The quality of bilge waters collected in the machinery space during normal conditions and difficulties with the bilge water systems have been considered. Analyzed systems concern contemporary cargo vessels in which the reciprocating diesel engines constitute the ships propulsion. The proposal of the bilge water system, as part of the existing bilge water installations, has been presented. That system will increase the bilge water efficiency that is pumped out overboard of the ship, decreasing the number of the international law violations. More over the proposed bilge water system can lead to decreasing the operational ships costs and raise the operational effectiveness of the engineers department

In the article theoretical bases of technology of purification of bilge water, which is formed during the operation of ship power plants. Theoretical foundations are based on theoretical premises Kulskij L.A. that the choice of methods of cleaning depends on the properties of the treated water. The basic properties of oil bilge water that oil present in this water emulsified oil products and oil as the individual phases. Also made an analysis other factors that determine the choice of technology cleaning of bilge water. The basic technological scheme of cleaning should contain methods for cleaning from free product and from emulsified. There is also the possibility to use such methods of water treatment, which improve the efficiency of methods of cleaning. Theoretical bases allow to develop effective devices for cleaning bilge water as marine and coastal or for floating treatment facilities.