Ballast water is one of the main routes for the introduction of non-indigenous marine species. Ballast water is fresh or salt water found in ballast tanks and / or in ship's cargo warehouses. It is used to ensure stability and maneuverability during navigation when ships are not carrying cargo, when they are not carrying heavy enough cargo or when due to bad weather and sea conditions, greater stability is needed. Ballast water can also be used to add weight so that the ship dives deep enough into the water to pass under bridges and other structures. What is specific for ballast water is their discharge in various ports. During the discharge of water, microorganisms are released, which in most cases have a negative impact on the environment. The main goal of this paper is to investigate how ballast water affects the environment and which disposal methods, ie which disposal methods are the most acceptable. All potential ballast water treatment methods include labor costs which are the main concerns of shipowners and often the most important parameter for selecting ballast water treatment technologies to be used on board. Nowadays, for ballast water combined methods are used based on the recommendations of the IMO (International maritime organisation). The methods are approved and are used after the initial assessment of the ballast water such as PERACLEAN ® Ocean Ballast Water Treatment- approved chemical method to assess ballast water. Optimarin uses a system to purify the ballast water by using a combination of filtration and UV radiation (physical method).