Chemical Engineering Journal 156: 305-312 (2010)
Ballast water is carried in cargo ships to maintain stability, but can contain microorganisms (e.g. Phyllorhiza punctata larvae) that have the potential to become invasive species in foreign waters. Researcher Efi Tsolaki from the Technical University of Crete, Greece and others have developed a potential disinfection method to treat ballast water involving electrolysis. The organism being tested was Artemia salina and salt was dissolved in the water to achieve the same conductivity as actual sea water. The electrical disinfection method works by running a current through the tank, which produces hypochlorite and hypochlorous acid from the chloride content in the sea water. These by-products kill microorganisms, and then can be removed from the water by a reduction agent such as sodium thiosulfate. The researchers ran several tests and found that a 135 mA/cm^2 current density held for 1 minute would kill all of the A. salina with minimal residual chlorine by-products of less that 10 micrograms per liter.
Using electrolysis to cleanse ballast water is an intriguing approach; this was a very thorough research highlight, and it seems like it would work well with your topic too. How the amount of residual chlorine compares to the by-products of other ballast water cleaning solutes is worth more elaboration if you include this in your MWP II.
This is an impressive new approach to solving the problem. I’m curious how well might this method work if deployed on a large scale.