Ten organisms per cubic metre.
That number is why an entire industry rebuilt its engine rooms. It is also the only place in this network where somebody outside the company has already tested our approach on exactly this duty.
Ballast water is the least romantic environmental problem in shipping and one of the most consequential. A vessel takes on water in one port for stability and discharges it in another, and whatever was living in the first port travels with it.
Zebra and quagga mussels reached the Great Lakes from Europe in the 1980s and spread through the eastern waterways from there. That is the shape of the problem in one example: once a population establishes, it does not get removed. It gets managed, annually, forever, by somebody who had no part in bringing it.
That permanence is what makes the regulation unusually strict for something so mundane. There is no remediation budget that buys the water back.
The convention, in four lines
| What | Detail |
|---|---|
| Ratification threshold met | 8 September 2016 — 30 states representing 35 per cent of world merchant shipping tonnage |
| Entry into force | 8 September 2017 |
| D-2 standard, ≥50 µm organisms | Fewer than 10 viable organisms per cubic metre of discharge |
| D-2 standard, 10–50 µm organisms | Fewer than 10 viable organisms per millilitre of discharge |
| Phase-in for existing ships | Completed 8 September 2024 |
Source: IMO — Ballast Water Management Convention and IMO — implementing the BWM Convention.
What NOAA's centres actually found
On 1 July 2020, NOAA's National Centres for Coastal Ocean Science published that NCCOS-affiliated testing, carried out under a cooperative research and development agreement, had evaluated a commercial nanobubble ozone system on ship ballast water. The system was found highly effective at controlling algae, bacteria and motile zooplankton.
Then the sentence that matters more. There was no statistically significant adverse residual-toxicity effect on organisms in the receiving water.
Read those two findings together and you have the whole design problem of ballast treatment. Killing what is in the tank is straightforward if you are willing to discharge something unpleasant. Killing what is in the tank and discharging water the harbour can live with is the actual engineering, and it is the part port states have learned to inspect for.
The caveat, in the same size type
That NOAA release names other technology and other partners. It does not name ChemSlayer, SeaBreather or Alarivean. It establishes that a nanobubble ozone approach can meet this duty without a residual-toxicity penalty. It does not establish our equipment, and any proposal we write says so on the first page.
Watch the initials as you read it. The system under test is called Nanobubble Ozone Technology there — NBOT, which is also how this network abbreviates Nano Bubble Oxidation Technology, and the two belong to different companies. The cooperative agreement covering that work is theirs as well. Alarivean holds one of its own with NOAA, private and unpublished as those agreements are, and it concerns inorganic toxins rather than ballast.
Why the same stage is on a vessel rather than in the ship
Type-approved systems live aboard the vessel and treat on uptake or on discharge. That is the right architecture for routine trading and it is not in dispute here. But there are situations it does not cover, and those situations are where a service hull earns its keep.
A ship arrives with a failed treatment unit and a port state that will not accept the discharge. A vessel is held in quarantine with tank water nobody wants moved. A basin has an established invasion problem that no individual ship caused and no individual ship will solve. A terminal wants assurance about what is entering its water rather than a certificate about what left another port.
In each case the problem belongs to the water, not to the hull that brought it, and a mobile treatment stage is a better fit than another retrofit.
For ship operators
The cost of the standard is not the equipment. It is the variance.
A convention is one document. Its enforcement is dozens of port states with different sampling regimes, different tolerances and different appetites for detention.
What a fleet operator buys from a service capability is not a cheaper way to meet D-2. It is coverage for the cases where the shipboard system is down, the port is unusually strict, or the tank water has to be dealt with rather than discharged. Those cases are rare per vessel and constant per fleet.
Pricing follows the same logic as the rest of the programme: held capacity in a defined port zone for a defined period, rather than a per-incident call-out that rewards us when your operations go badly.
For port and terminal authorities
You inherit every basin decision anyone else makes.
A port authority does not control what arrives. It controls what happens next, and it answers for the water in between — to a regulator, to a fishing community, to a city that can see the basin from its waterfront.
Ballast is one input into that basin. Discharge is another, spills are a third, and heat is a fourth. They arrive separately and they compound, which is why a port programme is usually scoped as a service zone with several capabilities rather than as a single procurement.
The practical version: a zone where the same hull can run a ballast quarantine duty on Monday, work a sheen on Wednesday and hold dissolved oxygen through an August week when the basin goes still. That is one contract and one crew, not three.
And the reporting is written for the body that will ask — method, dose, position, time, result, per pass.
Questions from the compliance desk
Straight answers
Does this replace a type-approved ballast water management system?
No. Where a flag or port state requires a type-approved system aboard the vessel, that requirement stands and we will say so in writing.
ChemSlayer is a service capability used alongside it: for tank water that cannot be discharged, for quarantine situations, and for basins where the authority rather than the ship owns the problem.
What exactly did NOAA validate?
NCCOS-affiliated testing under a cooperative research and development agreement evaluated a commercial nanobubble ozone system on ship ballast water. It was found highly effective against algae, bacteria and motile zooplankton, with no statistically significant adverse residual-toxicity effect on receiving-water organisms.
It names other technology and other partners. Not us.
Source: NOAA NCCOS, 1 July 2020
Does ozone treatment of seawater create bromate?
It can. Ozone reacts with bromide roughly eighty-three times faster than with chloride, and the hypobromite produced can go on to form bromate. Dose, contact time, pH and temperature are the controls.
Bounding the first two limits bromate formation and also limits disinfection efficiency. That trade-off is real, it is site-specific, and it is operated against a measured background rather than assumed away.
Source: Ozone: Science & Engineering
Can you certify compliance for us?
No. Certification is the business of the flag state, the port state and the recognised organisations they appoint. We are not one of them and we will not imply otherwise.
What we provide is treatment, instrumentation and a record of what was done — in a format an inspector can read without an interpreter.
Next step
Send the port, not the brochure request.
The basin, the traffic, the discharge regime you operate under and the failure mode that actually worries you. Alarivean returns a read on whether this belongs in your port — including when it does not.