The aim of the study, which was published in December 2019, was to provide 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 from 53 different ships. The vessels included cruise ships, bulk carriers and ferries.

Concerns have been raised about the environmental impact of washwater discharges, especially in port areas. The study is unique as it uses empirical data from almost 300 EGCS washwater samples, the most extensive dataset of this kind analysed in this manner, and because it employs the MAMPEC-BW model to calculate equilibrium concentrations in ports. MAMPEC-BW is a model that is widely used in a regulatory context, e.g. for the approval of ballast water management systems and antifouling agents.

The CE Delft study concludes that ‘ships that use Exhaust Gas Cleaning Systems (EGCSs) to comply with the IMO sulphur regulations have a small impact on the water quality in ports when compared to future EU standards for priority substances in water.’

The study was commissioned by the Cruise Lines International Association Europe (CLIA Europe) and a number of industry partners with the aim of furthering publicly available knowledge on the impact of washwater discharges from open-loop EGCSs on port water and sediment.

In recent years, five independent scientific studies have all reached the same conclusion that washwater from scrubbers do not harm the marine environment.  Three of the five studies are conducted by public bodies, two are ministeries and one is a higher-level university study. Two of the five studies are from the ministry of transport in Japan and the Danish ministry of environment. Both studies reached the same conclusions, that scrubber washwater does not impact the environment” Read more about these studies in this article.

“There is an overwhelming amount of scientific evidence that sulphur emission levels from scrubber washwater do not cause any harm to the marine environment. We hope that this latest research project can alleviate some ports’ unfounded concerns about the opposite. Ports around the world need to understand that sulphur in the form of sulphate is a natural constituent of seawater and therefore not harmful to sea, as a huge amount of scientific studies proves,” says Svein Ole Strømmen, chief operating officer of Clean Marine.