This Monthly EM&A report presents the EM&A works carried out during the period from 1 to 31 January 2025 for the Project in accordance with the updated EM&A Manual.

Exceedance of Action and Limit Levels for Air Quality

Two exceedances of the Limit Levels for Total Suspended Particulates (TSP) were recorded for air quality monitoring in the reporting period. The TSP exceedances at AM2 on 14 January and 20 January 2025 were deemed to Project-related activities upon further investigation.

Exceedance of Action and Limit Levels for Noise

No exceedance of Action and Limit Levels for operation/restoration phase noise monitoring was recorded in the reporting period.

Exceedance of Action and Limit Levels for Water Quality

One exceedance of the Limit Levels for groundwater (Chemical

Oxygen Demand (COD)) was recorded for water quality monitoring in the reporting period.

The groundwater (COD) exceedances at MWX-7 on 6 January 2025 is under investigation.

Exceedance of Action and Limit Levels for Landfill Gas

No exceedance of Action and Limit Levels for operation/restoration phase landfill gas monitoring was recorded in the reporting period.

Environmental Complaints, Summons and Prosecutions

There were no complaints, notification of summons or prosecution recorded in the reporting period.

Reporting Change

There was no reporting change in the reporting period.

Future Key Issues

Potential environmental impacts arising from the upcoming construction/ operational activities in the next reporting period of February 2025 are mainly associated with dust emission from the exposed area and loading and unloading operation of dusty materials.

1. Introduction

1.1 Background

The SENT Landfill Extension (SENTX) forms an integral part in the Strategic Plan in maintaining the continuity of landfill capacity in the Hong Kong for the cost-effective and environmentally satisfactory disposal of waste. The Environmental Impact Assessment (EIA) Report and the associated Environmental Monitoring and Audit (EM&A) Manual for the construction, operation, restoration and aftercare of the SENTX (hereafter referred to as “the Project”) have been approved under the Environmental Impact Assessment Ordinance (EIAO) in May 2008 (Register No.: AEIAR-117/2008) (hereafter referred to as the approved EIA Report) and an Environmental Permit (EP-308/2008) (EP) was granted by the Director of Environmental Protection (DEP) on 5 August 2008.

Since then, applications for Variation of an Environmental Permit (No. VEP-531/2017) were submitted to EPD and the Variation of Environmental Permits (EP-308/2008/A and EP-308/2008/B) were granted on 6 January 2012 and 20 January 2017, respectively, as the Hong Kong SAR Government has decided to reduce the scale of the design scheme of SENTX assessed in the approved EIA Report and SENTX will only receive construction waste. In May 2018, a Further Environmental Permit (FEP) (FEP-01/308/2008/B) was granted to the SENTX’s contractor, Green Valley Landfill, Limited (GVL). In February 2024, VEPs (EP-308/2008/C and FEP-01/308/2008/C) were granted to the Environmental Infrastructure Division of EPD and GVL, regarding updates on alternative measures to minimise surface odour emission.

ERM-Hong Kong, Limited (ERM) and Meinhardt Infrastructure and Environment Limited (Meinhardt) are commissioned to undertake the roles of Environmental Team (ET) and the Independent Environmental Checker (IEC), respectively, to undertake the EM&A activities for the Project in accordance with the requirements specified in the EP, updated EM&A Manual ([1]), approved EIA Report ([2]) taking account of the latest design and other relevant statutory requirements.

1.2 Project Description

The SENTX is a piggyback landfill, occupying the southern part of the existing SENT Landfill (including its infrastructure area) and 13 ha of Tseung Kwan O (TKO) Area 137. A layout plan of the SENTX is shown in Figure 1.1. Under the latest design, the SENTX has a net void capacity of about 6.5 Mm³ and provides an additional lifespan of about 6 years, commencing operation upon exhaustion of the SENT Landfill. The SENTX will receive construction waste only.

The key implementation milestones of the Project are indicatively summarised in Table 1.1. The construction works and operation of the Project commenced on 2 January 2019 and 21 November 2021, respectively.

Table 1.1 Estimated Key Dates of Implementation Programme

Key Stage of the Project	Indicative Date
Start construction	2 January 2019
Commissioning of new infrastructure facilities	2020
Demolition of existing infrastructure facilities	2021
Start waste intake at SENTX	21 November 2021
Estimated exhaustion date of SENTX	2027
End of aftercare for SENTX	2059

The major construction works of the SENTX includes:

• Site formation at the TKO Area 137 and the existing infrastructure area at SENT Landfill;

• Construction of surface and groundwater drainage systems;

• Construction of the leachate containment and collection systems;

• Construction of new leachate and landfill gas treatment facilities, site offices, maintenance yards at the new infrastructure area;

• Construction of new pipelines to transfer the leachate and landfill gas collected from the existing SENT Landfill to the treatment facilities at the new infrastructure area;

• Construction of the site access and new waste reception facilities; and

• Demolition of the facilities at the existing SENT Landfill infrastructure area.

1.3 Scope of the EM&A Report

This is the Monthly EM&A Report for the Project which summarises the key findings of the EM&A programme during the reporting period from 1 to 31 January 2025 for the construction and operation works.

1.4 Project Organisation

The organisation structure of the Project is presented in Figure 1.2.

Figure 1.2 Organisation Chart

A diagram of a project

Description automatically generated

Contact details of the key personnel are summarised in Table 1.2 below.

Table 1.2 Contact Information of Key Personnel

Party	Position	Name	Telephone
Contractor (Green Valley Landfill Limited)	Project Manager	Carl Lai	2706 8829
Environmental Team (ET) (ERM-Hong Kong, Limited)	ET Leader	Terence Fong	2271 3156
Independent Environmental Checker (IEC) (Meinhardt Infrastructure and Environment Limited)	IEC	Claudine Lee	2859 5409

1.5 SUMMARY OF CONSTRUCTION WORKS

The programme of the construction is shown in Annex A. As informed by the Contractor, the major works carried out in this reporting period include:

· Maintenance and improvement of temporary surface water drainage; and

· Restoration of Phase 1 and Phase 2 slopes.

The implementation schedule of the mitigation measured recommended in the Updated EM&A Manual is presented in Annex B.

1.6 SUMMARY OF EM&A PROGRAMME REQUIREMENTS

The status for all environmental aspects are presented in Table 1.3. The EM&A requirements remained unchanged during the reporting period.

Table 1.3 Summary of Status for the Environmental Aspects under the Updated EM&A Manual

Parameters	Status
Air Quality
Baseline Monitoring	The results of baseline air quality monitoring were reported in Baseline Monitoring Report and Pre-operation Baseline Monitoring Report and submitted to EPD under EP Condition 3.3
Impact Monitoring	On-going
Noise
Baseline Monitoring	The results of baseline noise monitoring were reported in Baseline Monitoring Report and submitted to EPD under EP Condition 3.3
Impact Monitoring	On-going
Water Quality
Baseline Monitoring	The results of baseline surface water quality monitoring were reported in Baseline Monitoring Report and Pre-operation Baseline Monitoring Report and submitted to EPD under EP Condition 3.3
Impact Monitoring	On-going
Landfill Gas
Impact Monitoring	On-going
Waste Management
Waste Monitoring	On-going
Landscape and Visual
Baseline Monitoring	The results of baseline landscape and visual monitoring were reported in Baseline Monitoring Report and submitted to EPD under EP Condition 3.3
Operation Phase Audit	On-going
Site Environmental Audit
Regular Site Inspection	On-going
Complaint Hotline and Email Channel	On-going
Environmental Log Book	On-going

Taking into account the operation works, impact monitoring of air quality, noise, water quality, landfill gas and waste management were carried out in the reporting period. The impact monitoring schedule of air quality, noise, water quality and landfill gas monitoring are provided in Annex C.

The EM&A programme also involved environmental site inspections and related auditing conducted by the ET for checking the implementation of the required environmental mitigation measures recommended in the approved EIA Report and relevant EP submissions. To promote the environmental awareness and enhance the environmental performance of the contractors, environmental trainings and regular environmental management meetings were conducted during the reporting period, which are summarized as below:

Ÿ One environmental management meeting was held with the Contractor, ET, IEC and EPD on 22 January 2025; and

Ÿ Environmental toolbox trainings on VOC and Smog and Green Procurement were provided on 17 January 2025 and by the Contractor to the workers.

1.7 Status of Statutory Environmental Compliance with the Environmental Permit

The status of statutory environmental compliance with the EP conditions under the EIAO, submission status under the EP and implementation status of mitigation measures are presented in Table 1.4.

Table 1.4 Status of Submissions required under the EP and Implementation Status of Mitigation Measures

EP Condition	Submission / Implementation Status	Status
2.3	Management Organisation of Main Construction Companies	Submitted and accepted by EPD.
2.4	Setting up of Community Liaison Group	Community Liaison Group was set up.
2.5	Submission of Detailed Landfill Gas Hazard Assessment Report	Submitted and accepted by EPD on 10 January 2019.
2.6	Submission of Restoration and Ecological Enhancement Plan	Submitted to EPD on 28 June 2019.
2.7	Setting up of Trial Nursery	Trial Nursery works was commenced on 28 August 2019.
2.8	Advance Screen Planting	Advance Screen Planting works were completed on 28 June 2019.
2.9	Provision of Multi-layer Composite Liner System	Under implementation.

1.8 STATUS OF OTHER STATUTORY ENVIRONMENTAL REQUIREMENTS

The environmental licenses and permits (including EP, Water Pollution Control Ordinance (WPCO) discharge license, registration as a chemical waste producer, and construction noise permit) that are valid in the reporting period are presented in Table 1.5. No non-compliance with environmental statutory requirements was identified.

Table 1.5 Status of Statutory Environmental Requirements

Description	Ref No.	Status
Environmental Permit	EP-308/2008	Granted on 5 August 2008
Variation of Environmental Permit	EP-308/2008/A	Granted on 6 January 2012
	EP-308/2008/B	Granted on 20 January 2017
	EP-308/2008/C	Granted on 29 February 2024
Further Environmental Permit	FEP-01/308/2008/B	Granted on 16 May 2018
Further Environmental Permit	FEP-01/308/2008/C	Granted on 29 February 2024
Water Discharge License under WPCO (Permit Holder: GVL)	Licence No.: WT10003277-2024	Validity from 23 August 2024 to 30 June 2026
Billing Account for Disposal of Construction Waste	Chit Account Number: 5001692	Approved on 28 December 2005
Registration as a Chemical Waste Producer (Permit Holder: GVL)	5296-839-G2228-01	Issued on 31 December 2015
Construction Noise Permit (Permit Holder: GVL)	GW-RE1103-24	Validity from 15 September 2024 to 14 March 2025

2. EM&A RESULTS

The EM&A programme for the Project required environmental monitoring for air quality, noise, water quality and landfill gas as well as environmental site inspections for air quality, noise, water quality, landfill gas, waste management, and landscape and visual impacts. The EM&A requirements and related findings for each component are summarised in the following sections.

2.1 Air Quality Monitoring

2.1.1 DUst Monitoring

2.1.1.1 Monitoring Requirements and Equipment

According to the updated EM&A Manual of the Project, impact dust monitoring (in term of Total Suspended Particulates (TSP)) was carried out at the four designated locations along the site boundary (i.e. AM1, AM2, AM3 and AM4) during the operation/restoration phase, at a 6-day interval.

The Action and Limit Levels of the dust monitoring is provided in Table 2.1 below.

Table 2.1 Action and Limit Levels for 24-hour TSP

Monitoring Station	Action Level	Limit Level
AM1 - SENTX Site Boundary (North)	• 260 µg m-³	• 260 µg m-³
AM2 - SENTX Site Boundary (West, near DP3)
AM3 - SENTX Site Boundary (West, near RC15)
AM4 - SENTX Site Boundary (West, near EPD building)

High volume air samplers (HVSs) in compliance with the specifications listed under Section 3.2.2 of the updated EM&A Manual were used to measure 24-hour TSP levels at the dust monitoring stations. The HVSs were calibrated upon installation and thereafter at bi-monthly intervals to check the validity and accuracy of the results.

The equipment used in the impact dust monitoring programme and monitoring locations are summarised in Table 2.2 and illustrated in Figure 2.1, respectively. Copies of the calibration certificates for the equipment are presented in Annex D1.

Table 2.2 Dust Monitoring Details

Monitoring Station	Location	Parameter	Frequency and Duration	Monitoring Dates	Equipment
AM1	SENTX Site Boundary (North)	• 24-hour TSP	• Once every 6 days	• 2, 8, 14, 20, 26 Jan 2025	• Tisch TE-5170 (S/N: 3976)
AM2	SENTX Site Boundary (West, near DP3)				• Tisch TE-5170 (S/N: 3573)
AM3	SENTX Site Boundary (West, near RC15)				• Tisch TE-5170 (S/N: 3572)
AM4	SENTX Site Boundary (West, near EPD building)				· Tisch TE-5170 (S/N: 3957)

2.1.1.2 Monitoring Schedule for the Reporting Month

The schedule for dust monitoring during the reporting period is provided in Annex C.

2.1.1.3 Results and Observations

The monitoring results for 24-hour TSP are summarised in Table 2.3. The detailed monitoring results and the graphical presentation of the 24-hour TSP results at each monitoring location are provided in Annex D2.

Table 2.3 Summary of 24-hour TSP Monitoring Results in the Reporting Period

Monitoring Station Location	Average 24-hr TSP Concentration (µg m^-3) (Range in bracket)	Action Level (µg/m³)	Limit Level (µg/m³)
AM1 - SENTX Site Boundary (North)	172 (95 – 228)	260	260
AM2 - SENTX Site Boundary (West, near DP3)	203 (63 – 329)	260	260
AM3 - SENTX Site Boundary (West, near RC15)	141 (59 – 176)	260	260
AM4 - SENTX Site Boundary (West, near EPD building)	103 (55 – 116)	260	260

The major dust sources in the reporting period included fugitive dust emission from exposed area in SENTX as well as nearby operations of the TKO Area 137 Fill Bank.

Action and Limit Levels exceedances were recorded for TSP monitoring in the reporting period and actions in accordance with the Event and Action Plan presented in Annex D3 were undertaken. Investigation of the Action and Limit Levels exceedances was conducted and the investigation reports are presented in Annex D8.

Based on the investigation conducted for the monitoring events with potential Action and Limit Levels exceedances with the Contractor and the IEC, the TSP exceedances at AM2 on 14 January and 20 January 2025 were deemed to Project-related activities.

The Contractor was reminded to implement all relevant mitigation measures for the construction and operation works and maintain good site practice. The ET will keep track on the monitoring data and ensure Contractor’s compliance of the environmental requirements.

2.1.1.4 Meteorological Data

Meteorological data obtained from the SENTX on-site meteorological monitoring station was used for the dust monitoring and is shown in Annex D4. It is considered that meteorological data obtained at the on-site meteorological monitoring station is representative of the Project area and could be used for the operation/restoration phase dust monitoring programme for the Project.

2.1.2 Odour Monitoring

2.1.2.1 Monitoring Requirements

According to the updated EM&A Manual of the Project, odour patrol was carried out along the site boundary during the operation/ restoration phase.

During the first month of operation, daily odour patrol (3 times per day) was conducted jointly by the ET and the IEC. The odour intensity detected was based on that determined by the IEC. In addition, an independent party (ALS Technichem (HK) Pty Ltd.) was appointed to undertake odour patrol together with the ET and IEC three times per week. During these patrols, the odour intensity detected was based on that determined by the independent third party.

Reduction of odour monitoring frequency from Period 1 (daily, three times per day) to Period 2 (weekly) was approved by EPD on 4 February 2022. Weekly odour patrol was conducted jointly by the ET and the IEC from 10 February 2022. In addition, an independent party (ALS Technichem (HK) Pty Ltd.) was appointed to undertake odour patrol together with the ET and IEC once every two weeks.

Reduction of odour monitoring frequency from Period 2 (weekly) to Period 3 (monthly) was approved by EPD on 2 June 2022. Monthly odour patrol was conducted jointly by the ET and the IEC from 28 June 2022. In addition, an independent party (ALS Technichem (HK) Pty Ltd.) was appointed to undertake odour patrol together with the ET and IEC quarterly. Furthermore, the odour patrol route has been reviewed against the latest construction / operation programme and approved by EPD on 17 June 2024.

The Action and Limit Levels for odour patrol is provided in Table 2.4 below.

Table 2.4 Action and Limit Levels for Odour Patrol

Parameter

Action Level

Limit Level

Perceived odour intensity and odour complaints

· Odour intensity ≥ Class 2 recorded; or

· One documented complaint received

· Odour intensity ≥ Class 3 recorded on 2 consecutive patrol ^{(a) (b)}

Notes:

(a) i.e. either Class 3-strong or Class 4-extreme odour intensity.

(b) The exceedances of the odour intensity do not need to be recorded at the same location.

Odour patrol was conducted by trained personnel/competent persons with a specific sensitivity to a reference odour (i.e. on reference materials n-butanol with the concentration of 50ppm in nitrogen (v/v)) in compliance with Section 3.7.2 of the updated EM&A Manual patrolling and sniffing along the SENTX Site boundary to detect any odour.

The odour monitoring programme and patrol route are summarised in Table 2.5 and illustrated in Figure 2.2 respectively. Copies of the certificates of the qualified odour panelist are presented in Annex D5.

Table 2.5 Odour Monitoring Details

Patrol Locations

Parameters

Patrol Frequency ^(a)

Monitoring Dates

Patrol along the SENTX Site Boundary (Checkpoints OP1 – OP17)

Odour Intensity (see Table 2.6)

Period 1 - First month of operation

Daily, three times a day in the morning, afternoon and evening/night (between 18:00 and 22:00 hrs) conducted by the ET and the IEC

Three times per week on different days conducted by an independent third party together with the ET and IEC ^(b)

Period 2 - Three months following period 1 ^(c)

Weekly conducted by the ET and the IEC

Once every two weeks conducted by an independent third party together with the ET and IEC ^(b)

Period 3 - Throughout operation following period 2 ^(c)

Monthly conducted by the ET and the IEC

Quarterly conducted by an independent third party together with the ET and IEC ^(b)

Conducted by ET & IEC:

17 Jan 2025

Conducted by an independent third party, ET & IEC:

Notes:

(a) Reduction of monitoring frequency will be subject to the monitoring results to demonstrate environmentally acceptable performance.

(b) Patrol shall be scheduled so that they are carried out together with the patrols to be carried out jointly by the ET and the IEC.

(c) Commencement of each period will be justified by the ET Leader and verified by the IEC and will be subject to agreement with the EPD (EIAO Authority) and Project Proponent.

Table 2.6 Odour Intensity Level

Class	Odour Intensity	Description
0	Not Detected	No odour perceived or an odour so weak that it cannot be easily characterised or described.
1	Slight	Identified odour, slight
2	Moderate	Identified odour, moderate
3	Strong	Identified odour, strong
4	Extreme	Severe odour

2.1.2.2 Monitoring Schedule for the Reporting Month

The schedule for odour patrol during the reporting period is provided in Annex C.

2.1.2.3 Results and Observations

The odour monitoring results are summarised and provided in Table 2.7 and Annex D6, respectively.

Table 2.7 Summary of Odour Monitoring Results in the Reporting Period

Odour Checkpoints	Odour Intensity Class	Action Level	Limit Level
OP1	0	Odour intensity ≥ Class 2 recorded	Odour intensity ≥ Class 3 recorded on 2 consecutive patrol
OP2	0
OP3	0
OP4	0
OP5	0
OP6	0
OP7	0
OP8	1
OP9	0
OP10	1
OP11	0
OP12	0
OP13	0
OP14	0
OP15	0
OP16	0
OP17	1

The potential odour source in the reporting period included the leachate from X10 channel at SENTX, and the nearby Towngas plant. All the odour monitoring results were below the Action and Limit Levels in the reporting period. No action is thus required to be undertaken in accordance with the Event and Action Plan presented in Annex D3.

2.1.3 Thermal Oxidiser, Landfill Gas Flare and Landfill Gas Generator Stack Emission Monitoring

2.1.3.1 Monitoring Requirements and Equipment

According to the updated EM&A Manual of the Project, the performance of the thermal oxidiser, landfill gas flare and landfill gas generator was monitored when they are in operation. Gas samples were collected from the stack of the thermal oxidizer, landfill gas flare and landfill gas generator for laboratory analysis for NO₂,CO, SO₂, Benzene and Vinyl chloride and in-situ analysis for exhaust gas velocity at monthly interval and for laboratory analysis for non-methane organic compounds and ammonia (for thermal oxidizer only) at quarterly interval. The operating conditions of the thermal oxidiser, landfill gas flare and landfill gas generator were also monitored continuously.

The Limit Levels for stack emission of the thermal oxidiser, landfill gas flare and landfill gas generator are provided in Tables 2.8 – 2.10 below.

Table 2.8 Limit Levels for Stack Emission of the Thermal Oxidiser

Parameters	Limit Level
NO₂	1.58 gs^-1
CO	0.53 gs^-1
SO₂	0.07 gs^-1
Benzene	3.01 x 10^-2 gs^-1
Vinyl chloride	2.23 x 10^-3 gs^-1
Gas combustion temperature	850^oC (minimum)
Exhaust gas exit temperature	443K (minimum) ^(a)
Exhaust gas velocity	7.5 ms^-1 (minimum)^(a)
Note: (a) Level under full load condition.

Table 2.9 Limit Levels for Stack Emission of the Landfill Gas Flare

Parameters	Limit Level
NO₂	0.97 gs^-1
CO	2.43 gs^-1
SO₂	0.22 gs^-1
Benzene	4.14 x 10^-4 gs^-1
Vinyl chloride	2.60 x 10^-4 gs^-1
Gas combustion temperature	815^oC (minimum)
Exhaust gas exit temperature	923 K (minimum) ^(a)
Exhaust gas velocity	9.0 m s^-1 (minimum)^(a)
Note: (a) Level under full load condition.

Table 2.10 Limit Levels for Stack Emission of the Landfill Gas Generator

Parameters	Limit Level
NO₂	1.91 gs^-1
CO	2.48 gs^-1
SO₂	0.528 gs^-1
Benzene	2.47 x 10^-4 gs^-1
Vinyl chloride	1.88 x 10^-5 gs^-1
Gas combustion temperature	450^oC (minimum)
Exhaust gas exit temperature	723K (minimum) ^(a)
Exhaust gas velocity	30.0 ms^-1 (minimum)^(a)
Note: (a) Level under full load condition.

Gas samples were collected from the centroid of the stack with stainless steel sampling probe, into inert sample containers (i.e. Canister and Tedlar Bag) and transferred to ALS Technichem (HK) Pty Ltd. (HOKLAS Registration No. 066) laboratory within 24 hours of collection for direct analysis on a gas chromatography within 48 hours after collection. The flue gas velocity of the gas stream at the exhaust of thermal oxidize was determined by S-Pitot tube during the emission sampling.

The stack emission monitoring programme and monitoring locations are summarised in Table 2.11 and illustrated in Figure 2.1, respectively.

Table 2.11 Thermal Oxidiser, Landfill Gas Flare and Landfill Gas Generator Stack Emission Monitoring Details

Monitoring Location	Parameter	Frequency	Monitoring Date
Stack of Thermal Oxidiser	Laboratory analysis for · NO₂ · CO · SO₂ · Benzene · Vinyl chloride In-situ analysis for · Exhaust gas velocity	Monthly for the first 12 months of operation and thereafter at quarterly intervals	8 Jan 2025
	Laboratory analysis for · Non-methane organic compounds CO	Quarterly for the 1^st year of operation ^(b)	-
	Laboratory analysis for · Ammonia · Gas combustion temperature · Exhaust temperature · Exhaust gas velocity ^(a)	Quarterly	-
	· Gas combustion temperature · Exhaust temperature · Exhaust gas velocity ^(a)	Continuously	1 – 31 Jan 2025
Stack of Landfill Gas Flare	Laboratory analysis for · NO₂ · CO · SO₂ · Benzene · Vinyl chloride In-situ analysis for · Exhaust gas velocity	Monthly for the first 12 months of operation and thereafter at quarterly intervals	9 Jan 2025
Stack of Landfill Gas Flare	Laboratory analysis for · Non-methane organic compounds CO	Quarterly for the 1^st year of operation ^(b)	-

Monitoring Location	Parameter	Frequency	Monitoring Date
Stack of Landfill Gas Flare	· Gas combustion temperature · Exhaust temperature · Exhaust gas velocity ^(a)	Continuously	1 – 31 Jan 2025
Stack of Landfill Gas Generator	Laboratory analysis for · NO₂ · CO · SO₂ · Benzene · Vinyl chloride In-situ analysis for · Exhaust gas velocity	Monthly for the first 12 months of operation and thereafter at quarterly intervals	9 Jan 2025
	Laboratory analysis for · Non-methane organic compounds	Quarterly for the 1^st year of operation ^(b)	-
	· Exhaust temperature · Exhaust gas velocity ^(a)	Continuously	1 – 31 Jan 2025
Notes: (a) The exhaust gas velocity is calculated based on the cross-section area of the stack and continuous monitored gas flow and combustion temperature data. (b) The monitoring results are being reviewed to determine if monitoring of this parameter can be terminated upon agreement by the EIAO Authority, IEC and Project Proponent.

2.1.3.2 Monitoring Schedule for the Reporting Month

The schedule for thermal oxidizer, landfill gas flare and landfill gas generator stack emission monitoring during the reporting period is provided in Annex C.

2.1.3.3 Results and Observations

The thermal oxidizer, landfill gas flare and landfill gas generator stack emission monitoring results and detailed continuous monitoring results are summarised in Tables 2.12 - 2.14 and provided in Annex D7, respectively.

Table 2.12 Summary of Thermal Oxidiser Stack Emission Monitoring in the Reporting Period

Parameters	Monitoring Results (Range in Bracket)	Limit Level
NO₂	1.56 gs^-1	1.58 gs^-1
CO	0.02 gs^-1	0.53 gs^-1
SO₂	<0.01 gs^-1	0.07 gs^-1
Benzene	<2.0 x 10^-4 gs^-1	3.01 x 10^-2 gs^-1
Vinyl chloride	<1.5 x 10^-4 gs^-1	2.23 x 10^-3 gs^-1
Gas combustion temperature	900^oC (897^oC – 907^oC)	850^oC (minimum)
Exhaust gas exit temperature	1,196K (1,189K – 1,202K)	443K (minimum) ^(a)
Exhaust gas velocity	8.2 ms^{-1 (b)}	7.5 ms^-1 (minimum)^(a)
Notes: (a) Level under full load condition. (b) The exhaust gas velocity was calculated based on the cross-section area of the stack and the gas flow and combustion temperature data measured during the stack emission monitoring.

Table 2.13 Summary of Landfill Gas Flare Stack Emission Monitoring in the Reporting Period

Parameters	Monitoring Results (Range in Bracket)	Limit Level
NO₂	0.03 gs^-1	0.97 gs^-1
CO	0.02 gs^-1	2.43 gs^-1
SO₂	0.05 gs^-1	0.22 gs^-1
Benzene	1.4 x 10^-4gs^-1	4.14 x 10^-4 gs^-1
Vinyl chloride	1.12 x 10^-4 gs^-1	2.60 x 10^-4 gs^-1
Gas combustion temperature	Flare 1: 839^oC (820^oC – 925^oC) Flare 2: 838^oC (820^oC – 880^oC)	815^oC (minimum)
Exhaust gas exit temperature	Flare 1: 1,147K (1,113K – 1,193K) Flare 2: 1,165K (1,133K – 1,193K)	923 K (minimum) ^(a)
Exhaust gas velocity	8.0 ms^{-1 (b)}	9.0 m s^-1 (minimum)^(a)
Notes: (a) Level under full load condition. (b) The exhaust gas velocity was calculated based on the cross-section area of the stack and the gas flow and combustion temperature data measured during the stack emission monitoring.

Table 2.14 Summary of Landfill Gas Generator Stack Emission Monitoring in the Reporting Period

Parameters	Monitoring Results (Range in Bracket)	Limit Level
NO₂	0.106 gs^-1	1.91 gs^-1
CO	1.02 gs^-1	2.48 gs^-1
SO₂	<0.001 gs^-1	0.528 gs^-1
Benzene	9.2 x 10^-5 gs^-1	2.47 x 10^-4 gs^-1
Vinyl chloride	<1.02 x 10^-5 gs^-1	1.88 x 10^-5 gs^-1
Exhaust gas exit temperature	ENGA: 874K (854K – 891K) ENGB: 872K (870K – 874K)	723K (minimum) ^(a)
Exhaust gas velocity	10.0 ms^-1 ^(b)	30.0 ms^-1 (minimum)^(a)
Notes: (a) Level under full load condition. The exhaust gas velocity was calculated based on the cross-section area of the stack and the gas flow and combustion temperature data measured during the stack emission monitoring. (b)

No Action and Limit Level exceedance was recorded for thermal oxidizer, landfill gas flare and landfill gas generator stack emission monitoring in the reporting period. No action is thus required to be undertaken in accordance with the Event and Action Plan presented in Annex D3.

2.2 Noise Monitoring

2.2.1 Monitoring Requirements and Equipment

According to the updated EM&A Manual of the Project, noise levels at noise monitoring location NM1 and NM2 should be monitored during first 3 years of operation and during the next 3 years of operation until the completion of the Restoration phase, respectively. Impact noise monitoring was conducted weekly at the monitoring location (i.e. at NM1 before 20 November 2024; and at NM2 from 20 November 2024) to obtain one set of 30-minute measurement between 07:00 and 19:00 hours on normal weekdays.

The Action and Limit Levels for operational noise of the Project are provided in Table 2.15 below.

Table 2.15 Action and Limit Levels for Operational Noise

Time Period	Action Level ^(a)	Limit Level ^(b)
07:00 – 19:00 hrs on all days	When one documented complaint is received from any one of the noise sensitive receivers (NSRs) or 75 dB(A) recorded at the monitoring station	65 dB(A) at NSRs ^(c)
19:00 – 23:00 hrs on all days		65 dB(A) at NSRs ^(c)
23:00 – 07:00 hrs on all days		55 dB(A) at NSRs ^(c)
Notes: (a) 75dB(A) along and at about 100m from the SENTX site boundary was set as the Action Level. (b) Limits specified in the GW-TM and IND-TM for construction and operational noise, respectively. (c) Limit Level only apply to operational noise without road traffic and construction activities noise.

Noise monitoring was performed by ALS Technichem (HK) Pty Ltd. (HOKLAS Registration No. 066) using sound level meter at the designated monitoring station NM1 (see Figure 2.1) in accordance with the requirements stipulated in the updated EM&A Manual. Acoustic calibrator was deployed to check the sound level meter at a known sound pressure level. Details of the deployed equipment are provided in Table 2.16. Copies of the calibration certificates for the equipment are presented in Annex E1.

Table 2.16 Noise Monitoring Details

Monitoring Station

Location

Parameter

Frequency and Duration

Monitoring Dates

Equipment

NM2

SENTX Site Boundary (East)

L_{eq
(30 min)} measurement between 07:00 and 19:00 hours on normal weekdays

(Monday to Saturday)

Once per week for 30 mins during operation of the Project

8, 15, 21, 27 Jan 2025

Sound Level Meter:

Rion NL-52 (S/N: 00331806)

Acoustic Calibrator:

CAL200 (S/N: 11333)

2.2.2 Monitoring Schedule for the Reporting Month

The schedule for noise monitoring during the reporting period is provided in Annex C.

2.2.3 Results and Observations

A total of 4 impact noise monitoring events were scheduled during the reporting period. Results for noise monitoring are summarised in Table 2.17. The monitoring results and the graphical presentation of the data are provided in Annex E2.

Table 2.17 Summary of Operation Noise Monitoring Results in the Reporting Period

	Measured Noise Level L_{eq (30 min)}, dB(A)
Monitoring Station	Average	Range	Action and Limit Level
NM2	48.9	44.5 – 52.3	75

Major noise sources identified during the noise monitoring included noise from insects. No Action and Limit Levels exceedance was recorded for operation noise monitoring in the reporting period. No action is thus required to be undertaken in accordance with the Event and Action Plan presented in Annex E3.

2.3 Water Quality Monitoring

2.3.1 Surface Water Quality Monitoring

2.3.1.1 Monitoring Requirements and Equipment

According to the updated EM&A Manual of the Project, impact surface water quality monitoring was carried out at the three designated surface water discharge points (i.e. DP3, DP4 and DP6) at monthly intervals during operation/ restoration phase to ensure that the SENTX will not cause adverse water quality impact.

The parameters as listed in Table 2.19 were determined by ALS Technichem (HK) Pty Ltd. (HOKLAS Registration No. 066).

The Limit Levels of the surface water quality impact monitoring are provided in Table 2.18.

Table 2.18 Limit Levels for Surface Water Quality

Parameters	Limit Level
DP3
Ammoniacal-nitrogen	> 0.5 mg/L
COD	> 80 mg/L
SS	> 30 mg/L
DP4 & DP6
Ammoniacal-nitrogen	> 7.1 mg/L
COD	> 30 mg/L
SS	> 20 mg/L
Note: The limit levels specified for other parameters in Table 10a of the Technical Memorandum Standards for Effluents Discharged into Drainage and Sewerage Systems, Inland and Coastal Waters shall also be followed.

The locations of the monitoring stations for the Project are shown in Figure 2.1. All in situ monitoring instruments were checked, calibrated and certified by a laboratory accredited under HOKLAS or other international accreditation scheme before use, and subsequently re-calibrated at 3 monthly intervals throughout all stages of the surface water quality monitoring programme. Calibration for a DO meter was carried out before measurement according to the instruction manual of the equipment model. Details of the equipment used in the impact surface water quality monitoring works are provided in Table 2.19. Copies of the calibration certificates for the equipment are presented in Annex F1.

Table 2.19 Impact Surface Water Quality Monitoring Details

Monitoring Station	Location	Frequency	Monitoring Dates	Parameter		Equipment
DP3	Surface water discharge point DP3	Monthly	7 Jan 2025	· pH · Electrical conductivity (EC) · DO · SS · COD · BOD₅ · TOC · Ammoniacal–nitrogen · Nitrate-nitrogen · Nitrite–nitrogen · TKN · TN · Phosphate · Sulphate · Sulphide · Carbonate · Oil & Grease	· Bicarbonate · Chloride · Sodium · Potassium · Calcium · Magnesium · Nickel · Manganese · Chromium · Cadmium · Copper · Lead · Iron · Zinc · Mercury · Boron	Horiba U-52G (S/N: AWE7D2V4
DP4	Surface water discharge point DP4
DP6	Surface water discharge point DP6

2.3.1.2 Monitoring Schedule for the Reporting Month

The schedule for surface water quality monitoring during the reporting period is provided in Annex C.

2.3.1.3 Results and Observations

One monitoring event for impact surface water quality monitoring was scheduled at all designated monitoring stations during the reporting period. However, sampling could not be carried out on 7 January 2025 due to insufficient flow. Details of impact water quality monitoring event are provided in Annex F2.

All surface water quality monitoring results were below the Action and Limit Levels in the reporting period. No action is thus required to be undertaken in accordance with the event and action plan presented in Annex F3.

2.3.2 Leachate Monitoring

2.3.2.1 Monitoring Requirements and Equipment

According to the updated EM&A Manual, continuous monitoring of leachate level and monthly monitoring of effluent quality were carried out during the operation/ restoration phase.

Reduction of effluent monitoring frequency (dry season) (from daily to monthly) was approved by EPD on 22 March 2022. Monthly effluent quality monitoring (dry season) shall be conducted from 23 March 2022. The reduction of effluent monitoring frequency (wet season) (from daily to monthly) was approved by EPD on 2 August 2022. Monthly effluent quality monitoring (wet season) shall be conducted from 3 August 2022.

Temperature, pH and volume of the effluent discharged from the leachate treatment plant were measured in-situ whereas the parameters as listed in Table 2.21 were determined by ALS Technichem (HK) Pty Ltd. (HOKLAS Registration No. 066).

The Limit Levels of the leachate monitoring are provided in Table 2.20.

Table 2.20 Limit Levels for Leachate Levels and Effluent Quality

Parameters	Limit Level
Leachate Levels
Leachate levels above the basal liner	1 m above the primary liner of the leachate containment system
Effluent Quality
Temperature	> 43 °C
pH Value	6 – 10
Volume Discharged	>2,000 m³
Suspended Solids (SS)	> 800 mg/L
Phosphate	> 25 mg/L
Sulphate	> 800 mg/L
Total Inorganic Nitrogen ^(a)	> 100 mg/L
Biochemical Oxygen Demand (BOD)	> 800 mg/L
Chemical Oxygen Demand (COD)	> 2,000 mg/L
Oil & Grease	> 20 mg/L
Boron	> 7,000 µg/L
Iron	> 5 mg/L
Cadmium	> 1 µg/L
Chromium	> 300 µg/L
Copper	> 1,000 µg/L
Nickel	> 700 µg/L
Zinc	> 700 µg/L
Note: (a) Total Inorganic Nitrogen include Ammoniacal-nitrogen, Nitrite-nitrogen and Nitrate-nitrogen.

All in situ monitoring instruments were checked, calibrated and certified by a laboratory accredited under HOKLAS or other international accreditation scheme before use, and subsequently re-calibrated at 3 monthly intervals throughout all stages of the leachate quality monitoring programme. Details of the equipment used are provided in Table 2.21. Copies of the calibration certificates for the equipment are presented in Annex F4.

Table 2.21 Leachate Levels and Effluent Quality Monitoring Details

Location	Frequency	Parameter	Monitoring Dates	Equipment
Leachate levels above the basal liner	Continuous	Leachate Levels	1 – 31 Jan 2025	Pairs of pressure transducers
Effluent discharged from LTP	Daily for the first 3 months upon full operation of the LTP at wet season (Apr to Sep) and dry season (Oct to Mar), respectively and reduce to monthly thereafter subject to the monitoring results of the first 3 months for each season and agreement with the EIAO Authority, IEC and IC. ^(a)	On-site Measurements: · Volume · pH · Temperature Laboratory analysis: · Suspended Solids · COD · BOD₅ · TOC · Ammoniacal–nitrogen · Nitrate-nitrogen · Nitrite–nitrogen · Total Nitrogen · Sulphate · Phosphate · Oil & Grease · Alkalinity · Chloride · Calcium · Potassium · Magnesium · Iron · Zinc · Copper · Chromium · Nickel · Cadmium · Boron	9 Jan 2025	Lutron PH-208 (S/N: TF31039)
Note: (a) Reduction of monitoring frequency will be subject to the monitoring results to demonstrate environmentally acceptable performance.

2.3.2.2 Monitoring Schedule for the Reporting Month

The schedule for leachate monitoring during the reporting period is provided in Annex C.

2.3.2.3 Results and Observations

The leachate levels and effluent quality monitoring results are summarised in Table 2.22 and Table 2.23, respectively. The detailed monitoring results are provided in Annex F5 and Annex F6, respectively.

Table 2.22 Summary of Leachate Levels in the Reporting Period

Monitoring Location	Average Leachate Head Levels (cm) (Range in Bracket)	Limit Level (cm)
Pump Station No. 1X (Cell 1X)
Meter No. X-1	117 (97 – 119)	>178
Meter No. X-2	88 (26 – 133)
Average	103 (71 – 126)
Pump Station No. 2X (Cell 2X)
Meter No. X-3	106 (104 – 109)	>180
Meter No. X-4	116 (93 – 119)
Average	111 (100 – 113)
Pump Station No. 3X (Cell 3X)
Meter No. X-5	111 (99 – 119)	> 175
Meter No. X-6	111 (99 – 119)
Average	111 (99 – 119)
Pump Station No. 4X (Cell 4X)
Meter No. X-7	109 (96 – 120)	> 186
Meter No. X-8	110 (98 – 120)
Average	109 (98 – 120)

Table 2.23 Summary of Effluent Quality Monitoring Results in the Reporting Period

Parameters		Monitoring Results	Limit Level
Effluent Discharged from LTP
Temperature	°C	26.5	> 43 °C
pH Value	pH unit	8.3	6 – 10
Volume Discharged	m³	1,003	>2,000 m³
Suspended Solids (SS)	mg/L	20.5	> 800 mg/L
Phosphate	mg/L	5.65	> 25 mg/L
Sulphate	mg/L	178	> 800 mg/L
Total Inorganic Nitrogen ^(a)	mg/L	54.99	> 100 mg/L
BOD	mg/L	12	> 800 mg/L
COD	mg/L	916	> 2,000 mg/L
Oil & Grease	mg/L	<5	> 20 mg/L
Boron	µg/L	6540	> 7,000 µg/L
Iron	mg/L	2.05	> 5 mg/L
Cadmium	µg/L	<1.0	> 1 µg/L
Chromium	µg/L	144	> 300 µg/L
Copper	µg/L	<10	> 1,000 µg/L
Nickel	µg/L	129	> 700 µg/L
Zinc	µg/L	28	> 700 µg/L
Note: (a) Total Inorganic Nitrogen include Ammoniacal-nitrogen, Nitrite-nitrogen and Nitrate-nitrogen.

All leachate levels and effluent quality monitoring results were below the Limit Levels in the reporting period. No action is thus required to be undertaken in accordance with the Event and Action Plan presented in Annex F3.

2.3.3 Groundwater Monitoring

2.3.3.1 Monitoring Requirements and Equipment

According to the updated EM&A Manual of the Project with incorporation of the proposed updates under the Amendment Summary approved by EPD on 15 June 2020, groundwater monitoring was carried out at 14 perimeter groundwater monitoring wells (including 3 up-gradient wells and 11 down-gradient wells) (i.e. MWX-1 to MWX-14) to monitor the groundwater quality and level of the perimeter groundwater monitoring wells at monthly interval.

The Limit Levels for groundwater quality is provided in Table 2.24 below.

Table 2.24 Limit Levels for Groundwater Quality

Location	Limit Levels
Location	Ammoniacal-nitrogen (mg L^-1)	COD (mg L^-1)
MWX-1	5.00	30
MWX-2	5.00	30
MWX-3	5.00	30
MWX-4	7.63	36
MWX-5	5.00	30
MWX-6	5.00	46
MWX-7	6.55	36
MWX-8	15.85	50
MWX-9	7.30	71
MWX-10	5.00	30
MWX-11	5.00	30
MWX-12	5.00	30
MWX-13	5.00	30
MWX-14	5.00	30

A bladder pump with Teflon sampling tube and adjustable discharge rates was used for purging and taking of groundwater sample from the monitoring wells. Filtered groundwater samples were collected by connecting a disposable in-line filter system to the tubing of the sampling pump, prior to storage and analysis by ALS Technichem (HK) Pty Ltd. (HOKLAS Registration No. 066). A portable dip meter with 5mm accuracy was used for measurement of groundwater level at each well. The dip meter has an audio indicator of the water level and was checked before use.

The measurements of pH and electrical conductivity (EC) were undertaken in situ. In situ monitoring instruments in compliance with the specifications listed under Section 4.3.2 of the updated EM&A Manual were used to undertake the groundwater quality monitoring for the Project. Details of the equipment used and the monitoring locations are summarised in Table 2.25 and illustrated in Figure 2.1, respectively. Copies of the calibration certificates for the equipment are presented in Annex F7.

Table 2.25 groundwater monitoirng details

Location

Frequency

Parameter

Monitoring Dates

Equipment

All groundwater monitoring wells (MWX-1 to MWX-14)

Monthly

· Water level

· pH

· EC

· COD

· BOD5

· TOC

· Ammoniacal–nitrogen

· Nitrate-nitrogen

· Nitrite–nitrogen

· TKN

· TN

· Sulphate

· Sulphide

· Carbonate

· Bicarbonate

· Phosphate

· Chloride

· Sodium

· Potassium

· Calcium

· Magnesium

· Nickel

· Manganese

· Chromium

· Cadmium

· Copper

· Lead

· Iron

· Zinc

· Mercury

· Boron

6 Jan 2025

Horiba U-52G (S/N: AWE7D2V4

2.3.3.2 Monitoring Schedule for the Reporting Month

The schedule for groundwater quality monitoring during the reporting period is provided in Annex C.

2.3.3.3 Results and Observations

The groundwater quality monitoring results and detailed monitoring results are summarised in Table 2.26 and provided in Annex F8, respectively.

Table 2.26 Summary of Groundwater Monitoring Results in the Reporting Period

Location	Ammoniacal-nitrogen (mg L^-1)		COD (mg L^-1)
Location	Monitoring Results	Limit Levels	Monitoring Results	Limit Levels
MWX-1	<0.01	5.00	5	30
MWX-2	0.06	5.00	5	30
MWX-3	1.47	5.00	21	30
MWX-4	2.87	7.63	19	36
MWX-5	0.48	5.00	16	30
MWX-6	3.49	5.00	42	46
MWX-7	4.91	6.55	48	36
MWX-8	4.18	15.85	33	50
MWX-9	0.38	7.30	<20	71
MWX-10	N/A ^(a)	5.00	N/A ^(a)	30
MWX-11	N/A ^(b)	5.00	N/A ^(b)	30
MWX-12	<0.01	5.00	5	30
MWX-13	<0.01	5.00	3	30
MWX-14	<0.01	5.00	4	30
Note: (a) Monitoring well MWX-10 is under maintenance. (b) Monitoring well MWX-11 is not accessible due to safety considerations.

Limit Level exceedances were recorded for groundwater monitoring in the reporting period and actions in accordance with the Event and Action Plan presented in Annex F3 were undertaken. The groundwater (COD) exceedances at MWX-7 on 6 January 2025 is under investigation.

2.4 Landfill Gas Monitoring

2.4.1 Monitoring Requirements

According to the updated EM&A Manual of the Project, landfill gas monitoring was carried out at the perimeter of the waste boundary (monitoring wells), area between the SENTX Site boundary and the waste boundary (surface emission), occupied on-site building, service voids, utilities pit and manholes in the vicinity of the SENTX (build-up of landfill gas) during the operation/restoration phase.

The Limit Levels for landfill gas monitoring is provided in Table 2.27 below.

Table 2.27 Limit Levels for Landfill Gas Constituents

Parameters	Monitoring Location	Limit Level (% (v/v))
Perimeter Landfill Gas Monitoring Wells ^(a)
Methane & Carbon Dioxide		Methane	Carbon Dioxide
	LFG1	1.0	3.2
	LFG2	1.0	4.3
	LFG3	1.0	6.3
	LFG4	1.0	7.0
	LFG5	1.0	3.4
	LFG6	1.0	9.1
	LFG7	1.0	1.5
	LFG8	12.6	2.4
	LFG9	2.5	1.7
	LFG10	3.5	1.6
	LFG11	3.0	2.0
	LFG12	13.2	1.5
	LFG13	22.5	2.7
	LFG14	5.2	1.8
	LFG15	18.2	2.0
	LFG16	1.0	2.0
	LFG17	17.8	2.4
	LFG18	2.3	2.1
	LFG19	6.3	3.1
	LFG20	1.0	4.6
	LFG21	1.0	4.8
	LFG22	1.0	4.0
	LFG23	1.0	10.3
	LFG24	1.0	4.7
	GP1	1.0	10.6
	GP2 (shallow)	1.0	11.4
	GP2 (deep)	1.0	10.4
	GP3 (shallow)	1.0	6.9
	GP3 (deep)	1.0	5.6
	GP4 (shallow)	1.0	11.6
	GP4 (deep)	1.0	7.7
	GP5 (shallow)	1.0	10.8
	GP5 (deep)	1.0	7.5
	GP6	1.0	8.4
	GP7	1.0	4.5
	GP12	1.0	2.3
	GP15	1.0	2.2
	P7	1.0	2.5
	P8	1.0	1.7
	P9	1.0	2.7
Service Voids, Utilities Pits and Manholes
Methane (or flammable gas)	Service voids, utilities pits and manholes	1% by volume
Permanent Gas Monitoring System
Methane (or flammable gas)	Permanent Gas Monitoring System	1% by volume (20% LEL)
Area Between the SENTX Site Boundary and Waste Boundary (Surface Emission)
Flammable gas	Area between SENTX site boundary and waste boundary	30 ppm
Note: (a) Limit Levels established based on the pre-operation phase baseline and additional landfill gas monitoring results in the Pre-operation Baseline Monitoring Report.

Gas analysers in compliance with the specifications listed under Section 5.4.1 of the updated EM&A Manual were used to monitor the gas parameters at the landfill gas monitoring wells, service voids, utilities pits and manholes. The gas analyser was calibrated by a laboratory accredited under HOKLAS at yearly intervals and checked before use to ensure the validity and accuracy of the results. A portable dip meter was used to monitor the water level in the monitoring wells.

Permanent gas monitoring systems with pre-set alarm levels for methane at 20% lower explosive limit (LEL, equivalent to 1% methane gas (v/v)) were installed and operated in all occupied on-site buildings at SENTX. A central control panel is equipped to alert site personnel when the gas concentration at any detector reaches the alarm level.

The equipment used in the landfill gas monitoring programme is summarised in Table 2.28. The landfill gas monitoring locations for perimeter landfill gas monitoring wells and service voids, utilities and manholes along the Site boundary are illustrated in Figure 2.3 and Annex G1, respectively. Copies of the calibration certificates for the equipment are presented in Annex G2.

Table 2.28 Landfill Gas Monitoring Details

Monitoring Location	Frequency	Parameter	Monitoring Dates	Equipment
Perimeter landfill gas monitoring wells (LFG1 to LFG24, P7 to P9, GP1 to GP7, GP12 and GP15)	Monthly	· Methane · Carbon dioxide · Oxygen · Atmospheric pressure	7 Jan 2025	GA5000 (S/N: G508090)
Service voids, utilities and manholes along the Site boundary and within the SENTX Site (UU1 to UU28)	Monthly	· Methane · Carbon dioxide · Oxygen	7 Jan 2025	GA5000 (S/N: G508090)
Permanent gas monitoring system in all occupied on-site buildings	Continuous	Methane (or flammable gas) by permanent gas monitoring system	1 – 31 Jan 2025	Permanent gas monitoring system
Areas between the SENTX Site boundary and the waste boundary and location of vegetation stress	Quarterly	Flammable gas emitted from the ground surface	-	-
Bulk gas sampling at least 2 of the perimeters LFG monitoring wells	Quarterly	· Methane · Carbon dioxide · Oxygen · Nitrogen · Carbon monoxide · Other flammable gas	-	Gas sampling pump and Tedlar bags

2.4.2 Monitoring Schedule for the Reporting Month

The schedule for landfill gas monitoring during the reporting period is provided in Annex C.

2.4.3 Results and Observations

The landfill gas monitoring results are summarised and provided in Tables 2.29 - 2.30 and Annex G3, respectively.

Table 2.29 Summary of Landfill Gas Monitoring Results at Perimeter LFG Monitoring Wells in the Reporting Period

Location	Methane (% (v/v))		Carbon Dioxide (% (v/v))
Location	Monitoring Results	Limit Levels ^(a)	Monitoring Results	Limit Levels ^(a)
LFG1	0.0	1.0	0.1	3.2
LFG2	0.0	1.0	0.2	4.3
LFG3	0.0	1.0	1.6	6.3
LFG4	0.0	1.0	0.1	7.0
LFG5	0.0	1.0	0.1	3.4
LFG6	0.0	1.0	0.1	9.1
LFG7	0.0	1.0	0.1	1.5
LFG8	0.0	12.6	0.1	2.4
LFG9	0.0	2.5	0.1	1.7
LFG10	0.0	3.5	0.1	1.6
LFG11	0.0	3.0	0.2	2.0
LFG12	0.0	13.2	0.5	1.5
LFG13	0.0	22.5	0.1	2.7
LFG14	0.0	5.2	0.1	1.8
LFG15	0.0	18.2	0.1	2.0
LFG16	0.0	1.0	1.6	2.0
LFG17	0.0	17.8	0.3	2.4
LFG18	0.0	2.3	1.8	2.1
LFG19	0.0	6.3	0.1	3.1
LFG20	0.0	1.0	0.2	4.6
LFG21	0.0	1.0	0.3	4.8
LFG22 ^(b)	N/A	1.0	N/A	4.0
LFG23	0.0	1.0	0.1	10.3
LFG24	0.0	1.0	0.1	4.7
GP1	0.0	1.0	7.0	10.6
GP2 (shallow)	0.0	1.0	0.5	11.4
GP2 (deep)	0.0	1.0	0.1	10.4
GP3 (shallow)	0.0	1.0	0.1	6.9
GP3 (deep)	0.0	1.0	0.1	5.6
GP4 (shallow)	0.0	1.0	0.5	11.6
GP4 (deep)	0.0	1.0	0.7	7.7
GP5 (shallow)	0.0	1.0	0.1	10.8
GP5 (deep)	0.0	1.0	0.2	7.5
GP6	0.1	1.0	0.4	8.4
GP7	0.0	1.0	1.2	4.5
GP12	0.0	1.0	0.2	2.3
GP15	0.0	1.0	0.2	2.2
P7	0.0	1.0	0.4	2.5
P8	0.0	1.0	0.2	1.7
P9	0.0	1.0	0.2	2.7
Notes: (a) Limit Levels established based on the pre-operation phase baseline and additional landfill gas monitoring results in the Pre-operation Baseline Monitoring Report. (b) Monitoring well LFG22 is not accessible due to safety considerations.

Table 2.30 Summary of Landfill Gas Monitoring Results at Service Voids, Utilities Pits and Manholes in the Reporting Period

Location	Methane (% (v/v))
Location	Monitoring Results	Limit Levels
UU01	0.0	1.0
UU02	0.0	1.0
UU03	Voided due to latest site programme and on-going operation work	1.0
UU04	0.0	1.0
UU05	0.0	1.0
UU06	0.0	1.0
UU07	0.0	1.0
UU08	0.0	1.0
UU09	0.0	1.0
UU10	0.0	1.0
UU11	0.0	1.0
UU12	Voided due to latest site programme and on-going operation work	1.0
UU13	0.0	1.0
UU14	0.0	1.0
UU15	0.0	1.0
UU16	0.0	1.0
UU17	Voided due to latest site programme and on-going operation work	1.0
UU18	Voided due to latest site programme and on-going operation work	1.0
UU19	Voided due to latest site programme and on-going operation work	1.0
UU20	0.0	1.0
UU21	0.0	1.0
UU22	0.0	1.0
UU23	0.0	1.0
UU24	0.0	1.0
UU25	0.0	1.0
UU26	0.0	1.0
UU27	0.0	1.0
UU28	0.0	1.0

The alarm of the permanent gas monitoring systems with pre-set levels for methane at 20% lower explosive limit (LEL, equivalent to 1% methane gas (v/v)) was not triggered at all occupied on-site buildings at SENTX in January 2025.

All the landfill gas monitoring results were below the Limit Levels in the reporting period. No action is thus required to be undertaken in accordance with the Event and Action Plan presented in Annex G4.

2.5 LANDSCAPE AND VISUAL Monitoring

2.5.1 Monitoring Requirements

According to the updated EM&A Manual of the Project, the monthly landscape and visual audit was conducted on 8 January 2025 to monitor the implementation of the landscape and visual mitigation measures during operation/ restoration phase.

All relevant environmental mitigation measures listed in the approved EIA Report and the updated EM&A Manual and their implementation status are summarized in Annex B.

2.5.2 Results and Observations

The Contractor has implemented environmental mitigation measures as stated in the approved EIA Report and the EM&A Manual.

Regarding the landscape and visual audit, the Contractor was reminded to maintain the advance screen planting works regularly to ensure effective screening of views of project works from the High Junk Peak Trail.

2.6 EM&A Site Inspection

Site inspections were carried out on a weekly basis with the Contractor, IEC and EPD to monitor the implementation of proper environmental pollution control and mitigation measures under the Project. In the reporting period, 5 site inspections were carried out on 2, 9, 16, 22 and 27 January 2025.

Key observations during the site inspections are summarised in Table 2.31.

Table 2.31 Key Observations Identified during the Site Inspection in this Reporting Month

Inspection Date	Environmental Observations and Recommendations
2 January 2025	· No observations during the site inspection
9 January 2025	· The Contractor shall remove the general refuse accumulated at DP3 sediment pit to ensure it is functioning properly at all times. · The Contractor shall remove the general refuse accumulated at X10 channel to ensure it is functioning properly at all times.
16 January 2025	· No observations during the site inspection.
22 January 2025	· No observations during the site inspection.
27 January 2025	· The Contractor shall remove the general refuse accumulated at DP3 sediment pit to ensure it is functioning properly at all times. · The Contractor shall remove the general refuse accumulated at DP4 outlet to ensure it is functioning properly at all times.

The Contractor has rectified all the observations identified during environmental site inspections in the reporting period. Key environmental deficiencies identified and the corresponding rectification actions are presented in Table 2.32.

Table 2.32 Summary of Environmental Deficiencies Identified and Corresponding Rectification Actions

Deficiencies	Rectifications Implemented	Proposed Additional Control Measures
Surface Water
Intercepting channels & drainage system	· Reviewed drainage plan.	· Addition of channels. · Expedite the construction of permanent sediment trap and discharge culverts.
DP channels (design & regular silt removal)	· Carried out regular maintenance and cleaning of channels. · DP4 channel: Area near the channel was paved with concrete and a bund was built. · DP6 channel: Gravel piles on the channel were covered with concrete which serve as blocks for running water and to divide the channel into several sections. A pump was placed in the water zone in the upstream section to pump water to the Wetsep for treatment prior to the discharge to the last section before the weir plate. · DP6: Pipes through the gravel piles between different channel sections were covered with geotextiles to block debris and silt.	N.A.
Stockpiles & exposed soil	· Installed silt fencing near surface water channel along DP6 channel.	· Improve soil covering. · Compaction and cover for stockpiles and soil slopes.
Wetsep (treatment capacity & number)	· Reviewed Wetsep capacity. · Chemicals dosage of the Wetsep was increased to enhance the efficiency.	· Install additional Wetsep.
Backflow / ponding during heavy rainfall	· Raised with EPD (LDG) and CEDD.	N.A.

2.7 Waste Management Status

The Contractor has registered as chemical waste producer under the Contract. Sufficient numbers of receptacles were available for general refuse collection and sorting.

As informed by the Contractor, waste generated during this reporting period include mainly inert construction waste. Reference has been made to the waste flow table prepared by the Contractor. The quantities of different types of wastes and imported fill materials are summarized in Table 2.33.

Table 2.33 Quantities of Different Waste Generated and Imported Fill Materials

Month/Year	Inert C&D Materials ^(a) (in ‘000m³)	Imported Fill (in ‘000kg)^(b)	Inert Construction Waste Re-used (in ‘000m³)	Non-inert Construction Waste ^(c) (in ‘000m³)	Recyclable Materials ^(d) (in ‘000kg)	Yard Waste (in ‘000kg)		Chemical Wastes (in ‘000kg)
						Y Park	SENT
1 – 31 Jan 25	202.42	0	0	0	0	0	0	0.80
Notes: (a) Inert construction wastes include hard rock and large broken concrete, and materials disposed as public fill. Density assumption: 1.6 (kg/L) for public fill. (b) Imported fill refers to materials generated from other project for on-site reuse. (c) Non-inert construction wastes include general refuse disposed at landfill. Density assumption: 0.9 (kg/L) for general refuse. (d) Recyclable materials include metals, paper, cardboard, plastics and others.

2.8 IMPLEMENTATION STATUS OF ENVIRONMENTAL MITIGATION MEASURES

A summary of the Environmental Mitigation Implementation Schedule is presented in Annex B. The necessary mitigation measures were implemented properly for the Project.

2.9 Summary of Exceedances of the Environmental Quality Performance Limit

The operation/ restoration phase noise and landfill gas monitoring results complied with the Action and Limit Levels in the reporting period.

Two exceedances of the Limit Levels for Total Suspended Particulates (TSP) and one exceedance of the Limit Levels for groundwater (COD) were recorded in the reporting period. The TSP exceedances at AM2 on 14 January and 20 January 2025 were deemed to Project-related activities upon further investigation. The groundwater (COD) exceedances at MWX-7 on 6 January 2025 is under investigation.

Cumulative statistics on exceedances is provided in Annex H.

2.10 Summary of Complaints, Notification of Summons and Successful Prosecutions

There were no complaints, notification of summons or prosecution recorded in the reporting period.

Statistics on complaints, notifications of summons, successful prosecutions are summarised in Annex H.

3. Future Key Issues

3.1 Construction Programme for the Coming Month

As informed by the Contractor, the major works for the Project in February 2025 will be:

• Maintenance and improvement of temporary surface water drainage; and

• Restoration of Phase 1 and Phase 2 slopes.

3.2 KEY ISSUES FOR THE COMING MONTH

Potential environmental impacts arising from the above upcoming construction activities in the next reporting period of February 2025 are mainly associated with dust emission from the exposed area and loading and unloading operation of dusty materials.

3.3 MONITORING SCHEDULE FOR THE COMING MONTH

The tentative schedule for environmental monitoring in February 2025 is provided in Annex I.

4. CONCLUSION AND RECOMMENDATION

This EM&A Report presents the findings of the EM&A activities undertaken during the period from 1 to 31 January 2025 in accordance with the updated EM&A Manual and the requirements of the Environmental Permit (EP-308/2008/C).

Air quality (24-hour TSP, odour, thermal oxidiser, landfill gas flare and landfill gas generator stack emission), noise, water quality (surface water, leachate and groundwater) and landfill gas monitoring were carried out in the reporting period. Results for air quality (odour, thermal oxidizer, landfill gas flare and landfill gas generator), noise, water quality (surface water and leachate) and landfill gas monitoring complied with the Action and Limit Levels in the reporting period.

Two exceedances of the Limit Levels for Total Suspended Particulates (TSP) and one exceedance of the Limit Levels for groundwater (COD) were recorded in the reporting period.

Environmental site inspections were carried out during the reporting period. Recommendations on remedial actions were given to the Contractor for the deficiencies identified during the site inspections.

There were no complaints, notification of summons or prosecution recorded in the reporting period.

The ET will keep track on the construction and operation/restoration works to confirm compliance of environmental requirements and the proper implementation of all necessary mitigation measures.

([1]) ERM (2018). South East New Territories (SENT) Landfill Extension: Environmental Monitoring & Audit Manual

([2]) ERM (2007). South East New Territories (SENT) Landfill Extension – Feasibility Study: Environmental Impact Assessment Report