IMO approves guidelines for scrubber discharge risk and impact assessment

IMO approves guidelines for scrubber discharge risk and impact assessment

Justification for restrictions on discharge water from exhaust gas cleaning systems (EGCS) continues to divide opinions, but newly approved IMO guidelines aim to provide more uniform criteria.

The 78th session of the Marine Environment Protection Committee (MEPC 78, 6-10 June) approved an 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 sensitive waters from EGCS discharge water.

The majority of Member States supported approving the draft guidelines presented to this MEPC 78 as they were, however there were some reservations. Two papers were submitted with comments on the draft guidelines.

MEPC 78/9/4 (CLIA) raised reservations about replacing the well-established Whole Effluent Toxicity (WET) method with the summation method in the draft IMO guidelines for evaluating the effect of chemical substances, asking for a scientific review by GESAMP prior to finalisation and approval of these guidelines.

MEPC 78/9/3 (Germany) proposed the addition of a list of emission factors for environmental risk assessment.

IBIA made a statement at MEPC 78 to say that we share the concerns raised by CLIA in MEPC 78/9/4 about the scientific rigour of the proposed draft 2022 guidelines. IBIA therefore agreed with the proposal for the Committee to invite GESAMP to evaluate and provide a technical opinion on the matters identified in the document prior to finalisation and approval of these guidelines. IBIA also suggested a GESAMP review of list of emission factors for environmental risk assessment proposed in MEPC 78/9/3.

MEPC 78 decided to go ahead with approving the 2022 guidelines, without the list of emission factors proposed in MEPC 78/9/3.

In light of comments and various concerns raised, MEPC agreed that the guidelines will be kept under review, which means further changes can be made as more experience is gained.

Late last year, MEPC 77 adopted the 2021 Guidelines for exhaust gas cleaning systems (2021 EGCS Guidelines), updating the 2015 EGCS Guidelines. These guidelines are there to ensure scrubbers are effective in meeting sulphur emission limits while also meeting environmental criteria for water discharges. See article below for more details.

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