Global scrubber washwater discharges by ship type 2020

In 2020, container ships were responsible for 32 percent of all scrubber washwater discharged worldwide. Bulk carriers and oil tankers accounted for 20 percent and 17 percent of global scrubber water discharges globally, respectively.
Scrubber washwater is a byproduct of vessel scrubbers. These are employed to remove nitrogen oxides (NO_x), sulfur oxides (SO_x), and other air pollutants from exhaust gases generated by engines, usually by spraying sea water over exhaust gases. This mixture of seawater and pollutants removed from exhaust gases - called scrubber washwater - is then discharged overboard. Scrubber washwater can seriously harm marine organism.