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Contents

Executive Summary

1                             inTroduction

1.1                         Purpose of the Report

1.2                         Structure of the Report

2                             Project information

2.1                         Background 

2.2                         General Site Description

2.3                         Major Activities Undertaken

2.4                         Project Organisation and Management Structure

2.5                         Status of Environmental Approval Documents

3                             Environmental Monitoring and Audit Requirements

3.1                         Environmental Monitoring

3.1.1                     Air Quality

3.1.2                     Odour

3.2                         Site Audit

3.2.1                     Water Quality

3.2.2                     Landscape and Visual

4                             Monitoring Results

4.1                         Air Quality 

4.1.1                     Operation Phase Monitoring 

4.2                         Odour

4.2.1                     Operation Phase Monitoring

4.3                         Water Quality

4.3.1                     Operation Phase Monitoring

4.4                         Waste Management

4.4.1                     Operation Phase Monitoring

5                             Site Audit

5.1                         Environmental Site Audit

5.1.1                     Operation Phase

5.2                         Landscape and Visual Audit

6                             Environmental Non-conformance

6.1                         Summary of Environmental Non-Compliance

6.2                         Summary of Environmental Complaint

6.3                         Summary of Environmental Summon and Successful Prosecution

7                             Future Key Issues

7.1                         Key Issues for the Coming Reporting Period

8                             Conclusions

LIST OF TABLES

Table 2.1   Summary of Activities Undertaken in the Reporting Period

Table 2.2 Summary of Environmental Licensing, Notification and Permit Status

Table 3.1   Sampling and Laboratory Analysis Methodology

Table 3.2   Emission Limit for CAPCS Stack

Table 3.3   Emission Limit for CHP Stack

Table 3.4   Emission Limit for ASP Stack

Table 3.5   Emission Limit for Standby Flaring Gas Unit)

Table 3.6   Odour Intensity Level

Table 3.7   Action and Limit Levels for Odour Nuisance

Table 3.8   Event and Action Plan for Odour Monitoring

Table 3.9   Discharge Limits for Effluent from the Effluent Storage Tank (as stipulated in WT00038391-2021)

Table 3.10 Discharge Limits for Effluent from the Petrol Interceptor(s) (as stipulated in WT00038391-2021)

Table 4.1  Hourly Average of Parameters Recorded for CAPCS

Table 4.2   Hourly Average of Parameters Recorded for CHP 1

Table 4.3   Hourly Average of Parameters Recorded for CHP 2

Table 4.4   Hourly Average of Parameters Recorded for CHP 3

Table 4.5   Hourly Average of Parameters Recorded for ASP

Table 4.6 Hourly Average of Parameters Recorded for the Standby Flaring Gas Unit

Table 4.7   Results of the Discharge Sample Collected from the Effluent Storage Tank in March 2022

Table 4.8   Results of the Discharge Sample Collected from the Effluent Storage Tank in April 2022

Table 4.9   Results of the Discharge Sample Collected from the Effluent Storage Tank in May 2022

Table 4.10 Results of the Discharge Sample from the Petrol Interceptor 1 on 13 April 2022

Table 4.11 Results of the Discharge Sample from the Petrol Interceptor 2 on 13 April 2022

Table 4.12  Quantities of Waste Generated from the Operation of the Project

Table 8.1    Exceedances for Stack Emissions

 

 LIST OF ANNEXES

Annex A Location of Project

Annex B Project Organisation Chart and Contact Detail

Annex C Implementation Schedule of Mitigation Measures

Annex D Waste Flow Table

Annex E Environmental complaint, Environmental Summons and Prosecution Log

Annex F Investigation Report

 

EXECUTIVE SUMMARY

The construction works of No. EP/SP/61/10 Organic Resources Recovery Centre Phase 1 (the Project) commenced on 21 May 2015.  This is the 28th quarterly Environmental Monitoring and Audit (EM&A) report presenting the EM&A works carried out during the period from 1 March 2022 to 31 May 2022 in accordance with the EM&A Manual.  Substantial completion of the construction works was confirmed on 3 December 2018.  In the meantime, the operation phase EM&A programme had commenced in March 2019.  Substantial Completion in respect of substantial part of the Works was confirmed on 24 February 2020.  The construction phase EM&A programme was completed in the end of February 2020.

Summary of Works undertaken during the Reporting Month

Works undertaken in the reporting month included:

         Operation of the Project, including organic waste reception, and operation of the pre-treatment facilities, anaerobic digesters, composting facilities, air pollution control systems, on-line emission monitoring system for the Centralised Air Pollution Control Unit (CAPCS), Co-generation Units (CHP)s and Ammonia Stripping Plant (ASP), and the wastewater treatment plant; and

         Process fine-tune, including adjustment of the ASP with new treatment media, modification of Continuous Environmental Monitoring System (CEMS) and Supervisory Control and Data Acquisition System (SCADA) rectification and improvement works following equipment failures and the alteration of different operation modes and measures to adapt to the high variation of SSOW nature and sources.

         Servicing (included adjusting of some of the operating parameters, valve check/adjustment, cable plug connection, ignition timing, spark plug checking, etc.) of the CHP2; and

         Modification of the ASP (included upgrading of the exhaust blower of the economizer, modification of the blower, motor, ducts and pipework and trials using various operation parameters to improve the performance of the equipment) to control the air emission.

Environmental Monitoring and Audit Progress

Air Quality Monitoring

Exceedances on SO2 and NOx from CHPs and CO, NOx, SO2, VOCs, NH3 and HF from ASP were recorded on the on-line monitoring system from March 2022 to May 2022.  It should be noted that measurements recorded under abnormal operating conditions, e.g. start up and stopping of stacks and unstable operation, as well as test runs and interference of sensor, are disregarded. 

 

In March 2022, the exceedance of SO2 from CHP1 occurred due to malfunctioning of an instrument (blower) of the de-sulphurisation system.  The exceedance of CO, NOx, VOCs and NH3 from ASP occurred due to system instability caused by leakage of the internal tubing of the economiser.  In April 2022, the exceedances of SO2 from CHP 1, 2 and ASP occurred due to malfunctioning of an instrument (blower) of the de-sulphurisation system. The exceedances of NOx from CHP 3 occurred due to unstable system caused by leakage in the CHP 3.  The exceedance of CO, NOx, VOCs and NH3 from ASP occurred due to system instability caused by motor overheating, unstable water flow and leakage of pump.  In May 2022, the exceedances of SO2 from CHPs and the ASP occurred due to tripping of the de-sulphurisation system caused by the failure of one of the columns of the system. The exceedances of NOx from CHP 3 in early May 2022 occurred due to insufficient feedstock. The exceedance of CO, NOx, VOCs, NH3 and HF from ASP occurred due to system instability caused by the ongoing performance optimisation of the ASP, resulting in a lowered temperature of the system and the incomplete combustion of biogas.

The Contractor has implemented mitigation measures to control the exceedance (including replacement of malfunctioned parts (desulphurisation system, columns of the ASP), cleaning for various parts (i.e. stripping column and packaging of the ASP), and carried out fine-tuning of equipment of the ASP).

The Contractor is recommended to closely monitor the processes of the modification of the ASP and the post-modification monitoring of emission level to avoid any exceedance. 

As similar issues have been re-occurred for sometimes, the Contractor is advised to undertake a comprehensive review of the operation of the concerned systems and the effectiveness of the existing mitigation measures and proposed further measures to avoid the exceedance.

Odour

No odour patrol was required to be conducted for this reporting period.

Water Quality

No non-compliance to the effluent discharge limit stipulated in the discharge licence issued by the EPD under the Water Pollution Control Ordinance was recorded during this reporting period.

Waste Management

Waste generated from the operation of the Project includes chemical waste, waste generated from pre-treatment process and general refuse. 

1,240 L of chemical waste was collected by licenced waste collector from the operation of the Project.

862.14 tonnes of waste generated from pre-treatment process from the operation of the Project was disposed of at landfill.  Among the recyclable waste generated from pre-treatment process from the operation of the Project, 0.00 tonnes of metals, 0.00 tonnes of papers/ cardboard packing and 0.00 tonnes of plastics were sent to recyclers for recycling during the reporting period.

Around 7.94 tonnes of general refuse from the operation of the Project was disposed of at landfill.  Among the recycled general refuse from the operation of the Project, 0.00 tonnes of metals, 0.00 tonnes of papers/ cardboard packing and 0.00 tonnes of plastics were sent to recyclers for recycling during the reporting period.

Findings of Environmental Site Audit

A summary of the monitoring activities undertaken in this reporting period is listed below:

         Joint Environmental Site Inspections

3 times

         Landscape & Visual Inspections

3 times

Monthly joint environmental site inspections were carried out.  The environmental control/ mitigation measures (related to air quality, water quality, waste (including land contamination prevention), hazard-to-life and landscape and visual) recommended in the approved EIA Report and the EM&A Manual were properly implemented by the Contractor during the reporting month. 

Environmental Exceedance/Non-conformance/Compliant/Summons and Prosecution

Exceedances for the air emission limits for the CHP and ASP stacks were recorded during the reporting period.

No complaint/ summon/prosecution was received in this reporting period.

Future Key Issues

Activities to be undertaken in the next reporting month include:

         Operation of the Project;

         Maintenance of CHP 2 (i.e. replacement of cylinder head) and modification of the ASP (i.e. repairing of economizers heat exchanger, mixing units and diesel generator) to control the air emission; and

         Cleaning of the Suspension Buffer Tank.

 

1                                            inTroduction

ERM-Hong Kong, Limited (ERM) was appointed by OSCAR Bioenergy Joint Venture (the Contractor) as the Environmental Team (ET) to undertake the construction Environmental Monitoring and Audit (EM&A) programme for the Contract No. EP/SP/61/10 of Organic Waste Treatment Facilities Phase I, which the project name has been updated to Organic Resources Recovery Centre (Phase I) (the Project) since November 2017.  ERM was also appointed by the Contractor to undertake the operation EM&A programme starting 1 March 2019.

1.1                                       Purpose of the Report

This is the 28th Quarterly EM&A report which summarises the monitoring results and audit findings for the EM&A programme during the reporting period from 1 March 2022 to 31 May 2022.

1.2                                       Structure of the Report

The structure of the report is as follows:

Section 1:   Introduction

It details the scope and structure of the report.

 

Section 2:   Project Information

It summarises the background and scope of the Project, site description, project organisation and status of the Environmental Permits (EP)/licences.

 

Section 3:   Environmental Monitoring and Audit Requirements

It summarises the environmental monitoring requirements including monitoring parameters, programmes, methodologies, frequency, locations, Action and Limit Levels, Event/Action Plans, as well as environmental audit requirements as recommended in the EM&A Manual and approved EIA report.

 

Section 4:   Monitoring Results

It summarises monitoring results of the reporting period.

 

Section 5:   Site Audit

It summarises the audit findings of the environmental as well as landscape and visual site audits undertaken within the reporting period.

 

Section 6:   Environmental Non-conformance

It summarises any exceedance of environmental performance standard, environmental complaints and summons received within the reporting period.

 

Section 7:   Further Key Issues

It summarises the impact forecast for the next reporting month.

 

Section 8:   Conclusions

 

2                                            Project information

2.1                                       Background

The Organic Resources Recovery Centre (ORRC) Phase I development (hereinafter referred to as the Project) is to design, construct and operate a biological treatment facility with a capacity of about 200 tonnes per day and convert source-separated organic waste from commercial and industrial sectors (mostly food waste) into compost and biogas through proven biological treatment technologies.  The location of the Project site is shown in Annex A.

The environmental acceptability of the construction and operation of the Project had been confirmed by findings of the associated Environmental Impact Assessment (EIA) Study completed in 2009.  The Director of Environmental Protection (DEP) approved this EIA Report under the Environmental Impact Assessment Ordinance (EIAO) (Cap. 499) in February 2010 (Register No.: AEIAR-149/2010) (hereafter referred to as the approved EIA Report).  Subsequent Report on Re-assessment on Environmental Implications and Report on Re-assessment on Hazard to Life Implications were completed in 2013, respectively.

An Environmental Permit (EP) (No. EP-395/2010) was issued by the DEP to the EPD (Project Team), the Permit Holder, on 21 June 2010 and varied on 18 March 2013 (No. EP-395/2010/A) and 21 May 2013 (No. EP-395/2010/B), respectively.  The Design Build and Operate Contract for the ORRC Phase 1 (Contract No. EP/SP/61/10 Organic Resources Recovery Centre (Phase 1) (the Contract)) was awarded to SITA Waste Services Limited, ATAL Engineering Limited and Ros-Roca, Sociedad Anonima jointly trading as the OSCAR Bioenergy Joint Venture (OSCAR or the Contractor).  A Further EP (No. FEP-01/395/2010/B) was issued by the DEP to the OSCAR on 16 February 2015.  Variation to both EPs (Nos. EP-395/2010/B and FEP-01/395/2010/B) were made in December 2015.  The latest EPs, Nos. EP-395/2010/C and FEP-01/395/2010/C, were issued by the DEP on 21 December 2015.

Under the requirements of Condition 5 of the EP (No. FEP-01/395/2010/C), an Environmental Monitoring and Audit (EM&A) programme as set out in the approved EM&A Manual (hereinafter referred to as EM&A Manual) is required to be implemented during the construction and operation of the Project.  ERM-Hong Kong, Ltd (ERM) has been appointed by OSCAR as the Environmental Team (ET) for the construction phase EM&A programme and the Monitoring Team (MT) for the operation phase EM&A programme for the implementation of the EM&A programme in accordance with the requirements of the EP and the approved EM&A Manual.

The construction works commenced on 21 May 2015.  The operation phase of the EM&A programme commenced on 1 March 2019 ([1]).  The construction phase EM&A programme was completed in the end of February 2020.

2.2                                       General Site Description

The Project Site is located at Siu Ho Wan in North Lantau with an area of about 2 hectares.  The layout of the Project Site is illustrated in Annex A.  The facility received an average of 115.12 to 136.07 tonnes and treated an average of 106.93 to 124.62 tonnes of source separated organic waste per day during the reporting month.

2.3                                       Major Activities Undertaken

A summary of the major activities undertaken in the reporting period is shown in Table 2.1.  

Table 2.1         Summary of Activities Undertaken in the Reporting Period

Activities Undertaken in the Reporting Period

         Systems being operated waste reception, pre-treatment, CAPCS extraction, the digesters, the centrifuge, the composting tunnels, the desulphurisation, the emergency flare, the CHPs, the ASP and the biological waste water treatment plant (about 115.12 136.07 t/d SSOW input); and

         Process fine-tune adjustment of the ASP operational parameters with new treatment media, CEMS/SCADA modification and improvement work following equipment failures and the alteration of different operation modes and measures to adapt to the high variation of SSOW nature and sources;

         Servicing (included adjusting of some of the operating parameters, valve check/adjustment, cable plug connection, ignition timing, spark plug checking, etc.) of the CHP2; and

         Modification of the ASP (included upgrading of the exhaust blower of the economizer, modification of the blower, motor, ducts and pipework and trials using various operation parameters to improve the performance of the equipment) to control the air emission.

2.4                                       Project Organisation and Management Structure

The project organisation chart and contact details are shown in Annex B.

2.5                                       Status of Environmental Approval Documents

A summary of the valid permits, licences, and/or notifications on environmental protection for this Project is presented in Table 2.2.

Table 2.2         Summary of Environmental Licensing, Notification and Permit Status

Permit/ Licences/ Notification

Reference

Validity Period

Remarks

Environmental Permit

FEP-01/395/2010/C

 

Throughout the Contract

 

Permit granted on 21 December 2015

 

Notification of Construction Works under the Air Pollution Control (Construction Dust) Regulation

Ref No. 386715

Throughout the Contract

-

Effluent Discharge License

WT00038391-2021

7 July 2021 30 June 2026

Approved on 7 July 2021

Chemical Waste Producer Registration

WPN 5213-961-O2231-01

Throughout the Contract

Approved on 29 April 2015

Chemical Waste Producer Registration

WPN 5213-961-O2231-02

Throughout the Contract

Approved on 10 November 2017

Waste Disposal Billing Account

Account number: 702310

Throughout the Contract

-

3                                            Environmental Monitoring and Audit Requirements

3.1                                       Environmental Monitoring

The air quality (including odour) monitoring to be carried out during the operation phase of the Project are described below.  Although water quality monitoring is not required for the operation phase under the EM&A programme, there are water quality monitoring requirement under the Water Discharge Licence of the plant under the Water Pollution Control Ordinance (WPCO).  As part of this EM&A programme, the monitoring results will be reviewed to check the compliance with the WPCO requirements.

3.1.1                                 Air Quality

According to the EM&A Manual and EP requirements, stack monitoring are required during the operation phase of the Project. 

On-line monitoring (using continuous environmental monitoring system (CEMS) shall be carried out for the centralised air pollution unit (CAPCS), cogeneration units (CHP) and the ammonia stripping plant (ASP) during the operation phase.  The last calibration was carried out in January 2023.

The monitoring data is transmitted instantaneously to EPD (Regional Office) by telemetry system.

When the on-line monitoring for certain parameter cannot be undertaken, monitoring will be carried out using the following methodology approved by the EPD.

Table 3.1         Sampling and Laboratory Analysis Methodology

Parameters

Method

Stacks to be Monitored

Gaseous and vaporous organic substances (including methane)

USEPA Method 18

         CAPCS

         CHP

         ASP

Particulate

USEPA Method 5

         CAPCS

         CHP

         ASP

Carbon monoxide (CO)

USEPA Method 10

         CHP

         ASP

Nitrogen oxides (NOx)

USEPA Method 7E

         CHP

         ASP

Sulphur dioxide (SO2);

USEPA Method 6

         CHP

         ASP

Hydrogen chloride (HCl)

USEPA Method 26A

         CHP

         ASP

Hydrogen fluoride (HF)

USEPA Method 26A

         CHP

         ASP

Oxygen (O2);

USEPA Method 3A

         CAPCS

         CHP

         ASP

Velocity and Volumetric Flow

USEPA Method 2

         CAPCS

         CHP

         ASP

Ammonia (NH3)

USEPA CTM 027

         ASP

Odour (including NH3 and H2S)

EN 13725

         CAPCS

Water vapour content (continuous measurement of the water vapour content should not be required if the sample exhaust gas is dried before the emissions are analysed)

USEPA Method 4

         CAPCS

         CHP

         ASP

Temperature

USEPA Method 4

         CAPCS

         CHP

         ASP

With reference to the EM&A Manual, the air emission of the stacks shall meet the following emission limits as presented in Tables 3.2 to 3.5.

Table 3.2         Emission Limit for CAPCS Stack

Parameter

Emission Level (mg/Nm3) (a)

VOCs (including methane)

680

Dust (or Total Suspended Particulates (TSP))

6

Odour (including NH3 & H2S)

220 (b)

Notes:

(a)     Hourly average concentration

(b)     The odour unit is OU/Nm3

Table 3.3         Emission Limit for CHP Stack

Parameter

Maximum Emission Level (mg/Nm3) (a) (b)

Dust (or Total Suspended Particulates)

15

Carbon Monoxide

650

NOx

300

SO2

50

NMVOCs (c)

150

VOCs (including methane) (d)

1,500

HCl

10

HF

1

Notes:

(a)  All values refer to an oxygen content in the exhaust gas of 6% and dry basis.

(b)  Hourly average concentration

(c)  NMVOCs should be monitored by gas sampling and laboratory analysis at an agreed interval.  For the first 12 months (starting from August 2019), monitoring should be carried out at quarterly intervals. The monitoring frequency should then be reduced to half-yearly for next 12 months (starting from August 2020).

(d)  The VOCs emission limit include methane as biogas is adopted as fuel in the combustion process.

Table 3.4         Emission Limit for ASP Stack

Parameter

Maximum Emission Level (mg/Nm3) (a) (b)

Dust (or Total Suspended Particulates)

5

Carbon Monoxide

100

NOx

200

SO2

50

VOCs (including methane) (c)

20

NH3

35

HCl

10

HF

1

Notes:

(a)        All values refer to an oxygen content in the exhaust gas of 11% and dry basis.

(b)        Hourly average concentration

(c)         The VOCs emission limit include methane as biogas is adopted as fuel in the combustion process.

Table 3.5         Emission Limit for Standby Flaring Gas Unit ([2])

Parameter

Maximum Emission level (mg/Nm3) (a) (b)

Dust (or Total Suspended Particulates)

5

Carbon Monoxide

100

NOx

200

SO2

50

VOCs (including methane) (c)

20

HCl

10

HF

1

Notes:

(a)     All values refer to an oxygen content in the exhaust gas of 11% and dry basis.

(b)     Hourly average concentration

(c)      The VOCs emission limit include methane as biogas is adopted as fuel in the combustion process.

3.1.2                                 Odour

To determine the effectiveness of the proposed odour mitigation measures and to ensure that the operation of the ORRC1 will not cause adverse odour impacts, odour monitoring of the CAPCS stack (see Section 3.1.1) and odour patrol will be carried out.

Odour patrol shall be conducted by independent trained personnel/ competent persons in summer months (i.e. from July to September) for the first two operational years of ORRC1 at monthly intervals along an odour patrol route at the Project Site boundary as shown in Annex A

The perceived odour intensity is divided into 5 levels.  Table 3.6 describes the odour intensity for different levels.

Table 3.6         Odour Intensity Level

Level

Odour Intensity

0

Not detected. No odour perceived or an odour so weak that it cannot be easily characterised or described

1

Slight identifiable odour, and slight chance to have odour nuisance

2

Moderate identifiable odour, and moderate chance to have odour nuisance

3

Strong identifiable, likely to have odour nuisance

4

Extreme severe odour, and unacceptable odour level

Table 3.7 shows the action level and limit level to be used for odour patrol. Should any exceedance of the action and limit levels occurs, actions in accordance with the event and action plan in Table 3.8 should be carried out.

Table 3.7         Action and Limit Levels for Odour Nuisance

Parameter

Action Level

Limit Level

Odour Nuisance (from odour patrol)

When one documented compliant is received (a), or Odour Intensity of 2 is measured from odour patrol.

Two or more documented complaints are received (a) within a week; or

Odour intensity of 3 or above is measured from odour patrol.

Note:

(a)        Once the complaint is received by the Project Proponent (EPD), the Project Proponent would investigate and verify the complaint whether it is related to the potential odour emission from the ORRC1 and its on-site wastewater treatment unit.

Table 3.8         Event and Action Plan for Odour Monitoring

Event

Action

 

Person-in-charge of Odour Monitoring

Project Proponent (a)

Action Level

 

 

Exceedance of action level (Odour Patrol)

1. Identify source/reason of exceedance;

2. Repeat odour patrol to confirm finding.

1. Carry out investigation to identify the source/reason of exceedance.   Investigation should be completed within 2 weeks;

2. Rectify any unacceptable practice;

3. Implement more mitigation measures if necessary;

4. Inform Drainage Services Department (DSD) or the operator of the Siu Ho Wan Sewage Treatment Works (SHWSTW) if exceedance is considered to be caused by the operation of the SHWSTW.

5. Inform North Lantau Refuse Transfer Station (NLTS) operator if exceedance is considered to be caused by the operation of NLTS.

Exceedance of action level (Odour Complaints)

1. Identify source/reason of exceedance;

2. Carry out odour patrol to determinate odour intensity.

1. Carry out investigation and verify the complaint whether it is related to potential odour emission from the nearby SHWSTW;

2. Carry out investigation to identify the source/reason of exceedance.  Investigation should be completed within 2 weeks;

3. Rectify any unacceptable practice;

4. Implement more mitigation measures if necessary;

5. Inform DSD or the operator of the SHWSTW if exceedance is considered to be caused by the operation of the SHWSTW.

6. Inform NLTS operator if exceedance is considered to be caused by the operation of NLTS.

Limit Level

 

 

Exceedance of limit level

1. Identify source/reason of exceedance;

2. Inform EPD;

3. Repeat odour patrol to confirm findings;

4. Increase odour patrol frequency to bi-weekly;

5. Assess effectiveness of remedial action and keep EPD informed of the results;

6. If exceedance stops, cease additional odour patrol.

1. Carry out investigation to identify the source/reason of exceedance.  Investigation should be completed within 2 week;

2. Rectify any unacceptable practice;

3. Formulate remedial actions;

4. Ensure remedial actions properly implemented;

5. If exceedance continues, consider what more/enhanced mitigation measures should be implemented;

6. Inform DSD or the operator of the SHWSTW if exceedance is considered to be caused by the operation of the SHWSTW.

Note:

(a)     Project Proponent shall identify an implementation agent.

3.2                                       Site Audit

Environmental mitigation measures (related to air quality, water quality, waste, land contamination, hazard-to-life, and landscape and visual) to be implemented during the operation phase of the Project are recommended in the approved EIA Report and EM&A Manual and are summarised in Annex C.  Monthly site audits for operation phase will be carried out to check the implementation of these measures.

3.2.1                                 Water Quality

Compliance audits are to be undertaken to ensure that a valid discharge licence has been issued by EPD prior to the discharge of effluent from the operation of the Project site.  Under Effluent Discharge Licence WT00038391-2021 (effective from July 2021), the effluent quality shall meet the discharge limits as described in Table 3.9 and Table 3.10

 

Table 3.9         Discharge Limits for Effluent from the Effluent Storage Tank (as stipulated in WT00038391-2021)

Parameters

Discharge Limit (mg/L)

Flow Rate (m3/day) (a)

645

pH (pH units) (b)

6-10 (c)

Suspended Solids (b)

800

Biochemical Oxygen Demand (5 days, 20) (b)

800

Chemical Oxygen Demand (b)

2,000

Oil & Grease (b)

40

Total Nitrogen (b)

200

Total Phosphorus (b)

50

Surfactants (total) (b)

25

Notes:

(a)     Flow rate is not a parameter required to be monitored and reported by the Contractor in accordance to Section B2 of the Effluent Discharge Licence under the WPCO. 

(b)     Parameters required to be monitored and reported by the Contractor in accordance to Section B2 of the Effluent Discharge Licence under the WPCO. 

(c)      Range.

Table 3.10       Discharge Limits for Effluent from the Petrol Interceptor(s) (as stipulated in WT00038391-2021)

Parameters

Discharge Limit (mg/L)

Flow Rate (m3/day)

245 (a)

Suspended Solids (b)

30

Chemical Oxygen Demand (c)

80

Oil & Grease (c)

20

Surfactants (total) (b)

15

Notes:

(a)     The surface runoff flow rate limit was estimated by the overall yearly rainfall data.  As the actual flowrate from the petrol interceptors depends on the weather condition instead of the performance of the petrol interceptor, monitoring and reporting of this parameter is not required.  Hence this parameter is not reported in Table 4.10. and Table 4.11

(b)     Parameter not required to be reported in accordance to Section B2 of the Effluent Discharge Licence under the WPCO. 

(c)      Parameters required to be reported in accordance to Section B2 of the Effluent Discharge Licence under the WPCO. 

3.2.2                                 Landscape and Visual

In accordance with EM&A Manual, the landscape and visual mitigation measures shall be implemented. 

For operation phase, site inspection shall be conducted once a month for the first year of operation of the Project.  All measures as stated in the implementation schedule of the EM&A Manual (see Annex C), including compensatory planting, undertaken by both the Contractor and the specialist Landscape Sub-Contractor during the first year of the operation phase shall be audited by a Registered Landscape Architect (RLA) to ensure compliance with the intended aims of the measures and the effectiveness of the mitigation measures. 

4                                             Monitoring Results

4.1                                       Air Quality

4.1.1                                 Operation Phase Monitoring

The concentrations of concerned air pollutants emitted from the stacks of the CAPCS, CHP, and ASP during the reporting period are monitored on-line by the continuous environmental monitoring system (CEMS).  During the reporting period, the standby flare operated on 14, 19, 20 April and 10 and 30 May 2022.

With reference to the emission limits shown in Tables 3.2, 3.3 and 3.4, the hourly average concentrations and the number of exceedances of the concerned air emissions monitored for the CAPCS, CHP, ASP and the Standby Flaring Gas Unit during this reporting period are presented in Tables 4.1 to 4.5.  

It should be noted that measurements recorded under abnormal operating conditions, e.g. start up and stopping of stacks and unstable operation, as well as test runs and interference of sensor, are disregarded.

Table 4.1         Hourly Average of Parameters Recorded for CAPCS

Parameter

Range of Hourly Average Conc. (mg/Nm3)

Emission Limit (mg/Nm3)

Exceedance Identified

Remarks

VOCs (including methane)

0.00 533.48

 

680

Nil

Nil

Dust (or TSP)

0.00 0.02

6

Nil

Nil

Odour (including NH3 & H2S) (a)

0.00 180.17

220

Nil

Nil

Note:

(a)     The odour unit is OU/Nm3.

 

Table 4.2         Hourly Average of Parameters Recorded for CHP 1

Parameter

Range of Hourly Average Conc. (mg/Nm3) (a)

Max. Emission Limit (mg/Nm3)

Exceedance

Identified

Remarks

Dust (or TSP)

0 - 12

15

Nil

Nil

Carbon Monoxide

0 - 639

650

Nil

Nil

NOx

0 - 300

300

Nil

Nil

SO2

0 - 297 (c)

50

Identified (c)

De-sulphurisation system tripped / Under Maintenance

VOCs (including methane) (b)

0 - 1,037

1,500

Nil

Nil

HCl

0 - 3

10

Nil

Nil

HF

0 - 1

1

Nil

Nil

Notes:

(a)     All values refer to an oxygen content in the exhaust gas of 6% and dry basis.

(b)     The VOCs emission limit include methane as biogas is adopted as fuel in the combustion process.

(c)       Dates with exceedances on SO2 (number of exceedance on the day) were identified on 25 (1) March 2022; 5 (1), 10 (16), 11 (13), 12 (2) and 15 (4) April 2022; 16 (6), 17 (1), 18 (1), 19 (10), 20 (24), 21 (24), 22 (4), 24 (6), 25 (1), 27 (4), 28 (8), 29 (3) and 30 (4) May 2022.

 

Table 4.3         Hourly Average of Parameters Recorded for CHP 2

Parameter

Range of Hourly Average Conc. (mg/Nm3) (a)

Max. Emission Limit (mg/Nm3)

Exceedance

Identified

Remarks

Dust (or TSP)

0 12

15

Nil

Nil

Carbon Monoxide

0 629

650

Nil

Nil

NOx

0 300

300

Nil

Nil

SO2

0 308

50

Identified (c)

De-sulphurisation system tripped / Under Maintenance

VOCs (including methane) (b)

0 800

1,500

Nil

Nil

HCl

0 1

10

Nil

Nil

HF

0 1

1

Nil

Nil

Notes:

(a)     All values refer to an oxygen content in the exhaust gas of 6% and dry basis.

(b)     The VOCs emission limit include methane as biogas is adopted as fuel in the combustion process.

(c)      Dates with exceedances on SO2 (number of exceedance on the day) were identified on 10 (5), 11 (13) and 15 (4) April 2022; 10 (4), 16 (1), 17 (9), 18 (21), 19 (22), 20 (22), 21 (11), 24 (11), 25 (16), 26 (24), 27 (24), 28 (22), 29 (19), 30 (24) and 31 (18) May 2022.

 

Table 4.4         Hourly Average of Parameters Recorded for CHP 3

Parameter

Range of Hourly Average Conc. (mg/Nm3) (a)

Max. Emission Limit (mg/Nm3)

Exceedances

Identified

Remarks

Dust (or TSP)

0 15

15

Nil

Nil

Carbon Monoxide

0 605

650

Nil

Nil

NOx

0 440

300

Identified (c)

System unstable (e.g. low efficiency, unstable column temperature )

SO2

0 427

50

Identified (d)

Desulpurisation system tripped / Under Maintenance

VOCs (including methane) (b)

0 1,149

1,500

Nil

Nil

HCl

0 3

10

Nil

Nil

HF

0 1

1

Nil

Nil

Notes:

(a)     All values refer to an oxygen content in the exhaust gas of 6% and dry basis.

(b)     The VOCs emission limit include methane as biogas is adopted as fuel in the combustion process. 

(c)      Dates with exceedances on NOx (number of exceedances on the day) were identified on 4 (1), 21 (6), 22 (12), 23 (22), 24 (18), 25 (13), 26 (15), 28 (3), 29 (7) and 30 (23) April 2022; and 1 (1) May 2022.

(d)     Date with exceedances on SO2 (number of exceedance on the day) was identified on 1 (1), 3 (1), 10 (4), 13 (1), 14 (22), 15 (18), 16 (3), 17 (16), 18 (24), 19 (12), 22 (21), 23 (24), 24 (18), 25 (18), 26 (22), 27 (16), 28 (15), 29 (19), 30 (20) and 31 (17) May 2022 .

 

Table 4.5         Hourly Average of Parameters Recorded for ASP

Parameter

Range of Hourly Average Conc. (mg/Nm3) (a)

Max. Emission Limit (mg/Nm3)

Exceedances

Identified

Remarks

Dust (or TSP)

0 5

5

Nil

Nil

Carbon Monoxide

0 1,046

100

Identified (c)

System unstable (e.g. low efficiency, unstable column temperature )

NOx

0 541

200

Identified (d)

System unstable (e.g. low efficiency, unstable column temperature )

SO2

0 323

50

Identified (e)

Desulpurisation system tripped

VOCs (including methane) (b)

0 1,486

20

Identified (f)

System unstable (e.g. low efficiency, unstable column temperature )

NH3

0 229

35

Identified (g)

System unstable (e.g. low efficiency, unstable column temperature )

HCl

0 4

10

Nil

Nil

HF

0 2

1

Identified (h)

System unstable (e.g. low efficiency, unstable column temperature )

Notes:

(a)     All values refer to an oxygen content in the exhaust gas of 11% and dry basis.

(b)     The VOCs emission limit include methane as biogas is adopted as fuel in the combustion process.

(c)      Date with exceedances on CO (number of exceedances on the day) were identified on 8 (1), 13 (1) and 27 (1) March 2022; 18 (1) April 2022; 20 (1) May 2022.

(d)     Date with exceedances on NOx (number of exceedances on the day) were identified on 1 (1), 3 (1), 4 (1), 6 (2), 7 (2), 8 (8), 13 (1), 14 (6), 15 (3), 16 (6), 17 (3), 24 (4), 25 (7), 27 (1), 28 (1) and 31 (4) March 2022; 1 (1), 2 (2), 5 (4), 8 (2), 9(8), 11 (7), 12 (6), 14 (4), 15 (4), 16 (5), 17 (12), 19 (10), 20 (10), 21 (3), 22 (5), 26 (1), 27 (3), 28 (4) and 29 (4) April 2022; 1 (2), 2 (2), 3 (2), 5 (9), 8 (18), 9 (10), 10 (5), 11 (7), 12 (19), 13 (15), 14 (20), 17 (2), 18 (5), 19 (11), 20 (1), 21 (5), 22 (7), 23 (2), 25 (4), 27 (3), 28 (5), 29 (14) and 30 (4) May 2022.

(e)     Dates with exceedances on SO2 (number of exceedances on the day) were identified on 6 (1) March 2022; 5 (3), 10 (16), 11 (9), 12 (2), 15 (5) and 28 (1) April 2022; 13 (8), 14 (23), 15 (24), 16 (24), 17 (24), 18 (24), 19 (18), 20 (23), 21 (24), 22 (18), 23 (24), 24 (24), 25 (23), 26 (24), 27 (23), 28 (20), 29 (15), 30 (18) and 31 (5) May 2022.

(f)      Dates with exceedances on VOCs (number of exceedances on the day) were identified on 13 (1) March 2022; 16 (1), 18 (1), 28 (1) and 29 (1) April 2022; 20 (1), 28 (1) and 29 (2) May 2022.

(g)     Dates with exceedances on NH3 (number of exceedances on the day) were identified on 2 (3), 3 (5), 4 (1), 6 (1), 8 (2), 12 (2), 13 (7), 14 (2), 16 (4), 17 (5), 24 (1), 25 (4), 26 (7), 27 (2), 28 (1), 30 (2) and 31 (4) March 2022; 3 (1), 6 (6), 8 (1), 9 (1), 11 (1), 12 (8), 13 (6), 17 (3), 18 (2), 21 (2), 23 (2), 28 (2) and 29 (1) April 2022; 3 (9), 5 (1), 15 (4), 17 (4), 18 (2), 20 (1), 22 (5), 23 (2) and 26 (6) May 2022.

(h)     Dates with exceedances on HF (number exceedances on the day) were identified on 5 (2) and 22 (2) May 2022.

 

Table 4.6         Hourly Average of Parameters Recorded for the Standby Flaring Gas Unit

Parameter

Range of Hourly Average Conc. (mg/Nm3) (a)(c)

Max. Emission Limit (mg/Nm3)

Exceedances

Identified

Remarks

Dust (or TSP)

0 0

5

Nil

Nil

Carbon Monoxide

0 0

100

Nil

Nil

NOx

0 19

200

Nil

Nil

SO2

0 30

50

Nil

Nil

VOCs (including methane) (b)

0 17

20

Nil

Nil

HCl

0 1

10

Nil

Nil

HF

0 1

1

Nil

Nil

Notes:

(a)     All values refer to an oxygen content in the exhaust gas of 11% and dry basis.

(b)     The VOCs emission limit include methane as biogas is adopted as fuel in the combustion process.

(c)      During the reporting period, the standby flare operated on 14, 19 and 20 April 2022; 10 and 30 May 2022

 

4.2                                       Odour

4.2.1                                 Operation Phase Monitoring

No odour patrol was required to be conducted for this reporting period.  

4.3                                       Water Quality

4.3.1                                 Operation Phase Monitoring

Effluent discharge was sampled from the outlet chamber of the Effluent Storage Tank monthly and from the Petrol Interceptor(s) bi-monthly as stipulated in the operation phase discharge licence. The results of the discharge samples from the outlet chamber of the Effluent Storage Tank are recorded in Table 4.7 to 4.9 and the results from the Petrol Interceptors are recorded in Table 4.10 and Table 4.11.

Table 4.7         Results of the Discharge Sample Collected from the Outlet Chamber of the Effluent Storage Tank in March 2022

Parameters

Discharged Effluent Concentration (mg/L)

Discharge Limit (mg/L)

Compliance with Discharge Limit

Flow Rate (m3/day) (a)

0 - 281 (e)

645

Yes

pH (pH units) (b)

7.60 8.27 (e)

6-10 (c)

Yes

Suspended Solids (b) (d)

76 (d)

800

Yes

Biochemical Oxygen Demand (5 days, 20) (b) (d)

34 (d)

800

Yes

Chemical Oxygen Demand (b) (d)

760 (d)

2,000

Yes

Oil & Grease (b) (d)

<5 (d)

40

Yes

Total Nitrogen (b) (d)

77.3 (d)

200

Yes

Total Phosphorus (b) (d)

20.2 (d)

50

Yes

Surfactants (total) (b) (d)

5.5 (d)

25

Yes

Notes:

(a)     Parameter not required to be reported in accordance to Section B2 of the Effluent Discharge Licence under the WPCO. 

(b)     Parameters required to be reported in accordance to Section B2 of the Effluent Discharge Licence under the WPCO. 

(c)      Daily Range.

(d)     Effluent sample collected on 30 March 2022.

(e)     Data collected daily in the reporting month.

Table 4.8         Results of the Discharge Sample Collected from the Outlet Chamber of the Effluent Storage Tank in April 2022

Parameters

Discharged Effluent Concentration (mg/L)

Discharge Limit (mg/L)

Compliance with Discharge Limit

Flow Rate (m3/day) (a)

34 - 244 (e)

645

Yes

pH (pH units) (b)

7.69 8.08 (e)

6-10 (c)

Yes

Suspended Solids (b) (d)

75 (d)

800

Yes

Biochemical Oxygen Demand (5 days, 20) (b) (d)

29 (d)

800

Yes

Chemical Oxygen Demand (b) (d)

756 (d)

2,000

Yes

Oil & Grease (b) (d)

<5 (d)

40

Yes

Total Nitrogen (b) (d)

50.2 (d)

200

Yes

Total Phosphorus (b) (d)

18.1 (d)

50

Yes

Surfactants (total) (b) (d)

<1.0 (d)

25

Yes

Notes:

(a) Parameter not required to be reported in accordance to Section B2 of the Effluent Discharge Licence under the WPCO.

(b) Parameters required to be reported in accordance to Section B2 of the Effluent Discharge Licence under the WPCO.

(c) Daily Range.

(d) Effluent sample collected on 22 April 2022.

(e) Data collected daily in the reporting month.

 

Table 4.9         Results of the Discharge Sample Collected from the Outlet Chamber of the Effluent Storage Tank in May 2022

Parameters

Discharged Effluent Concentration (mg/L)

Discharge Limit (mg/L)

Compliance with Discharge Limit

Flow Rate (m3/day) (a)

7 303 (e)

645

Yes

pH (pH units) (b)

7.30 8.10 (e)

6-10 (c)

Yes

Suspended Solids (b) (d)

148 (d)

800

Yes

Biochemical Oxygen Demand (5 days, 20) (b) (d)

33 (d)

800

Yes

Chemical Oxygen Demand (b) (d)

939 (d)

2,000

Yes

Oil & Grease (b) (d)

<5 (d)

40

Yes

Total Nitrogen (b) (d)

116 (d)

200

Yes

Total Phosphorus (b) (d)

28.0 (d)

50

Yes

Surfactants (total) (b) (d)

1.4 (d)

25

Yes

Notes:

(a) Parameter not required to be reported in accordance to Section B2 of the Effluent Discharge Licence under the WPCO.

(b) Parameters required to be reported in accordance to Section B2 of the Effluent Discharge Licence under the WPCO.

(c) Daily Range.

(d) Effluent sample collected on 19 May 2022.

(e) Data collected daily in the reporting month.

Table 4.10       Results of the Discharge Sample from the Petrol Interceptor 1 on 13 April 2022

Parameters

Discharged Effluent Concentration (mg/L)

Discharge Limit (mg/L)

Compliance with Discharge Limit

Suspended Solids (b)

<2 (a)

30

Yes

Chemical Oxygen Demand (c)

<5 (a)

80

Yes

Oil & Grease (c)

<5 (a)

20

Yes

Surfactants (total) (b)

<1.0 (a)

15

Yes

Notes:

(a)     Effluent sample collected on 13 April 2022.

(b)     Parameter not required to be reported in accordance to Section B2 of the Effluent Discharge Licence under the WPCO. 

(c)      Parameters required to be reported in accordance to Section B2 of the Effluent Discharge Licence under the WPCO. 

Table 4.11       Results of the Discharge Sample from the Petrol Interceptor 2 on 13 April 2022

Parameters

Discharged Effluent Concentration (mg/L)

Discharge Limit (mg/L)

Compliance with Discharge Limit

Suspended Solids (b)

<2 (a)

30

Yes

Chemical Oxygen Demand (c)

<5 (a)

80

Yes

Oil & Grease (c)

<5 (a)

20

Yes

Surfactants (total) (b)

<1.0 (a)

15

Yes

Notes:

(a)     Effluent sample collected on 13 April 2022.

(b)     Parameter not required to be reported in accordance to Section B2 of the Effluent Discharge Licence under the WPCO. 

(c)      Parameters required to be reported in accordance to Section B2 of the Effluent Discharge Licence under the WPCO. 

No non-compliance of discharge limit of all parameters from Petrol Interceptor 1 and 2 was recorded during the reporting period.

4.4                                       Waste Management

4.4.1                                 Operation Phase Monitoring

Wastes generated from the operation of the Project include chemical waste, wastes generated from pre-treatment process and general refuse ([3]).  Reference has been made to the Monthly Summary Waste Flow Table prepared by the Contractor (see Annex D).  With reference to the relevant handling records and trip tickets of this Project, the quantities of different types of waste generated from the operation of the Project in the reporting month are summarised in Table 4.12

Table 4.12       Quantities of Waste Generated from the Operation of the Project

Month / Year

Chemical Waste

Waste Generated from
Pre-treatment Process

General Refuse

 

Disposal of at CWTC

Disposed of at Landfill (a)

Recycled (b) 

Disposed of at Landfill (a) (c)

Recycled (d) 

March 2022

0 L

253.75 tonnes

0.00 tonnes

2.65 tonnes

0.00 tonne

April 2022

1,240 L (e)

253.45 tonnes

0.00 tonnes

2.53 tonnes

0.00 tonne

May 2022

0 L

354.94 tonnes

0.00 tonnes

2.76 tonnes

0.00 tonne

Notes:

(a)     Waste generated from pre-treatment process and general refuse other than chemical waste and recyclables were disposed of at NENT landfill by sub-contractors.

(b)     Among waste generated from pre-treatment process, 0.00 tonne of metals, 0.00 tonne of papers/ cardboard packing and 0.00 tonne of plastics were sent to recyclers for recycling during the reporting period.

(c)      It was assumed that four 240-litre bins filled with 80% of general refuse were collected at each collection.  The general refuse density was assumed to be around 0.15 kg/L.

(d)     Among general refuse, 0.00 tonnes of metals, 0.00 tonnes of papers/ cardboard packing and 0 tonnes of plastics were sent to recyclers for recycling during the reporting period.

(e)     It included 20 L of spent acid, 1,200 L of spent lube oil, 20 L of spent alkaline material.

 

5                                            Site Audit

5.1                                       Environmental Site Audit

5.1.1                                 Operation Phase

The monthly inspections of the operation phase of the Project covered the operation phase environmental site inspections.  The inspections checked the implementation of the recommended mitigation measures for air quality, landscape and visual, water quality, waste (land contamination) and hazard-to-life stated in the Implementation Schedule (see Annex C).  

Follow-up actions resulting from the site inspections were generally taken as reported by the Contractor.  The Contractor has implemented environmental mitigation measures recommended in the approved EIA Report and EM&A Manual. 

March 2022

The monthly inspection of the operation phase of the Project on 11 March 2022 covered the operation phase environmental site audit.  Joint site inspections was conducted by representatives of the Contractor, IEC and the MT on 11 March 2022 as required for the operation of the Project.

April 2022

The monthly inspection of the operation phase of the Project on 8 April 2022 covered the operation phase environmental site audit.  Joint site inspections was conducted by representatives of the Contractor, IEC and the MT on 8 April 2022 as required for the operation of the Project.

May 2022

The monthly inspection of the operation phase of the Project on 20 May 2022 covered the operation phase environmental site audit.  Joint site inspections was conducted by representatives of the Contractor, IEC and the MT on 20 May 2022 as required for the operation of the Project.

5.2                                       Landscape and Visual Audit

It was confirmed that the necessary landscape and visual mitigation measures during the operation phase as summarised in Annex C were generally implemented by the Contractor.  No non-compliance in relation to the landscape and visual mitigation measures was identified during the site audits in this reporting period and therefore no further actions are required.  The ET/MT will keep track of the EM&A programme to check compliance with environmental requirements and the proper implementation of all necessary mitigation measures.

March 2022

Monthly inspection of the landscape and visual mitigation measures for the operation phase of the Project was performed on 11 March 2022.

April 2022

Monthly inspection of the landscape and visual mitigation measures for the operation phase of the Project was performed on 8 April 2022.  

May 2022

Monthly inspection of the landscape and visual mitigation measures for the operation phase of the Project was performed on 20 May 2022. 

6                                            Environmental Non-conformance

6.1                                       Summary of Environmental Non-Compliance

March 2022

Non-compliance of emission limits of SO2 from CHP 1 and CO, NOx, VOCs and NH3 from ASP were recorded during the reporting period.

 

The Contractor has reviewed the organic waste treatment processes (i.e. waste reception, waste pre-treatment, anaerobic digesters, and composting processes) and found that they were operated normally during the reporting period. The Contractor has investigated the de-sulphurisation system and the ASP, the potential causes for the exceedance were identified.

 

The exceedances of SO2 from CHP 1 occurred due to malfunctioning of the control instrument. A blower within the de-sulphurisation system was tripped and immediate maintenance work was carried out by on-site maintenance team and the issue was fixed on the same day.

 

The exceedance of CO, NOx, VOCs and NH3 from ASP occurred due to system instability caused by leakage of the internal tubing of the economiser. The Contractor arranged urgent maintenance to the structure. The ASP has been under continuous upgrading work throughout the reporting month.

The investigation reports of the above exceedance are presented in Annex F.

April 2022

Non-compliance of emission limits of SO2 and NOx from the CHPs and CO, NOx, SO2, VOCs and NH3 from ASP were recorded during the reporting period.

 

The Contractor has reviewed the organic waste treatment processes (i.e. waste reception, waste pre-treatment, anaerobic digesters, and composting processes) and found that they were operated normally during the reporting period. The Contractor has investigated the de-sulphurisation system and the ASP, the potential causes for the exceedance were identified.

 

The exceedances of SO2 from CHP 1, 2 and ASP occurred due to tripping of the de-suphurisation system caused by malfunctioning of a blower. Immediate maintenance work and filter cleaning was carried out. The issue was fixed on the same day. The exceedances of NOx occurred due to unstable system caused by leakage in the CHP 3. The issues was temporarily fixed and the situation will be monitored continuously by the Contractor.

 

The exceedance of CO, NOx, VOCs and NH3 from ASP occurred due to system instability caused by motor overheating, unstable water flow and leakage of pump. The Contractor arranged urgent maintenance to the affected system and upgrading works are on-going.

 

The investigation reports of the above exceedance are presented in Annex F.

May 2022

Non-compliance of emission limits of SO2 from the CHPs, NOx from CHP3 and CO, NOx, SO2, VOCs, NH3 and HF from ASP were recorded during the reporting period.

 

The Contractor has reviewed the organic waste treatment processes (i.e. waste reception, waste pre-treatment, anaerobic digesters, and composting processes) and found that they were operated normally during the reporting period. The Contractor has investigated the de-sulphurisation system, CHPs and the ASP, the potential causes for the exceedance were identified.

 

The exceedances of SO2 from CHPs and ASP occurred due to tripping of the de-sulphurisation system caused by failure of one of the columns. The Contractor inspected the column and the pipes and pumps of the systems when exceedance and malfunctioning of the system were observed. Isolation of the affected system and maintenance of the columns were carried out and the performance of the system resumed to normal in late-May 2022. Activated carbon filter will be replaced in the coming reporting period to improve the SO2 removal efficiency.

 

The exceedances of NOx from CHP 3 in early May 2022 occurred due to insufficient feedstock. The exceedance of CO, NOx, VOCs, NH3 and HF from ASP occurred due to system instability caused by the ongoing performance optimisation of the ASP, resulting in a lowered temperature of the system and the incomplete combustion of biogas. The Contractor will continue to carry out maintenance and optimisation measures to restore the combustion efficiency so that the concerned pollutants will be effectively destroyed.

 

The investigation reports of the above exceedance are presented in Annex F.

6.2                                       Summary of Environmental Complaint

No complaint was received during the reporting period.

6.3                                       Summary of Environmental Summon and Successful Prosecution

No summon/prosecution was received during the reporting period.  The cumulative summons/prosecution log is shown in Annex E.

7                                            Future Key Issues

7.1                                       Key Issues for the Coming Reporting Period

Activities to be undertaken for the coming reporting period are:

         Operation of the Project; and

         Maintenance of CHP 2 (i.e. replacement of cylinder head) and modification of the ASP (i.e. repairing of economizers heat exchanger, mixing units and diesel generator) to control the air emission; and

         Cleaning of the suspension Buffer Tank.

8                                            Conclusions

This EM&A Report presents the EM&A programme undertaken during the reporting period from 1 March 2022 to 31 May 2022 in accordance with EM&A Manual (Version F) and requirements of EP (FEP-01/395/2010/C). 

For the operation phase, exceedances of the emission limits for stack monitoring (including CAPCS, CHP and ASP stacks) were recorded under normal operating conditions during the reporting period (see Table 8.1).

Table 8.1         Exceedances for Stack Emissions

Stack

Exceedances During the Reporting Period

Centralised Air Pollution Control Unit (CAPCS)

         Nil

Cogeneration Unit (CHP) 1

         Exceeded mission limit of SO2 on 25 March 2022; 5, 10, 11, 12 and 15 April 2022; 6, 17, 18, 19, 20, 21, 22, 24, 25, 27, 28, 29 and 30 May 2022.

Cogeneration Unit (CHP) 2

         Exceeded emission limit of SO2 on 10, 11 and 15 April 2022; 10, 16, 17, 18, 19, 20, 21, 24, 25, 26, 27, 28, 29, 30 and 31 May 2022.

Cogeneration Unit (CHP) 3

         Exceeded emission limit of NOx on 4, 21, 22, 23, 24, 25, 26, 28, 29 and 30 April 2022; 1 May 2022.

         Exceeded emission limit of SO2 on 1, 3, 10, 13, 14, 15, 16, 17, 18, 19, 22, 23, 24, 25, 26, 27, 28, 29, 30 and 31 May 2022.

Ammonia Stripping Plant (ASP)

         Exceeded emission limit of CO on 8, 13 and 27 March 2022; 18 April 2022; 20 May 2022.

         Exceeded emission limit of NOx on 1, 3, 4, 6, 7, 8, 13, 14, 15, 16, 17, 24, 25, 27, 28 and 31 March 2022; 1, 2, 5, 8, 9, 11, 12, 14, 15, 16, 17, 19, 20, 21, 22, 26, 27, 28 and 29 April 2022; 1, 2, 3, 5, 8, 9, 10, 11, 12, 13, 14, 17, 18, 19, 20, 21, 22, 23, 25, 27, 28, 29 and 30 May 2022.

         Exceeded emission limit of SO2 on 5, 10, 11, 12, 15 and 28 April 2022; 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 and 31 May 2022.

         Exceeded emission limit of VOCs on 13 March 2022; 16, 18, 28 and 29 April 2022; 20, 28 and 29 May 2022.

         Exceeded emission limit of NH3 on 2, 3, 4, 6, 8, 12, 13, 14, 16, 17, 24, 25, 26, 27, 28, 30 and 31 March 2022; 3, 6, 8, 9, 11, 12, 13, 17, 18, 21, 24, 28 and 29 April 2022; 3, 5, 15, 17, 18, 20, 22, 23 and 26 May 2022.

         Exceeded emission limit of HF on 5 and 22 May 2022.

 

In March 2022, the exceedances of SO2 from CHP 1 and CO, NOx, VOCs and NH3 from ASP were recorded during the reporting period. The exceedances of SO2 from CHP 1 occurred due to malfunctioning of an instrument (blower) of the de-sulphurisation system. The exceedance of CO, NOx, SO2, VOCs and NH3 from ASP occurred due to system instability caused by the leakage of the internal tubing of the economiser of the ASP. 

 

In April 2022, the exceedances of SO2 from CHP 1, 2 and CO, NOx, SO2, VOCs and NH3 from ASP were recorded during the reporting period. The exceedances of SO2 from CHP 1, 2 and ASP occurred due to malfunctioning of an instrument (blower) of the de-sulphurisation system. The exceedances of NOx from CHP 3 occurred due to unstable system caused by leakage in the CHP 3. The exceedance of CO, NOx, VOCs and NH3 from ASP occurred due to system instability caused by motor overheating, unstable water flow and leakage of pump. 

 

In May 2022, non-compliance of emission limits of SO2 from the CHPs, NOx from CHP 3 and CO, NOx, SO2, VOCs, NH3 and HF from ASP were recorded during the reporting period. The exceedances of SO2 from CHPs and the ASP occurred due to tripping of the de-sulphurisation system caused by the failure of one of the columns of the system. The exceedances of NOx from CHP 3 in early May 2022 occurred due to insufficient feedstock. The exceedance of CO, NOx, VOCs, NH3 and HF from ASP occurred due to system instability caused by the ongoing performance optimisation of the ASP, resulting in a lowered temperature of the system and the incomplete combustion of biogas.

The Contractor has replaced and maintained the malfunctioned parts (desulphurisation system, columns of the ASP, air blower), cleaning for various parts (i.e. stripping column and packaging of the ASP, air blows filter), reinstalled the ASP feed pump, and carried out fine-tuning of equipment of the ASP, the investigation on the underlying reasons of exceedances in CHP and ASP and the continuous seeking of better and more feedstock to increase biogas loading and testing at ASP to optimise combustion efficiency and overall performance.

No non-compliance to the effluent discharge limit was recorded during this reporting period.

The environmental control /mitigation measures related to air quality, water quality, waste (including land contamination prevention), hazard-to-life and landscape and visual recommended in the approved EIA Report and the EM&A Manual were properly implemented by the Contractor during the reporting period. 

Monthly landscape and visual monitoring were conducted in the reporting period.  The necessary landscape and visual mitigation measures recommended in the approved EIA Report were generally implemented by the Contractor. 

No complaint/summon/prosecution was received.


 

 

 

 

 

 



([1])     As some of the minor items are yet to be closed out in March 2019, the construction phase EM&A programme and Operation Phase EM&A programme were undertaking in parallel in March 2019.

([2])     A standby facility.  Only operate when the CHPs are not in operation or when the biogas generated exceeded the utilisation rate of the CHPs.

([3])     Public fill and construction waste may only be generated during maintenance works when there are civil or structural works.