Invisible passengers: How UV technology is stopping invasive species from travelling across oceans.

Every year, ships move around 10 billion tons of ballast water across the planet.

This water is essential to maritime operations. Ships take it onboard to remain stable, adjust their draft, and compensate for changes in cargo or fuel.

But ballast water carries more than weight.

It carries life.

Microscopic organisms, larvae, bacteria and plankton can enter a ship's ballast tanks in one part of the world and be released thousands of kilometres away.

Most will not survive. Some will. And when they establish themselves in a new ecosystem, the consequences can spread far beyond the port where they were discharged.

The blue crab in the Mediterranean and comb jelly in the Black and Caspian Seas are among the examples linked to biological invasions through shipping.

And with around 10 billion tons of ballast water transported worldwide every year, the scale of this invisible movement is considerable.

In this episode of BlueTech Around the World, I spoke with Maxime Dedeurwaerder, Head of the Maritime and Industrial Solutions Division at BIO-UV, to understand how ballast water became a major environmental and regulatory issue and how technologies such as filtration and UV-C disinfection are helping the maritime industry address it.

But the story goes beyond ballast water.

It is also about how environmental regulation can create an entirely new technology market, what happens when that market reaches maturity, and how expertise developed for shipping can find new applications across the blue economy, from aquaculture to floating offshore wind and water reuse.

First things first: why do ships carry ballast water?

From the outside, deliberately adding water, and therefore weight, to a ship may sound counterintuitive.

But ships need ballast to remain stable.

Seawater is pumped into dedicated tanks to balance the vessel from bow to stern and port to starboard, and to control its draft, meaning how deeply the ship sits in the water.

Ballast also compensates for changes during operations.

As a ship consumes fuel, for example, it becomes lighter and may need additional ballast. Cargo vessels experience even greater variations as they load and unload goods.

This is why bulk carriers, tankers, general cargo vessels and container ships are among the largest users of ballast water.

The system itself is simple and efficient.

The environmental problem comes from where that water goes next.

“When you bring some living organism from one spot to another, then you can have the same mechanisms as what happens on land, which is invasive species.”

Marine ecosystems are full of life, much of it invisible to us. When seawater enters a ballast tank, microscopic organisms, larvae and pathogens can enter with it. A ship may then carry them across an ocean and release them into an entirely different ecosystem.

If they survive the journey and find suitable conditions, some can establish populations outside their natural range, with consequences for local biodiversity, fisheries and coastal economies.

For a long time, the main mitigation measure was relatively basic: ships could exchange ballast water offshore, away from coastal areas.

This reduced some risks, but it did not eliminate them. Organisms could remain inside tanks, and many ballast operations still happened in ports.

The industry therefore needed to move from managing where ballast water was released to managing what was actually in it.

That shift came through regulation.

When regulation creates a technology market.

The International Maritime Organization's Ballast Water Management Convention was adopted in 2004 and entered into force in 2017.

Its principle is straightforward: ships operating under the Convention must meet defined biological standards when discharging ballast water.

The regulation targets both specific pathogens, such as E. coli, and the concentration of viable organisms according to their size.

This meant that shipowners could no longer simply take water onboard and discharge it elsewhere.

They needed a certified ballast water treatment system capable of reaching the required discharge standard.

And almost overnight, at least by maritime regulatory standards, an environmental obligation became a global technology market.

According to figures shared by Maxime during our conversation, around 50,000 to 60,000 ships worldwide needed to install treatment systems.

Several technologies emerged, mainly filtration combined with UV treatment, electrochlorination, and chemical injection.

Around 60% of equipped ships use filtration + UV, according to Maxime.

So how does it actually work?

Filtration + UV-C: treating ballast water in two steps.

The first step is easy to picture.

Filtration.

Maxime compared it to the drainer in a kitchen sink: water passes through small openings while larger elements are retained.

BIO-UV's ballast water system uses filtration at 20 microns.

This serves two purposes. It directly removes larger organisms targeted by the regulation, but it also reduces the turbidity of the water, preparing it for the second stage.

Because the next treatment relies on light.

UV-C disinfection.

UV has been used in water treatment for more than a century. For disinfection, the system uses UV-C light at around 254 nanometres.

Rather than adding a chemical substance to the water, UV acts directly on microorganisms by disrupting their genetic material.

“It’s not necessarily killing per se the living organism, but it’s preventing them from reproducing.”

Put simply, UV-C does not necessarily kill the microorganism. It makes it unable to reproduce, and therefore unable to establish a viable population elsewhere.

Light, in this case, becomes a disinfection tool.

Why has UV become so widely adopted?

There is no single “best” ballast water treatment technology for every ship and every situation.

As Maxime pointed out, certified systems using other technologies are also designed to be safe for crews and the environment.

But filtration + UV has several operational advantages.

The system is relatively straightforward, with two main treatment components connected through a common automation system.

It is also chemical-free during treatment.

Chemical injection systems require treatment chemicals to be stored onboard. Electrochlorination does not require the same chemical injection during treatment, but chemicals may be needed to neutralise residual chlorine before discharge.

UV avoids this handling requirement.

Another important factor is its ability to operate across very different marine environments.

UV treatment is not sensitive to salinity or water temperature, which matters for ships operating across different seas and climates.

“No technology is perfect because seawater is a very challenging environment.”

That nuance is important.

Water quality and particularly turbidity still matters.

And this is precisely why the filtration and UV stages complement each other: filtration removes larger organisms while also making it easier for UV light to penetrate the water effectively.

But even when the treatment works perfectly, there is another very maritime constraint: Where do you put the system?

Retrofitting ships that were never designed for it.

This part of the story is particularly interesting because it shows the difference between having a technology that works and having a technology that can actually be deployed.

Most of the ships that suddenly needed ballast water treatment had been designed years before the regulation required the equipment.

There was no dedicated space waiting for it.

Treatment systems are generally installed close to the ballast pumps, often in or around the engine room. But on existing ships, engineers had to work with whatever space was available.

One component might fit in one location, another somewhere else, with additional piping connecting the two.

It became a collaboration between shipowners, shipyards, engineering companies and technology providers to make the retrofit possible.

And sometimes, compactness became a real competitive advantage.

Maxime shared the example of SWATH vessels (Small Waterplane Area Twin Hull vessels). These vessels have two hulls with separate ballast systems. In some configurations, that meant installing not one but two treatment systems, in an already extremely constrained space.

BIO-UV had developed a range of particularly compact systems for smaller ballast water requirements, which eventually provided a solution after the shipowners had struggled to fit other configurations onboard.

It is a very concrete reminder that maritime innovation is not only about technological performance. Size, integration, reliability and adaptability to existing infrastructure can be just as decisive.

The best technology on paper is not necessarily the one that can work onboard.

From a retrofit boom to a service market.

The ballast water treatment market is also a fascinating example of what happens when regulation creates a deadline-driven technology cycle.

The first phase was straightforward: compliance.

Shipowners had to install certified systems. The retrofit market accelerated and peaked around 2021–2022.

By September 2024, Maxime explained, almost all vessels concerned by the implementation schedule had been equipped.

Or, as he put it:

“It was a compliance phase, let’s say, the equipment phase. Now we are slowly but surely leaning towards the implementation phase.”

That changes the market considerably.

Demand for retrofits is naturally declining, leaving primarily newbuild vessels on the equipment side.

But another market is growing: service, maintenance and replacement.

A ballast water treatment system cannot simply be installed and forgotten.

Crews change. Systems may not have been used regularly during the first years after installation. Sensors need calibration. Components require maintenance. Spare parts need replacing.

And now that implementation is becoming more closely scrutinised, shipowners need to demonstrate not only that a system exists onboard, but that it works and is operated correctly.

Port authorities and classification societies are also increasingly integrating ballast water implementation into their inspections and guidelines.

The market has therefore moved from: Do you have a compliant system? to: Can you demonstrate that your system remains compliant in operation?

For manufacturers, this means building global service networks, providing spare parts, training crews and increasingly developing maintenance agreements.

It also changes the business model. A regulation-driven equipment market gradually becomes a lifecycle and service market, where the relationship with the customer continues long after installation.

Entering a conservative industry as a newcomer.

BIO-UV's experience also offers an interesting lesson on market entry.

The company came into ballast water treatment primarily as a water treatment specialist, not as a traditional marine equipment manufacturer.

And maritime is not always an easy industry for newcomers.

Ships are high-value assets. Reliability is critical. Shipowners naturally look for proven technologies, established references and suppliers they trust.

BIO-UV initially relied on a network of agents and distributors to access shipowners across different markets.

But the company also segmented carefully.

It developed a particularly strong position in the yacht market, where compliance expectations are high and compact equipment is valuable.

It targeted general cargo vessels and offshore supply vessels, while deliberately staying away from segments such as oil tankers and LNG carriers that required explosion-proof certifications the company had not developed.

I found this part of the conversation particularly interesting because it shows that go-to-market is not only about identifying where demand exists.

It is also about understanding where your technology has a genuine competitive fit and where it does not.

And there was another factor behind BIO-UV's market entry: supporting shipowners beyond the equipment itself.

For many shipowners, ballast water treatment represented a pure compliance cost.

There was no direct financial return from installing the system.

And while large shipping groups have substantial technical teams, smaller owners operating a handful of vessels may not have the same internal resources.

BIO-UV therefore supported some clients with system integration, design work and understanding the regulatory and technical requirements, moving closer to a turnkey approach.

“If you see that somebody is by your side now, you know they’re going to be by your side tomorrow.”

That sentence says a lot about technology adoption in maritime.

In industrial markets, particularly when adoption is regulation-driven, the technology itself is only one part of the value proposition.

The ability to help a customer integrate, operate and maintain it in real conditions can be just as important.

Cross-sector spillovers: from shipping to aquaculture.

What makes UV particularly interesting is that ballast water treatment is only one application of the technology.

BIO-UV is fundamentally a water treatment specialist, working across UV, ozone and salt electrolysis, with applications ranging from swimming pools and drinking water to aquariums, wastewater and industrial processes.

And several of those applications connect directly with the blue economy.

Aquaculture is one of them.

As the industry develops more recirculating aquaculture systems (RAS), controlling water quality and biosecurity becomes increasingly important.

In a RAS facility, water circulates through a controlled production environment. UV can therefore be used at several points: on intake water, within the recirculation loop, or before effluent is discharged.

Its main role is pathogen control.

This is particularly important when fish are concentrated in controlled systems, where disease can spread rapidly if water quality is not properly managed.

“There’s no RAS without UV. I don’t think it ever exists.”

BIO-UV also works with ozone, which can complement UV.

Ozone can act as a disinfectant but also improve water clarity, which in turn can make UV treatment more effective.

The two technologies may work towards similar objectives, but not necessarily in the same way or under the same conditions, another example of why water treatment rarely comes down to one single solution.

According to Maxime, aquaculture currently represents around 10% of BIO-UV's turnover, but the company sees it as an important growth area, particularly as RAS continues to develop.

And then there is a less obvious connection.

What does ballast water have to do with floating offshore wind?

Quite a lot, as it turns out.

Some floating offshore wind foundations use water as ballast to control their stability and draft, essentially the same physical principle used by ships.

On a major floating wind project in France, stakeholders realised during construction that a significant quantity of water would be taken onboard at one location and later discharged elsewhere.

This raised questions from public authorities.

What was contained in that water?

And could operators guarantee that releasing it would not introduce anything harmful into the local environment?

This is where experience from ballast water treatment became useful.

Rather than installing permanent systems on the turbines, BIO-UV developed a containerised external treatment solution. Water could be treated before entering the ballast tanks and again before discharge.

The operators could then provide authorities with a documented treatment process and known discharge quality.

I particularly like this example because it shows how knowledge developed in one blue economy sector can solve a problem in another.

The initial technology was developed around shipping regulation.

The new application emerged in floating offshore wind, driven instead by local environmental expectations.

Same treatment principle.

Different infrastructure. Different stakeholders. Different regulatory driver.

And a technology adapted to a completely new use case.

Water reuse: the next major shift?

Beyond maritime applications, Maxime sees another important transformation ahead: water reuse.

And interestingly, he does not necessarily expect the biggest change to come from a completely new treatment technology.

UV and ozone already exist.

What is changing is how we think about water itself.

“What’s going to change in the mid and short term mostly are our behaviour and concerns.”

As water scarcity increases and industries look for ways to reduce consumption, reuse is becoming a growing priority.

But technology alone will not create the market.

Regulation needs to provide clear standards and certainty about where and how reused water can be applied.

And here, the ballast water story provides an interesting parallel.

UV technology existed long before tens of thousands of ships installed ballast water treatment systems.

What changed the market was a combination of environmental need, regulatory standardisation and a clear implementation timeline.

Water reuse may eventually follow a similar path.

The bigger picture: there is rarely one solution.

At the end of our conversation, I asked Maxime what advice he would give to people developing new technologies for the maritime and blue economy sectors.

His answer came back to time.

The Ballast Water Management Convention was adopted in 2004, entered into force in 2017, and continued driving fleet retrofits well into the 2020s.

Maritime transformation is rarely immediate.

“The changes in our industries, our journey takes time. It takes quite a lot of time.”

Technologies need to mature. Regulation takes time. Infrastructure needs to adapt. Shipowners need confidence. And many different stakeholders have to move together.

This is particularly true for sustainability.

Some technologies may offer more disruptive solutions in the future, while other solutions are already available today, perhaps imperfect, but capable of reducing environmental impacts now.

The two should not necessarily be opposed.

“Solutions are most of the time solutions with an S.”

The ballast water story is ultimately not only about UV.

It is about regulation, technology, engineering, operations and collaboration coming together to address an environmental challenge.

And from invasive species to aquaculture, floating offshore wind and water reuse, the same lesson applies across the blue economy: there is rarely one technology waiting to solve the problem.

More often, progress comes from finding the right combination and making it work in the real world.

Listen to the full episode

Listen to the full conversation with Maxime Dedeurwaerder from BIO-UV on your favourite podcast platform, or watch the episode on YouTube.

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