This is what is called a Wet Scrubber. It job in life is to remove particulate from the air before it is released into the atmosphere. This one removes B class smoke which is produced when you burnt oil or kero.
The Scrubber has a massive fan attached that moves some 9000 l/s of air through the Scrubber. Note that the unit has to be maintained on a very regular basis. This includes draining and cleaning the inside and charging with clean water.
Plus servicing the fan motor and blower that generates the 9000 l/s to make sure all the bearings are well greased .
This wet scrubber is involved in the mitigation of the smoke and particulate that is produced as part of the job. So that the exhaust to atmosphere is very clean and green.