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ballast water
Various methods for ballast water treatment are under development nowadays.
Both the development of treatment technology and the operational control of
ballast water treatment installations are best served by quantitative, fast, and
autonomous techniques to measure the treatment performance and efficiency.
One of the 'difficult' control entities are the small suspended particles,
consisting of bacteria, phytoplankton and other microorganisms as well as
organic debris and inorganic sediment particles.
The primary goal of the treatment of ballast water is to prevent the dispersion
of non indigenous marine and freshwater organisms. Selective removal of
specific organisms, especially microorganisms, from large water flows is
practically impossible. Therefore BWT systems tend to combine two or more
general treatments, such as general particle removal by cycloning or filtering,
killing organisms by UV or chemicals.
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Next to high capacity treatment during
ballasting, low capacity in-tank methods may also be effective such as blocking
of cell replication by ultrasound. Each of these methods has its challenges.
Cyclones are less effective with low density particles such as phytoplankton,
filtration is getting increasingly difficult with smaller particles, UV radiation or
chemicals are less effective with certain species and/or cysts. Similarly, no single
analysis technology is capable of direct detecting, counting and analysing the
complete range of target particles and concentrations to control and monitor
these processes: the development of BWT installations therefore requires a
comprehensive and complementary range of analysis technologies. Flow
cytometry is a versatile analysis technology for a wide range of particles and
concentrations that may well serve as the cornerstone for such a system, and
constitutes a good candidate technology for applications requiring a single
realtime technology such as a inline control of BWT systems performance or
control of discharged ballast water by authorities.
Scanning flow cytometry (SFC) yields 1-dimensional low resolution profiles
obtained from particles flowing through a laser beam, which limits the data load
as compared to collecting images and allows fast sample processing. The fast
and quantitative diagnostic capabilities of the CytoBuoy type of flow cytometers
may be of great help for the fast screening of ballast water by generating
countings and accurate size spectra for sediment particles, phytoplankton and
other groups of particles. This can be used to monitor the efficiency of organism
targeted treatments, or even serve as a feed back mechanism to actively
control treatment performance.
PDF brochures for download:
screening of ballast water
ferry-box
The ferrybox is a great concept that enables high frequency environmental
monitoring by placing scientific instrument packages on ferry ships. With
CytoSense the analysis of phytoplankton concentration and composition on the
individual cell level may be added to the available instruments for the ferrybox
concept. CytoSense is a robust, small, autonomous flow cytometer for
phytoplankton with tested mounting and sampling accessories for easy
integration in ferrybox setups.
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