1. Is the BWTS system regulatory compliant?

A BWTS’ system’s license to operate is compliance with regulatory requirements.

For most internationally trading vessels, the starting point is the IMO Ballast Water Management (BWM) Convention. The Convention requires ships to comply with the D-2 discharge standard, which limits the number of viable organisms that may be discharged with ballast water.

However, if the vessel trades to U.S. waters, IMO approval alone may not be sufficient. The United States requires compliance with US Coast Guard ballast water regulations. Systems generally need USCG type approval to be accepted as a BWTS in U.S. waters.

It is also important to bear in mind that your vessel's flag administration and classification society may impose additional certification, testing, documentation and survey requirements. Please check this prior to deciding which BWTS to purchase.

 

2. How do I choose the most reliable BWTS system?

This is the million-dollar question that every shipowner asks themselves. Because a non-functioning BWTS system not only costs money to repair, it can also cause even more expensive delays, detentions and commercial disruptions for the vessel.

2.1 How many vessels are successfully using this system?

Verifying the operational track-record of BWTS system is of vital importance. These are some of the key questions to ask:

• How many systems have been installed?

• How many vessels are successfully using this system?

• How many vessel-years in operation?

• Does the supplier have references from shipowners in your vessel segment?

• Does the supplier have repeat orders from the same shipowner? This indicates whether shipowners have been satisfied with the system's performance over time.

2.2 Are you ordering BWTS for a newbuild vessel or a retrofit?

Yes, this matters.

Today, most ship designers allocate space to the BWTS system when designing newbuild vessels. The BWTS can then either be installed from day one of operations, or you have already saved sufficient space and installed relevant infrastructure that enable a quick and easy retrofit operation at a later stage.

The challenges normally comes with retrofit BWTS installations on board older vessels. What you need to assess before deciding on which retrofit BWTS to purchase, is the following:

• How big is the BWTS vs how much available space do I have on board my vessel?

• And what about pipe layout for untreated and treated seawater?

• Do I have the necessary electrical infrastructure and generator capacity to install and run the BWTS?

• Can the vessel crew access the BWTS to perform maintenance?

The point is that poor integration can reduce reliability even when the core treatment system itself is robust.

Please also bear in mind that compact systems may preserve cargo space, work areas and maintenance access.

2.3 How does the system perform in my vessel’s operating conditions?

Most BWTS perform well during testing, but reliability is truly put to the test in brackish water and other challenging operating conditions involving high sediment concentrations. This typically includes rivers and estuaries and shallow harbours with intense vessel traffic, resulting in elevated concentrations of suspended solids.

• If you operate a cargo vessel that typically visits many harbours, then you are more exposed to challenging water conditions.

• If you operate an offshore vessel, you spend the majority of time far from shore where the water is cleaner and often more stable.

Hence, the vessel’s operating profile plays a critical role in selecting the right BWTS system.

Shipowners should therefore ask suppliers of BWTS systems to clearly define how the system’s track record is in the relevant operating conditions and identify how often systems require cleaning under such conditions.

2.4 How efficient is the BWTS system?

The best BWTS is the one the crew barely notices. However, before ordering a BWTS, shipowners should identify its capacity and efficiency. Simply because very additional hour spent ballasting or deballasting can have commercial consequences. Ask:

• Does treatment reduce ballasting rates?

• Does the system require flow reductions in poor water quality?

• Does it create operational bottlenecks?

• Can the vessel maintain normal port turnaround times?

In this context, it is important to understand the difference between the various BWTS technologies. Electrolysis-based systems require holding time in the ballast tank to ensure effective treatment before discharge, while many (but not all) UV/filter systems are approved with zero holding time, allowing immediate ballasting operations when needed.

2.5 How complex and user-friendly is the BWTS system?

A BWTS system that depends on highly sophisticated controls and numerous components may offer technical advantages but can also introduce additional failure modes. Purchasers of BWTS systems should therefore ask suppliers how many critical components the system consists of, including:

• Number of sensors

• Number of valves and actuators

• Number of moving parts

• Complexity of automation

From a reliability perspective, fewer critical components generally mean fewer failure points.

A well-functioning system is one factor. The crew’s ability to operate it is equally important. Here, the key question is:

• Is the BWTS control system intuitive and easy to operate?

If the answer to the latter question is “no”, then you should carefully consider whether the system is right for you.

2.6 How reliable is the system?

In general, there are two types of BWTS systems: UV/filter-based systems and electrolysis-based systems. There are pluses and minuses with both systems.

Both UV/filter and electrolysis-based BWTS technologies encounter challenges when operating in brackish or freshwater with high sedimentation levels. Such challenges are common for cargo vessels that sail from port to port.

Electrolysis-based BWTS solve this issue by adding salt to the water. The downside is that the shipowner has to purchase salt, which adds cost, and the vessels must carry it around. This takes up both valuable space on board and increases the vessels’ fuel consumption. Adding salt also requires added holding time in the ballast tanks before the shipowner is allowed to discharge the water. This could prove costly if time is of the essence.

For UV/filter-based BWTS, one must consider which filter size and UV transmittance (UVT) level that are best suitable for the type of water the vessel will operate in. UVT is a measure of how easily ultraviolet light can penetrate the ballast water, determining how effectively a UV-based system can expose and neutralize organisms in the water.

The filter's primary function is to act as the first treatment stage by physically removing sediment, suspended particles, and larger aquatic organisms from the ballast water before it reaches the disinfection stage (UV or electrolysis). The filters normally come with an automatic self-cleaning capability, often through so-called backflushing, to continuously keep the filter clean, and avoid clogging of the filter.

A competent BWTS supplier should always guide the shipowner in choosing the right filter size and UV reactor for the sailing pattern of each individual vessel.

Please remember: The operational value of a BWTS is ultimately linked to uptime. A system failure can lead to missed port calls, delays, additional inspections, compliance issues (e.g. vessel detention) and reduced operational flexibility. For most shipowners, the highest-value system is simply the one that works consistently.

2.7 How much maintenance does the BWTS require?

Before choosing your BWTS system, you should always identify its maintenance requirements. Maintenance takes time and could possibly cost money, if new spare parts are required.

On the other hand, performing maintenance in line with the BWTS system’s service and maintenance plan is the best way of ensuring its reliability and thereby keeping operating costs as low as possible. Such periodic maintenance is particularly important if your vessel sails in challenging waters such as brackish water or water of poor quality/high sedimentation levels.

If you do not maintain your BWTS system properly, the system’s performance and effectiveness can be reduced. Or even worse, you run the risk of equipment failures that can lead to costly repairs.

Here are some maintenance questions that it is advisable to clarify with your BWTS supplier:

• What are the system’s periodic/annual maintenance requirements?

• How long does it take to maintain the system?

• Can my vessel crew perform the maintenance without the need for an external service technician?

• Do you provide training and instruction manuals to my vessel crew?

• Do you provide remote technical support if required?

• How much do key spare parts cost, and how often do they need to be replaced?

• If you use an electrolysis-based BWTS technology: What are the system’s chemical handling requirements?

One benefit of utilizing a UV/filter-based BWTS system is that this is a chemical- and substance-free purification operation.

Please remember: Port state control can detain vessels that fail to present proper maintenance and operational records. Such cases are expected to become more frequent. Detention can result in costly delays, lost revenue, reputational damage, and increased scrutiny from regulators, insurers, and charterers.

2.8 How is the supplier’s spare parts availability and service network?

Reliability is partly about equipment and partly about support. An excellent BWTS system becomes a poor one if spare parts take weeks to arrive, service engineers are unavailable, or technical support is slow.

Questions shipowners should ask their BWTS supplier, are:

• Do you keep key spare parts in stock?

• What is the average spare-part lead time?

• Is remote support available?

• Do you ship spare parts worldwide?

• Do you have a network of service technicians that can provide quick support almost irrespective of where our vessel is located?

Please remember: Always review the type approval documentation carefully, as it normally stipulates the use of original components in order to maintain compliance and preserve warranty protection. Using non-original parts may conflict with the type approval requirements and could invalidate warranty coverage.

2.9 How much energy does the BWTS system need?

A BWTS that runs close to its design limits is often less reliable. Energy-optimization has therefore become more and more important. Shipowners should therefore assess:

• The BWTS system’s power consumption (kWh consumed per cubic metre treated)

• Design margin versus actual ballast flow

• Ability to handle peak loads

A system that operates comfortably below its maximum capacity will generally be more reliable than one continuously running at its limit.