3 minutes to 5 seconds. (d) A factor of 5 is applied to convert the results from 3 minutes to 5 seconds.

4.7 Evaluation of Impacts

4.7.1 Construction Phase

The cumulative hourly and daily TSP concentrations at 1.5m and 10m above ground of ASRs within 500m of the Extension site boundary were predicted taking account of the implementation of the suitable dust control measures and the predicted results are summarized in Tables 4.7a and 4.7b, respectively.

Table 4.7a Predicted Mitigated Cumulative Hourly TSP Concentrations at ASRs within 500m of the Extension Site Boundary

ASR	Description	Predicted Mitigated Cumulative Maximum Hourly TSP Concentrations (µgm^-3) ^(a)
		Blasting		Construction Activities
		1.5m Above Ground	10m Above Ground	1.5m Above Ground	10m Above Ground
A1-1	Proposed C&DM Handling Facility	310	204	272	174
A1-2 (1)	Planned Industrial Uses in TKO 137 (south of Extension) - 1	312	376	260	264
A1-2 (2)	Planned Industrial Uses in TKO 137 (south of Extension) - 2	195	243	183	218
A1-3 (1)	Planned Industrial Uses in TKO 137 (south of TVB City) - 1	462	424	371	309
A1-3 (2)	Planned Industrial Uses in TKO 137 (south of TVB City) - 2	336	254	297	217
A2	TVB City	363	345	312	282
A3	HAESL	214	213	202	201
A4	HAECO Component Overhaul Building	196	195	188	186
A7	Yan Hing Machinery Industrial Building	179	200	172	193
A8	Apple Daily	170	190	165	186
Hourly TSP Criterion		500	500	500	500
Note: (a) Background TSP concentration (ie 78 µgm^-3) has been included in the results.

ASR	Description	Predicted Mitigated Cumulative Daily TSP Concentrations (µgm^-3)
		Blasting (i)	Daytime Construction Works (ii)	Night-time Wind Erosion (iii)	Total = (i) + (ii) + (iii) + background ^(a)	Blasting (i)	Daytime Construction Works (ii)	Night-time Wind Erosion (iii)	Total = (i) + (ii) + (iii) + background ^(a)
A1-1	Proposed C&DM Handling Facility	28	24	9	139	25	19	6	128
A1-2 (1)	Planned Industrial Uses in TKO 137 (south of Extension) - 1	34	55	19	185	27	39	6	149
A1-2 (2)	Planned Industrial Uses in TKO 137 (south of Extension) - 2	16	24	5	123	15	20	4	117
A1-3 (1)	Planned Industrial Uses in TKO 137 (south of TVB City) - 1	36	48	11	173	31	35	6	150
A1-3 (2)	Planned Industrial Uses in TKO 137 (south of TVB City) - 2	29	23	7	138	26	20	6	130
A2	TVB City	39	27	7	151	31	22	6	136
A3	HAESL	15	10	4	107	14	10	4	105
A4	HAECO Component Overhaul Building	9	7	4	98	8	7	4	96
A7	Yan Hing Machinery Industrial Building	8	13	7	106	7	13	6	104
A8	Apple Daily	10	15	5	107	9	14	5	106
	Daily TSP Criterion	260	Daily TSP Criterion	260
Note: (a) Background TSP concentration (ie 78 µgm^-3) has been included in the total results.

ASR	Location	Highest Hourly Average Concentration (µg m^-3) ^{(a) (b)}	Highest Daily Average Concentration (µg m^-3) ^{(a) (b)}	Highest 8-hr Average Concentration (µg m^-3) ^{(a) (b)}	Highest Annual Average Concentration (µg m^-3) ^{(a) (b)}
A1-1	Proposed C&DM Handling Facility	75	1357	24.1	2.11	5.10	67.0	19.0	1326	66.10	18.11	2.100	5.100
A1-2 (1)	Planned Industrial Uses in TKO 137 (south of Extension) – 1	134	2273	118.1	2.19	5.16	90.3	51.2	1764	67.93	20.16	2.102	5.101
A1-2 (2)	Planned Industrial Uses in TKO 137 (south of Extension) - 2 (outside HKPSG 200m buffer distance)	77	1448	31.1	2.11	5.10	67.8	20.0	1361	66.12	18.14	2.100	5.100
A1-3 (1)	Planned Industrial Uses in TKO 137 (south of TVB City) – 1	71	1359	22.8	2.11	5.10	66.6	18.7	1312	66.09	18.09	2.100	5.100
A1-3 (2)	Planned Industrial Uses in TKO 137 (south of TVB City) - 2 (outside HKPSG 200m buffer distance)	71	1358	22.7	2.11	5.10	67.3	19.5	1325	66.11	18.11	2.100	5.100
A2	TVB City	71	1362	23.0	2.11	5.10	66.5	18.7	1312	66.08	18.09	2.100	5.100
A3	HAESL	71	1359	23.0	2.11	5.10	66.8	18.5	1310	66.24	18.08	2.100	5.100
A4	HAECO Component Overhaul Building	75	1358	23.0	2.11	5.10	67.0	18.7	1308	66.15	18.08	2.100	5.100
A7	Yan Hing Machinery Industrial Building	74	1360	23.1	2.11	5.10	67.5	19.6	1323	66.15	18.13	2.100	5.100
A8	Apple Daily	84	1358	23.1	2.11	5.10	67.3	19.2	1322	66.16	18.12	2.100	5.100
Background Concentration	66	1294	18	2.1	5.1	66	18	1294	66	18	2.1	5.1
AQO / Chronic or Acute Reference Concentration	300	30,000	800	1,300 ^(c)	180,000 ^(c)	150	350	10,000	80	80	30 ^(c)	100 ^(c)
Notes: (a) Detailed Assessment Results are summarized in Annex A5-1. (b) Background NO₂, CO, SO₂, benzene and vinyl chloride (presented in Table 4.3a) concentrations were included in the results. (c) Acute/Chronic Reference Concentrations are referred to Table 4.2d.

ASR	Location	Individual Highest Calculated Cancer Health Risk Level ^{(a) (b)}	Total Cancer Health Risk Level
A1-1	Proposed C&DM Handling Facility	7.0E-10	3.5E-10	1.1E-09
A1-2 (1)	Planned Industrial Uses in TKO 137 (south of Extension) – 1	1.6E-08	7.8E-09	2.3E-08
A1-2 (2)	Planned Industrial Uses in TKO 137 (south of Extension) - 2	9.4E-10	4.4E-10	1.4E-09
A1-3 (1)	Planned Industrial Uses in TKO 137 (south of TVB City) – 1	6.2E-10	3.5E-10	9.8E-10
A1-3 (2)	Planned Industrial Uses in TKO 137 (south of TVB City) - 2	8.6E-10	4.4E-10	1.3E-09
A2	TVB City	6.2E-10	2.6E-10	8.9E-10
A3	HAESL	4.7E-10	2.6E-10	7.3E-10
A4	HAECO Component Overhaul Building	4.7E-10	2.6E-10	7.3E-10
A7	Yan Hing Machinery Industrial Building	1.0E-09	5.3E-10	1.5E-09
A8	Apple Daily	8.6E-10	4.4E-10	1.3E-09
Notes: (a) Detailed calculated cancer health risk levels are summarized in Annex A5-2. (b) Unit risk factors of benzene and vinyl chloride (as presented in Table 4.2b) have been used for the calculation.

Table 4.7e Predicted Highest 5-second Odour Concentrations at the Identified Representatie ASRs During Operation/Restoration Phase

ASR	Location	Highest 5-second Odour Level ^{(a) (b)}
		Worst-case 1						Worst-case 2						Worst-case 3 ^(c)
		Source Height = 10m	Source Height = 30m	Source Height = 50m	Source Height = 70m	Source Height = 100m	Source Height = 130m	Source Height = 10m	Source Height = 30m	Source Height = 50m	Source Height = 70m	Source Height = 100m	Source Height = 130m	Source Height = 10m	Source Height = 30m	Source Height = 50m	Source Height = 70m	Source Height = 100m
A1-1	Proposed C&DM Handling Facility	6.1	6.3	5.9	5.0	1.5	2.0	6.3	4.1	3.2	2.3	1.5	1.3	3.2	2.2	1.8	1.4	1.2
A1-2 (1)	Planned Industrial Uses in TKO 137 (south of Extension) - 1	8.9	7.0	6.0	5.7	2.7	1.9	2.3	2.9	2.8	3.0	1.9	1.4	2.3	2.4	2.4	2.1	1.7
A1-2 (2)	Planned Industrial Uses in TKO 137 (south of Extension) - 2	2.7	3.3	3.1	3.0	1.5	1.0	1.9	2.1	1.8	1.8	0.9	0.7	1.3	1.6	1.5	1.2	0.7
A1-3 (1)	Planned Industrial Uses in TKO 137 (south of TVB City) - 1	2.4	2.2	2.2	2.9	3.6	3.4	5.5	6.4	7.0	6.2	3.8	2.2	23.2	14.4	11.2	6.4	2.9
A1-3 (2)	Planned Industrial Uses in TKO 137 (south of TVB City) - 2	1.7	2.0	2.2	2.1	2.2	2.0	5.1	6.4	3.9	2.8	2.6	2.4	11.4	7.3	6.9	3.3	2.6
A2	TVB City	1.9	1.8	1.9	2.0	3.8	2.3	4.1	3.9	4.6	4.6	3.3	3.2	12.5	13.1	14.0	6.5	5.4
A3	HAESL	1.1	1.2	1.2	1.2	1.7	1.9	1.9	1.9	2.1	2.2	2.6	2.3	3.3	4.2	5.2	3.1	3.8
A4	HAECO Component Overhaul Building	1.1	1.1	1.1	1.2	1.5	2.4	1.8	1.6	1.4	1.6	1.9	1.8	2.4	2.8	3.5	4.4	2.3
A5	Exhibition Services & Logistics Centre	0.9	0.8	0.8	0.9	1.1	1.3	1.2	1.2	1.3	1.3	2.2	0.9	1.7	1.8	3.0	1.9	1.1
A6	Gammon Skanska	0.6	0.6	0.8	0.8	0.7	0.9	1.0	1.0	1.0	0.8	1.1	0.7	1.2	1.6	1.7	1.1	0.8
A7	Yan Hing Machinery Industrial Building	1.0	1.2	1.3	1.3	1.5	2.1	1.6	1.9	2.0	1.9	2.1	4.1	2.7	3.3	3.4	3.5	3.7
A8	Apple Daily	0.9	1.0	1.1	1.2	1.2	1.5	1.2	1.5	1.6	1.6	1.6	2.5	1.9	2.4	2.7	2.6	2.8
A9	Mei Ah Industrial Building	1.0	1.1	1.1	1.0	1.1	1.6	1.5	1.6	1.4	1.3	1.9	2.4	2.4	2.2	2.4	3.0	3.8
A10	Asia Netcom	0.9	1.0	0.9	1.1	1.0	1.4	1.5	1.3	1.4	1.3	1.8	1.7	1.8	1.7	2.4	2.5	2.7
A11	Wellcome Storage	1.0	1.0	1.0	1.1	1.1	1.5	1.5	1.4	1.5	1.2	1.5	1.7	1.9	2.2	2.1	2.1	2.3
A12	Avery Dennison Machinery	0.8	0.8	0.9	1.1	1.1	1.4	1.0	1.2	1.3	1.4	1.5	1.7	1.5	1.7	2.1	2.3	1.8
A13	Hitachi	0.7	0.8	1.0	0.9	0.8	1.0	1.0	1.1	1.2	1.2	1.1	1.6	1.4	1.7	1.8	1.5	1.6
A14	Next Media Co. Ltd	0.7	0.7	0.8	0.8	0.9	1.0	0.8	1.0	1.1	1.2	1.3	1.2	1.2	1.3	1.5	1.6	1.6
A15	Varitronix	0.6	0.7	0.7	0.7	0.8	0.8	0.8	0.9	0.9	1.1	1.1	1.2	0.9	1.2	1.3	1.3	1.2
A16	Four Seas Food Processing Co. Ltd	0.5	0.5	0.6	0.7	0.7	0.7	0.7	0.7	0.8	0.8	0.8	1.0	0.9	0.9	1.1	1.0	0.9
A17	Committed HSBC Office	0.6	0.6	0.6	0.6	0.7	0.8	0.7	0.7	0.8	0.9	0.9	0.9	0.8	1.0	1.0	1.2	1.1
A18	Eastern Pacific Electronics	0.5	0.5	0.5	0.6	0.6	0.5	0.6	0.6	0.7	0.7	0.7	0.8	0.7	0.7	0.9	0.8	0.7
A19	Committed Tung Wah Group of Hospital Aided Primary & Secondary School	0.4	0.5	0.5	0.5	0.5	0.4	0.5	0.6	0.6	0.5	0.6	0.6	0.6	0.7	0.7	0.7	0.6
A20	LOHAS Park	0.3	0.4	0.3	0.3	0.4	0.3	0.4	0.4	0.3	0.3	0.4	0.4	0.5	0.4	0.4	0.5	0.4
A21	Chiaphua-Shinko Centre	0.3	0.3	0.3	0.4	0.4	0.4	0.4	0.4	0.4	0.5	0.4	0.4	0.4	0.4	0.6	0.5	0.5
A22	Shaw Film Studios	0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.4	0.4	0.4	0.3	0.3	0.4	0.4	0.4	0.4	0.4
A23	Oscar by the Sea	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2
A24	Tseung Kwan O Sport Ground	0.2	0.2	0.2	0.2	0.1	0.1	0.2	0.2	0.2	0.1	0.2	0.2	0.2	0.2	0.2	0.2	0.2
A25	Tseung Kwan O Town Park	0.1	0.1	0.1	0.1	0.1	0.2	0.2	0.1	0.1	0.1	0.1	0.2	0.1	0.2	0.2	0.1	0.2
A26	Leung Sing Tak Primary School	0.2	0.2	0.2	0.2	0.1	0.1	0.2	0.2	0.2	0.1	0.1	0.2	0.2	0.2	0.2	0.2	0.1
A27	Nan Fung Plaza	0.2	0.2	0.2	0.1	0.1	0.1	0.2	0.2	0.2	0.1	0.1	0.2	0.2	0.2	0.2	0.2	0.2
A28	St Andrew's Church	0.2	0.1	0.1	0.1	0.1	0.1	0.2	0.1	0.1	0.1	0.1	0.2	0.2	0.1	0.1	0.1	0.2
A29	Fung Ching Memorial Primary School	0.1	0.2	0.1	0.1	0.1	0.1	0.2	0.2	0.1	0.1	0.1	0.2	0.2	0.2	0.2	0.1	0.1
A30	On Ning Garden	0.1	0.1	0.1	0.1	0.1	0.1	0.2	0.1	0.1	0.1	0.1	0.2	0.2	0.1	0.1	0.1	0.2
A31	Sheung Ning Playground	0.1	0.1	0.1	0.1	0.1	0.2	0.1	0.1	0.1	0.1	0.1	0.2	0.1	0.1	0.1	0.1	0.2
A32	Tseung Kwan O Swimming Pool	0.1	0.1	0.1	0.1	0.1	0.2	0.1	0.1	0.1	0.1	0.1	0.2	0.1	0.1	0.1	0.2	0.2
A33	La Cite Noble	0.2	0.2	0.2	0.2	0.2	0.1	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2
A34	Yuk Ming Court	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2
A35	Ming Tak Estate	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2
A36	Tin Ha Wan Village	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2
A37	Tseung Kwan O Hospital	0.1	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2
A38	Ocean Shore Phase I	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2
A39	Choi Ming Estate, Choi Yiu Court	0.1	0.1	0.1	0.1	0.2	0.2	0.1	0.1	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2
A40	Park Central Block 1	0.2	0.1	0.1	0.2	0.2	0.1	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2
A41	Bauhinia Garden Block 5	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2
A42	Heng Fa Chuen	0.3	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2
A43	Island Resort	0.5	0.4	0.4	0.2	0.3	0.2	0.4	0.3	0.3	0.3	0.2	0.2	0.2	0.2	0.2	0.1	0.1
5-second Odour Criterion		5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5
Notes: (a) 5-second odour concentrations predicted at different elevations of ASRs in different worst case for different source heights are presented in Annex A6-1. (b) Bold and underlined figures show exceedance of 5-second odour criterion. (c) Since the waste filling area will be small when the waste filling height is at 130m, therefore, only 2 worst cases were identified in the assessment.

ASR	Location	Highest Hourly Average Concentration (µg m^-3) ^{(a) (b)}	Highest Daily Average Concentration (µg m^-3) ^{(a) (b)}	Highest 8-hr Average Concentration (µg m^-3) ^{(a) (b)}	Highest Annual Average Concentration (µg m^-3) ^{(a) (b)}
A1-1	Proposed C&DM Handling Facility	75	1350	24	2.103	5.100	66.5	18.8	1315	66.1	18.08	2.100	5.100
A1-2 (1)	Planned Industrial Uses in TKO 137 (south of Extension) - 1	129	2273	118	2.147	5.104	85.7	49.5	1764	67.0	19.48	2.101	5.100
A1-2 (2)	Planned Industrial Uses in TKO 137 (south of Extension) - 2	73	1395	28	2.105	5.102	67.2	19.6	1342	66.1	18.10	2.100	5.100
A1-3 (1)	Planned Industrial Uses in TKO 137 (south of TVB City) – 1	68	1328	21	2.102	5.100	66.4	18.6	1306	66.1	18.07	2.100	5.100
A1-3 (2)	Planned Industrial Uses in TKO 137 (south of TVB City) - 2	68	1326	21	2.102	5.100	66.7	19.1	1311	66.1	18.07	2.100	5.100
A2	TVB City	68	1326	21	2.102	5.100	66.4	18.5	1306	66.0	18.06	2.100	5.100
A3	HAESL	68	1325	21	2.102	5.100	66.7	18.4	1302	66.2	18.06	2.100	5.100
A4	HAECO Component Overhaul Building	75	1326	21	2.102	5.100	67.0	18.4	1302	66.1	18.06	2.100	5.100
A7	Yan Hing Machinery Industrial Building	74	1326	21	2.102	5.100	66.7	19.0	1308	66.1	18.09	2.100	5.100
A8	Apple Daily	84	1326	21	2.102	5.100	67.3	18.8	1309	66.1	18.09	2.100	5.100
Background Concentration	66	1294	18	2.1	5.1	66	18	1294	66	66.1	2.1	5.1
AQO / Chronic or Acute Reference Concentration	300	30,000	800	1,300 ^(c)	180,000 ^(c)	150	350	10,000	80	80	30 ^(c)	100 ^(c)
Notes: (a) Detailed Assessment Results are summarized in Annex A9-1. (b) Background NO₂, CO and SO₂ (presented in Table 4.3a) concentrations were included in the results. (c) Acute/Chronic Reference Concentrations are referred to Table 4.2d.

Table 4.7g Highest Calculated Cancer Health Risk Levels of Benzene and Vinyl Chloride During the Aftercare Phase

ASR	Location	Individual Highest Calculated Cancer Health Risk Level ^{(a) (b)}		Total Cancer Health Risk Level
		Benzene	Vinyl Chloride
A1-1	Proposed C&DM Handling Facility	3.1E-10	8.8E-11	4.0E-10
A1-2 (1)	Planned Industrial Uses in TKO 137 (south of Extension) - 1	5.9E-09	8.8E-10	6.7E-09
A1-2 (2)	Planned Industrial Uses in TKO 137 (south of Extension) - 2	4.7E-10	8.8E-11	5.6E-10
A1-3 (1)	Planned Industrial Uses in TKO 137 (south of TVB City) - 1	3.1E-10	8.8E-11	4.0E-10
A1-3 (2)	Planned Industrial Uses in TKO 137 (south of TVB City) - 2	3.1E-10	8.8E-11	4.0E-10
A2	TVB City	2.3E-10	8.8E-11	3.2E-10
A3	HAESL	2.3E-10	8.8E-11	3.2E-10
A4	HAECO Component Overhaul Building	2.3E-10	8.8E-11	3.2E-10
A7	Yan Hing Machinery Industrial Building	3.9E-10	8.8E-11	4.8E-10
A8	Apple Daily	3.9E-10	8.8E-11	4.8E-10
Notes: (a) Detailed calculated health risk levels are summarized in Annex 9-2. (b) Unit risk factors of benzene and vinyl chloride (as presented in Table 4.2b) have been used for the calculation.

4.7.5 Odour Emissions from the Operation of LTP during Aftercare Phase

As discussed in Section 4.5.3, during this phase, the sources of odour emissions will be the two SBR tanks. With reference to the total odour emission rates summarized in Table 4.6e, the total odour emission rate of SBRs is only 6% of the total during landfill operation.

According to the odour impacts predicted for the last waste tipping phase (ie Phase 6, the source height at 130m), no exceedance of odour criterion was predicted at any of the ASRs and the odour impact is confined within the Extension. During the aftercare phase (without waste tipping activities), as the odour emission rate is lower than that estimated during the last tipping phase (see Table 4.7e), the predicted odour levels at the ASRs will be lower than those predicted for the last tipping phase. Hence, no adverse odour impact is anticipated during the aftercare phase.

4.8 Mitigation Measures

4.8.1 Construction Phase

The following control measures are set out in the Air Pollution Control (Construction Dust) Regulations and will be implemented to limit the dust emissions from the construction works.

Blasting

· The area within 30m of the blasting area will be wetted prior to blasting.

· Blasting will not be carried out when the strong wind signal or tropical cyclone warning signal No. 3 or higher is hoisted, unless this is with the express prior permission of the Commissioner of Mines.

· Loose material and stones in the Site will be removed prior to the blast operation.

· Blast nets, screens and other protective covers will be used to prevent the projection of flying fragments and material resulting from blasting.

Rock Drilling

· Watering will be carried out at the rock drilling activities to avoid fugitive dust emissions.

Site Access Road

· The main haul road will be kept clear of dusty materials or sprayed with water.

· The main haul road will be laid with aggregate or gravel.

· Vehicle speed will be limited to 10 kph.

Stockpiling of Dusty Materials

· Any stockpile of dusty materials will be covered entirely by impervious sheeting or placed in an area sheltered on the top and three sides or sprayed with water so as to ensure that the entire surface is wet.

Loading, unloading or transfer of dusty materials

· All dusty materials will be sprayed with water immediately prior to any loading, unloading or transfer operation so as to maintain the dusty material wet.

Site Boundary and Entrance

· Where a site boundary adjoins a road, street, service lane or other area accessible to the public, hoarding of not less than 2.4m from ground level will be provided along the entire length of that portion of the site boundary except for the site entrance or exit.

Excavation Works

· Working area of any excavation or earth moving operation will be sprayed with water immediately before, during and immediately after the operation so as to ensure that the entire surface is wet.

Building Demolition

· The area where the demolition works are planned to take place will be sprayed with water immediately prior to, during and immediately after the demolition activities.

· Any dusty materials remaining after a stockpile is removed will be wetted with water and cleared from the surface of roads or street.

Construction of the Superstructure of Building

· Effective dust screens, sheeting or netting will be provided to enclose the scaffolding from the ground level up to the highest level of the scaffolding.

The control measures recommended in the Best Practicable Means Requirement for Mineral Works (Stone Crushing Plants) BPM 11/1 will be implemented during the operation of the stone crushing plant.

Good site practices such as regular maintenance and checking of the diesel powered mechanical equipment will be adopted to avoid any black smoke emissions and to minimize gaseous emissions.

4.8.2 Operation/Restoration Phase

Fugitive Emissions at Landfilling Area at the Extension

The following measures will be implemented to minimize any fugitive emissions during landfilling at the Extension:

· The main haul road to the waste filling area will be watered regularly to keep wet at any time.

· The exposed daily and intermediate covered areas will be compacted well to avoid fugitive dust emission.

· The vehicle speed will be limited within the Extension.

· Vehicle washing bay will be provided to avoid vehicles carrying dust to public roads.

· The engine will be switched off when the diesel-driven equipment is idling.

· The construction equipment will be properly maintained to avoid any black smoke emission.

· Sufficient underground landfill gas collection system will be provided to capture the landfill gas generated as much as possible.

· Periodic inspections of the final cover will be undertaken to ensure that the capping layer is in good conditions at all times.

Gaseous Emissions from the Operation of LFG Treatment Facility, LTP and LFG Generator

No mitigation measures are required associated with the gaseous emissions from the operation of LFG treatment facility LTP and LFG generator as no exceedance of criteria are predicted.

Odour Emissions from Waste Filling Activities and Operation of LTP

Exceedance of the 5-second odour criterion was predicted at some ASRs, mitigation measures are recommended to minimize the odour impacts.

Odour management and control measures, as summarized in Table 4.8a, will be incorporated into the outline design. These measures will be implemented during the operation/restoration phase of the Extension to minimize the potential odour impacts to identified ASRs.

Table 4.8a Summary of Odour Management and Control Measures During Operation/Restoration Phase

Proposed Odour Management and Control Measures ^(a)
(i) Installing deodorizers along the site boundary adjacent to the ASRs
(ii) Erecting a vertical barrier, wall or structure soften by planting rows of trees/shrubs or landscape feature along the site boundary, particularly in the areas near the ASRs
(iii) Enclosing the weighbridge area (iv) Providing a vehicle washing facility before the exit of the landfill and providing sufficient signage to remind RCV drivers to pass through the facility before leaving the landfill
(v) Reminding the RCV drivers to empty the liquor collection sump and close the valve before leaving the tipping face.
(vi) Washing down the area where spillage of RCV liquor is discovered promptly
(vii) Reminding operators to properly maintain their RCVs properly and that liquor does not leak from the vehicles
(viii) Installation of vertical and/or horizontal LFG extraction system to enhance extraction of LFG from the waste mass and hence minimise odour associated with fugitive LFG emissions
(ix) Progressive restoration of the areas which reach the finished profile (a final capping system including an impermeable liner will be put in place) and installation of a permanent LFG extraction system
(x) Maintaining the size of the active tipping face only not greater than 40 m x 30 m, of which the size of the active tipping face for MSW + construction waste will be limited to 20 m x 30 m and the size of the active tipping face for construction waste only will be limited to 20 m x 30 m
(xi) Promptly covering the MSW with soil or selected inert materials to reduce odour emissions
(xii) Maintaining the size of the special waste trench not greater than 6m x 2.5m
(xiii) Covering daily covered area with 300mm of soil at 11pm
(xiv) Covering special waste trench with 600 mm of soil and an impervious liner after 5 pm
(xv) Covering the non-active tipping face with 600mm of soil and an impermeable liner (on top of the intermediate cover), which will not only prevent odour emissions from landfilled waste but also enhance LFG extraction by the LFG extraction system
(xvi) Applying deodorizers or odour suppression agents to control odour emissions from the active tipping face and special waste trench, if any, through spraying or fogging equipment
(xvii) Providing a mobile cover with retractable or suitable opening to cover the special waste trench except during waste deposition. The air trapped inside the trench will be extracted and scrubbed by a mobile odour removal unit prior to discharge to the atmosphere
(xviii) Providing thermal oxidizer (one duty and one standby) for the LTP
(xix) Enclosing all the leachate storage and treatment tanks (except for the SBR tanks) and diverting the exhaust air from these tanks to a thermal oxidizer to avoid potential odour emissions from the LTP
Note: (a) Items (iii) to (xv), (xviii) and (xix) have been considered in the assessment. As the removal efficiency of deodorizer cannot be quantified, it was not included in the odour modelling. As a conservative assessment, the odour modelling assumed that there were no cover and air scrubbing for the special waste trench.

In particular, rephasing of the waste tipping activities on-site has been considered to minimize the potential odour impact at A1-3 and A2 as far as practicable. By avoiding waste tipping activities at the northern area of the site in the months between July to November (see Figures 4.9a-1 and 4.9a-2), the number of exceedances can be reduced by 70% (maximum) at A2.

4.8.3 Aftercare Phase

No mitigation measures regarding gaseous emission are required.

Odour management and control measures to be carried out during aftercare phase are summarized in Table 4.8b.

Table 4.8b Summary of Odour Management and Control Measures During Aftercare Phase

Proposed Odour Management and Control Measures
(i) Continue to maintain the integrity of the capping system
(ii) Provision of vertical and/or horizontal LFG extraction system to enhance extraction of LFG from the waste mass and hence minimise odour associated with fugitive LFG emissions
(iii) Enclosing all the leachate storage and treatment tanks (except for the SBR tanks) and diverting the exhaust air from these tanks to an air scrubber or the flares to avoid potential odour emissions from the LTP

4.9 Residual Impacts

4.9.1 Construction Phase

No residual impact is anticipated after the implementation of the recommended mitigation measures described in Section 4.8.1.

4.9.2 Operational/Restoration Phase

Gaseous Emissions from LFG Treatment Facility and Thermal Oxidizers, Vehicle Emissions from Traffic associated with the Extension and Fugitive Emissions from Active Tipping Face

No residual impact is anticipated associated with the gaseous emissions from LFG treatment facility and LTP, vehicle emissions and fugitive emissions from active tipping face.

Odour Emissions Arising from Waste Filling Activities and Operation of LTP

As noted above the predicted odour levels exceed the odour assessment criterion at those ASRs in close proximity to the Extension and hence residual impacts are predicted.

TKO Area 137 (ie A1-1 to A1-3) has been zoned “Other Specified Uses” annotated “Deep Waterfront Industry”. The intent is for the land adjacent to the Extension to be used for industrial uses. Under Column 1 in the OZP Explanatory Note, 23 types of uses ([20]) are always permitted to be located at TKO Area 137. Among them, some of the permitted uses including government refuse collection point, public vehicle park and warehouse are considered less sensitive to odour impacts than land zoned for residential, commercial or institutional development. Furthermore, under the HKPSG “acceptable uses” of land within 200m of odour sources include industrial development. The waste tipping activities will be scheduled to avoid waste tipping at the northern sectors of the Extension between July and November in order to reduce the number of exceedances of the odour criterion at A2 to the greatest extend feasible (please refer to Figures 4.9a-1 and 4.9a-2). Annex A11-1 presents the reduction of odour levels and Annex A11-2 shows the reduction of the number of exceedances after rephasing. It also shows that the number of exceedances gradually reduces to zero over six years.

A2 is the nearest location of TVB City to the Extension. It is predicted to have residual impacts at this location when waste is being disposed in the northern sector of the landfill (ie, Worst Case 3). No exceedances are predicted at A2 when landfilling is in the middle and southern sectors of the site. With the proposed rephasing of landfilling activities (ie by avoiding waste tipping at northern sector of the site between July and November), the predicted highest odour concentrations at A2 will reduce from 14 OU to 9.5OU and the number of exceedances at A2 will decline by 58% from 26 to 11 events in the first year and 71% from 21 to 6 events in the second year of operation (please see Annexes A10, A11-1 and A11-2). This is an upper bound estimate due to the adoption of a series of conservative assumptions in the impact assessment. As the landfill works progress, the frequency of exceedances of the odour criterion at A2 will diminish to zero over the six year period (ie, from 11 events in the first year of operation to 0 events in the last year).

Table 4.9a presents an assessment of the residual impacts at the representative assessment points of the TKO Area 137 and TVB City (ie A1-1, A1-2 (1), A1-2 (2), A1-3 (1), A1-3 (2) and A2) with respect to the guidelines described in Section 4.4.3 and Annex 20 of the EIAO-TM.

Figures 4.9b-1 and 4.9b-2 show the zones of possible impact (the area with a potential for exceedance of odour criterion) and summarize the predicted highest odour levels at A1-1 (the only committed facility at TKO Area 137 as identified during the EIA Study) to A3 and the number of exceedances during different waste tipping phases after rephasing. The figures indicate that the size of the zones of possible impact (the area with a potential for exceedance of odour criterion) close to A1-3 and A2 are slightly reduced. It should be noted that only the ASRs located downwind of the active tipping face may experience an odour level exceeding the odour criterion and the actually affected area at any given time would be a much smaller than the area within the 5OU contour line (see Figures 4.9b-1 and 4.9b-2). In addition, the number of exceedances will be reduced (ie, 71 instances will be reduced to 21 instances at A1-3 (1) in the first year) after rephasing of the waste tipping activities for Phase 1. As the waste tipping face moves further away from the ASRs as the Extension is developed, the number of exceedances decreases to zero over a six-year period. The southern and eastern areas of TVB City may also be affected by emissions from the operation/restoration of the Extension.

The residual impacts will be infrequent, transient and limited to the areas within 350m from the Extension and will not affect any residential developments. As discussed in Section 4.7.2, the odour emission rate of the special waste trench adopted in the assessment is conservative and the actual rate is expected to be much lower as the trench will be covered and the air inside the trench will be scrubbed prior to discharge to the atmosphere. Furthermore, no sludge will be received in the Extension. Hence, the residual impacts will be lower and the number of exceedances will be less than those predicted.

Taking account of the nature of the developments affected (industrial and commercial premises), the number of people impacted, the transient nature, low frequency and magnitude of the exceedances, the residual impacts are considered acceptable.

Odour assessment criteria adopted by other countries was also referenced and the comparison with the assessment results and different odour assessment criteria adopted by other countries are summarized in Annex A12.

Table 4.9a Evaluation of Residual Odour Impacts

Factors to Evaluate Residual Impacts

TKO Area 137 (A1-1, A1-2 (1), A1-2 (2), A1-3 (1) and A1-3 (2))

TVB City (A2)

Effects on public health and health of biota or risk to life

TKO Area 137 has been zoned ”Other Specified Uses” annotated “Deep Waterfront Industry” for industrial uses and some of the permitted uses in this area under Column 1 in the OZP Explanatory Note (such as government refuse collection point, public vehicle park and warehouse) are not considered to be particularly sensitive to odour impacts.

Impacts to public health are not predicted and there is no reliable evidence linking odour to adverse health outcomes. Any health issues would be related to emissions of substances such as VOCs. Regular monitoring at the boundary of the existing SENT Landfill shows that concentrations of such substances remain well within the trigger level. Odour is widely considered to be related to amenity value rather than public health.

No impact to the health of biota, are predicted (including rare and/or endangered species).

Impacts to public health are not predicted and there is no reliable evidence linking odour to adverse health outcomes. Regular monitoring at the boundary of the existing SENT Landfill shows that concentrations of such substances remain well within the trigger level. Odour is widely considered to be related to amenity value rather than public health.

No impact to the health of biota, are predicted (including rare and/or endangered species).

Magnitude of the adverse environmental impacts

The affected areas at the worst affected height of the representative assessment points (ie A1-1, A1-2(1), A1-2(2), A1-3(1), and A1-3(2), at TKO Area 137 during different waste tipping phases are indicated in Figures 4.7f to 4.7k and the zones of possible impacts (the area with a potential for exceedance of odour criterion) during different waste tipping phases are also illustrated in Figures 4.7l-1 and 4.7l-2.

As discussed above, industrial premises are planned for development in TKO Area 137 and 23 types of uses are always permitted to be located at TKO Area 137 under Column 1 in the OZP Explanatory Note. Some of the permitted uses such as government refuse collection point, public vehicle park and warehouse are not considered to be particularly sensitive to odour impacts.

There will be no concurrent projects that generated similar type of odour in the vicinity; therefore, no cumulative odour impacts are predicted.

Without rephasing, the affected areas at the worst affected height of the representative assessment point (ie A2, which is the nearest point to the Extension) at TVB City during different waste tipping phases are indicated in Figures 4.7f to 4.7k and the affected zone during different waste tipping phases are also illustrated in Figures 4.7l-1to 4.7l-2.

After rephasing of the waste tipping activities (by avoiding waste tipping at northern sector between July and November), the numbers and levels of exceedance at the representative assessment point of TVB City will be significantly reduced (please also refer to Annexes A10-1 and A10-2 for detail).

Waste Tipping	No. of Exceedance of 5-sec Odour Criterion			Highest 5-sec Odour Concentration
	Without Rephasing	With Rephasing	% Reduction	Without Rephasing	With Rephasing
Phase 1	26	11	58	12.5	8.9
Phase 2	21	6	71	13.1	9.5
Phase 3	10	5	50	14.0	8.6
Phase 4	4	2	50	6.5	6.5
Phase 5	1	1	0	5.4	5.4
Notes: (a) Each phase will last for about 1 year. (b) Please refer to Annex A5 for detailed calculation.

After rephasing of the tipping operation, the highest 5-second odour concentration predicted at A2 will be reduced to 9.5 OU and the number of exceedance per year will be reduced by about 70% (maximum) at A2 and will diminish over time.

There will be no concurrent projects that generated similar type of odour in the vicinity; therefore, no cumulative odour impacts are predicted.

Geographic extent of the adverse environmental impacts

The residual impacts will be localized and limited to the area in close proximity to the Extension (refer to Figures 4.7f to 4.7k). Out of 43 ASRs assessed, only 4 ASRs (in TKO Area 137 (consisting of group of 3 planned ASRs which are industrial developments) and TVB City) will experience residual impacts. The Extension will not cause widespread adverse odour impact to residential developments. For all other ASRs, the predicted odour impacts are well within the odour criterion.

The areas in TKO Area 137 which exceed the odour criterion are limited to a distance of about 350 m from the Extension site boundary.

Long range transportation of odour is not predicted.

The area which exceeds the odour criterion is limited to the southern and eastern areas of the TVB City.

Duration and frequency of the adverse environmental impacts

The predicted residual impacts are intermittent and will last for about five years (from 2013 to 2017). The number and level of exceedance will reduce over time as the tipping area moves to higher levels and further away from the ASRs. The residual impacts will be reduced to zero.

After rephasing, the number of exceedance of the 5-second odour criterion at the representative assessment point of TVB City (ie A2, nearest point to the Extension) will be reduced to a maximum of 11 events per year and gradually decline to zero over six years. The predicted residual impacts are intermittent and will last for about five years (from 2013 to 2017).

Likely size of the community or the environment that may be affected by the adverse impacts

The number of workers in the industrial developments at TKO Area 137 to be impacted by the residual impacts will depend on future developments. The only committed development in the TKO Area 137 is the CEDD’s C&DM Handling Facility. With respect to the nature of this development, it is anticipated that the number of workers impacted will be less than 50.

According to the Adopted Departmental Plan, L/TKO-137/1, TKO Area 137 is planned for PHI development. With reference to its explanatory note, it is stated that the maximum worker density should not exceed 20 workers per hectare. Based on the contour plots in Figures 4.7f to 4.7k, the maximum affected area (area within contour line of 5OU) for all assessment cases is approximately 13.5 ha. Therefore, it is estimated that up to 270 workers will be impacted.

It is estimated that the total number of people working within the affected zone of A2 will be about 1,000.

According to the predicted odour levels at different elevations of A2 (refer to Annex A10-1), the worst affected heights are 1.5m and 10m above ground during different waste tipping phases. The buildings within the affected area are equipped with centralised air conditioning system and the fresh air intakes are located at the rooftop of the TVB main building (ie 30m above ground) and at the level of about 13m above ground for the buildings (which is the lowest) along Wan Po Road. As the odour levels predicted at levels higher than 10m above ground at A2 are well below the odour criterion, there will be no adverse odour impact to the people (about 900) working indoor.

In conclusion, 100 people who are working outdoor will be potentially affected.

It should be noted that the number of people affected will reduce when the waste tipping activities will move higher and further away from the TVB City.

Degree to which the adverse environmental impacts are reversible or irreversible

Odour impact is transient in nature and therefore is reversible. After the Extension is closed and restored, no residual impacts are anticipated.

Ecological context

N/A - Odour nuisance will not cause adverse ecological impacts.

Degree of disruption to sites of cultural heritage

N/A – The Project will not impact on cultural heritage resources.

International and regional importance

It is not anticipated that the residual odour impact will affect an issues of international and regional concern.

Both likelihood and degree of uncertainty of adverse environmental impacts

As the odour impact assessment (including the odour modeling and odour sampling) has adopted a number of conservative assumptions, it is considered that the predicted odour impacts are overstated.

The odour emission rate of construction waste tipping is conservative. The construction waste comprises mainly wood and some inert materials and the odour generated from this kind of waste is low compared to that generated from the MSW covered with 300mm soil.

The number of exceedances may vary due to the different meteorological condition in the future six years of operation.

The odour emission rate of the trench adopted in the assessment is conservative and the emissions will be much lower as the trench will be covered and the air trapped inside the trench will be scrubbed prior to discharge to the air as well as no sludge will be received in the Extension. Hence, the level and number of exceedances will be less than the predicted in reality.

In Annex A3, the sensitivity test demonstrated that doubling the odour emission rate of the trench will only cause a slightly increase of the residual impact. Therefore, the uncertainty in the odour emission rate of the trench at 30 °C would not cause significant increase of residual impact.

Resolving uncertainties in the assessment would tend to lead to a lowering of the predicted impacts.

As the odour impact assessment (including the odour modeling and odour sampling) has adopted a number of conservative assumptions, it is considered that the predicted odour impacts are overstated.

The number of exceedances may vary due to the different meteorological condition in the future six years of operation.

The odour emission rate of the trench adopted in the assessment is conservative and the emissions will be much lower as the trench will be covered up and the air trapped inside the trench will be scrubbed prior to discharge to the air as well as no sludge will be received in the Extension. Hence, the level and number of exceedances will be less than the predicted in reality.

Resolving uncertainties in the assessment would tend to lead to a lowering of the predicted impacts.

Parameter	Monitoring Programme
24-hr TSP	· once every 6 days at four designated locations along the site boundary when major maintenance works is required
Ambient VOCs, Ammonia and H₂S	· VOCs, ammonia and H₂S · Monitoring frequency : quarterly
Stack emission from flares	· NO₂, CO, SO₂, benzene, vinyl chloride and NMOC · Monitoring frequency : quarterly · Gas combustion temperature, exhaust gas temperature and exhaust gas velocity will be monitored continuously
Stack emission from LFG generator	· NO₂, CO, SO₂, benzene, and vinyl chloride · Exhaust gas temperature and velocity · Monitoring frequency : quarterly
Odour Patrol	· weekly patrol along the Extension site boundary when major maintenance works is required
Meteorological Station	· continue to operate

([1]) Since the annual average concentration of TSP, RSP, NO2 and SO2 in year 2002 are not available, the data recorded in 2001 was used instead.

([2]) Reference to http://www.ccohs.ca/oshanswers/chemicals/chem_profiles/ammonia/working_ammonia.html

([3]) Maximum design capacity of the LTP in order to handle the leachate generated from the last year of operation of the existing SENT landfill. Once the existing SENT Landfill is closed and capped, the leachate volume will be reduced to about 23 m3d-1. The average volume of leachate to be treated at the LTP during the operation/restoration phase (including the leachate generated from the closed SENT Landfill) will be about 335 m3d-1. In the assessment, the LFG consumption rate of 3,125 m3hr-1has been used as a conservative assessment.

([4]) The maximum traffic flow is predicted in 2018.

([5]) The ambient daily TSP concentration measurements were taken at four ambient monitoring stations located at four sides of the site boundary (ie VOC/1, VOC/5, VOC/6 and VOC/8 shown in Figure 4.3a) once every six days.

([6]) Development & Management of SENT Landfill – Operation and Environmental Monitoring Annual Report, 2002 – 2005

([7]) The 39 individual VOCs include dichlorodifluoromethane, vinyl chloride, methanol, ethanol, dimethyl sulphide, carbon disulphide, methylene chloride, chloroform, methyl propionate, butan-2-ol, 1,1,1-trchloroethane, 1,2-dichlroethane, benzene, carbon tetrachloride, di-n-propyl ethene, heptane, trichloroethylene, ethyl propionate, methyl butyrate, methanethiol, toluene, ethyl butyrate, octane, propyl propionate, 1,2-dibromoethane, n-butyl acetate, tetrachloroethylene, ethylbenzene, xylene, nonane, ethanethiol, terpenes, propyl benzene, decane, dichlorobenzene, limonene, butyl benzene, undecane and butanethiol. These compounds may be found in LFG generated from municipal solid waste landfill.

([8]) Special waste means animal carcasses, asbestos waste, chemical waste, incineration residues and clinical waste.

([9]) Reference to the Sludge Treatment Facilities - Project Profile (ESB 169/2007) submitted for the application of EIA Study Brief (http://www.epd.gov.hk/eia/register/profile/latest/esb169/esb169.pdf) dated 20 August 2007.

([10]) Half of the area for MSW mixed with construction waste and half of the area for construction waste tipping only.

([11]) For preparation of the active tipping face, the top layer of intermediate cover soil (600mm) will be removed and stockpiled for daily cover at the end of the working day.

([12]) Reference to EIA Report for Agreement No. CE 20/2004 (EP) North East New Territories Landfill Extension (EIA 133/2007), Table 3.30. Effective temporary covers with impermeable plastic sheets will be applied at the inactive tipping areas.

([13]) Reference to EIA Report for Agreement No. CE 20/2004 (EP) North East New Territories Landfill Extension (EIA 133/2007). The final cover of both SENT and NENT Extensions adopt similar design concept which includes (from bottom to top) a soil layer, non-woven geotextile, HDPE liner, sub-soil drainage layer, and a final cover soil layer. LFG will be extracted for flaring or utilization. The contractor will be responsible for regular maintaining the restoration facilities (including the capping, LFG and leachate management systems) for up to 30 years. Both Extensions will require the Extension Contractors to undertake routine monitoring integrity of the capping system, operation of the flares, surface emission of LFG, ambient VOC emissions and sub-surface migration of LFG.

([14]) Reference to http://www.ccohs.ca/oshanswers/chemicals/chem_profiles/ammonia/working_ammonia.html

([15]) Reference to http://www.odour.unsw.edu.au/flux-hood-sampling.html

([16]) The odour concentration drops significant against the increase of height at ASRs, therefore, the prediction level is set at 90m above ground. The odour concentration predicted at the height higher than 90m is much lower.

([17]) Warren Spring Laboratory, "Odour Control - A Concise Guide", 1980.

([18]) Figure 4.7c-2 presents an isopleths showing the 2nd highest concentration of NO2 within 500m area from the Extension site boundary.

([19]) The contour plots are approximations only and the assessment results at the individual ASRs should be referred to Annex A6-1.

([20]) 23 types of uses include ambulance depot, cargo handling and forwarding facility, eating place, government refuse collection point, government use, industrial uses (motor-vehicle assembly plant, paint manufacturing, service trades, steel works only), IT and Telecommunications industries, marine fuelling station, open storage of construction materials, open storage of cement/sand, petrol filling station, pier, public convenience, public transport terminus or station, public utility installation, public vehicle park, recyclable collection centre, research, design and development centre, refuse disposal installation, ship-building, ship-breaking and ship-repairing yard, utility installation for private project and warehouse.

([21]) No waste tipping activity at the northern sector of the Extension between July and November.

([22]) It should be noted that the odour measurement that formed the basic for the emission rates were made in area in which sludge has been disposed. This is not planned at the Extension.

4.2.1 Air Pollutants Covered by Hong Kong Air Quality Objectives (HKAQOs)

4.2.2 Air Pollutants Not Covered by HKAQOs

Cancer Health Risk Assessment

Non-Cancer Health Risk Assessment

4.3.1 Baseline Conditions

4.3.2 Background Air Quality

4.5.1 Construction Phase

4.5.2 Operational/Restoration Phase

Gaseous Emissions from the LFG Treatment Facility

Table 4.5a Designed Performance Standards of the LFG Flare

Gaseous Emissions from Thermal Oxidizer of LTP

Gaseous Emissions from LFG Generator

Vehicular Emissions from Traffic Associated with the Extension

Fugitive Emissions at Landfilling Area in the Extension

Odour Emissions from Waste Filling Activities and Operation of LTP

Odour Emissions from Waste Filling Area

Main Haul Road to Active Tipping Face: The MSW will be delivered in RCVs with enclosed compactor body. It is therefore anticipated that the potential odour emission from the RCVs along the haul road of the Extension will be minimal.

Daily Covered Area: At the end of each working day (ie after 11 pm), the active tipping face will be covered with 300 mm of soil and compacted.

4.5.3 Aftercare Phase

Operation of LTP

Operation of LFG Treatment Facility

LFG Generator

4.5.4 Cumulative Impacts

Construction Phase

Operation/Restoration and Aftercare Phases

4.6 Assessment Methodology

4.6.1 Construction Phase

4.6.2 Cumulative Gaseous Emissions During Operation/Restoration and Aftercare Phases

4.6.3 Odour Emissions from Waste Filling Activities and Operation of LTP During Operation/Restoration Phase

Selection of Emission Source Locations for Worst Cases

Reasonable Worst-case Odour Modelling Parameter

Sampling Time and Locations: Measurements were taken between 9:00 am and 9:30 pm at four locations (see Table 4.6c). The sampling locations and the ambient temperature during sampling are presented in Table 4.6c.

Assessment Height and Presentation of Predicted Results

Conversion of Modelled Results From 3-minute Averaging Time to 5-second Averaging Time

4.7 Evaluation of Impacts

4.7.1 Construction Phase

4.7.2 Gaseous Emissions from LFG Flares, Thermal Oxidizer of LTP and LFG Generator During Operation/Restoration Phase

NO2, CO and SO2

Benzene and Vinyl Chloride

4.7.3 Odour Emissions from Waste Filling Activities and Operation of LTP During Operation/Restoration Phase

4.7.4 Gaseous Emissions from LFG Flares and LFG Generator During Aftercare Phase

NO2, CO and SO2

Benzene, Vinyl Chloride and VOCs

4.7.5 Odour Emissions from the Operation of LTP during Aftercare Phase

4.8.1 Construction Phase

4.8.2 Operation/Restoration Phase

Fugitive Emissions at Landfilling Area at the Extension

Gaseous Emissions from the Operation of LFG Treatment Facility, LTP and LFG Generator

Odour Emissions from Waste Filling Activities and Operation of LTP

4.8.3 Aftercare Phase

4.9 Residual Impacts

4.9.1 Construction Phase

4.9.2 Operational/Restoration Phase

Gaseous Emissions from LFG Treatment Facility and Thermal Oxidizers, Vehicle Emissions from Traffic associated with the Extension and Fugitive Emissions from Active Tipping Face

Odour Emissions Arising from Waste Filling Activities and Operation of LTP

4.9.3 Aftercare Phase

4.10.1 Construction Phase

4.10.2 Operation/Restoration Phase

Ambient TSP Monitoring at Site Boundary

Ambient VOC, Ammonia and Hydrogen Sulphide (H2S) Monitoring at Site Boundary

Monitoring of Flares and Thermal Oxidizer Stacks

Monitoring of LFG Generator Stack

Odour Patrol

On-site Meteorological Station

4.10.3 Aftercare Phase

4.11.1 Construction Phase

4.11.2 Operation/Restoration Phase

Gaseous Emissions

Odour Impacts

EM&A Requirement

4.11.3 Aftercare Phase

NO₂, CO and SO₂

NO₂, CO and SO₂

Ambient VOC, Ammonia and Hydrogen Sulphide (H₂S) Monitoring at Site Boundary