Abstract
The transfer of non-native, possibly invasive species in ship’s ballast water is of global concern, and the International Maritime Organization and U.S. Coast Guard have adopted standards to minimize the environmental footprint caused by the maritime industry. In this study, seawater spiked with the phytoplankter Tetraselmis suecica, was treated with Knutsen Ballast Water Treatment Technology (KBAL), combining UV irradiation with an in-line vacuum drop. The test water was subsequently incubated in dark tanks, simulating what happens onboard a ship, where ballast water is treated at intake, stored in dark ballast tanks during the voyage, and then treated at discharge. Our results of the test water treated with KBAL and stored 5 days in the dark showed < 10 viable T. suecica cells ml−1 when assessing reproduction and > 10 living cells ml−1 when assessing metabolism. This highlights the challenge UV-based BWTS can encounter when meeting testing regimes assessing different characteristics of life. By comparing the effects caused by KBAL treatment with effects caused by UV irradiation only, we demonstrated that the pressure/vacuum technology seems to improve the disinfection effect. In addition, our investigations point out possible challenges with in situ conditions getting representative ballast water samples.
Highlights
Non-native, possibly invasive species in ship’s ballast water can cause ecological changes and threat the biological diversity and the economy
Since only one bottle was collected from the first treatment stored 5 days in the 1 m3 outdoor Knutsen Ballast Water Treatment Technology (KBAL) tank, no most probable number (MPN) results were available for this sample. Both International Maritime Organization (IMO) and U.S Coast Guard (USCG) have similar test water requirements when it comes to minimum concentration of organisms needed during land-based testing
For the ≥ 10 to < 50 μm size class, ≥ 1000 org. ml−1 is required at intake, > 100 org. ml−1 is required in the control discharge, and < 10 org. m l−1 in the treated discharge according to the D-2 discharge standard [1, 3, 4]
Summary
Non-native, possibly invasive species in ship’s ballast water can cause ecological changes and threat the biological diversity and the economy. The transfer of organisms is of global concern, and the International Maritime Organization (IMO) and U.S Coast Guard (USCG) have adopted standards to minimize the environmental footprint caused by the maritime industry [1, 2]. The commercialization rely on BWTS type approvals, which includes land-based tests and shipboard trials [3, 4]. One of these systems, the Knutsen Ballast Water Treatment Technology (KBAL) developed by Knutsen OAS Shipping AS, combines UV irradiation with an in-line vacuum drop.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
