In open loop system, the Sulphur in the exhaust gases dissolves in the process water and there is no need for water treatment as the natural alkalinity in the seawater neutralizes the acid. Wash water is continuously monitored to make sure it is in line with the regulations from IMO before it is discharged into the sea with no harm to the environment.

The hybrid scrubber system can run in both closed or open loop mode.

When the scrubber system works in closed loop, an alkali, such as Caustic Soda (NaOH) or Magnesium Oxide (MgO) is needed to clean the washwater that is held in the washwater tank.
The conversion projects of hybrid loop include the fabrication of two pump rooms to provide water to the scrubbers and other systems, as a dilution tank, hydrocyclons, a sludge tank, a magnesia tank, to collect and treat the outlet water when operating as closed loop.