Koninklijke Vereniging - Société Royale



Putting a value on ballast water management

One of the most important environmental developments in the marine sector in recent years, the Ballast Water Management Convention (BWMC) introduces new challenges for vessel owners and operators.

The challenges are not just the cost of upgrading their systems but also in managing the overheads incurred in the water treatment process. PSM’s Mark Jones looks at how digital tank gauging systems can help.
Marine bio-invasion is a growing issue, with shipping identified as a major cause in the transfer and introduction of invasive new species and dangerous pathogens across the world’s oceans. With the increase in traffic and use of water as ballast in steel-hulled vessels, the problem has increased exponentially in recent years, and according to the IMO may not yet have reached its peak. *

Ballast water is an essential component of ship operations in steel hulled vessels, with large vessels requiring many thousands of cubic metres of water to maintain stability and manoeuvrability, both at sea and in port.

The load may contain thousands of aquatic or marine microbes, plants and animals, which are then transported and released across the globe, with potentially devastating effects on local marine ecosystems. Threats include for example the European Green Crab which is a carnivore that preys upon clams, mussels, oysters and gastropods, as well as out competing them for food to the spread of bacteria such as cholera and the invasive Asian Kelp.**

Hidden price tag

The new ballast water standards will be phased in gradually. Over time, all ships in international traffic will be required to fit an approved water treatment system to minimise the uptake of organisms and to remove sediments and unnecessary discharge. In addition, ships will be required to carry a ballast water management plan and to record and report on ballast exchanges. Ships of 400 gt and above will also require appropriate certification.

However, the bill for compliance extends beyond the initial investment in treatment systems to the ongoing costs of processing the vast amounts of water involved. Water treatment systems operate at high voltage: depending on the treatment method, energy consumption can be considerable, to which the cost of additional consumables, such as  chemicals, must be added.

The result is that ballast water can no longer effectively be considered as a free commodity but becomes an overhead that needs to be incorporated into already heavy operational costs. Moreover, older vessels may have limited space, restricting the power available to drive these systems, which makes it even more essential to manage their use carefully.

Controlling consumption

Modern tank level gauging systems can help cut costs by continuous measurement of ballast water levels to ensure that the treatment is run for only as long as required. In addition, they provide accurate data in real time to inform ship systems to comply with new recording and reporting standards, which require vessels to hold data in a ballast water record book.

Failure to product such data could lead to delays in port as well as the infringement of regulations.

The new legislation presents an opportunity to upgrade to the latest digital tank gauging systems. Although BWMS now being fitted to new ships may incorporate tank gauging equipment, where existing ships are being refitted this assumption cannot be made, with potentially up to 40,000 ships affected.

As with all new marine regulations, implicit also in the introduction of new standards is the issue of safety. Maintaining the ship’s stability during ballast water exchange is paramount.

Tank level gauging systems enable the proces to be monitored and the correct sequencing of tanks to be observed, with automatic start/ stop and high/low alarm functions built in to prevent stresses on the hull which might lead to deformation. An equally important factor is the protection of the ship’s propellers, with both outcomes having additional repair cost implications.

Ballasting a vessel is also essential during voyages to optimise its manageability and to ensure safe navigation during heavy weather conditions. The latest digital systems incorporate a range of transmitters, gauges and switches to enable balancing of the ship to compensate for weight loss due to consumption of water and fuel and to maximise fuel efficiency through control of the ship’s draft and trim.

Where these tank gauging systems are part of a ship-wide system, such as PSM/Scanjet’s Intelligent Tank Management System ITAMA, vessels also benefit from additional synergies to assist with satisfying these legal requirements while maximising efficiency and energy consumption.


* International Convention for the Control and Management ofShips’ Ballast Water and Sediments (http://www. imo. org/en/About/Conventions/ ListOfConventions/Pages/International-Convention-for-the-Control-and-Management-of-Ships’-Ballast-Water-and-Sediments-(BWM).asp)


** Ballast water management - the control of harmful invasive species ( HotTopics/BWM/Pages/default.aspx)



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