Contents
Executive Summary
1.1 Purpose of the Report
1.2 Structure of the Report
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
4.1 Air Quality
4.1.1 Commissioning Phase Monitoring
4.1.2 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
5.1 Environmental Site Audit
5.1.1 Operation Phase
5.2 Landscape and Visual Audit
6 Environmental Non-conformance and Deficiencies
6.1 Summary of Environmental Non-Compliance and Deficiencies
6.2 Summary of Environmental Complaint
6.3 Summary of Environmental Summon and Successful Prosecution
7.1 Key Issues for the Coming Month
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 3.1Sampling and Laboratory Analysis Methodology
Table 3.2Emission Limit for CAPCS Stack
Table 3.3Emission Limit for CHP Stack
Table 3.4Emission Limit for ASP Stack
Table 3.5Emission Limit for Standby Flaring Gas Unit ()
Table 3.6Odour Intensity Level
Table 3.7Action and Limit Levels for Odour Nuisance
Table 3.8Event and Action Plan for Odour Monitoring
Table 3.9Discharge Limits for Effluent
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 4.5Hourly Average of Parameters Recorded for ASP
Table 4.6Results of the Discharge Sample
Table 4.7 Quantities of Waste Generated from the Construction of the Project
Table 4.8 Quantities of Waste Generated from the Operation of the Project
LIST OF ANNEXES
Annex A |
|
Annex B |
|
Annex C |
Calibration Certification for the On-line Stack Monitoring System |
Annex D |
|
Annex E |
|
Annex F |
Environmental complaint, Environmental Summons and Prosecution Log |
Annex G |
|
Annex H |
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 75th
monthly Environmental Monitoring and Audit (EM&A) report presenting the
EM&A works carried out during the period from 1 to 31 August 2021 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.
Environmental
Monitoring and Audit Progress
Air Quality
Monitoring
Exceedances on NOx and SO2 from CHP and NOx, SO2, VOCs and NH3 from ASP were recorded on the on-line monitoring
system. It should be noted that measurements recorded under
abnormal operating conditions, e.g. start up and stopping of stacks, unstable
operation, test runs and interference of sensor, are disregarded.
Exceedances in NOx of CHP were
found to be a result of the low biogas loading at the CHPs and the unstable
condition of CHP1. The exceedances of SO2 of CHPs and the ASP were found
to be a result of the tripping of the desulphurisation system. The
exceedances of ASP were found to be result of unstable condition at the thermal
destructor of the ASP.
The Contractor has implemented
mitigation measures to control the exceedance including regular maintenance of
the CHP by the supplier and regular fine-tuning, finding better and more
feedstock to increase biogas loading and testing at ASP to optimise combustion
efficiency and overall performance.
The Contractor is recommended to
closely monitor the processes of the modification of the CHP and 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.
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 ([6]).
Waste generated from the operation
of the Project includes chemical waste, waste generated from pre-treatment
process and general refuse.
3,420 L of chemical waste was
collected by licenced waste collector from the operation of the Project.
687.05 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 tonne of metals, 0.00 tonnes of papers/
cardboard packing and 0.00 tonne of plastics were sent to recyclers for
recycling during the reporting period.
Around 3.00 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 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.
Findings of
Environmental Site Audit
A
summary of the monitoring activities undertaken in this reporting period is
listed below:
· Joint
Environmental Site Inspections |
1
time |
1
monthly joint environmental site inspection was carried out by the
representatives of the Contractor and the MT. The IEC was also present at
the joint inspections on 3 August 2021. 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.
·
Modification of the CHP and ASP to control the air emission.
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.
This is the 75th EM&A report which summarises the monitoring results and audit findings for the EM&A programme during the reporting period from 1 to 31 August 2021.
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
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.
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 and treated an average of 93 tonnes of source separated organic waste per day during the reporting month.
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 100-130 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. |
The project organisation chart and contact details are shown in Annex B.
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 |
Effluent Discharge Licence |
WT00038391-2021 |
7 July 2021 – 30 June 2026 |
Approved on 7 July 2021 |
Chemical Waste Producer Registration |
WPN 5213-961-O2231-02 |
Throughout the implementation of the Project |
Approved on 10 November 2017 |
Waste Disposal Billing Account |
Account number: 702310 |
Throughout the Contract |
- |
The air quality (including odour) monitoring to be carried out during the commissioning and 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.
According to the EM&A Manual and EP requirements, stack monitoring are required during the commissioning and 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 commissioning and operation phase. The calibration certificate for the on-line monitoring equipment is provided in Annex C.
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. |
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([3]).
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. |
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 D. Monthly site audits for operation phase will be carried out to check the implementation of these measures.
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. The audit shall be conducted to ensure that the effluent quality is in compliance with the discharge licence requirements. The effluent quality shall meet the discharge limits as described in Table 3.9.
Table 3.9 Discharge Limits for Effluent
Parameters |
Discharge Limit (mg/L) |
Flow Rate (m3/day) |
685 |
pH (pH units) |
6-10 (a) |
Suspended Solids |
800 |
Biochemical Oxygen Demand (5 days, 20°) |
800 |
Chemical Oxygen Demand |
2,000 |
Oil & Grease |
40 |
Total Nitrogen |
200 |
Total Phosphorus |
50 |
Surfactants (total) |
25 |
Note: (a) Range. |
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 D), 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. After the one-year maintenance period, the landscape maintenance and monitoring shall be carried out by the Contractor.
Monitoring results of air quality parameters from stack emissions of the centralised air pollution control system, the ammonia stripping plant and the cogeneration units will be provided once available to show compliance with the monitoring requirements stated in the EM&A Manual (Rev. F) to support the termination of the commissioning phase EM&A programme.
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, there is no need to operate the standby flare and therefore no monitoring of the flare stack was undertaken.
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 and ASP 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, unstable operation, 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 – 13.69 |
680 |
Nil |
Nil |
Dust (or TSP) |
0.00 – 0.00 |
6 |
Nil |
Nil |
Odour (including NH3 & H2S) (a) |
0.59 – 218.09 |
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 – 5 |
15 |
Nil |
Nil |
Carbon Monoxide |
0 – 182 |
650 |
Nil |
Nil |
NOx |
0 – 331 |
300 |
Identified (d) |
System unstable (e.g. low efficiency, unstable column temperature ) |
SO2 |
0 – 45 |
50 |
Nil |
Nil |
NMVOCs (b) |
Nil |
150 |
- |
Nil |
VOCs (including methane) (c) |
0 – 943 |
1,500 |
Nil |
Nil |
HCl |
0 – 0 |
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) No sampling was undertaken at CHP 1 as biogas production rate could not sustain the operation of the CHP stack for the scheduled sampling on 8 February 2021. (c) The VOCs emission limit include methane as biogas is adopted as fuel in the combustion process. (d) Dates with exceedances on NOx (number of exceedances on the day) were identified on 15 (1), 16 (4) and 20 (1) August 2021. |
Table 4.3 Hourly Average of Parameters Recorded for CHP 2
Parameter |
Range of Hourly Average Conc. (mg/Nm3) (a) (b) |
Max. Emission Limit (mg/Nm3) |
Exceedance Identified |
Remarks |
Dust (or TSP) |
0 – 13 |
15 |
Nil |
Nil |
Carbon Monoxide |
0 – 292 |
650 |
Nil |
Nil |
NOx |
0 – 301 |
300 |
Identified (d) |
System unstable (e.g. low efficiency, unstable column temperature ) |
SO2 |
0 – 159 |
50 |
Identified (e) |
De-sulphurization system tripped / Under Maintenance |
NMVOCs (b) |
6.0 |
150 |
Nil |
Nil |
VOCs (including methane) (c) |
0 – 1,284 |
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) Bi-annual sampling of NMVOCs was conducted in CHP 2 on 8 February 2021. No exceedance was identified. (c) The VOCs emission limit include methane as biogas is adopted as fuel in the combustion process. (d) Dates with exceedances on NOx (number of exceedances on the day) were identified on 23 (1) and 27 (1) August 2021. (e) Date with exceedances on SO2 (number of exceedances on the day) were identified on 1 (5), 27 (6), 28 (23) and 31 (14) August 2021. |
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 – 4 |
15 |
Nil |
Nil |
Carbon Monoxide |
0 – 263 |
650 |
Nil |
Nil |
NOx |
0 – 379 |
300 |
Identified (d) |
System unstable (e.g. low efficiency, unstable column temperature ) |
SO2 |
0 – 148 |
50 |
Identified (e) |
De-sulphurization system tripped / Under Maintenance |
NMVOCs (b) |
Nil |
150 |
Nil |
Nil |
VOCs (including methane) (c) |
0 – 1,125 |
1,500 |
Nil |
Nil |
HCl |
0 – 10 |
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) No sampling was undertaken at CHP 3 as biogas production rate could not sustain the operation of the CHP stack for the scheduled sampling on 8 February 2021. (c) The VOCs emission limit include methane as biogas is adopted as fuel in the combustion process. (d) Dates with exceedances on NOx (number of exceedances on the day) were identified on 17 (1) and 29 (1) August 2021. (e) Date with exceedances on SO2 (number of exceedances on the day) were identified on 17 (1), 28 (5) and 31 (14) August 2021. |
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 - 0 |
5 |
Nil |
Nil |
Carbon Monoxide |
0 – 44 |
100 |
Nil |
Nil |
NOx |
0 – 687 |
200 |
Identified (c) |
System unstable (e.g. low efficiency, unstable column temperature ) |
SO2 |
0 – 101 |
50 |
Identified (d) |
De-sulphurization system tripped / Under Maintenance |
VOCs (including methane) (b) |
0 – 101 |
20 |
Identified (e) |
System unstable (e.g. low efficiency, unstable column temperature ) |
NH3 |
0 – 246 |
35 |
Identified (f) |
System unstable (e.g. low efficiency, unstable column temperature ) |
HCl |
0 – 0 |
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) Dates with exceedances on NOx (number of exceedances on the day) were identified on 1 (15), 2 (7), 5 (1), 6 (3), 7 (7), 8 (3), 11 (5), 12 (5), 13 (21), 14 (6), 16 (9), 17 (10), 18 (4), 19 (2), 20 (1), 21 (2), 22 (1), 23 (2), 24 (2), 25 (1), 27 (2), 28 (3) and 29 (4) August 2021. (d) Date with exceedances on SO2 (number of exceedances on the day) was identified on 1 (5) August 2021 (e) Date with exceedances on VOCs (number of exceedances on the day) was identified on 1 (2) August 2021. (f) Dates with exceedances on NH3 (number of exceedances on the day) were identified on 1 (1), 9 (1), 20 (3), 25 (5), 26 (4), 27 (2) and 28 (2) August 2021. |
Odour patrol was conducted by the independent odour patrol team of ALS Technichem (HK) Pty Ltd on 9 August 2021. According to the EM&A Manual and EP requirements, it is considered an exceedance if the odour intensity recorded by the panellists is Level 2 or above. During this reporting period, no Level 2 Odour Intensity was recorded. The odour patrol result is shown in Annex H.
Effluent discharge was sampled monthly from the Effluent Storage Tank as stipulated in the operation phase discharge licence. The results of the discharge sample is recorded in Table 4.6.
Table 4.6 Results of the Discharge Sample
Parameters |
Discharged Effluent Concentration (mg/L) |
Discharge Limit (mg/L) |
Compliance with Discharge Limit |
pH (pH units) |
7.49 – 8.40 |
6-10 (a) |
Yes |
Suspended Solids (b) |
628 |
800 |
Yes |
Biochemical Oxygen Demand (5 days, 20°) (b) |
82 |
800 |
Yes |
Chemical Oxygen Demand (b) |
1,830 |
2,000 |
Yes |
Oil & Grease (b) |
<5 |
40 |
Yes |
Total Nitrogen (b) |
146 |
200 |
Yes |
Total Phosphorus (c) |
46.8 |
50 |
Yes |
Surfactants (total) (b) |
2.5 |
25 |
Yes |
Notes: (a) Daily Average. (b) Effluent sample collected on 11 August 2021. (c) Effluent sample collected on 30 August 2021. A joint sampling with the EPD was carried out on 11 August 2021. While the monitoring result of the sample collected by the EPD shown no exceedance, exceedance was found in the sample collected by the Contractor. The Contractor has investigated the operating conditions of the on-site wastewater treatment plant afterwards and found no major abnormality. Therefore, additional sampling was carried out by the Contractor on 30 August 2021, here shows the updated result. |
Wastes generated from the operation of the Project include chemical waste, wastes generated from pre-treatment process and general refuse ([4]). Reference has been made to the Monthly Summary Waste Flow Table prepared by the Contractor (see Annex E). 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 4.7.
Table 4.7 Quantities of Waste Generated from the Operation of the Project
Month / Year |
Chemical Waste |
Waste
Generated from |
General Refuse |
||
|
Disposal of at CWTC |
Disposed of at Landfill (a) |
Recycled (b) |
Disposed of at Landfill (a) |
Recycled (c) |
August 2021 |
3,420 L (d) |
687.05 tonnes |
0.00 tonnes |
3.00 tonnes (e) |
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) Among general refuse, 0.00 kg of metals, 0.00 kg of papers/ cardboard packing and 0.00 kg of plastics were sent to recyclers for recycling during the reporting period. (d) It includes 1,200 L of spent lube oil, 2,000 L of sodium hydroxide solution and 220 kg (regarded as 220 L) of spent absorbents contaminated with acids. (e) 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. |
The monthly inspection for the operation phase of the Project on 3 August 2021 covered the operation phase environmental site audit. Joint site inspection was conducted by representatives of the Contractor, IEC, and the MT on 3 August 2021 as required for the operation of the Project.
The audits 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 D).
Follow-up actions resulting from the last site inspections were generally taken as reported by the Contractor.
Key observations during the reporting period are summarised as follows:
3 August 2021
· No particular observation during this inspection.
Other than the above observations, the Contractor has implemented environmental mitigation measures recommended in the approved EIA Report and EM&A Manual.
Inspection of the landscape and visual mitigation measures for the operation phase of the Project was performed on 3 August 2021.
It was confirmed that the necessary landscape and visual mitigation measures during the operation phase as summarised in Annex D were generally implemented by the Contractor. No specific observation was found during the joint site inspection on 3 August 2021. 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.
Non-compliance of emission limits for CHP and 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 air pollution control system and the combustion system of the CHP and ASP and identified the following potential causes for the exceedance.
(a) The NOx exceedances from the CHPs occurred mainly when the feedstock quantity was at less than half of its designed treatment capacity, which could hinder the performance of the CHPs to achieve optimal efficiency. Therefore, they could not effectively remove NOx which leads to the exceedance;
(b) The exceedances of SO2 limit at the CHPs and the ASP occurred due to equipment tripping of the desulphurisation system.
(c) The ASP was experiencing unstable condition in the column and the thermal oxidiser, which resulted in the incomplete combustion of biogas and NH3. These have led to the exceedances of NOx, SO2, VOCs and NH3 in ASP.
For item (a), insufficient biogas available for CHPs has been identified as the key reason that led to the reduced performance of the CHP, resulting in emission exceedances from the CHP. As advised by the Contractor, it is more desirable that the plant can receive at least 150 tonnes of SSOW daily in order to generate sufficient biogas for the CHP to be able to operate at optimal efficiency. In this reporting period, the plant has received on average around 93 tonnes of SSOW daily. As a result, exceedances from the CHPs occurred when the quantity of SSOW was lower than the desirable quantity. The Contractor will continue to liaise with EPD (Food Waste Recycling Group) in their monthly meeting with an aim to explore the possibility of increasing the quantity of SSOW that can be treated daily. CHP1 was also found unstable and was shut down from 21 to 31 August 2021 for supplier inspection, a site inspection was carried out in late August.
For item (b), the SO2 exceedances recorded in CHPs and ASP were due to tripping of air blower within the desulphurisation system, which were stopped temporary for urgent maintenance. The desulphurisation system resumed to normal operation after urgent maintenance, an additional filter was also put in place to lower the emission from the CHPs. The Contractor is arranging inspection by the supplier of the CHPs to investigate the cause of tripping.
For item (c), the exceedances of NOx, VOCs and NH3 were found to be due to unstable column conditions in the ASP column and unstable temperature in the thermal oxidiser for biogas combustion, which have led to incomplete combustion of biogas and NH3 and hence exceedances in ASP. The Contractor has carried out fine-tuning of the conditions (e.g. air flow, water flow and temperature, etc.) of the ASP column and temperature fine-tuning of the thermal oxidiser throughout the month to optimise its performance. The Contractor will continue to carry out maintenance measures as per the supplier’s manual. The investigation report is presented in Annex G.
Activities to be undertaken for the coming reporting period are:
· Operation of the Project.
· Modification of the CHP and ASP to control the air emission.
This EM&A Report presents the EM&A programme undertaken during the reporting period from 1 to 31 August 2021 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 CHP and ASP stack monitoring 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 |
Cogeneration Unit (CHP) |
· Exceeded emission limit of NOx on 15, 16, 17, 20, 23, 27 and 29 August 2021. · Exceeded emission limit of SO2 on 1, 17, 27, 28, 29 and 31 August 2021. |
Ammonia Stripping Plant (ASP) |
· Exceeded emission limit of NOx on 1, 2, 5, 6, 7, 8, 11, 12, 13, 14, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28 and 29 August 2021. · Exceeded emission limit of SO2 on 1 August 2021. · Exceeded emission limit of VOCs on 1 August 2021. · Exceeded emission limit of NH3 on 1, 9, 20, 25, 26, 27 and 28 August 2021. |
Exceedances in NOx of CHP were found to be a result of the low biogas loading at the CHPs and the unstable condition of CHP1. The exceedances of SO2 of CHPs and ASP were found to be a result of the tripping of the desulphurisation system. The exceedances of ASP were found to be result of unstable condition at the thermal destructor of the ASP.
The Contractor has implemented mitigation measures to control the exceedance including the continuous monitoring of CHP and ASP to optimise overall performance. 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 patrol was conducted in accordance to the EM&A requirements. No exceedance of odour intensity limit for the odour patrol.
No non-compliance to the effluent discharge limit was recorded during this reporting period ([5]).
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.
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]) The odour patrol route was changed during this reporting period to include sampling points that are frequently visited by visitors and eliminate sampling points that are not visited by visitors.
([4]) Public fill and construction waste may only be generated during maintenance works when there are civil or structural works.
([5]) A joint sampling with the EPD was carried out on 11 August 2021. While the monitoring result of the sample collected by the EPD shown no exceedance on Total Phosphorus, exceedance was found in the sample collected by the Contractor. The Contractor has investigated the operating conditions of the on-site wastewater treatment plant afterwards and found no major abnormality. Therefore, additional sampling was carried out by the Contractor on 30 August 2021, and the result shown no exceedance on Total Phosphorus.
([6]) A joint sampling with the EPD was carried out on 11 August 2021. While the monitoring result of the sample collected by the EPD shown no exceedance on Total Phosphorus, exceedance was found in the sample collected by the Contractor. The Contractor has investigated the operating conditions of the on-site wastewater treatment plant afterwards and found no major abnormality. Therefore, additional sampling was carried out by the Contractor on 30 August 2021, and the result shown no exceedance on Total Phosphorus.