The path towards 2020 sulphur cap remains challenging, especially for those operators that have invested in open loop scrubbers, after many ports have announced that they are restricting or completely banning ships from using fuel cleaning systems that pump waste water into the sea.
In essence, open loop scrubbers use seawater to remove pollutants from exhaust gases released by ships, which are then end up into the sea as liquid emissions, raising concerns about the concurrent effect of this...
https://safety4sea.com/cm-scrubber-discharges-bans-in-ports-what-you-should-know/