Fitting a BWTS on a tanker

Ballast water treatment system (BWTS) manufacturers are under close scrutiny, from shipowners, to regulators and, of course, competitors. *

Different vessels have different needs for managing ballast; there is no one solution that fits all ship types, sizes or trading patterns and, for those in the market for a solution, there are many available options.

A BWTS that fits one ship may be an altogether inadequate solution for another and shipowners are now trying to navigate this decision. A product tanker, an Aframax and a VLCC share the same cargo types but this is where the similarity ends when it comes to ballast water treatment.

Ballast treatment systems have come a long way since the early days. Makers listened to ship operators and have developed systems that address the needs of the owner while delivering compliance.

Slip stream electrochlorination (EC) installations are more flexible and less intrusive than ever, while also providing cost effective solutions. In contrast, a filter-UV system on a tanker will, in many cases, require multiple filters and multiple reactors installed on the main ballast lines and another complete filter-UV installation to provide an AFT treatment.

With a BALPURE® slipstream EC system the same EC pack can serve the requirements of both the main ballast line and AFT treatment with the provision of a dedicated filter. This means fewer components, duplication reduction, decreased maintenance needs, and less CAPEX and OPEX costs.

Furthermore, with a lower number of critical components, the reliability is inherently improved, along with system availability.

The fact remains that UV systems still need to be located on the main ballast line of a ship and with the inclusion of a filter, this adds significant complexity to the pipework and installation. With a slip-stream EC system, the filter, an injection penetration and some instruments are the only components within the hazardous zone. The majority of the slip-stream EC system can be installed outside of this zone allowing for easy access.


Once this configuration has been established, there are also maintenance factors to negotiate. Crews frequently experience an influx of additional tasks that require both time and training, which causes understandable trepidation for shipowners and operators. It goes without saying, that there can be no shortcuts when it comes to safeguarding.

With this in mind, it is important to ask the following questions: can the safety of your crew be guaranteed if they have to enter a hazardous zone to perform essential maintenance? Have the additional time implications been factored in to such a scenario?

For example, if a lamp fails on a UV system and requires replacing, the space needs to be adequately purged to ensure gas free conditions before it is safe to enter and carry out essential maintenance. Compliance and welfare hinge on these considerations and must not be taken lightly.

A slipstream electrochlorination system with a flexible footprint, such as De Nora’s BWTS, can help overcome many of these challenges. It allows the BWTS to be installed away from the ballast line, with all major equipment located in the engine room – the only equipment required in the hazardous zone are low energy parts which, in the case of the BALPURE® system, is the filter and some sensors.

When it comes to maintenance, a system that relies on self-cleaning technology takes away a lot of the headache. With the BALPURE® system’s patented self-cleaning electrode coating, there is no need for regular crew intervention or maintenance activities within the hazardous zone to deal with cell fouling.
On a typical EC system, crews would need to be trained to clean electrodes every eight to 10 months, most commonly with hydrochloric acid, and provided with the relevant safety equipment. An additional maintenance consideration frequently hidden is the environmentally acceptable disposal of the wastes from the cleaning process.

US flagged vessels

With news of applications and certifications for ballast manufacturers’ USCG Type-Approval permeating the maritime landscape every week, it does bring to light another interesting consideration – how many of these manufacturers actually have the credentials to install their systems on US-flagged vessels?

Approval for ballast-compliant trade in US waters is one thing – however without the relevant additional certification, specifically 46 CFR Subpart 111.105, manufacturers are not able to install their BWTS in hazardous areas on US flagged ships.

De Nora’s commitment to both compliance and safety extend to this additional certification.

Investment in a system that works with your vessel and your goals is paramount in the journey towards safe, long-term compliance. It is one thing for a manufacturer to announce that they can work out an installation programme for you, but another for them to work together with you on the long-term factors such as training, support and service.

It really is no wonder that with so many issues to consider, a clear-cut solution is hard to come-by.

* This article was written by Dr Stelios Kyriacou, General Manager ofBALPURE® BWMS, De Nora.




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