Environmental Engineering Reference
In-Depth Information
Should a pump be used, this should have a capacity to pump up water from
greater depths and at the same time its application should not cause damage to
organisms. Several pumps are available (see examples given above), but all were not
specifi cally designed for shipboard ballast water sampling. Pumps which require
(external) power supply, impose a limiting factor especially for their use on board
vessels that transport oil and oil products or different dangerous cargoes. To over-
come this limitation pumps which are driven by compressed air may be used as
compressed air is already available on almost all ships. The current sounding pipes
design allows the water and associated sediment only to enter from the bottom end
of the pipe, which is also recognized as a possible factor impacting the representa-
tiveness of sounding pipe samples.
In-Line Sampling Arrangements on Vessels
To enable sampling from a vessels' ballast water discharge line, appropriate perma-
nent sampling arrangements need to be installed on the vessel in an area with suf-
fi ciently enough space to safely conduct a sampling event. The permanently installed
sampling arrangements would include a:
• sampling point installed in the ballast water discharge line (see below);
• isokinetic sampling facility (see below),
• discharge point for the discharge of the sampled water (after fi ltration) which
may be installed in the ballast water discharge line after the sampling point,
• space suffi cient to place a sampling bin,
• hook or other installation that the plankton net can be hang ca. 100 cm directly
over the middle over the sampling bin, and
• discharge pump of adequate capacity to empty the sampling bin during sam-
pling. The pump to pump out the exciding water from the sampling bin, after it
was fi ltered through the sampling net, should be of a capacity to withstand the
head pressure in the ballast discharge line. It is also important to install a valve
which allows for the regulation of the discharge fl ow from the sampling bin to
provide for an adequate level of water in the bin during sampling, i.e., after hav-
ing achieved an adequate level of water in the sampling bin to enable the sam-
pling plankton net sitting in the water as much as possible a simultaneous water
discharge from the bin is needed in the same dimension as the sampling water
infl ow to the bin to avoid an overfl ow and sample water spillage at the sampling
point.
The equipment for a temporary use at the sampling point, but which should be
stored on the vessel include:
• a sampling bin used to place the plankton net in water during sampling,
• a valve at the discharge point of the sampling bin and/or a pump to manipulate
the water level in the sampling bin,
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