A new study by research establishment CE Delft shows that while there are increases in traceable pollutants from open-loop scrubbers in port water and sediments, the levels are far below the established guidelines
CE Delft is an independent research and consultancy organisation specialising in developing innovative solutions to environmental problems. In the study “The impacts of EGCS washwater discharges on port water and sediment” CE Delft worked with another research establishment, Deltares, to model the impact of exhaust gas cleaning systems (EGCS or scrubbers) on port water and sediment. The study calculated the predicted equilibrium concentrations for 11 metals and 16 polycyclic aromatic hydrocarbons (PAHs) and compared this with the EU Water Framework Directive.
The study found the increase in concentrations caused by continuous discharge of a relatively high amount of EGCS washwater is less than 0.1% of the limit value in the EU WFD for 2021 for these priority substances. In ports located in zones with small tidal ranges, such as the Baltic Sea, the increase in concentration can amount to 0.6% of the limit value for a few PAHs.
To put this into context, the findings would have needed results of 100% or higher to breach the EU WFD guidelines.
The study was commissioned by the Cruise Lines International Association Europe (CLIA Europe) following concerns raised about the environmental impact of open-loop scrubber wash wastewater in ports, and the banning by some authorities of their operation in some ports. CE Delft presented the paper to IMO during PPR 7 in February 2020, and CE Delft senior researcher and consultant Dagmar Nelissen presented the paper to delegates at the 2020 Clean Shipping Alliance in London.
The results of the paper seem to indicate that ports were too quick to ban open-loop scrubbers without scientific evidence but mainly based on pressure from the general public. This points to the ongoing conflict as shipping strives to meet IMO greenhouse gas emissions goals.
Hear and see the latest progress at one of the Maritime Air Pollution Conferences near you:
Maritime Air Pollution Conference, Americas, 5-6 March | Miami | maritimeairpollution.com
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