Contents

Executive Summary

1 Introduction

1.1 Background

1.2 Project Description

1.3 Scope of the EM&A Report

1.4 Project Organisation

1.5 Summary of Construction Works

1.6 Summary of EM&A Programme Requirements

1.7 Status of Statutory Environmental Compliance with the Environmental Permit

1.8 Status of Other Statutory Environmental Requirements

2 EM&A Results

2.1 Air Quality Monitoring

2.2 Noise Monitoring

2.3 Water Quality Monitoring

2.4 Landfill Gas Monitoring

2.5 Landscape and Visual Monitoring

2.6 EM&A Site Inspection

2.7 Waste Management Status

2.8 Implementation Status of Environmental Mitigation Measures

2.9 Summary of Exceedances of the Environmental Quality Performance Limit

2.10 Summary of Complaints, Notification of Summons and Successful Prosecutions

3 Future Key Issues

3.1 Construction Programme for the Coming Month

3.2 Key Issues for the Coming Month

3.3 Monitoring Schedule for the Coming Month

4 Conclusion and Recommendation

 


 

Annexes

Annex A Work Programme

Annex B Environmental Mitigation Implementation Schedule

Annex C Monitoring Schedule for This Reporting Period

Annex D Air Quality
Annex D1 Calibration Certificates for Dust Monitoring Equipment
Annex D2 24-hour TSP Monitoring Results
Annex D3 Event and Action Plan for Dust Monitoring
Annex D4 Meteorological Data

Annex D5 Certificates of the Qualified Odour Panelist

Annex D6 Odour Monitoring Results

Annex D7 Thermal Oxidizer, Landfill Gas Flare and Landfill Gas Generator Stack Emission Monitoring Results

Annex D8 Investigation Reports of Environmental Quality Limit Exceedance

Annex E Noise
Annex E1 Calibration Certificates for Noise Monitoring Equipment
Annex E2 Noise Monitoring Results
Annex E3 Event and Action Plan for Noise Monitoring

Annex F Water Quality
Annex F1 Calibration Certificates for Surface Water Quality Monitoring Equipment
Annex F2 Surface Water Quality Monitoring Results
Annex F3 Event and Action Plan for Surface Water Quality Monitoring

Annex F4 Calibration Certificates for Effluent Quality Monitoring Equipment

Annex F5 Leachate Levels Monitoring Results

Annex F6 Effluent Quality Monitoring Results

Annex F7 Calibration Certificates for Groundwater Monitoring Equipment

Annex F8 Groundwater Monitoring Results

Annex F9 Investigation Reports of Environmental Quality Limit Exceedance

Annex G Landfill Gas
Annex G1 Landfill Gas Monitoring Locations for Service Voids, Utilities and Manholes Along the Site Boundary and Within the SENTX Site

Annex G2 Calibration Certificates for Landfill Gas Monitoring Equipment
Annex G3 Landfill Gas Monitoring Results
Annex G4 Event and Action Plan for Landfill Gas Monitoring

Annex H Cumulative Statistics on Exceedances, Environmental Complaints, Notification of Summons and Status of Prosecutions

Annex I Monitoring Schedule for the Next Reporting Period

 

 

Executive Summary

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. ERM-Hong Kong, Limited (ERM) is commissioned to undertake the role of Environmental Team (ET) for the construction, operation/restoration and aftercare of SENTX Project (the Project) in accordance with the requirements specified in the Environmental Permit (EP), updated Environmental Monitoring and Audit (EM&A) Manual, the approved Environmental Impact Assessment (EIA) Report of the Project taking account of the latest design and other relevant statutory requirements. The construction (not including works related to site clearance and preparation) and operation of the Project commenced on 2 January 2019 and 21 November 2021, respectively.

This Monthly EM&A report presents the EM&A works carried out during the period from 1 to 31 December 2021 for the Project in accordance with the updated EM&A Manual.

Exceedance of Action and Limit Levels for Air Quality

One exceedance of the Limit Level for Total Suspended Particulates (TSP) and one exceedance of the Limit Level for landfill gas flare stack emission (Carbon Monoxide (CO)) were recorded for air quality impact monitoring in the reporting period.  The TSP exceedance at AM4 on 13 December 2021 was considered non Project-related upon further investigation. The landfill gas flare stack emission (CO) exceedance on 17 December 2021 was found to be Project-related.

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 Level for groundwater (Chemical Oxygen Demand (COD)) was recorded for water quality impact monitoring in the reporting period.  The groundwater (COD) exceedance at MWX-6 on 8 December 2021 was considered non Project-related upon further 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 January 2022 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 SENTXs contractor, Green Valley Landfill, Limited (GVL).

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

2057

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 December 2021 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

 

 

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

Gary Barnicott

2706 8827

Environmental Team (ET) (ERM-Hong Kong, Limited)

 

ET Leader

Frank Wan

2271 3152

Independent Environmental Checker (IEC)

(Meinhardt Infrastructure and Environment Limited)

 

IEC

W.K. Chiu

2858 0738

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:

           Follow up on civil provision work defects at Landfill Gas (LFG) Plant, Leachate Treatment Plant (LTP), infrastructure area and waste reception area;

           Construction of MSE wall;

           Site formation for Cell 4X;

           Liner works at Cell 4X; and

           Maintenance and improvement of temporary surface water drainage.

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 summarised as below:

Ÿ   One environmental management meeting was held with the Contractor, ER, ET, IEC and EPD on 16 December 2021; and

Ÿ   Environmental toolbox trainings on Noise Control Ordinance and Air Pollution Control (NRMM) Regulation were provided on 8 December and 22 December 2021 respectively 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

Further Environmental Permit

FEP-01/308/2008/B

Granted on 16 May 2018

Water Discharge License under WPCO (Permit Holder: Chun Wo)

Licence No.: WT00033525-2019

Validity from 27 March 2019 to 31 March 2024

Water Discharge License under WPCO (Permit Holder: GVL)

Licence No.: WT00036269-2020

Validity from 21 June 2020 to 30 June 2022

Billing Account for Disposal of Construction Waste

Chit Account Number: 5001692

Approved on 28 December 2005

Registration as a Chemical Waste Producer (Permit Holder: Chun Wo)

5213-839-C3507-10

Issued on 23 August 2018

Registration as a Chemical Waste Producer (Permit Holder: REC)

5518-839-R2289-06

Issued on 24 October 2019

Construction Noise Permit (Permit Holder: GVL)

GW-RE0990-21

Validity from 6 October 2021 to 5 April 2022

Construction Noise Permit (Permit Holder: Chun Wo)

GW-RE0564-21

Validity from 7 June 2021 to 6 December 2021

Construction Noise Permit (Permit Holder: Paul Y.)

GW-RE1138-21

Validity from 16 November 2021 to 15 February 2022

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

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 g m-

260 g m-

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

1, 7, 13, 19, 25, 31 Dec 2021

Tisch TE-5170 (S/N: 1190)

AM2

SENTX Site Boundary (West, near DP3)

Tisch TE-5170 (S/N: 1047)

AM3

SENTX Site Boundary (West, near RC15)

Tisch TE-5170 (S/N: 1258)

AM4

SENTX Site Boundary (West, near EPD building)

Tisch TE-5170 (S/N: 1101)

Monitoring Schedule for the Reporting Month

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

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

Average 24-hr TSP Concentration (g m-3) (Range in bracket)

Action Level (g/m3)

Limit Level (g/m3)

AM1 - SENTX Site Boundary (North)

112 (57 173)

260

260

AM2 - SENTX Site Boundary (West, near DP3)

129 (100 156)

260

260

AM3 - SENTX Site Boundary (West, near RC15)

182 (128 258)

260

260

AM4 - SENTX Site Boundary (West, near EPD building)

168 (102 282)

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 SENTX and the TKO Area 137 Fill Bank.

Action and Limit Levels exceedance was 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 exceedance was conducted and the investigation report is presented in Annex D8.

Based on the investigation conducted for the monitoring event with potential Action and Limit Levels exceedance with the Contractor and the IEC, the TSP exceedance at AM4 on 13 December 2021 was considered non Project-related.  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 Contractors compliance of the environmental requirements.

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

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.

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 and Time

Patrol along the SENTX Site Boundary (Checkpoints OP1 OP11 (d))

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:

1 31 Dec 2021

(10:30 12:00, 14:30 16:00, 18:00 19:30)

 

Conducted by an independent third party, ET & IEC:

1 Dec 2021 (14:30 16:00), 3 Dec 2021 (10:00 12:00), 6 Dec 2021 (14:30 16:00), 8 Dec 2021 (10:00 12:00), 10 Dec 2021 (10:00 12:00), 13 Dec 2021 (10:00 12:00), 15 Dec 2021 (10:00 12:00), 17 Dec 2021 (14:30 16:00), 20 Dec 2021 (10:00 12:00), 22 Dec 2021 (14:30 16:00), 24 Dec 2021 (14:30 16:00), 28 Dec 2021 (14:30 16:00), 29 Dec 2021 (10:00 12:00), 31 Dec 2021 (14:30 16:00)

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.

(d)    The revised odour patrol route with the addition of checkpoint OP11 was applied from 10 December 2021.

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

Monitoring Schedule for the Reporting Month

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

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 (Range)

Action Level

Limit Level

OP1

0 1

Odour intensity ≥ Class 2 recorded

Odour intensity ≥ Class 3 recorded on 2 consecutive patrol

OP2

0 1

OP3

0 1

OP4

0 1

OP5

0 1

OP6

0 1

OP7

0 1

OP8

0 1

OP9

0 1

OP10

0

OP11

0 1

 

 

The potential odour sources in the reporting period included the construction works, operation of leachate treatment plant, generator, slurry truck, excavator, vehicles and vegetation at SENTX, as well as nearby operations of the Town Gas 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

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. 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

850oC (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

815oC (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

450oC (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

20 Dec 2021

     Gas combustion temperature

     Exhaust temperature

     Exhaust gas velocity (a)

Continuously

1 31 Dec 2021

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

17 Dec 2021

     Gas combustion temperature

     Exhaust temperature

     Exhaust gas velocity (a)

Continuously

1 31 Dec 2021

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

17 Dec 2021

     Exhaust temperature

     Exhaust gas velocity (a)

Continuously

1 31 Dec 2021

Note:

(a) The exhaust gas velocity will be calculated based on the cross-section area of the stack and continuous monitored gas flow and combustion temperature data.

 

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.

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

0.38 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 x 10-5 gs-1

3.01 x 10-2 gs-1

Vinyl chloride

<2 x 10-5 gs-1

2.23 x 10-3 gs-1

Gas combustion temperature

943oC (932oC - 984oC)

850oC (minimum)

Exhaust gas exit temperature

1,237K (1,219K 1,316K)

443K (minimum) (a)

Exhaust gas velocity

15.3 (b)

7.5 ms-1 (minimum) (a)

Note:

(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. The limit level was not applicable as the stack was not operated under full load condition.

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

Parameters

Monitoring Results (Range in Bracket)

Limit Level

NO2

<0.02 gs-1

0.97 gs-1

CO

2.81 gs-1

2.43 gs-1

SO2

0.11 gs-1

0.22 gs-1

Benzene

9.9 x 10-5 gs-1

4.14 x 10-4 gs-1

Vinyl chloride

<1.4 x 10-5 gs-1

2.60 x 10-4 gs-1

Gas combustion temperature

Flare 1: 864oC (820oC - 935oC)

Flare 2: 853oC (820oC - 894oC)

815oC (minimum)

Exhaust gas exit temperature

Flare 1: 1,059K (1,025K 1,115K)

Flare 2: 1,027K (944K 1,097K)

923 K (minimum) (a)

Exhaust gas velocity

9.1 (b)

9.0 m s-1 (minimum) (a)

Note:

(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. The limit level was not applicable as the stack was not operated under full load condition.

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

Parameters

Monitoring Results (Range in Bracket)

Limit Level

NO2

0.007 gs-1

1.91 gs-1

CO

0.046 gs-1

2.48 gs-1

SO2

0.074 gs-1

0.528 gs-1

Benzene

4 x 10-6 gs-1

2.47 x 10-4 gs-1

Vinyl chloride

<1.2 x 10-6 gs-1

1.88 x 10-5 gs-1

Exhaust gas exit temperature

838K (748K 847K)

723K (minimum) (a)

Exhaust gas velocity

17.6 (b)

30.0 ms-1 (minimum) (a)

Note:

(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. The limit level was not applicable as the stack was not operated under full load condition.

Limit Levels exceedance was recorded for landfill gas flare stack emission (CO) in the reporting period and actions in accordance with the Event and Action Plan presented in Annex D3 were undertaken. Investigation of the Limit Levels exceedance was conducted and the investigation report is presented in Annex D8.

Based on the investigation conducted for the monitoring event with potential Limit Levels exceedance with the Contractor and the IEC, the landfill gas flare stack emission (CO) exceedance on 17 December 2021 was found to be Project-related. 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 Contractors compliance of the environmental requirements.

2.2                               Noise Monitoring

2.2.1                          Monitoring Requirements and Equipment

According to the updated EM&A Manual of the Project, impact noise monitoring was conducted weekly at the monitoring location (i.e. NM1) to obtain one set of 30 minutes 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 (1)

Location

Parameter

Frequency and Duration

Monitoring Dates

Equipment

NM1

SENTX Site Boundary (North)

Leq (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

2, 9, 14, 22, 28 Dec 2021

Sound Level Meter:

B&K 2238 (S/N: 2285722)

 

Rion NL-52 (S/N: 00921191)

 

Acoustic Calibrator:

Rion NC-74 (S/N: 34246492)

Rion NC-73 (S/N: 10655561)

 

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 5 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

Monitoring Station

Measured Noise Level Leq (30 min), dB(A)

Average

Range

Action and Limit Level

NM1

49.9

47.0 51.1

75

Major noise sources identified during the noise monitoring included noise from operations of the SENTX and the TKO Area 137 Fill Bank, aircrafts and 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

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. Temporary relocation of surface water discharge point DP4 to DP4 (Future, temporary) as an interim arrangement due to site constraints and construction sequence was approved by EPD on 14 May 2019. Surface water quality monitoring was carried out at DP4 (Future, temporary) (i.e. DP4T) from the monitoring event on 16 May 2019. In addition, suspension of impact surface water quality monitoring at DP3 was approved under the Baseline Monitoring Report by EPD on 24 July 2019 until the actual commencement of construction works affecting DP3 in 2021.

The level of Ammoniacal-nitrogen, chemical oxygen demand (COD) and suspended solids (SS) 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

DP4 & DP6

 

Ammoniacal-nitrogen

> 7.1 mg/L

COD

> 30 mg/L

SS

> 20 mg/L

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

DP4 (Future, temporary)

Surface water discharge point DP4

Monthly

28 Dec 2021

    pH

    Electrical conductivity (EC)

    DO

    SS

    COD

    BOD5

    TOC

    Ammoniacalnitrogen

    Nitrate-nitrogen

    Nitritenitrogen

    TKN

    TN

    Phosphate

    Sulphate

    Sulphide

    Carbonate

    Oil & Grease

 

    Bicarbonate

    Chloride

    Sodium

    Potassium

    Calcium

    Magnesium

    Nickel

    Manganese

    Chromium

    Cadmium

    Copper

    Lead

    Iron

    Zinc

    Mercury

    Boron

 

YSI Professional DSS (S/N: 17B102764)

 

DP6

Surface water discharge point DP6

Notes:

(a)    DP4 was temporary relocated to DP4 (Future, temporary) (i.e. DP4T) as an interim discharge point from the monitoring event on 16 May 2019.

(b)    Impact surface water quality monitoring at DP3 was suspended from the monitoring event on 25 July 2019 until the actual commencement of construction works affecting DP3 in 2021.

Monitoring Schedule for the Reporting Month

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

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 28 December 2021 due to insufficient flow. Details of impact water quality monitoring event are provided in Annex F2.

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

Monitoring Requirements and Equipment

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

Temperature, pH and volume of the effluent discharged from the leachate treatment plant were measured in-situ whereas the parameters as listed in Table 2.19 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

>1,500 m

Suspended Solids (SS)

> 800 mg/L

Ammoniacal-nitrogen

> 100 mg/L

Nitrite-nitrogen

> 100 mg/L

Phosphate

> 25 mg/L

Sulphate

> 900 mg/L

Nitrate-nitrogen

> 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 g/L

Iron

> 7.5 mg/L

Cadmium

> 1 g/L

Chromium

> 400 g/L

Copper

> 1,000 g/L

Nickel

> 800 g/L

Zinc

> 800 g/L

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 Dec 2021

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

    Ammoniacalnitrogen

    Nitrate-nitrogen

    Nitritenitrogen

    Total Nitrogen

    Sulphate

    Phosphate

    Oil & Grease

    Alkalinity

    Chloride

    Calcium

    Potassium

    Magnesium

    Iron

    Zinc

    Copper

    Chromium

    Nickel

    Cadmium

    Boron

 

1 31 Dec 2021

Lutron WA-2017SD (S/N: T.016811)

 

 

 

 

Note:

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

Monitoring Schedule for the Reporting Month

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

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

65 (44 111)

> 178

Meter No. X-2

78 (10 111)

 

Average

71 (48 101)

 

Pump Station No. 2X (Cell 2X)

Meter No. X-1

81 (70 88)

> 180

Meter No. X-2

82 (73 88)

 

Average

81 (72 87)

 

Pump Station No. 3X (Cell 3X)

Meter No. X-1

89 (79 99)

> 175

Meter No. X-2

89 (79 99)

 

Average

89 (79 89)

 

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

Parameters

Average Monitoring Results (Range in Bracket)

Limit Level

Effluent Discharged from LTP

Temperature

25.7C (20.0C 30.6C)

> 43 C

pH Value

8.4 (8.3 8.5)

6 10

Volume Discharged

1,025m (473m - 1,435m)

>1,500 m

Suspended Solids (SS)

20.0mg/L (10.1mg/L - 33.8mg/L)

> 800 mg/L

Ammoniacal-nitrogen

0.34mg/L (0.15mg/L 0.75mg/L)

> 100 mg/L

Nitrite-nitrogen

0.24mg/L (0.14mg/L 0.70mg/L)

> 100 mg/L

Phosphate

10.0mg/L (7.7mg/L 11.5mg/L)

> 25 mg/L

Sulphate

68mg/L (57mg/L 92mg/L)

> 900 mg/L

Nitrate-nitrogen

62.0mg/L (42.4mg/L 80.3mg/L)

> 100 mg/L

BOD

10mg/L (6mg/L 24mg/L)

> 800 mg/L

COD

987mg/L (785mg/L 1,430mg/L)

> 2,000 mg/L

Oil & Grease

<5mg/L (<5mg/L <5mg/L)

> 20 mg/L

Boron

5,143g/L (4,530g/L 6,050g/L)

> 7,000 g/L

Iron

1.44mg/L (1.21mg/L 1.74mg/L)

> 7.5 mg/L

Cadmium

<1.0g/L (<1.0g/L <1.0g/L)

> 1 g/L

Chromium

129g/L (112g/L 146g/L)

> 400 g/L

Copper

43g/L (24g/L 61g/L)

> 1,000 g/L

Nickel

114g/L (98g/L 124g/L)

> 800 g/L

Zinc

57g/L (40g/L 100g/L)

> 800 g/L

All the 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

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 5 up-gradient wells and 9 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

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 was 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 have 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 Monitoring Details

Monitoring Location

Frequency

Parameter

Monitoring Dates

Equipment

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

Monthly

   Water level

   pH

   EC

   COD

   BOD5

   TOC

   Ammoniacalnitrogen

   Nitrate-nitrogen

   Nitritenitrogen

   TKN

   TN

   Sulphate

   Sulphide

   Carbonate

   Bicarbonate

   Phosphate

   Chloride

   Sodium

   Potassium

   Calcium

   Magnesium

   Nickel

   Manganese

   Chromium

   Cadmium

   Copper

   Lead

   Iron

   Zinc

   Mercury

   Boron

7-8 Dec 2021

YSI Professional DSS (S/N: 17B102764)

Monitoring Schedule for the Reporting Month

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

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)

Monitoring Results

Limit Levels

Monitoring Results

Limit Levels

MWX-1

0.29

5.00

11

30

MWX-2

0.02

5.00

3

30

MWX-3

1.33

5.00

19

30

MWX-4

6.79

7.63

36

36

MWX-5

1.95

5.00

28

30

MWX-6

3.52

5.00

56

46

MWX-7

5.42

6.55

23

36

MWX-8

12.50

15.85

44

50

MWX-9

5.34

7.30

20

71

MWX-10

0.03

5.00

6

30

MWX-11

0.02

5.00

4

30

MWX-12

<0.01

5.00

<2

30

MWX-13

0.04

5.00

<2

30

MWX-14

<0.01

5.00

<2

30

Limit Levels exceedance was recorded for groundwater monitoring in the reporting period and actions in accordance with the Event and Action Plan presented in Annex F3 were undertaken. Investigation of the Limit Levels exceedance was conducted and the investigation report is presented in Annex F9.

Based on the investigation conducted for the monitoring event with potential Limit Levels exceedance with the Contractor and the IEC, the groundwater quality (COD) exceedance at MWX-6 on 8 December 2021 was considered non Project-related.  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 Contractors compliance of the environmental requirements.

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

2.2

 

LFG2

1.0

4.2

 

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

1.0

1.7

 

LFG9

2.5

1.7

 

LFG10

1.0

1.6

 

LFG11

3.0

2.0

 

LFG12

13.2

1.5

 

LFG13

22.5

2.7

 

LFG14

1.0

1.6

 

LFG15

18.2

2.0

 

LFG16

1.0

1.7

 

LFG17

10.5

2.1

 

LFG18

2.3

1.9

 

LFG19

6.3

3.1

 

LFG20

1.0

4.2

 

LFG21

1.0

4.3

 

LFG22

1.0

3.9

 

LFG23

1.0

10.3

 

LFG24

1.0

4.0

 

GP1

1.0

8.5

 

GP2 (shallow)

1.0

11.4

 

GP2 (deep)

1.0

10.4

 

GP3 (shallow)

1.0

3.9

 

GP3 (deep)

1.0

1.9

 

GP4 (shallow)

1.0

2.3

 

GP4 (deep)

1.0

5.6

 

GP5 (shallow)

1.0

9.5

 

GP5 (deep)

1.0

7.5

 

GP6

1.0

7.8

 

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)

Notes:

(a)     Provisional 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 and within the SENTX site 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

Ÿ  Methane

Ÿ  Carbon dioxide

Ÿ  Oxygen

Ÿ  Atmospheric pressure

14 Dec 2021

GA5000 (S/N: G507306)

Service voids, utilities and manholes along the Site boundary and within the SENTX Site (UU1 to UU28)

Monthly

Ÿ  Methane

Ÿ  Carbon dioxide

Ÿ  Oxygen

16 Dec 2021

GA5000 (S/N: G507306)

Permanent gas monitoring system in all occupied on-site buildings

Continuous

Ÿ  Methane (or flammable gas) by permanent gas monitoring system

1 31 Dec 2021

Permanent gas monitoring system

Monitoring Schedule for the Reporting Month

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

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))

Monitoring Results

Limit Levels (a)

Monitoring Results

Limit Levels (a)

LFG1

0.0

1.0

0.1

2.2

LFG2

0.0

1.0

0.1

4.2

LFG3

0.0

1.0

0.9

6.3

LFG4

0.0

1.0

0.0

7.0

LFG5

0.0

1.0

0.2

3.4

LFG6

0.0

1.0

0.1

9.1

LFG7

0.0

1.0

0.0

1.5

LFG8

0.0

1.0

0.0

1.7

LFG9

0.0

2.5

0.1

1.7

LFG10

0.0

1.0

0.0

1.6

LFG11

0.0

3.0

0.1

2.0

LFG12

0.0

13.2

0.0

1.5

LFG13

19.6

22.5

0.0

2.7

LFG14

0.0

1.0

0.0

1.6

LFG15

1.8

18.2

0.4

2.0

LFG16

0.0

1.0

0.1

1.7

LFG17

0.0

10.5

0.2

2.1

LFG18

0.0

2.3

0.1

1.9

LFG19

0.0

6.3

0.1

3.1

LFG20

0.0

1.0

1.1

4.2

LFG21

0.0

1.0

2.0

4.3

LFG22

0.0

1.0

1.0

3.9

LFG23

0.0

1.0

2.1

10.3

LFG24

0.0

1.0

0.9

4.0

GP1

0.2

1.0

5.2

8.5

GP2 (shallow)

0.5

1.0

0.3

11.4

GP2 (deep)

0.2

1.0

0.1

10.4

GP3 (shallow)

0.3

1.0

2.5

3.9

GP3 (deep)

0.1

1.0

0.2

1.9

GP4 (shallow)

0.6

1.0

0.7

2.3

GP4 (deep)

0.7

1.0

1.7

5.6

GP5 (shallow)

0.1

1.0

5.4

9.5

GP5 (deep)

0.1

1.0

0.3

7.5

GP6

0.0

1.0

5.6

7.8

GP7

0.0

1.0

0.1

4.5

GP12

0.0

1.0

0.0

2.3

GP15

0.0

1.0

0.0

2.2

P7

0.0

1.0

0.0

2.5

P8

0.0

1.0

0.0

1.7

P9

0.0

1.0

0.0

2.7

Notes:

(a) Provisional Limit Levels established based on the pre-operation phase baseline and additional landfill gas monitoring results in the Pre-operation Baseline Monitoring Report.

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

Location

Methane (% (v/v))

Monitoring Results

Limit Levels

UU01

0.1

1.0

UU02

0.0

1.0

UU03

0.0

1.0

UU04

0.1

1.0

UU05

0.0

1.0

UU06

0.0

1.0

UU07

0.1

1.0

UU08

0.0

1.0

UU09

0.2

1.0

UU10

0.1

1.0

UU11

Inaccessible due to on-going construction work

1.0

UU12

Inaccessible due to on-going construction work

1.0

UU13

Inaccessible due to on-going construction work

1.0

UU14

Inaccessible due to on-going construction work

1.0

UU15

0.1

1.0

UU16

0.1

1.0

UU17

0.3

1.0

UU18

0.1

1.0

UU19

0.0

1.0

UU20

0.1

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 December 2021.

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 22 December 2021 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 summarised 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 as soon as possible to ensure effective screening of views of project works from the High Junk Peak Trail. The Contractor shall consider the mitigation measures during the design phase, including the preparation of the Construction Drawings and Detailed Landscape Design Drawings.

2.6                               EM&A Site Inspection

Site inspections were carried out on a weekly basis with the Contractor, IEC and ER 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, 23 and 30 December 2021.

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 December 2021

           The Contractor shall clean up the oil spillage at sediment trap and handle the clean-up materials as chemical waste.

           The Contractor shall trim the climbing plants around the transplanted trees near DP6 regularly.

9 December 2021

           The Contractor shall provide drip trays for the chemicals stored near EPD building, diesel fuel tank and at Cell 1X slope.

           The Contractor shall provide drip trays for the chemicals stored near EPD building, diesel fuel tank and at Cell 1X slope.

16 December 2021

           The Contractor shall replace the faded NRMM labels displayed on the excavators near Cell 4X and EPD building.

           The Contractor shall remove the general refuse accumulated near town gas plant and at the sediment trap and dispose of the waste regularly.

23 December 2021

           The Contractor shall replace the faded NRMM label displayed on the excavator near Cell 4X.

           The Contractor shall remove the general refuse accumulated near water services house and dispose of the waste regularly.

           The Contractor shall cover/ remove the stockpile of dusty materials near EPD building to minimise dust impact.

30 December 2021

           The Contractor shall clean up the oil spillage at the generators near GVL building and handle the clean-up materials as chemical waste.

           The Contractor shall remove the general refuse accumulated in the refuse skip near LTP regularly to minimise odour and pest issues.

           The Contractor shall remove the stagnant water accumulated at the channel near sump house 3 and spray larvicides for mosquito control, if necessary.

The Contractor has rectified all 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

Ÿ   Reviewed drainage plan.

Ÿ   Addition of channels.

Ÿ   Expedite the construction of permanent sediment trap and discharge culverts.

 

DP channels (design & regular silt removal)

Ÿ   Carried out regular maintenance and cleaning of channels.

Ÿ   DP4 channel: Area near the channel was paved with concrete and a bund was built.

Ÿ   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.

Ÿ   DP6: Pipes through the gravel piles between different channel sections were covered with geotextiles to block debris and silt.

 

N.A.

Stockpiles & exposed soil

Ÿ   Installed silt fencing near surface water channel along DP6 channel.

Ÿ   Improve soil covering.

Ÿ   Compaction and cover for stockpiles and soil slopes.

 

Wetsep (treatment capacity & number)

Ÿ   Reviewed Wetsep capacity.

Ÿ   Chemicals dosage of the Wetsep was increased to enhance the efficiency.

Ÿ   Install additional Wetsep.

Backflow / ponding during heavy rainfall

Ÿ   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 C&D materials. 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 summarised 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)

Chemical Wastes
(in 000kg)

Rock

Soil

1 31 Dec 2021

0.412

0

2043.810

0

0.058

11.660

0.800

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. One exceedance of the Limit Level for TSP and one exceedance of the Limit Level for landfill gas flare stack emission (CO) were recorded for air quality impact monitoring in the reporting period.  The TSP exceedance at AM4 on 13 December 2021 was considered non Project-related upon further investigation. The landfill gas flare stack emission (CO) exceedance on 17 December 2021 was found to be Project-related. One exceedance of the Limit Level for groundwater (COD) was recorded for water quality impact monitoring in the reporting period.  The groundwater (COD) exceedance at MWX-6 on 8 December 2021 was considered non Project-related upon further 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 January 2022 will be:

Ÿ   Excavation and removal of unsuitable fill materials;

Ÿ   Import materials for Cell 4X;

Ÿ   Construction of Cell 4X formation;

Ÿ   Liner works at Cell 4X;

Ÿ   Construction of perimeter bund along the West side of Cell 4X;

Ÿ   Defects rectification for waste reception area, including weighbridge, vehicle washing facilities, wheel wash bay and guard house;

Ÿ   Defects rectification for infrastructure buildings;

Ÿ   Defects rectification for pavement works at Part X1 area;

Ÿ   Defects rectification for surface water channels along the road pavement;

Ÿ   Installation of the remaining LFG and leachate HDPE pipes at Cell 3X and Cell 4X;

Ÿ   Construction of MSE wall; and

Ÿ   Landscape work.

3.2                               Key Issues for the Coming Month

Potential environmental impacts arising from the above upcoming construction activities in the next reporting period of January 2022 are mainly associated with dust emission from the exposed area and loading and unloading operation of dusty materials. The ET will keep track on the construction and operation works to confirm compliance of environmental requirements and the proper implementation of all necessary mitigation measures.

3.3                               Monitoring Schedule for the Coming Month

The tentative schedule for environmental monitoring in January 2022 are 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 December 2021 in accordance with the updated EM&A Manual and the requirements of the Environmental Permit (EP-308/2008/B).

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 noise and landfill gas monitoring complied with the Action and Limit Levels in the reporting period. One exceedance of the Limit Level for TSP, one exceedance of the Limit Level for landfill gas flare stack emission (CO) and one exceedance of the Limit Level 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