IMO Sub-Committee on pollution prevention and response (PPR 11)

The 11th session of IMO’s Sub-Committee on Pollution Prevention and Response (PPR11) was held from 19 to 23 February 2024.  A wide range of topics was on the agenda, including exhaust gas cleaning systems discharges, engine multi-mapping, in-water cleaning, Black Carbon and HFO in the Arctic, review of the oily bilge treatment systems guidelines, revisions of MARPOL Annex IV (sewage) and marine plastic litter.

by Karin

One of the sub-committees of MEPC, PPR’s (pollution Prevention and Response) 11th session was held in mid-February. As is usual, the sub-committee had established a number of working and drafting groups to work on the various agenda topics in the run up to the actual meeting.

An 18-point agenda included some administrative items but there were a number of topical items to be discussed.  This included, exhaust gas cleaning systems discharges, engine multi-mapping, in-water cleaning (removal of biofouling from hulls), Black Carbon and HFO in the Arctic, review of the oily bilge treatment systems guidelines, revisions of MARPOL Annex IV (sewage) and associated guidelines and marine plastic litter.

More work needed on EGCS wash water rules

Exhaust gas cleaning systems (EGCS) or scrubbers have been heavily criticised as shifting removal of air pollution by SOx and instead contaminating the aquatic environment. Guidelines for EGCS were set out in November 2021 in MEPC.340(77) these apparently contained an error in sections 7.2.4 and 7.2.6 and the meeting requested a correction to edit the errors.

PPR 11 considered proposals relating to the identification and development of regulatory measures on the discharge of discharge water from EGCS. There was no consensus on the issue from delegates with some suggesting that the body of scientific evidence of harm is growing.  While others said this was unclear and more scientific research needs to be done before changes to water discharge rules are made. Some said that any attempt to penalise ships that have complied with the rules as they exist would impair the credibility of the IMO and significantly affect world trade. It was agreed to invite interested parties to submit further proposals to PPR 12.

Since 2020, numerous states have limited use of ECGS in territorial waters.  PPR 11 had received proposals for the development of a database containing local/regional restrictions/conditions on the discharge water from EGCS. The current lack of clarity and transparency with respect to the existence of some local restrictions was also highlighted. Member states were invited to use the “National Maritime Legislation” module of GISIS to provide information and the IMO will explore other reporting options in GISIS, such as in the MARPOL Annex VI module.

The meeting continued the discussion on the development of unified and representative emission factors for use in the environmental risk assessment of the discharge water from EGCS. Again, a number of views were expressed on the methodology of collecting data and development of the emission factors. Discussion on this subject will continue at a future PPR Sub-Committee session, pending further submissions from member States.

Oily Bilge water treatment

At MEPC 78 it was agreed in principle that forced evaporation was acceptable as a means for the disposal of oily bilge water and had invited proposals to PPR 10 to add an appropriate regulation in MARPOL Annex I. No proposals had been received then or at PPR 11, so it was again agreed to defer further consideration of this to PPR 12.

Engine multi-mapping and NOx

Operators and engineers have long complained that regulations – and in particular the NOx Code – prevent ships from making the most efficiency and environmental gains out of the ability of modern electronically controlled engines to have more than one operating profile or map. Under present rules, the NOx emissions for engines can only be calculated using a single profile and the engine must be run under the conditions relating to that profile.

PPR has been working on amendments to the NOx Code that could allow multiple profiles to be assigned. PPR 11 finalised draft amendments to the code and to MARPOL Annex VI covering this issue. Both sets of amendments will be submitted to MEPC 82 for approval, with a view to subsequent adoption. Also to be submitted to MEPC 82 were recommendations for converting existing engines to run on alternative fuels to reduce carbon intensity. Under present rules this would mean the engine would be ‘substantially modified’ and thus need to meet current NOx rules rather than those when it was built.

A paper submitted to PPR 11 by Belgium, Denmark, France, Germany, Ireland, Netherlands, Spain and Sweden under any other business raised an interesting point about how NOx emissions are regulated and a failing that has been revealed in several studies.

The paper highlights that vessels employing selective catalytic reduction (SCR) to reduce NOx emissions in line with Tier III levels, often had emissions above the Tier III level when operating at low engine loading. This often occurs when vessels are manoeuvring or idling in ports and at anchor. The paper says the findings ‘puts into question the effectiveness of regulation 13 of MARPOL Annex VI and the NOX Technical Code 2008, aiming at reducing NOX emissions from ships through a tiered approach’.

Plastic waste

Turning to plastic pollution, the focus was on two main areas, carriage of plastic pellets (used as raw material for plastic moulding) as cargoes and fishing gear. Draft recommendations for the carriage of plastic pellets by sea in freight containers and draft guidelines for the clean-up of plastic pellets from ship source spills were agreed.

The importance of proper packaging and stowage of containers on will be submitted for urgent consideration by the MEPC 81 in March. The draft guidelines on clean up of pellets from spills will be submitted to MEPC 82 in October 2024. As well as the guidelines, PPR also held extensive discussions on possible amendments to IMO mandatory instruments related to the transport by ship of plastic pellets. These discussions will continue at future sessions.

Fishing gear losses are a significant contributor to plastic waste at sea and PPR 11 discussed what type of data needs to be reported by ships when fishing gear is lost or abandoned, and how to collect, transmit, access and manage this data. A correspondence Group will take up the issue to determine the fishing gear reporting obligations in MARPOL Annex V and other relevant international regulatory frameworks. The Correspondence Group will report back to PPR 12 for further action.

Arctic issues

Black Carbon emissions in the Arctic have been an emotive subject for some time. The meeting agreed on draft guidance on best practices to assist ship operators’ efforts to reduce emissions and draft guidelines for measuring, monitoring and reporting Black Carbon emissions, which will help with collecting data to support the development of recommendations and regulations. The guidance will be submitted for adoption at MEPC 82.

July this year sees a ban on HFO fuels in Arctic regions coming into effect. Ships which meet certain construction standards with regard to oil fuel tank protection will need to comply on and after 1 July 2029. There is a five year moratorium for ships operating solely in the waters of an Arctic state. PPR 11 agreed draft guidelines on risk mitigation measures which will be submitted to MEPC 82.

Other matters addressed

Biofouling contributes to air pollution because of increased fuel use and transfer of invasive species. In water clearing between dry dockings is identified as a good preventative measure for both issues. PPR 11 continued its work to develop guidance on matters relating to in-water cleaning. A Correspondence Group will work on preparing draft guidance and will submit a report to PPR 12.

Work on the revision of MARPOL Annex IV (sewage) and the associated guidelines, regarding the discharge of sewage from ships into the sea continues with PPR 11 agreeing on a preliminary timeline for the revision aiming for adoption of the whole package in 2028/2029. The revision would also cover provision of adequate reception facilities in ports.

Also approved at PPR 11 were draft guidelines for ‘developing a local oil/hazardous and noxious substances marine pollution contingency plan’ and draft amendments to MEPC.1/Circ.590 – Revised Tank Cleaning Additives Guidance Note and Reporting Form which will be submitted to MEPC 82.

Work on amendments to improve effectiveness of cargo stripping and tank washing operations as set out in MARPOL Annex II was agreed to be passed over to the ESPH 30 sub-committee meeting.

Find out more information on the Committee’s historical activities.

Read the previous Committee’s summary.