North East New Territories (NENT) Landfill Extension


Updated Environmental Monitoring & Audit Manual


18 January 2024

ET Certification

IEC Verification


1   Introduction. 1

1.1        Background. 1

1.2        Purpose and Scope of this Manual 1

1.3        Description of the Project 2

1.4        Project Programme. 4

2   Scope of EM&A Programme. 5

2.1        Objective of EM&A Programme. 5

2.2        Organisation for EM&A Programme. 6

2.3        Structure of the EM&A Manual 8

2.4        Environmental Management Plan. 8

2.5        Waste Management Plan. 9

2.6        Baseline Monitoring. 10

2.7        Impact Monitoring. 10

2.8        Compliance with Actions and Limit Levels. 10

2.9        Event and Action Plan. 11

2.10      Environmental Audit 11

2.11      Reporting. 11

2.12      Cessation of EM&A Programme. 12

3   Air Quality Monitoring. 13

3.1        Construction Dust 13

3.2        Odour 20

3.3        Precautionary Measures During Operational, Restoration and Aftercare Phases. 24

4   Noise Monitoring. 27

4.1        Monitoring Parameters. 27

4.2        Monitoring Equipment 27

4.3        Monitoring Location. 27

4.4        Baseline Monitoring. 28

4.5        Construction Noise. 28

4.6        Operational Noise. 29

4.7        Traffic Noise. 29

4.8        Event and Action Plan. 30

4.9        Environmental Mitigation Measures. 33

5   Water Quality Monitoring. 34

5.1        Introduction. 34

5.2        Precautionary / Mitigation Measures during Construction and Operation Phases. 34

5.3        Leachate Monitoring. 36

5.4        Groundwater Monitoring. 42

5.5        Surface Water Monitoring. 45

5.6        Event and Action Plan. 49

6   Waste Management 53

6.1        Introduction. 53

6.2        Waste Control and Mitigation Measurement 53

7   Landfill Gas Monitoring. 56

7.1        Background. 56

7.2        General Requirement 56

7.3        Monitoring Parameters. 57

7.4        Monitoring Equipment 57

7.5        Monitoring Location. 58

7.6        Monitoring Frequency. 59

7.7        Monitoring Procedures. 59

7.8        A/L Levels and EAP. 61

7.9        Mitigation Measures. 61

8   Landscape and Visual Monitoring. 63

8.1        Introduction. 63

8.2        Monitoring Details. 63

9   Cultural Heritage Monitoring. 66

9.1        Introduction. 66

9.2        Monitoring Requirements. 66

9.3        Ngong Tong (North and West of Sheh Tsai Ha Road: Western & Central Section) 66

9.4        Tong To Shan (North Shek Tsai Ha Road: East Section) 66

9.5        The Relevant Requirements for Survey and Preservation. 67

10 Ecological Monitoring. 69

10.1      Introduction. 69

10.2      Ecological Mitigation Measures. 69

10.3      Monitoring and Audit for Ecology. 71

10.4      Post - Transplantation Maintenance. 73

10.5      Post - Transplantation Monitoring and Reporting. 74

10.6      Post - Translocation Monitoring and Reporting. 75

11 Environmental Audit 76

11.1      Site Inspection. 76

11.2      Compliance with Environmental Requirements. 76

11.3      Environmental Complaints. 77

12 Reporting. 78

12.1      General 78

12.2      Baseline Monitoring Report 78

12.3      Impact EM&A Report 78

12.4      Data Keeping. 83

12.5      Interim Notification of Environmental Exceedance. 83


Appendix A

Tentative Outline Programme

Appendix B

Project Organization

Appendix C

Environmental Mitigation Implementation Schedule

Appendix D

A Sample List of VOC Monitoring Parameters

Appendix E

Sample of Monitoring Data Record Sheet


Figure 1.1

Location Plan of the Project Site

Figure 1.2

Landfill Extension Layout

Figure 3.1

Air, Odour & VOC Monitoring Location

Figure 4.1

Noise Monitoring Location

Figure 5.1

Landfill Extension Monitoring Plan

Figure 5.2

Water Quality Monitoring Location

Figure 9.1

Archaeological Findings

Figure 10.1

Recorded Plant Species of Conservation Importance with NENTX under the Current Study

1                   Introduction

1.1              Background

The North East New Territories Landfill Extension (the NENTX Project) is located adjacent to the existing North East New Territories (NENT) Landfill at Ta Kwu Ling. The extension site is located in a valley covering mainly the existing NENT Landfill Stockpile and Borrow Area that was formed to the east of the existing landfill as part of the original site development of the landfill, and layout plan shown in Figure 1.1.

The NENTX is a designated project. The Environmental Impact Assessment (EIA) Report (AEIAR-111/2007) and an Environmental Monitoring and Audit Manual were approved on 20 September 2007. The project is governed by an Environmental Permit (EP) (EP-292/2007) which was granted on 26 November 2007. A further of EP (FEP) was applied and the FEP (FEP-01/292/2007) was subsequently granted on 28 April 2022.

As per requirement of EP Condition 2.5 and FEP Condition 2.3, the Permit Holder shall, no later than one month before the commencement of construction of the Project, submit to the Director of Environmental Protection for approval an updated EM&A Manual for the Project, which shall include the latest information on the EM&A requirements for ecological, landscape, water and landfill gas hazard. All measures recommended in the approved EM&A Manual shall be fully and properly implemented according to the requirements and time schedules set out in the EM&A Manual. The submissions shall be certified by the Environmental Team (ET) Leader and verified by the Independent Environmental Checker (IEC).

This updated EM&A Manual has been prepared with reference to the approved EM&A Manual prepared in March 2007, the current EP, the latest design and EIAO-TM. The purpose of the Manual is to provide information, guidance and instruction to personnel charged with environmental duties and those responsible for undertaking EM&A work during construction, operation, restoration and aftercare phases of the NENTX. It provides systematic procedures for the environmental monitoring and auditing of the potential environmental impacts that may arise from the Project. The monitoring details of the establishment of the endemic freshwater crab, Somanniathelphusa zanklon community in the translocation site has been included in Section 10.6 of this EM&A Manual for fulfilling EIA Report Approval Condition No. 4 (Register No.: AEIAR-111/2017) on 20 September 2007.

1.2              Purpose and Scope of this Manual

Environmental Monitoring and Audit (EM&A) is an important aspect in the EIA process which specifies the timeframe and responsibilities for the implementation of environmental mitigation measures. The requirements on environmental monitoring (including baseline and impact monitoring) are given in the updated EM&A Manual (the Manual) which is a supplementary document to the EIA Study for the Project and prepared in accordance with the requirements in the EIA Study Brief and Technical Memorandum on Environmental Impact Assessment Process (TM-EIAO).

The purpose of this updated EM&A Manual is to guide the establishment of an EM&A programme to ensure compliance with the EIA recommendations, to assess the effectiveness of recommended mitigation measures, and to identify further need for additional mitigation measures or remedial action.

This updated Manual outlines the monitoring and audit requirements for the construction, operation, restoration and aftercare stages of the NENT Landfill Extension. It aims to provide systematic procedures for monitoring, auditing and minimising environmental impacts associated with construction works and operational activities.

Hong Kong environmental regulations and the Hong Kong Planning Standards and Guidelines have served as environmental standards and guidelines in the preparation of this updated Manual. This updated EM&A Manual was prepared in accordance with the requirements as stipulated in Annex 21 of the TM-EIAO.

This updated Manual contains the following information:

•       Organisation, hierarchy and responsibilities of the Contractor, Environmental Team (ET), Independent Environmental Checker (IEC), and Independent Consultant (IC), with respect to the EM&A requirements during the construction, operation, restoration and aftercare phases of landfill extension;

•       Information on project organisation and programming of construction activities;

•       Requirements with respect to the construction schedule and necessary EM&A programme to track the varying environmental impacts;

•       Full details of methodologies to be adopted, including all field, laboratory and analytical procedures, and details on quality assurance;

•       Procedure for undertaking on-site environmental audits;

•       Definition of Action and Limit Levels;

•       Establishment of Event and Action Plans;

•       Requirements of reviewing pollution sources and working procedures required in the event of non-compliance of environmental criteria and complaints;

•       Requirements for reviewing the EIA predictions, implementation of mitigation measures, and effectiveness of environmental protection and pollution control measures adopted; and

•       Presentation of requirements for EM&A data and appropriate reporting procedures.

1.3              Description of the Project

1.3.1             General Description of the Project

The development of the NENT Landfill Extension will involve the following works:

•       Site formation, drainage diversion and preparation;

•       Installation of liner system;

•       Installation of leachate collection, treatment and disposal facilities;

•       Installation of landfill gas collection, utilization and management facilities;

•       Operation and environmental monitoring of landfill; and

•       Restoration and aftercare.

1.3.2             Key Project Requirement

The key project requirements for the NENT Landfill Extension are:

•       Development of sanitary landfill that covers an area of about 70ha with an estimated void space of 19Mm3;

•       Provision of liner system for the landfill to prevent contamination of land and water resources;

•       Provision of leachate collection, treatment and disposal facilities with sufficient capacity for handling the leachate arising from the new landfill;

•       Provision of IandfiII gas (LFG) collection, utilisation and management facilities;

•       Provision of utilities, drainage and road network necessary for the proper operation of the Project;

•       Provision of facilities (both civil works and electrical and mechanical equipment) for waste reception, inspection, charging, handling and compaction, and plant maintenance;

•       Provision of facilities for site administration;

•       Operation of landfill in compliance with all relevant engineering, geotechnical and environmental standards;

•       Restoration of landfill in compliance with all relevant engineering, geotechnical and environmental standards;

•       Provision of aftercare for the landfill for a period of about 30 years;

•       Carrying out environmental monitoring and audits throughout construction, operation, restoration and aftercare of the landfill; and

•       Implementation of environmental measures necessary for the protection of the surrounding environment.

1.3.3             Size, Scale, Shape and Design of the Project

The landfill extension site will be a bowl-shape area with a large void space in the middle for waste filling. The northwestern and southeastern boundaries of the landfill extension site follow the ridgelines to maximise the landfill capacity. Some set back of the northern boundary is included to minimise the impact to woodland and Lin Ma Hang Catchment. The total site area is about 70ha and the final height of the landfill would not be exceeded +255 mPD (Figure 1.1 & Figure 1.2). Various activities during construction, operation, restoration and aftercare of landfill are discussed in the following sub-sections. The key design features are summarised below:

•       Bottom liner system — separate waste mass and leachate from groundwater;

•       Landfill cells — store waste within the unit;

•       Storm water drainage system — collect rain water run off on the landfill;

•       Leachate collection system — collect liquid leaching from the waste mass and convey it to a leachate treatment plant prior to discharging to Shek Wu Hui Sewage Treatment Works;

•       Gas collection system — collect gases formed during the decomposition of waste. These gases will be treated and utilised for production of electricity on site; and

•       Covering and capping — seal off the top of the landfill with a gas venting layer, an impermeable mineral layer, a drainage layer of at least 0.5m and at least 1m of top soil.

1.3.4             Construction Phase Activities

Simple excavation and slope formation works will be carried out during the construction stage. The permanent works comprise cut and fill earthworks, slope formation and earth wall construction. The temporary works will involve the formations of temporary ditches along the sides of excavations and associated drainage works, and material storage areas. During site formation, sediment will be contained in permanent detention ponds/silt traps that will be constructed according to landfill phasing. Final design and location of sediment traps are yet to be decided, but are likely to be down gradient of each landfill phase or in the downstream valleys near the existing waste reception area. Where possible they will be maintained during the operation of each phase to ensure the effective control of operational soil erosion problem.

1.3.5             Operation Phase Activities

During operation, waste will be disposed of at individual landfill cells. Deposited waste will be compacted to thin layers of up to two metres in thickness. The works will be maintained at a gradient of not greater than 1 in 3 to ensure the effectiveness of the compaction equipment. Daily cover (the active tipping area shall be covered about at least 150mm of soil together with a layer of Posi-Shell on completion of each day’s operation.) will be applied to control environmental nuisances such as windblown litter, odour, vermin, flies and birds. There are other alternative biodegradable materials for use as daily cover which may be applicable at NENTX, including:

•       Heavy duty reusable and biodegradable sheets;

•       Biodegradable, non-reusable plastic films;

•       Geotextiles; and

•       Foams and sprays.

1.3.6             Restoration Phase Activities

Restoration is a process to restore a landfill site to a condition suitable for afteruse. After completion of waste filling, final capping will be applied to minimise infiltration of rainwater into the waste mass thus reducing the amount of leachate generated. The capping system normally includes a number of components including topsoil, subsoil, drainage layer and barrier layer.

1.3.7             Aftercare Phase Activities

Aftercare is the work done after the replacement of the soil and includes cultivations, fertilisation, planting, construction of pathways, access points, vegetation maintenance and an ongoing long-term commitment to the restored landfill. Landscaped berms will be created and tree planting will be provided during the aftercare period for aesthetic purpose.

1.4              Project Programme

The Landfill Extension will start receiving waste only when the Existing NENT Landfill has ceased operation. The timing of this has yet to be determined as it depends on the rate of waste deliveries in the forthcoming period. Based on current predictions, the capacity of the Existing Landfill will probably run out by 2026, it is estimated that the operation commencement date of the Phase 1 of NENTX will be in 2026 based on the tentative outline programme.

Taking into account of the time needed for mobilization and preparatory works prior to commencement of receipt of waste, the EPD awarded the Landfill Extension contract in February 2022. In order to ensure that new landfill space will be available before the capacity of the existing landfill runs out.

The tentative outline Programme of Landfill Extension is indicatively summarised in Appendix A.

2                 Scope of EM&A Programme

The requirements of EM&A programme should include the recommendations from the EIA study and with reference to EPD's “Environmental Monitoring and Audit Guidelines for Development Projects in Hong Kong". Detailed requirements of the EM&A programme for construction, operation, restoration and aftercare phases of this Project are described in the following sections of this updated EM&A Manual. Table 2.1 summarises the requirements at various phases of the Project.

Table 2.1 Summary of EM&A Requirements


Project Phase


Operation/ Restoration



Ambient Volatile Organic Compound (VOC), Ammonia and hydrogen Sulphide (H2S)


Stack emission from LFG Generators, Flares and Thermal Oxidizers



(Flare only)




Surface Water