A sampling device for sampling organisms above 50 micron from ballast water onboard ships Experience has shown that sampling ships’ ballast water is a challenge. Adequate sampling methods for efficacy tests of ballast water treatment systems and compliance control for the ballast water discharge standard as set forth in Regulation D-2 of the IMO Ballast Water Management Convention (both being quantitative approaches) must be able to reliably testify that less than 10 viable organisms per cubic meter greater than or equal to 50 micrometers in minimum dimension are discharged by the Ballast Water Treatment System. As a result more than 1,000 liters of water need to be sampled – and this needs to be carried out multiple times at more than one sampling point, several replicates and various sampling occasions are required for a proof of significance.
The Ballast Water Sampling Kit has been designed exactly for such accurate sampling. This sampling approach delivers a representative sample of larger organism density when being discharged from a ship in both cases (a) for compliance control and (b) for efficacy tests of ballast water treatment systems. This device consists of a specially designed flexible filter net with a filtering cod end. This cod-end has removable filtering panels and can be unscrewed from the filter net. An integrated flowmeter allows for accuracy to document the filtered volume of water.
As the IMO standards refer to living organisms, samples taken during a ships’ voyage need to be analyzed onboard. When using Petri dishes and a stereo microscope, counting may be inaccurate as the ship movement induces water movements in the Petri dish, resulting in over- or undercounting of organisms. To avoid this, modified Bogorov counting chambers have been designed, allowing for greater accuracy in counting larger organisms onboard.
