Discharge of exhaust gas recirculation (EGR) bleed-off water.
06 March 2019
Applicability: Engine Manufacturers and Owners and operators of ships that are subject to air emission controls under MARPOL Annex VI
The 2018 Guidelines for the discharge of exhaust gas recirculation (EGR) bleed-off water were adopted by IMO Resolution MEPC.307(73) on 26 October 2018.
The Guidelines apply to marine diesel engines fitted with EGR NOx-reducing devices, which are initially issued with an Engine International Air Pollution Prevention (EIAPP) certificate on or after 1 June 2019 to comply with MARPOL Annex VI.
As required in the Guidelines, the following documents should be retained on board the ship and are subject to survey and inspection, if applicable to the marine diesel engine fitted with an EGR device:
1) Manual for EGR bleed-off discharge system.
2) EGR record book.
3) Oil content meters: type approval certificate (MED certificate if applicable) and their operation and maintenance manuals.
The Guidelines also require:
1) Different requirements for EGR bleed-off water discharge, when the marine diesel engine is using fuel oil either compliant or non-compliant with the relevant sulphur content limit in Regulation 14 of MARPOL Annex VI.
2) The residues from EGR water treatment system to be delivered ashore and not discharged to the sea or incinerated on board.
3) Additives used for enhancing the bleed-off water quality to be assessed and documented or documented with a Material Safety Data sheet, if applicable.
4) The EGR bleed-off discharge system and the EGR record book to be subject to survey on installation and at initial, annual/intermediate and renewal surveys and be subject to inspection by relevant parties.
What should engine manufacturers do?
The applicability of the Guidelines is linked with the issuance date of the engine’s EIAPP certificate at the end of the engine approval process, and not the application date for the approval, or the date when the engine testing is undertaken. Therefore, engine manufacturers are encouraged to review and comply with the Guidelines as soon as possible, rather than waiting for 1 June 2019.
EGR is one of the methods used to control NOx emissions (as required by MARPOL Annex VI regulation 13). By means of this process, condensate of exhaust gas is generated and discharged as bleed-off water, which should be handled differently depending on the fuel oil sulphur content. These Guidelines were developed to specify requirements for the discharge to the sea of bleed-off water when using EGR.
For further information: