Understanding the issues with Ballast Water Treatment systems today, can be summed up as: Shipowners face a difficult process in choosing a Ballast Water Treatment system, as there are no clear guidelines about which system operates best for their needs The global market for ballast water treatment systems will be worth hundreds of millions of dollars, running easily into billions of dollars over the next few years (do the maths on 47,000 ships over 500 gt!), shipowners need to make sure that they understand the systems they are purchasing There are many emerging ballast water treatment technologies that have recently received, or will soon receive, type approval certificates Many vessels will require retrofitting in the near future - will it be the case that those owners that wait too long will be caught in a seller's market? We now have Standard D1, which includes sequential mid-ocean de-ballasting and re-ballasting or flow-through ballasting, but these two methods are, at best, estimated to be only 90% effective. Ballast pumps run for 3-4 days at a time lead to increased fuel consumption, wear and tear on equipment and increased air emissions.
The nature of ballast water exchange can result in increased hull stresses and stability problems and there will always be clingage and sediment in the ballast tanks The next stage, depending on the size of ship, will be when Standard D2 comes into force, which will require the treatment of ballast water typically in systems using a combination of filters, hydrocylones, cavitation, centrifuges, chemicals, UV radiation and deoxygenation with inert gas, ozone, hydrogen peroxide etc.
Publisher: Witherby Seamanship International Ltd