Feature 3 | BALLAST WATER TREATMENT Shine a light
Testing of Cathelco Ltd’s new ballast water treatment (BWT) system onboard ro-ro vessel Eddystone is now complete. Te BWT system, which utilises filtration and innovative UV treatment technology, is now navigating the type approval process
use of type-approved ballast water treatment systems, to ensure that ballast discharges meet with its Standard D-2. At mid-April, 36 states had ratified the Convention, representing 29.07% of the world’s tonnage. Before it can be ratified, states representing 35% of the world’s tonnage must have signed up to the convention. It is likely that this will be achieved before the year is out, with the Convention then entering into force 12 months later. In the lead up to the Convention’s ratification, BWTS manufacturers are working towards type approval of their systems. Many system manufacturers are
T
safeguarding their designs against uncertainty surrounding some ballast water management legislation and the potential
Cathelco’s BWT installed onboard Eddystone, shipboard tests were completed in the first quarter of 2013
for more
stringent criteria in the future. Following the completion of testing, Cathelco’s BWT system is going through the IMO type approval stage, and the company anticipates that this will be received by early autumn when it will then market the system. “In some respects the IMO’s guidance
is quite general and therefore open to interpretation,” says Robert Field, technical manager at Cathelco. “When Cathelco began the BWT
project there was some uncertainty regarding USCG and regional legislation. Terefore, we decided to extend the scope of shipboard testing on the Eddystone to include the full integration of the system, rather than using more basic skid-mounted equipment. To allow for the requirements of regional legislation, it was decided to make the system completely chemical free. In addition, the land-based tests at NIOZ [Netherlands test facility] were made more stringent to allow for the uncertainties. We also believe that the IMO’s rules are restrictive when applied to any future improvements to system.”
58 Field tells Ship & Boat International that
the land-based tests, carried out in Spring 2012, included heavy phytoplankton blooms as well as stormy conditions, which increase the turbidity of the water. He points out that the NIOZ facility is “well known for its challenging water quality conditions which include high sediment loads and a very diverse plankton community”. Richard Woolley, publicity manager,
Cathelco, also highlights that: “To arrive at a globally acceptable system we included fresh water testing within our programme which is a requirement of [USCG] Alternate Management System (AMS) approval. “When IMO approval has been achieved,
Cathelco will apply for AMS accreditation, which is valid for up to five years. Tis will give the company sufficient time to obtain US type approval.”
Innovative twists Cathelco’s BWT system, which made its debut at SMM Hamburg in 2012, combines both filtration and UV technology. While
both of these technologies are well established processes in the realm of water treatment, Cathelco has incorporated a number of unique features within its BWT system that streamline the processes and further enhance their treatment capabilities. During the design of the UV treatment
chamber, Cathelco utilised computational fluid dynamics (CFD) software to help create a helix flow pattern of the ballast water as it circulates through the system. This helix pattern maximises the surface area of seawater exposed to the UV light source. Te company also used soſtware to simulate the UV dosage and calculate its absorption levels at different flow rates. Aſter it has gone through the filtration
system, which removes larger particles and organisms from the ballast water, the ballast water is passed through the chamber where it is exposed to UV light; each chamber can treat seawater at up to 200m3
/h. Te UV treatment
process effectively sterilises the ballast water, rendering remaining organisms, pathogens and bacteria harmless. Te water is passed
Ship & Boat International May/June 2013
he forthcoming IMO Ballast Water Management Convention includes standards governing the
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