Ship delays, port penalties and frequent spells of off-hire are the price that ship operators will pay unless they choose ballast water treatment systems with great care.

This is the message from experts who reveal a number of cases where owners have taken short cuts to save money; where European treatment systems copied and reproduced in the Far East fail to perform; and where South Korean shipyards demand premiums running into millions of dollars if an owner chooses not to install the builder’s system of choice.

The IMO’s Ballast Water Convention is due to enter force on September 8, 2017. After that, ship operators will need to install type-approved ballast water treatment systems by the time that the International Oil Pollution Prevention (IOPP) certificate falls due for renewal, usually at Special Survey.

Estimates over the number of ships affected by the Convention vary, and the new regulation will certainly hasten the disposal of old ships for which the chunky capital outlay makes no sense. In recent analysis, Clarkson Research Services identified about 35,000 ships less than 20 years old which are likely to require installations.

The company’s database lists more than 250 shipyards and 520 drydocks with potential repair capacity. But various sources suggest that when demand for treatment systems peaks, shortages of dock capacity, hardware, engineering expertise and pre-installation planning could all lead pose problems.

Quite apart from these practical issues, however, there is growing dismay over the Convention itself, the type approval process itself and how it is carried out in different jurisdictions, and of course the lack of a global agreement which includes the US. Following its entry into force, there are also worries over a potential lack of uniform testing standards between port states.

However, the biggest challenge for ship operators is the choice of treatment technology. Most systems work on one or more of filtration, electro chlorination (EC), ultra violet (UV) or ozone. All have shortcomings and cannot be completely effective but the challenge for ship operators is to identify a system that is as fit for purpose as possible, to minimise the risk of operational disruption and financial penalties in the future.

Briefly, system disadvantages are as follows. Even with back-flushing, filters get blocked and ballast flow rates fall, causing delay and affecting power requirements. Meanwhile the size and shape of planktonic organisms varies widely and many smaller ones pass through filters, typically of 40 microns, into ships’ ballast tanks.

EC systems use sodium hypochlorite but regulations restrict the dosage level to less than 12 ppm to avoid damage to coatings and ultimately, the structure of the vessel. Lloyd’s Register recommends a limit of five ppm. The cleaning product Domestos contains 100,000 ppm of sodium hypochlorite but, for those who remember the advertisement, it still only kills “99% of all known germs”.

UV treatment relies on effective transmission through water and this is sharply reduced by sediment. In waters of high turbidity with many particles in suspension, UV efficacy can be reduced by more than a third. Coastal waters where ships often take on ballast often contain high levels of sediment.

Ozone can only be used in low concentrations and has been shown to be effective at killing microscopic organisms but not larger ones. It must be distributed evenly within ships’ ballast tanks to work effectively and its efficacy depends on the characteristics of the source water.

If a ship’s ballast water fails to meet discharge standards, her operator may be forced to sail for international waters, re-ballast and then return to port when space is available. Over time, such delays could cost millions of dollars.

If a ship continues to fail tests, both her and her operator are likely to be ‘named and shamed’, causing further possible operational disruption. Similarly, when port states identify treatment systems which don’t work properly, ships with those systems on board are more likely to attract attention.

However, one of the biggest concerns – not effectively addressed by either the IMO’s type approval process or the US Coast Guard’s regulations – is the issue of in-tank organism re-growth after treatment. In a letter to IMO Secretary General Kitack Lim earlier this year, Coldharbour Marine, a ballast water treatment system manufacturer with its own unique patented technology based on inert gas, pointed out that the IMO’s testing protocol for type approval only requires ballast water to be held for five days whilst the USCG’s process calls for a holding time of just one day.

Thousands of ships have ballast hauls lasting more than one week during which organisms not killed initially could thrive and multiply, feeding on an abundance of dead organisms. Therefore a treatment system which passed the IMO’s type approval process after five days might not pass again if the type approval test protocol had been set at 10 or 20 days.

Ship operators who opt to save a few dollars now by choosing a second-rate treatment system could pay a very high price later. Delays, deviation, extra time on the terminal and off-hire all mount up and ultimately, a poor choice now could even affect a ship’s value in the future.

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