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Studies �

Air Emissions. It’s generally accepted that the air emissions from exhaust gas cleaning systems are better quality than from use VLSFO (very low sulphur fuel oil), and better than MGO (marine gasoil) in SOx, NOx, and PAH content, and some of the following scientific studies also cover that.

Water Emissions (Discharge Water). The most important areas of interest for EGCS water discharges are the discharge water quality, the potential for accumulation in ports, and the impact on the marine environment. One or more of these key areas are covered by each of the following studies, and a summary of each is in the following slides:

Danish EPA, 2012 Assessment of Possible Impacts of Scrubber Water
Carnival/DNVGL, 2019 Assessment of Lab Samples of EGCS Washwater
Japan MLIT, 2019 Environmental Impact Assessment, EGCS Discharge Water
CE Delft, 2019 Impact of EGCS Discharges on Port Water & Sediment
IMO-GESAMP, 2019 EGCS: A Roadmap to Risk Assessment
CE Delft, 2020 Comparison of CO2 Emissions of Marine Fuels
Danish Hydraulic Institute, 2021 Eco-Toxicity & Risk Assessment of EGCS Discharge Water
CLIA, Port of Seattle, DOE, 2023 Puget Sound EGCS Washwater Ecological Risk Assessment

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Studies

It’s generally accepted that the air emissions from exhaust gas cleaning systems are better quality than from use VLSFO (very low sulphur fuel oil), and better than MGO (marine gasoil) in SOx, NOx, and PAH content, and the following recent scientific studies cover that but also all important areas of interest for EGCS water discharges, including discharge water quality, accumulation in ports, and impact on the marine environment:

Carnival/DNV-GL, 2019 Washwater Quality

Japan MLIT, 2019 Impact of Washwater on Marine Environment

CE Delft, 2019 Accumulation in Ports

IMO GESAMP, 2019 Report of the GESAMP Task Team on EGCS

CE Delft, 2020 Comparison of Marine Fuels: CO₂ to Atmosphere

Danish Hydraulic Institute, 2021 Toxicology of Impact of Washwater on Marine Life

7. CLIA, Port of Seattle, WashDOE 2024 Puget Sound EGCS Washwater Ecological Risk Assessment

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Washwater Quality

Compares laboratory analysis of 281 EGCS washwater samples from 53 ships worldwide with major national and international water quality standards.
EGCS were tested against 54 parameters, including PAHs and metals, for comparison to IMO discharge water criteria and selected national and International quality standards and land-based wastewater discharge limits.
Conclusion: Washwater meets all regulatory and major national and international standards, plus EU Water Framework Directive Environmental Quality Standards (EQS).

Carnival/DNV-GL

February 2019

Link to the Study

DNV-GL is a world leading provider in the following market segments: maritime, oil and gas, energy, business assurance, and digital solutions. A body of deep technical expertise and detailed market insights in more than 100 countries that manages risk, assures product quality and certifies management systems.

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Impact on Marine Life

Japanese Government evaluated both short-and long-term environmental risks caused by discharge water from the Exhaust Gas Cleaning Systems (EGCS) to the marine environment and the marine aquatic.
As result of the study, it was concluded that the discharge water with chemical substances such as SOx, PAHs, and metals cannot cause unacceptable effects either to the marine environment or to the marine aquatic organisms and the sea water quality around the country.
Conclusion: Japan is of the position that there would NOT be a scientific justification to prohibit the use of open looped scrubber, as long as the IMO’s discharge criteria were met.

Japan Ministry of Land, Infrastructure, Transport and Tourism (MLIT)

July 2018

Link to the Study

Report released by the Japanese Ministry of Land, Infrastructure, Transport and Tourism.

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Accumulation in Ports

Provision of a method for evaluating the impacts of using open-loop exhaust gas cleaning systems in ports on water and sediment and to test the methodology conservatively in a series of model ports, using empirical data of almost 300 washwater samples as inputs for the MAMPEC-BW model.
Evaluated accumulations from a number EGCS ships in different port configurations in North Europe for 365 days/year and the results were compared with EU Water Quality and global dredging standards.
Conclusion: The washwater from EGCS easily meets the EU water quality standards of the Water Framework Directive, including the new and more rigorous standards starting in the 2021. Further, accumulation in water or sediment even over decades remains a very small percentile of the limits.

CE Delft

December 2019

Link to the Study

CE Delft is an independent research and consultancy organization specialized in developing innovative solutions to environmental problems. CE Delft is skilled across a wide range of environmental topics and also familiar with the associated policy networks: trade and industry, government and non-governmental organizations alike.

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IMO – Risk Assessment

IMO – GESAMP

December, 2019

The Task Team on Exhaust Gas Cleaning Systems (EGCS) was convened on a request of the Marine Environmental Protection Committee) MEPC to the Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP) to give an opinion on the potential environmental and public health effects of EGCS effluent.

The Task Team drew initial conclusions that adverse effects from EGCS washwater on marine life would most likely not be from chemicals but from the pH of the washwater, which would be sufficiently mitigated by normal dilution and the buffering effects from the natural alkalinity of the seawater.

It also summarizes the majority of EGCS studies to date using WET testing for toxicology evaluation of EGCS discharge water, and notes that most are using incorrect methods and therefore reaching invalid conclusions.

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Air Emissions Quality

The objective of the study was to compare the CO₂ emissions of the two most common alternatives to comply with the sulfur regulation: using either EGCS with higher-sulfur fuels, or using low-sulfur fuels.
A fully integrated comparison of CO2 emissions was conducted on a well-to-wake (lifecycle) basis, with all GHG emissions over the lifecycle of both compliance options considered.
The study found that the typical refining and desulphurization processes creates an increase in CO₂ emissions from 10-25% higher than the removal of sulfur by onboard EGCS.
Conclusion: The use of exhaust scrubbers plus heavy fuel oil (HFO) produces significantly lower CO₂ emissions to atmosphere than using very low sulfur fuel oil (VLSFO) or marine gasoil (MGO).

CE Delft

August 2020

Link to the Study

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Ecotoxicity Testing and Risk Assessment

Danish Hydraulic Institute

June 2021

Link to the Study

Commissioned by EGCSA, who appointed research group DHI to undertake the ecotoxicity assessment in accordance with generally accepted methods and IMO GESAMP guidelines.
Washwater was taken from 4 ships operating in northern Europe with open loop scrubbers which were homogenized and used to immerse multiple levels of marine organisms, from micro to fish.
Using conservative assumptions, three restricted ocean environments were modeled, including two typical ports and a channel.
Conclusion: The risk characterization rate (RCR) of the washwater samples analyzed is below 1, meaning that the “risks” to the marine environment are considered acceptable (i.e. negligible)..

With 50 years of dedicated research and real-life experience from more than 140 countries, DHI strives to make this knowledge globally accessible to clients and partners by channeling it through our local teams and unique software. In addition to research and consultancy services, DHI provides support through our advanced technologies as well as global training and knowledge sharing activities.

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All-In-One: Chemical Analysis, Ecotoxicity Testing, Fate Modeling and Risk Assessment

CLIA, Port of Seattle, Washington State Dept of Ecology

Puget Sound Exhaust Gas Cleaning System (EGCS) Washwater Ecological Risk Assessment

February, 2024

Link to the Study:

https://ir.library.oregonstate.edu/concern/technical_reports/f4752r24m

Study Team led by Oregon State University and research group EcoAnalysts to undertake the ecotoxicity assessment in accordance with current scientific accepted methods and IMO Guidelines.

This comprehensive study uniquely combines chemical analysis and comparison to water quality standards, predictive models for PAH’s, Whole Effluent Toxicity testing, and dispersion modeling for both transit and port scenarios to reach a risk assessment conclusion. Washwater was taken from 6 ships operating in Puget Sound with open loop scrubbers and was used to immerse multiple levels of marine organisms, from micro-algae to fish.

Conclusion: The risk of the washwater samples analyzed in both scenarios is considered very low, and limited to the area very close to the discharge point.

Puget Sound Exhaust Gas Cleaning System (EGCS) Washwater Ecological Risk Assessment

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Summing Up: EGCS and the Environment

Air Emissions. The combination of EGCS + HFO provides a significant air emission benefit, including lower SOx, NOx and PAH’s than VLSFO or MGO, plus significantly less CO2 released to atmosphere.
Water Emissions. No adverse impact on the ocean environment:

How about water quality? EGCS washwater quality meets all major national and international water quality standards, including the Environmental Quality Standards (EQS) of the EU’s Water Framework Directive (WFD), and even including most drinking water standards.
What about accumulation in ports? Modeling of multiple ports by CE Delft with a high EGCS-usage scenario shows the potential accumulation of key washwater parameters in port sediments over decades to be far under the limits of major dredging standards.
Any impact on marine life? Using washwater quality data, modeling and toxicology testing by the Japanese government (MLIT) in 2019, and separately by the Danish Hydraulics Institute (DHI) in 2021 and the Puget Sound Study in 2024 -- all independently reach the same conclusion: negligible impact on marine life.

Conclusion: the most credible scientific literature finds no impact on the marine environment, which is consistent with the experience of EGCS systems operating for several decades with no evidence of harm.

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Some General Points About the Science Related to EGCS �

There is no evidence of harm, anywhere, actually caused to the marine environment by EGCS.

EGCS + HFO have high quality air emissions, lower in sulphur and CO than the compliant fuels MGO and VLSFO.

EGCS discharge water quality meets all all major national/international water quality standards, including the Environmental Quality Standards (EQS) of the EU’s Water Framework Directive.

None of the coastal states that currently have restrictions on the use of EGCS have actually done a formal risk assessment related to EGCS potential harm in their territorial waters, which is strongly recommended by IMO prior to enacting any restrictions; the restrictions are all precautionary, none are science-based. The few risk assessments that states have completed have found little or no risk.

Like the few risk assessments that exist, there is a substantial and growing body of credible scientific work that is also finding little or no risk to the marine environments from these systems.

Potential risks of these systems were extensively explored by the IMO before MARPOL VI entered into force, evaluating EGCS as a alternate means of compliance. All Member States supported this option, and the EU issued the EU Sulphur Directive, which confirmed use of EGCS in EU waters; this is still in force today.