IMO approves stricter guidelines on wash water from scrubbers in ships

In order to reduce air pollution emissions, some ships have fitted ‘Exhaust Gas Cleaning Systems‘ (EGCS), also known as ‘scrubbers’ to clean exhaust gases. This equipment ‘cleans’ the ship’s fumes by leading exhaust gases through a fine spray of seawater that washes out acidifying sulphur oxide.

However, this process creates very large volumes of heavily-acidified and contaminated water. Too often, ships flush this water out into the sea, undermining action to achieve good environmental status in maritime areas.

In 2020 KIMO issued “Resolution 20/1  – Wash water from scrubbers in ships” in which we urged national governments, the EU and the International Maritime Organisation (IMO) to

take vigorous action to ban or set strict limits regarding discharge of wash water from scrubbers in shipping for the Baltic Sea and the North Sea, so that it does not compromise achievement of good environmental status and good ecological and chemical status.

In this context, the most recent meeting of the IMO’s Marine Environment Protection Committee (MEPC 78) approved:

• MEPC Circular on 2022 Guidelines for risk and impact assessments of the discharge water from exhaust gas cleaning systems, to provide information on recommended methodology for risk and impact assessments that Member States should follow when considering local or regional regulations to protect the sensitive waters/environment from the discharge water from EGCS.
• MEPC Circular on 2022 Guidance regarding the delivery of EGCS residues to port reception facilities, providing best practices intended to assist both ship operators and port States in assuring the proper management and disposal of EGCS residues and stored discharge water from EGCSs into port reception facilities.

EGCS discharge water contains various contaminants such as sulphur oxides, nitrogen oxides and other mixtures originated from the engines exhaust gas. It was noted that the mixtures of compounds when discharged overboard were identified to have negative impacts on the marine environment. Accordingly, many countries have been regulating the discharge of wash water from open-loop scrubber in their territorial water and port limits via their national legislation.

MEPC 78 considered the outcomes from the IMO’s Sub-Committee on Prevention of Pollution  meeting (PPR 9), which included draft Guidelines for risk and impact assessments of the discharge water from EGCS and draft Guidance regarding the delivery of EGCS residues and stored discharge water to port reception facilities. They also approved MEPC.1/Circ.899 and MEPC.1/Circ.900, respectively.

These guidelines are for flag administrations which intend to carry out a risk assessment of the discharge of EGCS discharge water and are of a voluntary nature. Member states should use the new stricter guidelines when undertaking risk assessments to ascertain whether EGCS discharge water can be discharged in their port limits. The revised guidelines also state that ships fitted with EGCS should keep their discharge water in dedicated holding tanks for delivery to port reception facilities in the port areas where the discharge of EGCS discharge water is prohibited. The residues generated by the EGCS should be delivered to the reception facilities, and port States should provide adequate reception facilities for this purpose.

While the guidelines are voluntary, they do give additional sanction to national level legislation aimed at limiting pollution of national waters with harmful substances discharged from Exhaust Gas Cleaning Systems in ships. Belgium and Germany have already banned the discharge of scrubber water. KIMO would like to see other governments follow suit.