As ship owners globally face the eventual mandate to install ballast water management technology onboard their ships – a refit which is touted as the most expensive equipment refit ever – Maritime Reporter & Engineering News in its February 2013 edition examines emerging Ballast Water Technologies for consideration.
PureBallast was among the first ballast water treatment systems to receive Ballast Water Type Approval. Operating under real-life conditions since 2003, PureBallast provides ballast water treatment that is 100% chemical-free, in contrast to “chemical-free” systems that produce chemicals during the treatment process.
The process is based on a patented form of advanced oxidation technology (AOT), developed in cooperation with Wallenius Water. Treatment occurs in a closed chamber known as a Wallenius AOT unit, in which radicals are generated. These radicals are potent yet exist for only a few milliseconds, which means they neutralize microorganisms but are incapable of leaving the treatment system. A 40 μm mesh filter is used during ballasting operations. This blocks the intake of larger organisms, but also reduces the amount of sediment in the ballast water tanks. The number of AOT units is determined by the system’s flow rate, with individual units handling a flow of 250 cu. m./hr.. The performance of the AOT units is safeguarded by an automatic Cleaning-in-Place (CIP) system, which circulates a biodegradable solution to prevent seawater scaling within the AOT units. This solution is reusable and is replaced once annually when its pH level becomes too high. The automatic cleaning cycle occurs after each operation. The filter is also rinsed once ballasting is completed. A flow meter regulates the certified flow rate and records the volume of ballast that been treated. The water then continues through the AOT units, which treat the water to IMO established limits before it enters the ballast water tanks. The de-ballasting process is the same as ballasting, but bypasses the filter system (which is cleaned via automatic back-flushing). Outgoing ballast water passes through the Wallenius AOT units to eliminate any re-growth of microorganisms that may have occurred.
A single PureBallast system can handle flow rates of 250-3000 cu. m./hr.. If more capacity is required, even higher flow rates can be achieved by installing multiple systems in parallel. Sold to all vessel types, container vessels, RO/RO and pure car/truck carriers account for about one-third of all units sold. For Alfa Laval, the 250 to 2,000 cu. m./hr. sector is strongest target market.
Alfa Laval has achieved IMO Basic and Final approvals as well as Type Approval from DNV.
(As published in the February 2013 edition of Maritime Reporter & Engineering News - www.marinelink.com)