Ballast water management system made economical for smaller vessels

Co-inventors (from left) Jan Tilman (Van Oord) with Isabel van der Star and Marcel Veldhuis of MEA-nl. Credit: Bert Visser
Co-inventors (from left) Jan Tilman (Van Oord) with Isabel van der Star and Marcel Veldhuis of MEA-nl. Credit: Bert Visser

For smaller vessels, the cost and space requirements for an infrequently used ballast water management system are not economically justifiable. Now Van Oord and Marine Eco Analytics (MEA-nl) have claimed a breakthrough by creating a system addressing those issues and they believe it could have industry-wide impact.

Rotterdam-based dredging and marine contractor Van Oord received its type approval certificate from the Dutch Ministry of Infrastructure and the Environment, for an innovative ballast water management (BWM) system in November last year. It was the culmination of close co-operation between Van Oord and specialised testing company MEA-nl from Den Oever, the Netherlands.

The partners’ outside-the-box thinking led to an unconventional but fit-for-purpose system, known as VO-BWMS.

Uncontrolled discharge

Ever since steel-hulled ships were introduced, ballast water has been used for stabilisation. With shipping traffic covering the globe, it is very common for water taken on at one place to be discharged in a completely different part of the world. Along with this water, a multitude of marine organisms, such as bacteria, microbes, small and larger invertebrates, and even fish eggs or larvae, are also discharged.

Some of these non-indigenous species can be very invasive once introduced to a new environment. Often with no natural enemies present, they can take over a complete ecological system and disrupt the local natural balance. With the expanded marine traffic of the last decades of the 20th century, the problem of invasive species could not be neglected any more and the IMO’s Marine Environment Protection Committee (MEPC) and individual countries became aware that something had to be done.

However, it was not until 13 February 2004, after a long period of negotiations between IMO member states, that the International Convention for the Control and Management of Ships’ Ballast Water and Sediments (BWM Convention) was adopted in London. Under the convention, all seagoing vessels are required to have a ballast water management plan in order to disinfect their ballast water before discharge. Now in 2016, although the convention has yet to be ratified by enough member states for it to come into force, shipping companies worldwide are already taking action in anticipation of future developments. In some countries, such as the United States, legislation has already been implemented.

Large versus small vessels

In recent years a variety of BWM systems have been developed and certified, but mainly for larger vessels. These systems are mostly based on water filtration treatment, ultraviolet radiation, electro-chlorination, chemical additives, or a combination of these.

Although these systems all work differently and have their own specifications, what those already developed and certified have in common is that they are cumbersome and costly to retrofit and maintain in an existing fleet. Total investment could easily top USD300,000 per vessel, depending on the type and capacity of treatment used.

IHS IHS Markit spoke to Jan Tilman of Van Oord and MEA-nl scientists Marcel Veldhuis and Isabel van der Star about the Van Oord ballast water management system, which, between them, they designed exclusively for use on board small vessels.

For large ships that make regular ocean voyages, the size of a system is not a major problem (although the ensuing cost is still an issue), since it is not something that contributes to the financial bottom line. Large ships generally offer enough space for the installation and the fact that it has to be used on a regular basis, which is dozens of times ayear, make the high costs justifiable.

However, as Tilman explained, for smaller vessels that work on dredging and maritime projects, such as dredgers, hopper barges, stone dumping vessels, workboats, and other auxiliary craft, the situation is entirely different.

Such vessels do not offer enough space for existing systems on the market and they spend most of their time on one project site. Only once in a while would they have to use the ballast water tank, when making a longer trip from one project to the other.

This makes the high investment cost something that is completely out of proportion to the number of times the system is used, on top of which the installation space required is rarely available.

Low capacity, low frequency

Van Oord’s BWMS is particularly meant for vessels with a low ballast water capacity (up to 450 m3) and with a low ballasting frequency. The system is based on the use of potable water and, as such, it requires no mechanical modifications on board.

Other than the potable water itself, the system only requires a disinfecting chemical (a commercially available chlorine solution), an auto-diagnostic portable microprocessor to check the chlorine concentration, and a chlorine neutralising agent (sodium bisulphite).

The application of a resource such as potable water for this purpose has been much debated and, on a large-scale basis, was considered irresponsible. However, in the case of Van Oord’s system, this is no objection, since it will only be applied infrequently and used in a responsible and acceptable way.

Since it is designed for vessels with a small ballast water capacity, the total volume of potable water used will be quite small.

Testing and approval

As part of the BWM Convention, it has been arranged that an institute accredited by the National Administration of each member state will take care of the approval procedure.

For the Netherlands, this is the Human Environment and Transport Inspectorate (Inspectie Leefomgeving en Transport: ILT), which falls under the responsibility of the Ministry of Infrastructure and the Environment.

Van Oord and MEA-nl received full co-operation from the Dutch authorities during the G9 and G8 approval processes, resulting in a relatively short timeframe to obtain final approval.

During the type approval procedure two main steps have to be taken. First, the system has to be checked for compliance with the guidelines for approval of ballast water management systems (G8) as stipulated in Regulation D-3 of the BWM Convention. Then, Regulation D-3 requires that systems that make use of active substances such as chlorine must comply with the convention and be approved in accordance with the procedure for approval of ballast water management systems that make use of active substances (G9).

Testing constitutes an important part of the approval procedure and an adapted test programme was carried out by MEA-nl for Van Oord’s BWM system after being granted approval by the Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP) committee of the IMO.

MEA-nl is well located to test treatment systems with all kind of relevant types of water. For conventional BWM systems, which make use of surface water, its facility in Den Oever has three different water systems nearby: the North Sea with salt water, the Wadden Sea with brackish water, and the IJsselmeer (lake IJssel) with fresh water.

For testing, MEA-nl has a dedicated pontoon, MEA Innovator, which has a well-equipped field laboratory. Any type of BWM or other treatment system that has to be tested can be installed. MEA Innovator allows tests to be carried out under very realistic conditions. MEA-nl also has its own laboratory facilities.

Van Oord’s BWM system did not require testing with surface water; instead a special testing programme was developed with different sources of potable water.

First, a land-based test was carried out in Den Oever, during which municipal drinking water from the town of Den Oever was used as the main resource. This was followed by a test on board Van Oord’s multipurpose support vessel Jan Steen. The water used for this test was produced by the ship’s own evaporator. This reverse osmosis installation can turn seawater, in this case from the North Sea, with a high salinity, into suitable potable water to be used as ballast.

The third part of the testing programme was aimed at using potable water from a completely different part of the world, and was carried out in Batam, Indonesia, on board the flat top barge Guavina. Here, the water originated from a locally available water boat.

The results

Once the test programme was completed, the results proved that Van Oord’s BWM system complied fullywith the IMO guidelines.

With the certification of its system, Van Oord has now the advantage of being independent of the supply of expensive and cumbersome systems for most of its smaller vessels.

For a substantial part of its fleet it is now possible to comply with the requirements of the BWM Convention without major technical modifications and to make use of equipment that is already installed on board.

It is an innovative but, above all, simple solution that can serve as an example for many other vessels worldwide.

MEA-nl estimates that there is a market of about 26,000 vessels, such as tugs, dredgers, offshore support vessels, and supply boats, that could use this simple solution to a global problem.

>> bvisser@dredgers.nl