Ballast Water Dechlorination
Definition - What does Ballast Water Dechlorination mean?
Ballast water dechlorination is a process that removes chlorine from a ship's ballast water before the water is released into the ocean. It is an important step performed by large vessels, cargo ships and cruise ships.
Corrosionpedia explains Ballast Water Dechlorination
Water is pumped into the ship's ballast tanks to gives them stability and maneuverability. However, untreated ballast water discharged into the ocean is considered water pollution and can cause extensive ecological and economic damage to the aquatic ecosystem.
Normally, ballast water is treated with chlorine (a disinfectant) to remove any toxic bacterial organisms. However, releasing chlorinated water can negatively affect the aquatic ecosystem. Residual chlorine in the water or that accumulates at the ballast tank's edges must be dechlorinated or removed. Dechlorination is a process in which the chlorine is removed from the disinfected wastewater before dumping this wastewater into the environment. The most commonly used dechlorination agent is sulfur dioxide.
Another reason to dechlorinate ballast water is that chlorine increases the corrosion rate of cast iron and cast steel ballast tanks.