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 Air Quality 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 Ambient VOCs, Ammonia and H2S Monitoring Results

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 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 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 August 2022 for the Project in accordance with the updated EM&A Manual. 

Exceedance of Action and Limit Levels for Air Quality

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

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

Nine exceedances of the Limit Level for Leachate Level was recorded at Pump Station No. 4X in the reporting period.  The leachate level exceedances at Pump Station No. 4X from 12 August to 20 August 2022 are under investigation.  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-7 on 18 August 2022 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 September 2022 are mainly associated with potential surface water impact in the rainy season.


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 August 2022 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

Carl Lai

2706 8829

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

ET Leader

Frank Wan

2271 3152

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:

             Rectification of defects at Landfill Gas (LFG) Plant, Leachate Treatment Plant (LTP), infrastructure area and waste reception area;

             Landscaping works at infrastructure area;

             Rectification of defects for underground utilities and pipe;

             Construction of Cell 4X and SENT tie in area;

             Construction of road pavement at diesel fuel tank and installation of railing;

             Construction of road pavement at Western perimeter bund;

             Maintenance and improvement of temporary surface water drainage; and

             Rectification of utilities installation along Western bund of Cell 4X.

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 18 August 2022; and

Ÿ   Environmental toolbox trainings on Noise Control Ordinance and NRMM were provided on 11 August and 29 August 2022 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: GVL)

Licence No.: WT00041447-2022

Validity from 17 June 2022 to 30 June 2024

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-RE0565-22

Validity from 15 June 2022 to 14 December 2022

Construction Noise Permit (Permit Holder: Paul Y.)

GW-RE0278-22

Validity from 31 March 2022 to 22 September 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

4, 10, 16, 22, 28 August 2022

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)

61 (26 94)

260

260

AM2 - SENTX Site Boundary (West, near DP3)

67 (36 111)

260

260

AM3 - SENTX Site Boundary (West, near RC15)

95 (43 150)

260

260

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

67 (35 134)

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.

All the 24-hour TSP results were below the Action and Limit Levels at the monitoring locations in the reporting period.  No action is thus required to be undertaken in accordance with the Event and Action Plan presented in Annex D3.

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.  On-site meteorological monitoring was suspended from 8 August to 10 August 2022 due to system failure.  Wind speed monitoring was also suspended from 4 August to 31 August 2022 due to disconnection of wind speed sensor.  At the time of reporting, the daily extract of meteorological observations at Tseung Kwan O Station (the nearest weather station) in August 2022 is not available on Hong Kong Observatory website.

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.

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. 

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 OP11)

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:

22 August 2022

 

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

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

Odour intensity ≥ Class 2 recorded

Odour intensity ≥ Class 3 recorded on 2 consecutive patrol

OP2

0

OP3

0

OP4

0

OP5

1

OP6

0

OP7

0

OP8

0

OP9

0

OP10

0

OP11

1

 

 

The potential odour source in the reporting period included the excavator from Area 137 Fill Bank and waste from tipping area.  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 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

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

8 August 2022

Laboratory analysis for

         Non-methane organic compounds

Quarterly for the 1st  year of operation (b)

8 August 2022

Laboratory analysis for

         Ammonia

Quarterly

8 August 2022

     Gas combustion temperature

     Exhaust temperature

     Exhaust gas velocity (a)

Continuously

1 31 August 2022

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 August 2022

Laboratory analysis for

         Non-methane organic compounds

Quarterly for the 1st  year of operation (b)

9 August 2022

     Gas combustion temperature

     Exhaust temperature

     Exhaust gas velocity (a)

Continuously

1 31 August 2022

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 August 2022

Laboratory analysis for

         Non-methane organic compounds

Quarterly for the 1st  year of operation (b)

9 August 2022

     Exhaust temperature

     Exhaust gas velocity (a)

Continuously

1 31 August 2022

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 will be reviewed towards the end of the first year of operation to determine if monitoring of this parameter can be terminated upon agreement by the EIAO Authority, IEC and Project Proponent.

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

0.86 gs-1

1.58 gs-1

CO

<0.01 gs-1

0.53 gs-1

SO2

<0.02 gs-1

0.07 gs-1

Benzene

<3 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

Non-Methane Organic Carbon

0.0055 gs-1

-

Ammonia

0.232 gs-1

-(c)

Gas combustion temperature

923oC (880oC 933oC)

850oC (minimum)

Exhaust gas exit temperature

1,231K (1,181K 1,241K)

443K (minimum) (a)

Exhaust gas velocity

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

(c) The emission limit for ammonia is under review and will be supplemented in subsequent revision.

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

0.83 gs-1

2.43 gs-1

SO2

0.12 gs-1

0.22 gs-1

Benzene

<2.5 x 10-5 gs-1

4.14 x 10-4 gs-1

Vinyl chloride

<2.0 x 10-5 gs-1

2.60 x 10-4 gs-1

Non-Methane Organic Carbon

<0.002 gs-1

-

Gas combustion temperature

Flare 1: 890oC (826oC 966oC)

Flare 2: 846oC (820oC 890oC)

815oC (minimum)

Exhaust gas exit temperature

Flare 1: 1,110K (993K 1,248K)

Flare 2: 1,061K (1,023K 1,103K)

923 K (minimum) (a)

Exhaust gas velocity

8.9 ms-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

0.04 gs-1

1.91 gs-1

CO

0.622 gs-1

2.48 gs-1

SO2

0.015 gs-1

0.528 gs-1

Benzene

<8.7 x 10-5 gs-1

2.47 x 10-4 gs-1

Vinyl chloride

<2.1 x 10-6 gs-1

1.88 x 10-5 gs-1

Non-Methane Organic Carbon

0.0012 gs-1

-

Exhaust gas exit temperature

ENGA: 861K (856K 868K)

ENGB : 860K (855K 866K)

723K (minimum) (a)

Exhaust gas velocity

9.3 ms-1 (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.

All thermal oxidizer, landfill gas flare and landfill gas generator stack emission 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 D3.

2.1.4                     Ambient VOCs, Ammonia and H2S Monitoring

Monitoring Requirements and Equipment

According to the updated EM&A Manual of the Project, ambient VOCs, ammonia and H2S monitoring 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 quarterly interval.

The Limit Levels for ambient VOCs, ammonia and H2S monitoring is provided in Table 2.15 below.

Table 2.15      Limit Levels for Ambient VOCs, Ammonia and H2S Monitoring

Parameters

Limit Level (g m-)

Methane

NA (a)

Ammonia

180

H2S

42

Dichlorodifluoro-methane

NA (a)

Vinyl Chloride

26

Methanol

2,660

Ethanol

19,200

Dimethylsulphide

8

Carbon Disulphide

150

Methylene Chloride

3,530

Chloroform

99

Methyl propionate

353

Butan-2-ol

667

1.1.1-Trichloroethane

5,550

1.2-Dichloroethane

210

Benzene

33

Carbon Tetrachloride

64

Dipropyl ether

NA (a)

Heptane

2,746

Trichloroethylene

5,500

Ethyl propionate

29

Methyl butanoate

30

Methanethiol

10

Toluene

1,244

Ethyl butanoate

71

Propyl benzene

19

Octane

7,942

Propyl propionate

276

1.2-Dibromoethane (EDB)

39

Butyl acetate

7,240

Tetrachloroethylene

1,380

Ethyl benzene

738

Nonane

11,540

Ethanethiol

13

Decanes

3,608

Limonene

212

Butyl benzene

47

Undecane

5,562

Butanethiol

4

Terpenes

NA (a)

Xylenes

534

Dichlorobenzene

120

Notes:

(a)   No relevant WHO/USEPA/CARBs ambient criteria, odour thresholds and WEL available.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VOCs

Ambient air samples were drawn into the pre-cleaned and vacuum canister directly when the valve of the flow controller (with preset flow rate) was opened.  After sampling, the valve will be closed manually and the canister with VOCs gas samples were transported for laboratory analysis.

Methane

Pre-cleaned Tedlar bag was placed in the vacuum chamber.  Ambient air was collected in the Tedlar bag under the vacuum condition when the pump is switched on.  The Tedlar bag was filled up to 90% of total capacity to avoid leakage and bag deformation.  After sampling, pump is switched off and the valve of Tedlar bag was closed manually.  The air samples were transported back to laboratory for analysis.

Ammonia

Calibrated personal air pump was used to pump the air through a sulfuric acid-treated silica gel sorbent tube.  Gaseous ammonia in air was then trapped in the sorbent tube.  The tube was transported back to laboratory for analysis.

H2S

H2S in air is collected in mid-get impingers by aspirating a measured   volume of air through an alkaline suspension of cadmium hydroxide (as the absorbing solution).  The sulphide is precipitated as cadmium sulphide to prevent air oxidation of the sulphide.  Arabinogalactan is added to the cadmium hydroxide slurry prior to sampling to minimize photo-decomposition of the precipitated cadmium sulphide.  The solution is transported back to laboratory for analysis.

All air samples collected for laboratory analysis were transported to ALS Technichem (HK) Pty Ltd. (HOKLAS Registration No. 066) laboratory within 24 hours and analysed within 48 hours. 

The ambient VOCs, ammonia and H2S monitoring programme and monitoring locations are summarised in Table 2.16 and illustrated in Figure 2.1, respectively.

 

Table 2.16      Ambient VOCs, Ammonia and H2S Monitoring Details

Monitoring Station

Location

Parameter

Frequency

Monitoring Date

 

AM1

SENTX Site Boundary (North)

     Methane

     Ammonia

     A suite of VOCs (a)

     H2S

Quarterly

8 August 2022

 

AM2

SENTX Site Boundary (West, near DP3)

 

AM3

SENTX Site Boundary (West, near RC15)

 

AM4

SENTX Site Boundary (West, near EPD building)

 

Notes:

(a)  A suite of VOCs includes:

 

         Trichloroethylene

         Vinyl chloride

         Methylene chloride

         Chloroform

         1,2-dichloroethane

         1,1,1-trichloroethane

         Carbon tetrachloride

         Tetrachloroethylene

         1,2-dibromoethane

         Benzene

         Toluene

         Carbon disulphide

         Propyl benzene

         Ethyl benzene

         Butyl benzene

         Xylenes

         Decanes

         Undecane

         Limonene

         Terpenes

         Ethanol

         Butan-2-ol

         Dimethylsulphide

         Methyl propionate

         Ethyl propionate

         Propyl propionate

         Butyl acetate

         Ethyl butanoate

         Dichlorobenzene

         Methyl butanoate

         Dipropyl ether

         Methanethiol

         Ethanethiol

         Butanethiol

         Methanol

         Heptanes

         Octanes

         Nonanes

         Dichlorodifluoro-methane

         Methane

Monitoring Schedule for the Reporting Month

The schedule for ambient VOCs, ammonia and H2S monitoring during the reporting period is provided in Annex C.

Results and Observations

The ambient VOCs, ammonia and H2S monitoring results are summarised in Table 2.17 and provided in Annex D8.

 

 

 

 

Table 2.17      Summary of Ambient VOCs, Ammonia and H2S Monitoring Results in the Reporting Period

Parameters

Limit Level (g m-)

Monitoring Results (g m-)

AM1

AM2

AM3

AM4

Ammonia

180

18

19

25

26

H2S

42

<15

<15

<15

<15

Methane

NA (a)

0.00023% (v/v)

0.00022% (v/v)

0.00036% (v/v)

0.00032% (v/v)

1.1.1-Trichloroethane

5,550

<0.9

<0.9

<0.9

<0.9

1.2-Dibromoethane (EDB)

39

<1.3

<1.3

<1.3

<1.3

1.2-Dichloroethane

210

<0.6

<0.6

<0.6

<0.6

Benzene

33

<0.5

<0.5

<0.5

<0.5

Butan-2-ol

667

<0.6

<0.6

<0.6

<0.6

Butanethiol

4

<1.2

<1.2

<1.2

<1.2

Carbon Disulphide

150

<0.5

<0.5

11.4

1.6

Carbon Tetrachloride

64

<1.0

<1.0

<1.0

<1.0

Chloroform

99

<0.8

<0.8

<0.8

<0.8

Decanes

3,608

1.3

<1.0

1.1

<1.0

Dichlorobenzene

120

<1.0

<1.0

<1.0

<1.0

Dichlorodifluoro-methane

NA (a)

1.4

1.7

2.1

2

Dimethylsulphide

8

<0.4

<0.4

<0.4

<0.4

Dipropyl ether

NA (a)

<0.8

<0.8

<0.8

<0.8

Limonene

212

<0.9

<0.9

<0.9

<0.9

Ethanethiol

13

<0.6

<0.6

<0.6

<0.6

Ethanol

19,200

<3.8

<3.8

<3.8

25.4

Ethyl butanoate

71

<1.0

<1.0

<1.0

<1.0

Ethyl propionate

29

<0.8

<0.8

<0.8

<0.8

Ethyl benzene

738

<0.8

<0.8

<0.8

1.3

Heptane

2,746

<0.8

<0.8

<0.8

<0.8

Methanethiol

10

<0.4

<0.4

<0.4

<0.4

Methanol

2,660

13

<2.6

7.6

29.5

Methyl butanoate

30

<0.8

<0.8

<0.8

<0.8

Methyl propionate

353

<0.7

<0.7

<0.7

<0.7

Methylene Chloride

3,530

<0.6

<0.6

2.7

4

Butyl acetate

76

<1.0

<1.0

<1.0

<1.0

Butyl benzene

47

<1.0

<1.0

<1.0

<1.0

Nonane

11,540

<0.9

<0.9

<0.9

<0.9

Propyl benzene

19

<0.8

<0.8

<0.8

<0.8

Octane

7,942

<0.9

<0.9

<0.9

<0.9

Propyl propionate

276

<1.0

<1.0

<1.0

<1.0

Terpenes

NA (a)

1

<0.8

1.1

1.4

Tetrachloroethylene

1,380

<1.2

<1.2

<1.2

<1.2

Toluene

1,244

<0.6

<0.6

0.7

2.7

Trichloroethylene

5,500

<1.1

<1.1

<1.1

<1.1

Undecane

5,562

<1.2

<1.2

<1.2

<1.2

Vinyl Chloride

26

<0.4

<0.4

<0.4

<0.4

Xylenes

534

<0.5

<0.5

<0.5

2.5

Notes:

(a)    No relevant WHO/USEPA/CARBs ambient criteria and WEL available.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

All ambient VOCs, ammonia and H2S 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 D3.

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-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 2.18 below. 

Table 2.18      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 2.19.  Copies of the calibration certificates for the equipment are presented in Annex E1

Table 2.19      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

1, 11, 17, 23, 29 August 2022

Sound Level Meter:

Rion NL-52 (S/N: 00921191)

 

Rion NL-52 (S/N: 00809405)

 

Acoustic Calibrator:

Rion NC-74 (S/N: 34246492)

 

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. However, noise monitoring on 11 August 2022 was cancelled due to adverse weather condition. Results for noise monitoring are summarised in Table 2.20.  The monitoring results and the graphical presentation of the data are provided in Annex E2.

Table 2.20      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

52.3

51.1 53.0

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.  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 2022.

The parameters as listed in Table 2.22 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 2.21.

Table 2.21      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

Notes:

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 2.22.  Copies of the calibration certificates for the equipment are presented in Annex F1


 

Table 2.22      Impact Surface Water Quality Monitoring Details

Monitoring Station

Location

Frequency

Monitoring Dates

Parameter

Equipment

DP4

Surface water discharge point DP4

Monthly

23 August 2022

     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: 15H103928)

 

DP6

Surface water discharge point DP6

Notes:

(a)   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 2022.

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 regular 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 23 August 2022 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. 

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 2.23 were determined by ALS Technichem (HK) Pty Ltd. (HOKLAS Registration No. 066).

The Limit Levels of the leachate monitoring are provided in Table 2.23.

Table 2.23      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 m

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 g/L

Iron

> 5 mg/L

Cadmium

> 1 g/L

Chromium

> 300 g/L

Copper

> 1,000 g/L

Nickel

> 700 g/L

Zinc

> 700 g/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 2.24.  Copies of the calibration certificates for the equipment are presented in Annex F4

Table 2.24      Leachate Levels and Effluent Quality Monitoring Details

Location

Frequency

Parameter

Monitoring Dates

Equipment

Leachate levels above the basal liner

 

Continuous

Leachate Levels

1 31 August 2022

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

 

1-3 August 2022

TOA HM-30P (S/N: 790332)

 

 

 

 

 

 

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 2.25 and Table 2.26, respectively.  The detailed monitoring results are provided in Annex F5 and Annex F6, respectively.

Table 2.25      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

69.0 (53.0 86.0)

> 178

Meter No. X-2

80.0 (66.0 97.0)

 

Average

74.7 (60.0 91.0)

 

Pump Station No. 2X (Cell 2X)

Meter No. X-3

75.7 (62.0 98.0)

> 180

Meter No. X-4

79.7 (66.0 99.0)

 

Average

77.7 (64.0 98.5)

 

Pump Station No. 3X (Cell 3X)

Meter No. X-5

67.5 (48.0 97.0)

> 175

Meter No. X-6

70.8 (59.0 97.0)

 

Average

69.2 (57.0 97.0)

 

Pump Station No. 4X (Cell 4X)

Meter No. X-7

171.3 (48.0 329.0)

> 186

Meter No. X-8

173.3 (50.0 331.0)

 

Average

172.2 (49.0 330.0)

 

Table 2.26      Summary of Effluent Quality Monitoring Results in the Reporting Period

Parameters

Monitoring Results

Limit Level

Effluent Discharged from LTP

Average

Min

Max

 

Temperature

C

36.9

36.7

37.0

> 43 C

pH Value

pH unit

8.3

8.3

8.4

6 10

Volume Discharged

m

983.7

831.0

1202.0

>2,000 m

Suspended Solids (SS)

mg/L

26.1

24.5

27.0

> 800 mg/L

Phosphate

mg/L

6.8

6.5

7.3

> 25 mg/L

Sulphate

mg/L

174.3

163.0

193.0

> 800 mg/L

Total Inorganic Nitrogen (a)

mg/L

41.3

37.2

48.6

> 100 mg/L

BOD

mg/L

9.3

8.0

10.0

> 800 mg/L

COD

mg/L

983.7

921.0

1030.0

> 2,000 mg/L

Oil & Grease

mg/L

<5.0

<5.0

<5.0

> 20 mg/L

Boron

g/L

5760.0

5500.0

5900.0

> 7,000 g/L

Iron

mg/L

1.9

1.8

2.0

> 5 mg/L

Cadmium

g/L

<1.0

<1.0

<1.0

> 1 g/L

Chromium

g/L

126.0

115.0

134.0

> 300 g/L

Copper

g/L

<10.0

<10.0

<10.0

> 1,000 g/L

Nickel

g/L

116.0

106.0

124.0

> 700 g/L

Zinc

g/L

65.7

59.0

71.0

> 700 g/L

Note:

(a)   Total Inorganic Nitrogen include Ammoniacal-nitrogen, Nitrite-nitrogen and Nitrate-nitrogen.

Limit Levels exceedances were recorded for leachate level monitoring in the reporting period and actions in accordance with the Event and Action Plan presented in Annex F3 were undertaken.  The leachate level exceedances at Pump Station No. 4X from 12 August 2022 to 20 August 2022 are under investigation.

All 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 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 2.27 below.

Table 2.27      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 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 situIn 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 2.28 and illustrated in Figure 2.1, respectively.  Copies of the calibration certificates for the equipment are presented in Annex F7

Table 2.28      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

17, 18 August 2022

YSI Professional DSS (S/N: 15H103928)

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 2.29 and provided in Annex F8, respectively.

Table 2.29      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

0.20

5.00

10

30

MWX-2

1.38

5.00

17

30

MWX-3

1.29

5.00

19

30

MWX-4

1.91

7.63

21

36

MWX-5

0.55

5.00

20

30

MWX-6

2.79

5.00

30

46

MWX-7

5.63

6.55

43

36

MWX-8

9.22

15.85

29

50

MWX-9

0.97

7.30

28

71

MWX-10

0.01

5.00

8

30

MWX-11

0.01

5.00

7

30

MWX-12

<0.01

5.00

6

30

MWX-13

0.03

5.00

6

30

MWX-14

<0.01

5.00

5

30

Limit Level 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.  The groundwater (COD) exceedance at MWX-7 on 18 August 2022 is under investigation.

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 2.30 below.

Table 2.30      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

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.

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.

Flammable gas detector in compliance with the specifications listed under Section 5.4.1 of the updated EM&A Manual was used to measure flammable gas concentration.  Flammable gas surface emission survey was conducted at a slow pace with the inlet tube of the meter probe a few centimeters above ground surface to detect flammable gas emitted from the ground surface. 

Bulk gas samples were collected into inert sample containers (i.e. 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 equipment used in the landfill gas monitoring programme is summarised in Table 2.31.  The landfill gas monitoring locations for perimeter landfill gas monitoring wells and service voids, utilities and manholes along the Site boundary and surface emission between the SENTX site and waste boundary are illustrated in Figure 2.3, Figure 2.4 and Annex G1, respectively. Copies of the calibration certificates for the equipment are presented in Annex G2.

Table 2.31      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

15 August 2022

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

5 August 2022

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 August 2022

Permanent gas monitoring system

Areas between the SENTX Site boundary and the waste boundary and location of vegetation stress

Quarterly

Ÿ  Flammable gas emitted from the ground surface

16 August 2022

GMI Leak Surveyor (S/N: 554846)

Bulk gas sampling at least 2 of the perimeters LFG monitoring wells

Quarterly

Ÿ  Methane

Ÿ  Carbon dioxide

Ÿ  Oxygen

Ÿ  Nitrogen

Ÿ  Carbon monoxide

Ÿ  Other flammable gas

15 August 2022

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 2.32 - 2.35 and Annex G3, respectively.

Table 2.32      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

0.4

3.2

LFG2

0.0

1.0

1.0

4.3

LFG3

0.0

1.0

0.0

6.3

LFG4

0.0

1.0

0.5

7.0

LFG5

0.0

1.0

0.2

3.4

LFG6

0.0

1.0

2.1

9.1

LFG7

0.0

1.0

0.0

1.5

LFG8

0.0

12.6

0.0

2.4

LFG9

0.2

2.5

0.0