The tightening of environmental regulations in the shipping industry, particularly the implementation of the regulation limiting the sulfur content in marine fuels, has led to the increased adoption of emission control technologies on ships. One of the primary means of compliance is exhaust gas cleaning systems, also known as scrubbers.
Scrubbers allow for the continued consumption of high-sulfur fuels (HFO) by effectively removing sulfur dioxide (SO₂) from ship exhaust gases. Their operation is based on the physical and chemical absorption of SO₂ through the contact of exhaust gases with wash water.
Depending on the method of processing and disposing of the wash water, scrubbers are divided into two main types:
However, scrubbers –mainly the open-loop type– are at the center of growing environmental concerns, as they discharge acidic water containing polycyclic aromatic hydrocarbons (PAHs), heavy metals (such as nickel, lead, copper, and mercury) and other polluting residues into the sea. These discharges are linked to serious impacts on marine biodiversity and water quality, a fact that has led to a global trend of restricting or even completely banning them.
Already more than 90 countries, regions, and ports –including Denmark and Sweden– have adopted measures against scrubbers. This development indicates that the international community is gradually turning towards a stricter stance, questioning the viability of this specific technology as a means of compliance.
Source for the types of scrubbers: DNV
