IMO Sub-Committee on pollution prevention and response (PPR 10)

The 10th session of the IMO’s Sub-Committee on Pollution Prevention and Response (PPR 10) was held in London from 24 to 28 April 2023. A wide range of topics was on the agenda, including biofouling, ballast water management, black carbon, sewage treatment and marine plastic litter.

by Gillian Lovering

With MEPC 80 due to take place in July, the PPR10 sub-committee meeting at the end of April set the tone for measures likely to be adopted and added to the list of environmental regulation by the IMO.

Pollution Prevention and Response – to give the sub-committee its full name – had a full agenda for its April meeting and passed a number of measures relating to ballast water treatment monitoring devices, biofouling, plastics, thermal waste treatment devices and more.

Near the top of the agenda was the new Operational Guide on the Response to Spills of Hazardous and Noxious Substances. The text of this has been divided into two parts volume one of the document gives guidance on preparedness for spills well volume 2 provides guidance on the response to spills. The text has been finalised and sent to MEPC80 for approval.

Also sent for approval were the draft 2023 guidelines for thermal waste treatment devices. These have been written on the basis of a technology neutral goal based approach that can be applied to any device using gasification, hydrothermal carbonization, pyrolysis, plasma or other thermal means for the disposal of permitted garbage another shipboard wastes generated during normal service on a ship.

Ballast water treatment on most ships became mandatory in 2017 when the Ballast Water Management Convention received the necessary endorsement from IMO member states. Under the five year rollout, which ends on 7 September 2024, ships engaged on international voyages need to treat ballast to the convention’s D2 standard.

Although the treatment systems themselves need to be type approved to the IMO (or the USCG for vessels trading to the US) standard, monitoring is not always done onboard, and it could be possible for illegal discharges to take place without the crew being aware. There are a number of monitoring systems on the market that can be added to treatment systems, but no standard method of verification had been agreed. At PPR10 work on a finalised and agreed framework was completed and the draft BWM.2 circular – Protocol for verification of ballast water compliance monitoring devices – was adopted for approval at MEPC80.

Also on the matter of ballast water treatment, the question of when the convention should apply to ships which undergo major conversion after 8 September 2017 was determined. It was agreed that ships constructed before 8 September 2017 which undergo major conversion on or after that date should be deemed as being built after the date and meet the D2 standard.

If the conversion occurred before the first or second IOPP survey, the hip should met the D2 standard from the date of completion of the conversion but if the conversion occurred after the first or second IOPP survey, the ship should meet the standard from the date of completing the first or second IOPP survey.

Another vector for transferring invasive species – Biofouling – also occupied much of the agenda. Although not yet subject to mandatory international regulation, biofouling has risen up the regulatory agenda and some member states have implemented local rules governing heavily fouled vessels. The IMO has issued voluntary guidelines on biofouling with the last version being issued in 2011.

PPR 10 agreed a new revised text which include a Biofouling Management Plan and Record Book templates to be sent to MEPC80 for approval. Work is continuing on new guidelines for verification of in-water cleaning systems used to remove biofouling and the meeting decided to request MEPC 80 to set a 2025 target date for a new document – Development of guidance on matters relating to in-water cleaning. Interested parties were invited to submit proposals on guidance to PPR 11.

Due to time constraints, consideration of best practices for biofouling inspections and cleaning actions was not undertaken and omitted from the new guidelines but member states and organisations were invited to submit relevant information as it becomes available.

Also up for discussion was the matter of multi-mapping for engines. Operational profiles, particularly for modern electronically controlled engines, can be relatively easily adapted to behave differently at various loads thus optimising performance although multiple engine operating parameters (MEOPS) are presently not permitted under MARPOL rules.

There is a balance between NOx emissions and specific fuel oil consumption (SFOC) in that an engine optimised for SFOC and therefore lower CO2 emissions will produce higher NOx emissions, with the converse also being true. These operating modes are referred to as maps, and clarification is sought under which conditions a map can be changed for an engine without contravening regulation 13.9 of MARPOL Annex VI. Some progress has been made on the key issues related to MEOPs and a work scope to progress the issue was agreed for further consideration at PPR 11:

Bilge water treatment also came up at PPR10 especially with regard to forced evaporation treatment systems and related amendments to onboard documentation and MARPOL Annex I. This dated back to PPR7 and MEPC 78 when it was agreed in principle that forced evaporation was acceptable as a means for the disposal of oily bilge water. Proposals had been invited to be submitted to PPR10 but there were none, so the matter has been deferred to PPR11.

Also deferred to PPR11 was the matter of ships requiring a sewage record book and a sewage management plan. This comes after records show that a staggering 97% of ships did not meet sewage effluent discharge standards despite being equipped with a type-approved sewage treatment system. Poor maintenance of systems and an ineffective type-approval process have been cited as causes. A correspondence group has been set up to develop the matter.

Plastic litter from ships whether in the form of fishing gear or plastic pellets transported as cargoes was also discussed. Both were considered important enough for PPR11 to develop guidelines and best practices as well as possible new regulations on the carriage of plastic pellets as cargo.

Other items discussed at the meeting included the question of black carbon emissions in the Arctic, use and carriage of HFO as fuel in Arctic waters, the use of electronic bunker delivery notes and how the question of VOC emissions should feature in the IMO’s GHG reduction measures.