Regional training and workshop on the legal implementation of the ballast water management (BMW) convention was held in Lagos, Nigeria to support the timely and harmonized implementation of ballast water convention in the West and Central Africa region. There has been a growing concern over the problem of invasive alien species in the marine environment as a result of ballast water carried by ships. Ship ballast water serves as a vector for the transfer of alien species and harmful aquatic algae and other pathogenic organisms from one part of the world to the other.
Ballast is the additional weight a ship traveling without cargo or partially laden must take on board to enable it to operate effectively and safely by keeping the ship deep enough in the water to ensure efficient propeller and rudder operation. Shipping, which is essential to the global economy, provides the most effective means of transporting bulk goods over great distances. With some 50,000 merchant ships sailing the world’s oceans, with a combined tonnage of around 600 million gross tonnes, ships carry over 90 percent of all global trade.
Although ballast water is crucial to the safe operation of ships, studies have shown that when ballast water is taken on board the ship, the organisms living in that water are also drawn into the ballast tanks. Depending on duration of voyage and other factors, many of these organisms survive the journey and are subsequently released live into the waters of destination port when the ballast water is discharged.
At the regional training and workshop by the GloBallast Partnership of International Maritime Organisation (IMO) in collaboration with the Interim Guinea Current Commission (IGCC) and the Nigerian Maritime Administration and Safety Agency (NIMASA), which held at the NIMASA Resource Centre at Kirikiri, Lagos, 12 countries from the sub region participated.
In response to these threats, the IMO adopted the international convention for the control sand management of Ships ballast water and sediments, to minimize the transfer of harmful aquatic organisms and pathogens. As part of the international response, the convention on biological diversity came out in 1992. At the IMO, discussions already started in 1973, while preliminary guidelines for BMW developed in 1991 and full guidelines adopted by IMO assembly in 1997. International convention for the control and management of Ship’s Ballast Water and Sediments was adopted 13 February 2004.
Treatment methods include mechanical treatment, mainly by filtration or cyclonic separation; Chemical treatment, addition of ‘active’ or other substances that will render Harmful Aquatic Organisms and Pathogens (HAOP) harmless and Physical treatment which includes Thermal, ultraviolet magnetic and ultrasound devices. It was agreed that the modern and best way of treating ship’s ballast water globally is through ozone disinfectant, to sterilize the water before discharging it back into the ocean. Ozone is a widely used disinfectant for a variety of water treatment applications.