The idea that electrochlorination is more suitable for large flows than UV technology has persisted since the early days of ballast water treatment. Indeed, the first generations of UV treatment systems were often larger and more power-intensive. But modern solutions such as Alfa Laval PureBallast 3, the third generation of Alfa Laval’s ballast water treatment technology, are changing this preconception.
UV ballast water treatment systems now compete easily on power and footprint parameters, even at flows of 1500–3000 m3/h or above. As a result, their simplicity and lower operating costs are tipping the balance in major projects. Earlier this year, for example, Alfa Laval signed a deal to supply multiple vessels with PureBallast 3 systems for 3000 m3/h.
Power and footprint on equal footing
As many shipowners have realized, the power consumption of today’s UV and electrochlorination systems is similar in practice. Electrochlorination systems are dependent on seawater temperature and salinity, which means they use considerably more power in low-temperature or low-salinity conditions. PureBallast 3 systems, as well as having effective power management, are certified for all water types and are completely unaffected by temperature or salinity.
In terms of footprint, UV ballast water treatment systems can actually be smaller than electrochlorination systems. With a range of four different reactor sizes, a PureBallast 3 system can be optimally configured to match the vessel and its ballast water flow. In part because no heaters or major auxiliaries are needed, UV systems are also easier and less costly to install.
Operational advantages with UV technology
When power consumption and footprint are largely equivalent, the operational advantages of UV treatment become compelling arguments against electrochlorination. In particular, UV treatment is both safer and easier for the crew.
Electrochlorination requires strong safety measures for chemical storage and handling. These may include explosion-proof storage compartments with additional ventilation, as well as additional safety equipment and crew training. Electrochlorination generates both hydrogen and chlorine gases, which are not only toxic, but also highly flammable if mixed.
By contrast, UV treatment systems are chemical-free and simple for the crew to handle. Because they generate no harmful substances, they require no measures to prevent corrosion or neutralize residual oxidants. In total, such factors mean less risk, less maintenance and less operating cost for the vessel.
Simply put, it may be worthwhile for ship owners to reconsider their stance when it comes to large ballast water treatment systems. Given the advances of recent years, operational factors may now be the deciding factor.