The subject of this final paper is the comparison of the two devices for the treatment of ballast water. The GloEn-Patrol Panasia device and the Erma First ballast water treatment devices were compared. Ballast is the water that ship takes in to maintain balance and stability while without cargo. The main problem of ballast water is pollution, which results in the transfer of several types of microorganisms. Panasia ballast water treatment devices use UV lights together with a filter to treat ballast water. Water is treated during ballasting and deballasting. In addition, the filter not only eliminates organisms larger than 50μm it also reduces sediment in the ballast tank. This filtering alone increases the efficiency of the UV unit. Erma First ballast water treatment device uses electrolysis process. The main components of the system are the countercurrent pumping unit and the electrolysis chamber. The filter body is self-cleaning and filters up to 40μm. It is not necessary to use the system for deballasting and it is bypassed and the water is discharged outside the ship after the neutralization has been carried out.