IMSML Website Article 05/2025: Resolution MEPC.373(80) - 2023 Guidelines for Thermal Waste Treatment Devices (TWTD)
The origins of the 2023 Guidelines for Thermal Waste Treatment Devices can be traced back to Resolution MEPC.176(58). A revised MARPOL Annex VI, Paragraph 5.2 of Regulation 16 stipulates that the regulation should not preclude the development, installation and operation of alternative design shipboard thermal waste devices that meet or exceed the requirements of the resolution. This is premised on Regulation 4 of MARPOL Annex VI which allows the use of alternative compliance methods at least as effective in terms of emissions reductions. Therefore Guidelines were developed for thermal waste devices as alternative methods to comply with Regulation 16 on shipboard incineration.
Resolution MEPC.373(80) was adopted on 7 July 2023 by the Marine Environment Protection Committee (MEPC). It is applicable in this country via Malaysian Shipping Notice (MSN) 14/2024.
ANNEX, see Annex 8, p 2
Section 1 - Introduction
What do the guidelines cover? Section 1.1 identifies the following:
[1] Approval, certification and in-service controls applicable to thermal waste treatment devices (TWTD);
[2] Equivalent means (under Regulation 4 of MARPOL Annex VI);
[3] Incinerators (covered by Regulation 16 of MARPOL Annex VI).
What is the basis for writing the Guidelines? Section 1.2 stipulates the following approaches:
[1] Technology-neutral;
[2] Goal-based.
Can the approach adopted approach be used to any thermal waster treatment devices? Yes. Examples in Section 1.2 include:
[1] gasification;
[2] hydrothermal carbonisation;
[3] pyrolysis;
[4] plasma;
[5] other thermal means for the disposal of permitted garbage and other shipboard wastes generated during a ship’s normal service.
Do these thermal waste treatment devices remain subject to the same prohibitions as to those materials which are not supposed to be so disposed of as given in Regulation 16.2 of MARPOL Annex VI? Yes, see Section 1.3.
What performance standards should these certified TWTD under the Guidelines meet? Performance Level 1 in terms of emissions to air which is comparable to the emission limit requirements given in the ‘2014 Standard Specification for Shipboard Incinerators’ (see Resolution MEPC.244(66), as amended), see Section 1.4.
Should Performance Level be demonstrated by in-service emission measurements? Yes, see Section 1.4.
What should be done when there is a related water discharge to the sea? It should be controlled as given in these Guidelines, see Section 1.4.
Could an applicant request certification to Performance Level 2? Yes. Not only should Performance Level 1 requirements be met, but there are detailed testing requirements which should be met prior to approval as an equivalent means together with tighter in-service emission limits, see Section 1.5.
Section 2 - General - Basis of these Guidelines
What is the meaning of ‘technology neutral’ and ‘goal based approach’? Section 2.1 explains that this consists of the following:
[1] In-service monitoring and recording of specified emissions, see Section 2.1.1;
[2] Identification of the relevant Functional Objectives, see Section 2.1.2;
[3] Applicant-proposed/demonstrated resolution of each Functional Objective by means of an applicant-compiled ‘Thermal Waste Treatment Device Technical Report’, see Section 2.1.3.
Note, this may include (but are not limited to) the items listed in Table 2 of the Guidelines.
How should the TWTD Technical Report be assessed? For completeness in respect of the ‘Functional Objectives’, by reviewing Administration (eg IMO) together with physical surveys as required of the device in production (ie as a unit) as installed and in operation, see Section 2.2.
Is the TWTD Technical Report a part of the overall approval package of the thermal waster treatment device? Yes. It is an equivalent means to incineration for permitted onboard garbage and waste disposal, see Section 2.2.
Should each individual unit certification be in accordance with the procedures as agreed in respect of the ‘Functional Objective’? Yes. This results in the issue to each unit of a TWTD Certificate (see the Annex for the given form), and the approval of that unit’s TWTD file, see Section 2.2.
Do the Guidelines cover only MARPOL Annex IV governing prevention of air pollution that relate to the use of TWTD? Yes. The manufacturer, installer, shipowner and others (as applicable) are responsible for ensuring that all other relevant statutory requirements (together with relevant classification requirements) are complied with (as and where appropriate), see Section 2.3.
Do the Guidelines involve hazardous materials, operations and equipment? No. The Guidelines do not purport to address the safety aspects associated with the use of thermal waste treatment devices. It is the responsibility of the user of the Guidelines to establish appropriate safety and health practice, as well as to determine the applicability of regulatory and classification limitations prior to use (including Port State limitations), see Section 2.4.
Section 3 - Definitions
The definitions are contained in Table 1. Among terms defined range from ‘Applicant’ to ‘PAH’, ‘Performance Level 1’ to ‘Thermal Waste Treatment Device (TWTD)’ and ‘TWTD File’ to ‘UTC’.
Section 4 - Emission Limits
Section 4.1 - Discharges to Air
Section 4.1.1 - Performance Level 1
How should Carbon Monoxide be measured for Performance Level 1? Direct measurement and monitoring should be in accordance with the NOX Technical Code. The frequency for monitoring should not less than 0.05Hz, see Section 4.1.1.2.
What other matters should be monitored and controlled in accordance with the relevant ‘Functional Objective’? Oxygen content, temperature and pressure profiles, see Section 4.1.1.3.
Section 4.1.2 - Performance Level 2
What is involved in certification to meet the requirements of Performance Level 2? This certification could be done when requested by the applicant. It involves a detailed pre-certification test together with in-service emission limits which are tighter than those of Performance Level 1, see Section 4.1.2.1.
Section 4.1.3 - Pre-Approval Test
Why should the TWTD model be subject to a Pre-Approval Test for Performance Level 2? This is a part of the initial approval test, see Section 4.1.3.1.
How long should the Pre-Approval Test take? Around 6-8 hours duration with the TWTD in its operating condition, see Section 4.1.3.2.
Are pre-approval test emission limit values given on a dry basis? Yes, other than that for HC which is measured on a wet basis (at 11.00 percent O2 concentration at 273K, 101.3 kPa), see Section 4.1.3.3.
What are the pre-approval test procedures? Section 4.1.3.4 provides for the following 8 procedures:
[1] Testing should be undertaken while operating with (see Section 4.1.3.4.1):
[a] Sludge oil (if applicable to the TWTD system); AND …
[b] Solid waste compositions (both as given in Paragraph 1 of Appendix IV to MARPOL Annex VI).
[2] Sampling position should be after any exhaust gas treatment components (eg water washing), but prior to the dilution of that exhaust gas, see Section 4.1.3.4.2;
[3] CO, NOXn and HC should be monitored at a frequency of not less than 0.05 Hz, see Section 4.1.3.4.3;
[4] CO and NOX limits are given on a dry basis, see Section 4.1.3.4.4;
[5] Correction to reference 11.00% O2 should on the basis of the following formula (see Section 4.1.3.4.5):
C(reference) = C(measured) x (20.95 - O2 measured) / (20.95 - 11.00)
[6] Oxygen content, temperature and pressure profiles (as applicable), see Section 4.1.3.4.6;
[7] Not less then three separate HCl and particulate matter readings should be taken (see Section 4.1.3.4.7):
[a] Over the duration of each test period;
[b] At approximately equally spaced intervals;
[c] Those results averaged to give the results to be compared the limit value;
[d] For TWTDs with intermittent loading, those test procedures should commence no later than 10 minutes after loading.
[8] Alternative emission species test methods which provide equivalent results to those given above may be used with the agreement of IMO, see Section 4.1.3.4.8.
What should a test report detailing the TWTD tested contain? Section 4.1.3.5 requires the following:
[1] Test sequence followed;
[2] Measurement devices / procedures used;
[3] Traces of the CO, NOX, HC and O2;
[4] Temperature and pressure profile readings;
[5] Test results which should form part of the TWTD Technical Report:
[a] Details of actual sludge oil (if applicable); AND …
[b] Solid waste compositions; AND …
[c] Waste loading qualities and times.
What is the in-service maximum emissions limits for TWTD certified to Performance Level 2? According to Section 4.1.3.6:
[1] CO 50 ppm (dry basis) at 11.00% O2 - averaged over each UTC three hour period;
[2] Opacity 10%.
What should CO be measured against? Monitored at a frequency of 0.05 Hz and in accordance with Section 6.4 of the NOX Technical Code 2008.
What should the TWTD be monitored and controlled against? The relevant ‘Functional Objective’ such as (see Section 4.1.3.8):
[1] Oxygen content;
[2] Temperature;
[3] Pressure profiles.
Section 4.2 - Discharge Water to Sea
What is the scope and application of this Section? According to Section 4.2.1, the section is applicable if there is:
[1] A direct water discharge as a by-product of the thermal waste treatment process used, see Section 4.2.1.1; AND / OR …
[2] Water used to Wah the exhaust gas from the TWTD before discharge to the atmosphere, were that water is then subsequently discharged to sea, see Section 4.2.1.2.
Note, alternatively the discharge water streams may be collected in a holding tank for discharge on shore, see Section 4.2.1.
What should not be done when there is discharge of water to the sea? Section 4.2.2 provides the following:
[1] Discharge water should not be diluted or mixed with water from other sources before monitoring for the turbidity and PAH limit parameters;
[2] After monitoring for PAH and turbidity, the discharge water may be diluted as required or chemically treated prior to pH monitoring.
Are there limits to the discharge water into the sea when TWTD is in operation? Section 4.2.3 makes the following provisions:
[1] Level of pH (see Section 4.2.3.1):
[a] Min 6.5, or Max differentiated of 2 PJ unit berwenang the inlet water and the Disc hargai water after dilution values;
[b] If chemically treated, the following requirements should be applied: Section 10.1.6.1 of the 2021 Guidelines for Exhaust Gas Cleaning Systems, see Resolution MEPC.340(77).
[2] Turbidity (see Section 4.2.3.2) - Maximum continuous turbidity in the discharge water should not be greater than:
[a] 25 FNU (formative nephelometric units), OR …
[b] 25 NTU (nephelometric turbidity units), OR …
[c] Equivalent units, above the inlet water turbidity assessed on the basis of 15 minute average values.
[3] PAH (see Section 4.2.3.3):
[a] Phenanthrene equivalent concentration;
[b] Should not exceed that equivalent to 2.2 g/h per nameplate capacity in MW;
[c] Measured at the discharge water flow rate(s) above the inlet water PAH concentration.
What is the benchmark for monitoring methods used for pH, turbidity and PAH? 2021 Guidelines for exhaust gas cleaning systems, see Resolution MEPC.340(77), and should be monitored at a frequency of not less than 0.05 Hz, see Section 4.2.4.
Note, that the 2021 Guidelines are also applicable to performance, calibration and permissible deviations of the discharge water monitoring devices, see Section 4.2.5.
Section 4.3 - Residues from Thermal Waste Treatment Devices
What should be discharged ashore to appropriate shore reception facilities? Section 4.3.1 stipulates the following:
[1] Any solid residues;
[2] Other materials from TWTD, including:
[a] Any washings; OR …
[b] Other material collected as part of maintenance or servicing activities.
When should residues from a TWTD discharge water treatment system be discharged ashore to appropriate reception facilities? Section 4.3.2 provides for residues collected either:
[1] In service, OR …
[2] During maintenance or servicing activities.
Section 5 - Functional Objectives and TWTD Technical Report
What core ‘Functional Objectives’ represent a technology-neutral approach to the review of design, manufacture, installation, use and ongoing management of a TWTD? Section 5.1 makes the following provisions:
[1] Identify ‘Functional Objectives’ which may affect the devices’s performance in terms of emissions to air and water (if applicable);
[2] Duly address part of the TWTD Technical Report to ensure that Regulation 4.4 of MARPOL Annex VI are met;
[3] For the case of operational, servicing or maintenance requirements, the TWTD Technical Report may cite the relevant section of the TWTD Operating Manual which is supplied with the device rather than reproducing the full applicable text;
[4] ‘Not applicable’ is to be used when a particular Functional Objective is not applicable due to the operating principle applied, eg due to the waster streams to be processed of other factors. Note for this, strong supporting justification needs to be provided in the TWTD Technical report.
What happens when commercially sensitive information need to be provided to IMO to demonstrate that a particular functional objective has been met by the design of the TWTD and later in service? Such information may instead be included in a supporting ‘Information Annex’ to the TWTD Technical Report. This Annex would not be circulated outside IMO. It is usually cited rather than being given in full in the TWTD Technical Report itself, see Section 5.2.
Table 2 deals with the ‘Functional Objective’ of Thermal Waste Treatment, see Annex 8, p 8 to 17. The Applicant should stipulate which ‘Functional Objectives’ are not applicable to the TWTD under consideration, and provide justification, see Section 5.2. Table 2 provides for 8 functional objectives and the accompanying content of the TWTD Technical Report. The ‘functional objectives’ identified in Table 2 (see Section 5.2) are as follows:
[1] Device design and manufacture, see Annex 8, p 9;
[2] Installation on board, see Annex 8, p 11;
[3] In-service operation, see Anne 8, p 12;
[4] Record keeping, see Annex 8, p 14;
[5] Maintenance and servicing, see Annex 8, p 14;
[6] Instructions and training, see Annex 8, p 15;
[7] TWTD File, see Annex 8, p 15;
[8] Performance Level 2, see Annex 8, p 17.
Section 6 - Certification Process
How many parts are there to the certification process? According to Section 6.1, there are two parts:
[1] Part 1 - The approval of the proposed TW model as an equivalent means under Regulation 4 of MARPOL Annex VI;
[2] Part 2 - The approval of individual units of that TWTD operating on the basis of the equivalent means as approved.
How does approval by IMO of the TWTD model operate as an equivalent means? It should be made on the basis of the applicant submitted TWTD Technical Report, together with (if appropriate), any additional information in the supporting information annex, see Section 6.2
Should the TWTD Technical Report specify whether the units are to be certified to Performance Level 1 or Performance Level 2? Yes. In the case for Performance Level 2, the report should contain the necessary supporting data including the Pre-Approval Test Report, see Section 6.2.
What if there are subsequent amendments to the information as given in the TWTD Technical Report? If it affects emissions performance as controlled by these Guidelines, it should be approved by IMO before being applied to individual thermal waste treatment devices in service, see Section 6.3.
What happens after approval of the TWTD model as an equivalent means? Individual units should be certified by the Administration in accordance with the agreement procedures as set out in the TWTD Technical Report as approved, see Section 6.4.
Should an approved TWTD be issued with a TWTD Certificate? Yes, as set out in the Annex by IMO and the file as approved by IMO, see Section 6.5
What happens after a satisfactory completion of the installation test procedure as given in the TWTD File? The Section 2.6 Supplement to the Air Pollution Prevention Certificate should be updated, see Section 6.6.
Should individual thermal waste treatment devices be subject to survey procedures as given in the approved TWTD File? Yes, for reports filed at those times the ship on which the device installed is survey in accordance with MARPOL Annex VI survey regime, see Section 6.7.
Should amendments to the TWTD as installed, operated or monitored be duly covered by amendments to the TWTD File as approved by IMO before they are applied in service? Yes, see Section 6.8.
ANNEX - FORM OF TWTD CERTIFICATE
At the top of the certificate, is the ‘Name of Administration’. This is followed by the description, ‘Thermal Waste Treatment Device Approval Certificate’. The certificate then declares that it is issued under the following:
Protocol of 1997 (as amended) to amend the International Convention for the Prevention of Pollution from Ships 1973 (as modified by the Protocol of 1978).
It is followed by the fulled designation of the country under which the approval is given, including the full designation of the ‘competent person’.
The certificate stipulates that a TWTD (or it equivalent) under Regulation 4 to Regulation (incineration) has surveyed and related documents have been approved in accordance with the 2023 Guidelines for Thermal Waste Treatment Devices. The certificate also requires documentation of which MEPC Resolution the regulatory acts are being carried out.
The certificate also requires documentation of the following:
[1] Manufacturer;
[2] Model type;
[3] Serial number;
[4] Maximum capacity;
[5] Equivalent means - approval reference;
[6] Whether certification is for Performance Level 1, or Performance Level 2;
[7] Title of the TWTD File and its approval reference.
The Certificate then stipulates that the approved TWTD File should be carried on board the ship that has been fitted with this TWTD, at all times and should be available as required. This is followed by the validity period of the TWTD as survey in accordance with Regulation 5 of MARPOL Annex VI.
The Certificate concludes with the:
[1] Place of issue;
[2] Date of issue;
[3] Signature of the duly authorised official issuing the Certificate;
[4] Seal / stamp of the authority (as appropriate).
Thank you for reading IMSML Website Article 05/2024
Stay tuned for the next IMSML Website Article 06/2025: Resolution MEPC.374(80) - Amendments to the 2022 Guidelines on Survey and Certification of the Energy Efficiency Design Index (EEDI)
Signing-off for today,
Dr Irwin Ooi Ui Joo, LL.B(Hons.)(Glamorgan); LL.M (Cardiff); Ph.D (Cardiff); CMILT
Professor of Maritime and Transport Law
Head of the Centre for Advocacy and Dispute Resolution
Faculty of Law
Universiti Teknologi MARA Shah Alam
Selangor, Malaysia
Tuesday, 4 February 2025
Note that I am the corresponding author for the IMSML Website Articles. My official email address is: uijoo310@uitm.edu.my