Ballast water is essential to control ships’ trim, draught, stability and stresses. However, when ballast water is taken in one port, for example in the Bay of Biscay, and pumped out in the Baltic, the water may carry harmful aquatic organisms and pathogens, which out-compete native species, disrupting the native ecology seriously.
According to HELCOM (Baltic Marine Environment Protection Commission), more than 130 non-indigenous species have appeared in the Baltic Sea since the 19th century. Globally, it has been estimated that ships carry 3,000–4,500 different species in their ballast tanks.
The shipping community started to combat invasive aquatic species by issuing guidelines and national regulations some 30 years ago. In 2004, the International Ballast Water Management Convention was adopted by IMO. However, ratification took twelve years as the requirement was to have as many as 30 countries, representing 35% of world merchant shipping tonnage, to sign the Convention. Finally, it was Finland that triggered the entry into force and the Convention became effective on 8 September 2017.
Today, ships must exchange their ballast water with an efficiency of 95% if they are not equipped with a treatment system. It must be noted that exchange involves hazards and it must be planned carefully in order not to risk ship’s safety. In fact, the master is responsible for considering if the conditions, including vessel stability, allow exchange of ballast water. The master may suspend ballast operations in adverse weather and sea conditions.
Ships operating exclusively in the Baltic Sea are exempted from the exchange requirement as the geographic location requirements are not met. The distance must be at least 200 nm from the nearest land (or at least 50 nm if 200 nm is not practicable) and water depth must be at least 200 m.
Ships must be fitted with ballast water treatment equipment no later than 2024. The due dates for equipment installations are linked to the ship’s IOPP-certificate, which is valid for a maximum of five years at a time. There are several treatment technologies, such as ultra violet light and electro chlorination, and more than 60 type-approved systems on the market. Nevertheless, each ship is individual and many parameters must be considered during decision taking. A treatment system, which works well in the Mediterranean, may be inefficient in the Baltic where salinity of water is lower and temperatures colder.
Finnlines has investigated ballast water treatment options, but we expect technologies to make great progress in the near future. The shipping industry welcomes the Convention although it faces many challenges in implementing the new requirements.