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Feature 5 | BALLAST AND WASTE WATER TREATMENT Raising the temperature


Ballast water treatment system installation constitutes yet another costly operational expense _ but what if a vessel could convert waste heat from its engines to complete this process, for free?


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o far, ballast water treatment systems (BWTS) have mainly fallen into two camps; those utilising


active substances (chemicals) and those depending on ultra-violet (UV) solutions to destroy invasive species within ballast water. In anticipation of the forthcoming IMO International Convention for the Control and Management of Ships’ Ballast Water, due to enter force as soon as flag states representing 35% of the world fleet commit to its implementation, a fairly small number of ship owners have already begun to retrofit BWTS aboard their existing vessels, or to order such systems for their newbuilds. As Jean-Francois Segretain, deputy


technical director, Bureau Veritas, puts it: “Te delay won’t be indefinite; it just takes one large flag state, such as Panama, to sign up to the Convention for the process to begin. Japanese yards have indicated that at least 40 vessels would have to be fitted with BWTS daily, to meet the requirements of the convention, and there is growing concern over a potential bottleneck of orders, as some owners leave their BWTS retrofits until the last minute.” However, while Segretain agrees that


active substance and UV systems have emerged as the most credible BWTS options to date, both are not without their drawbacks. In the case of active substance-based systems, the chemicals used to kill off the alien species must be removed from the ballast water prior to discharge; some have bemoaned the extra safety precautions that need to be taken when the crew is charged with handling chemicals; and the ongoing investment in chemical substances could become a steep one over time, especially if the cost of particular agents increases – a scenario that has affected the marine coatings sector. On the other hand, UV equipment can constitute an expensive power drain on shipboard energy, and


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the lamps required to enact the process can sometimes be bulky. Some potential


customers


subsequently held back on ordering a system, amidst uncertainty as to what type of solution will suit their vessel and operational needs best – and the news, announced on 29 February this year, that Wilhelmsen Technical Solutions has withdrawn its Unitor BWTS from the market (citing doubts over the system’s ability to adequately remove organisms from “varied and dynamic water conditions”) has done little to ease some end users’ concerns.


Heat recycling In response, Norwegian manufacturer Ulmatec Pyro has announced that it is working on what it terms “free ballast water treatment”, courtesy of its Pyro Heat Recovery System. Currently under development and undergoing a series of land-based tests, the system aims to achieve IMO’s target of reducing the number of living organisms larger than 50microns (μm) to less than 10 per tonne. Rather than use chemicals, UV or sonic means, Ulmatec hopes that the system will instead utilise the vessel’s waste heat to kill all unwanted aquatic life within the ballast tank. Jan Petter Urke, Ulmatec managing


director, claims that approximately 70% of the energy generated by a typical marine diesel engine is squandered, mainly “lost in coolant water and exhaust fumes”. Te principal behind the Pyro Heat Recovery System is to capture this energy and divert it back towards energy-dependent onboard applications. Among these applications, UImatec has identified BWT as a possible beneficiary of the recovered heat. “We’ve looked at how this heat can be used aboard vessels transporting live fish to factories,” Urke tells Ship & Boat International. “The water can be heated to 100˚C to kill off


have


any bacteria, before the fish are placed in the holding tank.” From this application, he says, Ulmatec began to consider the possible benefits of transferring this process to BWT. Although testing is far from complete


and the company is yet to negotiate the patenting process, Urke says that the Pyro Heat Recovery System could be utilised for BWT as follows: “Our tests have shown us that we can heat the water up to 100˚C in about 15 seconds. However, for BWT, the system would heat up the water to approximately 70˚C over a longer period of time, which should be adequate to kill most of the living organisms. It’s no problem for the system to achieve higher temperatures, but the process would be more akin to pasteurising milk at a temperature of 65˚C – heating it up slowly, and then allowing it to cool down, to get rid of any organisms within.” Although testing is still at an early


stage, Urke confirms that Ulmatec intends to also explore the possibility of using the system to treat grey- and blackwater, prior to discharge. The first version of the BWT test system is rated at 250m3


per hour, and


Urke says that “to scale the system down, to suit smaller vessels, is no problem.” After land testing has been completed, the Pyro Heat Recovery System will run through BWT-related sea trials over a six-month period, and, Urke predicts, the end product should be on the market towards the end of 2013, should all go well. “It certainly looks promising – we just want to continue the system’s development and see,” he comments. While it may be the case that ratification of the IMO convention occurs before that date,


the notion is certainly


worth consideration as a cost-efficient means of BWT – and may just pose a serious competitive threat to the so-far established BWTS manufacturers. SBI


Ship & Boat International March/April 2012


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