Ballast water: Definition and current legislation

Ballast water treatment on vessels is an essential procedure to reduce the environmental impact of large ships. Popularly known in the naval sector by its acronym BWTS (Ballast Water Treatment System), it is regulated by the International Maritime Organization (IMO) through the “International Convention for the Control and Management of Ballast Water and Sediments from Ships ”.

Role of the ship's ballast system

To achieve the stability of a ship, the system admits or takes directly a quantity of water from the environment in which it is found and depending on its size and the loading conditions. The objective is to achieve a total or partial flooding of specially designed tanks inside the hull. This process can be reversed and the water can be expelled from the vessel in a place that, in general, is usually far from the original point of intake.

This technique was developed at the end of the 19th century to replace the traditional use of solids for ballasting, which was considerably more expensive to prepare. However, ballast water was quickly recognized as a possible source of serious environmental problems in the maritime industry, so new techniques and better ballast systems were soon developed.

Impact on the marine ecosystem

The main problem with this system lies in the ballast tanks, where the water and sediments can contain forms of resistance of marine organisms, bacteria and viruses that can remain alive for weeks or even months. For this reason, the discharge of ballast water in port with living organisms that have survived in the tank has been a source of great concern for different international organizations due to the impact on the marine ecosystem.

The introduction of non-native and invasive spices through ballast water poses a serious environmental and economic threat, and may even cause serious and irreversible losses of biodiversity and other natural and non-natural damages. In addition to putting the marine ecosystem at risk, improper ballast water management can favor the transport of bacteria such as Vibrio Cholerae, known to transmit diseases such as cholera.

Through a study carried out in the Port of Barcelona, ​​in which the ballast tanks of five vessels of diverse origin were sampled, 54 different phytoplankton taxa and 69 zooplankton taxa were found.

Regulations applicable to ballast water

Although in 1991 the Marine Environment Protection Committee (MEPC) adopted the resolution “Standards to prevent the introduction of unwanted organisms and pathogens by the discharge of ballast water and sediments from ships”, it was not until 2004 when the International Maritime Organization (IMO) adopted the current “International Convention for the Control and Management of Ships' Ballast Water and Sediments”.

This agreement, known simply as the “Ballast Water Agreement”, requires all ships to implement a Ballast Water and Sediment Management Plan approved by the Maritime Administration of the Governments. This agreement reflects, on the part of ships, the obligation to have a filtration or sterilization system on board for the discharge of ballast water in other ports far from the water intake point.

SYM Naval is specialized in designing and installing ballast water system in ships. We have an engineering department in charge of studying each of the projects and challenges that arise in order to offer the best possible solution.