The 10 Step Guide to Selecting a Ballast Water Management System

Selecting the most suitable ballast water management system (BWMS) for a specific vessel is a critical, and often, underestimated task. With over 50 commercial systems available, operating on numerous combinations of different technologies and treatment processes, the suitability of any one system to a specific vessel cannot simply be presumed.

The criterion for comparison of different systems for a specific vessel is not simply technical. Commercial considerations, operational requirements and through life and after sales support are all just as critical. Indeed, in many cases, owners and operators are simply identifying the cheapest option and installing it without due consideration of the system’s otherwise suitability.

We have developed this article as a comprehensive, step-by-step guide to vessel owners and operators in the selection of the most suitable BWMS for a specific vessel. It is in no way a replacement for a thorough vessel feasibility study (such as the entry level BWMS selection studies we offer), but will hopefully assist key stakeholders in the down-selection of suitable options.


Which Technology?

Often the first question we are asked by shipowners and operators is; “Which technology is most suitable for our vessel?” The short answer to this is; there is no short answer..!

Identification of the most suitable technology is driven by much more than just the vessel type or size, and has to incorporate a variety of key considerations, such as:

  • Vessel trading patterns
  • Required technology approvals / certification
  • Existing ballast operations
  • Installation location
  • Access for installation
  • Power availability
  • Existing pump capabilities
  • Life cycle costs
  • Availability & Logistics
  • Manufacturer corporate viability & sustainability

This guide will identify these key considerations, and outline key discussions points of each.


Step 1 – Vessel Trading Patterns

The first step in the selection of a BWMS is building an understanding of the trading patterns of the vessel, and any limitations on system selection that these may cause. Vessel trading patterns are a critical consideration for treatment system selection, for a combination of reasons, namely:

  • Individual port state requirements or local legislation
  • Specific water quality limitations

Of course in a global sense, the first geographical consideration is whether the vessel has, or is, trading to the United States – or if the vessel requires the ability to do so in the future. If so, then immediately the treatment system options are limited to either USCG Type Approved systems, or AMS approved systems with USCG Type Approval pending, or in the works.

Installing a system without USCG Type Approval, and without any likelihood of obtaining it, on a vessel trading into the US, could have significant commercial consequences.

Water quality limitations are also highly important in the early stages of system selection. Water quality not only varies from country to country, but also from port to port. Various aspects such as turbidity, salinity, total suspended solids and silt contents impact the operation and performance of a BWMS – sometimes critically. It is important to understand any significant water quality issues associated with ports where the vessel conducts ballast water operations, and cross check these with the limitations of each BWMS independently.


Step 2 – Required Approvals / Certification

The second step in the selection of a BWMS is understanding the required approvals and certification of the system itself.

First and foremost, owners and operators must, of course, ensure that any BWMS considered hold appropriate IMO Type Approvals from a suitable Flag State. In general, most Type Approvals will be in accordance with either the G8 or G9 guidelines, and comply with IMO Resolution MEPC.174(58).

For vessels which have been identified as currently trading to the US, or requiring the ability to do so, will require suitable USCG approvals. The first consideration is whether the BWMS currently holds a valid USCG Type Approval. For those that don’t it is important that owners satisfy themselves that the manufacturer has a valid AMS approval, and is in the process of obtaining full USCG Type Approval. Long-term compliance with USCG legislation will require a fully USCG Type Approved system be onboard, beyond the 5 year grace period that AMS approval provides.

Owners and operators are advised to pay particular attention to any subtle differences between a manufacturers current AMS approved system, and their system going through USCG testing. In some cases, there are slight technology differences which may require additional expense to upgrade after the fact. However, in cases, manufacturer’s USCG based systems are completely different to their AMS approved systems – which may actually require complete replacement once the original AMS approval has expired.

Alternatively, owners and operators trading into the US can utilise one of the other acceptable methods indicated by the USCG – as outlined in our Guide to Ballast Water Management Legislation. LINK


Step 3 – Existing Ballast Operations

The third step in the selection of a BWMS is ensuring a thorough understanding of the vessel’s existing ballast operations and the total treatment flow rate capacity required.

Understanding how, when and where the vessel currently, and historically, conducts ballasting / de-ballasting operations is crucial in determining the suitability of a system, and understanding the technical limitations these typical operations impose is of prime importance.

The total treatment capacity itself is a significant driver of suitability, particularly on the commercial side, as different technology types can immediately be discounted from consideration depending on the total capacity. Chemical based treatment systems, for example, are not cost efficient for lower flow rates, whilst UV based treatment systems, for example, tend to have significant operational costs at very high flow rates, due to their high power demand. Hence the importance in understanding the total treatment capacity required.

In many cases, the operational approach of the vessel can drive the suitability of particular technologies or even individual systems, and in some cases, simple changes to the operational approach of the vessel can help widen the scope of suitable systems – such as dropping from two ballast pumps to one – halving the required treatment capacity immediately.

Some key ballasting / de-ballasting considerations to make include:

  • Operational times – if during significant cargo operations this may have an impact on power availability and/or personnel availability to operate
  • Operational locations – if the vessel tends to conduct ballasting / de-ballasting operations in deeper water prior to entering port, this may remove water quality issue limitations
  • How many pumps? – whether the vessel ballasts or de-ballasts with a single pump or two pumps will drive the total treatment capacity required
  • Stripping procedures – if the vessel conducts stripping operations this will drive the selection of a system

Owners and operators should liaise closely with the vessel crew to establish a benchmark of the existing ballasting / de-ballasting operations, before embarking on the selection process. If changes to the operational approach of the vessel are being considered, it is important to conduct a thorough investigation, with all parties involved, into the impact of the proposed operational changes on the vessel’s efficiency, safety and, of course, suitability under its charter.


Step 4 – Installation Location

Exactly where onboard the vessel the BWMS components would likely be situated is a significant driver in the selection process, and has to be a combined effort in conjunction with Step 2 – existing ballast operations.

For conventional vessels with engine room ballast pumps and no hazardous areas, the location of the BWMS components is generally driven by space availability – not just for the BWMS components themselves, but also the associated pipework, fittings and maintenance access. In many cases, the lack of availability of suitable space, or the size limits of the space, can drive the selection of the BWMS.

It is for this reason that Cleanship Solutions feasibility studies include a comprehensive conceptual 3D arrangement analysis of each BWMS – to ensure that the suitability of each respective system within the space available has been thoroughly considered. An example of our walkthrough video deliverable as part of our feasibility study is available here – LINK

For vessels with complex ballasting / de-ballasting operations and/or hazardous area limitations, the suitability of particular technologies becomes more obvious. First off, if the BWMS components are required to be installed in the hazardous area, perhaps due to the vessel utilising Framo pumps, then the BWMS selection process immediately requires systems that come with a suitable “EX” rating. Generally, these vessels will also have limitations on where, within the hazardous area, the components can be installed – again driving the need for smaller components that can suit the space available. More often than not, vessels with hazardous area considerations will require a new, dedicated, deckhouse be design and installed to house the new BWMS.

This stage does tend to be somewhat iterative, but is crucial in selecting the most suitable system.


Stage 5 – Access for Installation

Once the vessels trading patterns are understood, the ballasting / de-ballasting operations have been investigated, and proposed installation locations identified, the next step is understanding the limitations on accessing the installation location onboard.

For vessels with conventional engine room ballast pumps, and hatch access directly from main deck into the engine room, access for installation is not an issue. However, for many vessel types and sizes, the proposed installation locations for the BWMS components may be somewhat difficult to access, and hence due consideration to the modularity and portability of the BWMS components has to be made.

Owners and operators should ensure that for complex installation locations, accessible only via watertight doors or small hatches, examination of the modularity of the BWMS components is undertaken.  We have witnessed, on many projects, numerous BWMS be discounted from consideration simply due to their smallest components being too large to transport into the installation locations. Indeed, in some instances we have witnessed BWMS that claim to have been designed to be modular and fit through doors and hatches, be too large to do so! So owners and operators should be acutely aware of these limitations prior to selecting a BWMS.

The modularity and access for transportation internally is not the only consideration. Owners and operators should also pay close attention to the practicality and safety implications of transporting such heavy, and often unwieldy, components within vessel’s machinery spaces.

In many cases, cutting access holes to load components, either in various decks or in the sideshell of the vessel, may be the only course of action, but with some clever engineering and careful consideration during the feasibility and engineering phases, such drastic action may be able to be avoided.


Step 6 – Power Availability

Power availability is a critical consideration during the selection of a BWMS, and is an aspect that many stakeholders overlook.

Owners and operators have to conduct a detailed review of the existing power balance calculations for the vessel, reviewing the load conditions during which the BWMS would also be operating, and build an understanding of the power limitations, namely:

  • Maximum free power available under current operating conditions prior to an additional generator being required
  • Total maximum free power available

In many cases, the addition of the load of the BWMS will result in another generator running which will, of course, have implications on the operational costs of the vessel itself. In some critical cases, particularly on vessels with high ballast dependency (such as tankers and bulk carriers), vessels may not have sufficient power for the BWMS – and may have to examine more drastic alterations to the vessel’s powering.

The disparity in power consumption not only between different technology types, but also between different systems within a single technology branch, is astounding, particularly at higher flow rates. Vessels with limited power and high ballast flow rates will undoubtedly face the biggest challenge.

Understanding the numerical power limitations, and the commercial implications of exceeding them, is a key step in the selection of a BWMS.


Step 7 – Existing Pump Capabilities

Step 7 involves the examination of the existing ballast pumps onboard, and their suitability to not only meet the hydraulic requirements of the BWMS, but also their ability to cope with the inherent pressure drop that BWMS create in the ballast system.

The majority of BWMS that incorporate a self-backflushing filter state very specific minimum inlet pressure requirements – typically around 1 bar – 1.6 bar. These requirements are to ensure that the backflushing process can be carried out efficiently and failure to meet these requirements can cause clogging or blocking of the filter elements. Indeed, very few BWMS manufacturers will guarantee their system if the inlet pressure of the ballast system does not meet these requirements during the commissioning phase.

Whilst many ballast systems will have been designed with pumps providing in excess of 1.6 bar, some systems, particularly on smaller vessels or older vessels, may struggle with reaching this requirement. Conversely, some vessels, such as PSVs and OSVs, which may have combined ballast / drill water pumps, may operate at a pressure which far exceeds the pressure limitations of the BWMS system – which tends to be around the 6 bar mark.

Ballast water treatment systems, by their very nature, also create an increase in pressure drop. The extent of the pressure drop varies depending on technology employed and specific system components, however pressure drops of 0.3 bar – 0.8 bar are not uncommon. Such additional pressure drops will have one of two effects on the existing ballast pumps:

  • The pump flow rate will drop due to the increase in pressure drop
  • The new system pressure demand will be unachievable by the pump, which will result in zero flow and/or erratic running

Whether the pumps are struggling to meet the inlet pressure requirements of the BWMS, or they are struggling to cope with the additional pressure drop, owners and operators may be faced with upgrading or, in worst case scenarios, replacing existing ballast pumps. Indeed, we observe this on many of the retrofit projects that we are involved in.

Analysing the capability and suitability of the existing ballast pumps is an important step in the BWMS selection process.


Step 8 – Life Cycle Costs

Ultimately, and understandably, owners and operators are mostly interested in the life cycle costs of the BWMS.

Capital costs of each BWMS are fairly easy to identify from the manufacturers quotations, however, the installation costs can vary significantly not only based on complexity, but also based on which shipyard, and/or installation company is employed. Installation itself could be undertaken in a variety of ways, including:

  • During scheduled drydocking
  • Whilst vessel is alongside
  • During vessel operation using riding squads

The suitability of each option depends on the vessels trading plans, the complexity of the installation and, often most, the availability of appropriate cabins onboard (if using riding squads).

Ultimately, the installation phase costs do represent a significant portion of the total life cycle costs, and owners and operators should examine different installation companies and options.

The operational costs of each BWMS can also be difficult to quantify – as these are based not only on the vessel type, size and frequency of ballasting operations, but also on a number of, currently, unquantifiable operational expenses, such as consumables and spares. There remains insufficient operating experience and hours on existing BWMS to understand the life expectancy of key spares, other than accelerated tests.

From our experience, whilst the life cycle costs are of significant importance, they are driven, ultimately, by all of the preceding elements discussed within this article, so owners and operators are better served identifying, reviewing and addressing the key stages from 1 – 7, to help better clarify the life cycle costs, rather than focusing on initial capital costs, or somewhat unsubstantiated installation costs based on purely budget pricing. Focus on the detail, per this article, and determine the life cycle costs from this.


Step 9 – Availability & Logistics

Whilst an element that, through correct planning, should not be of prime importance, the availability of the BWMS itself, and the logistics of meeting the retrofit timetable is becoming more and more of an issue as the deadlines for compliance approach.

With BWMS, in general, having lead times of up to 24 weeks, plus the time required for all of the upfront engineering services, such as; vessel survey; feasibility study; detailed engineering; class approval etc, a retrofit project can take anywhere from 6 – 9 months. If planned appropriately, owners and operators can ensure sufficient time is allocated to enable the correct selection of a BWMS.

However, should owners and operators delay on undertaking retrofit projects, their choice of system may become entirely limited to which manufacturer can meet their tight deadlines, rather than which system is most suitable.

Owners and operators are strongly advised to plan sufficiently ahead to ensure they can make their BWMS selection correctly. Initial vessel surveys and feasibility studies can represent less than 1% of the total retrofit cost for the vessel, so can be undertaken well in advance of compliance dates. Indeed, for owners and operators with large fleets, it is a prudent approach to commission these surveys and feasibility studies over a sustained period, rather than rush them all last minute.

Similarly, the detailed engineering phase, which may represent 5% of the total retrofit cost, can also be phased over a planned period, again avoiding any last minute challenges.


Step 10 – Corporate Viability & Sustainability

The final step in the selection of a BWMS concerns the corporate viability and sustainability of the BWMS manufacturer. The ability of the manufacturer to deliver the BWMS on time is not only important, for time sensitive installation projects, it is critical.

But beyond the manufacturer’s ability to deliver the BWMS on time, there are a number of other key considerations that fall under our unique Corporate Viability & Sustainability scoring:

  • Service network – does the manufacturer offer a suitable service network in locations appropriate for the trading patterns of the vessel?
  • Spares and technical support – does the manufacturer offer expedient availability and delivery of spares as well as technical support?
  • Sustainability – is the manufacturer, and its associated after sales support, likely to still be trading after the inevitable “boom” of the ballast water management market has passed?

The final point is of prime importance, as it is highly probable that of the 50 + manufacturers to date, there will remain only a fraction of these beyond 2024. Owners and operators should ensure they satisfy themselves that the manufacturer they are selecting, is a good long term investment for the vessel and their ongoing operation.



Overall, the selection of a BWMS is a complex and important process, and one that should earn appropriate devotion of time to addressing. There are many aspects to consider, and whilst this guide addresses ten of the key steps, there remain numerous other considerations that can only be obtained through experience.

This is why we offer our entry level BWMS selection feasibility studies, which examine all aspects discussed in this guide, along with our extensive experience of the market, for a specific vessel. Delivery of a comprehensive summary report, identifying the most suitable BWMS for the specific vessel, along with visually stunning walkthrough videos of each BWMS option within the proposed installation location, not only future-proof owners and operators, they do so at an incredibly attractive low fixed price.

For more information on our BWMS Selection Feasibility Studies, please get in touch.