Mixing Biocides into Ship's Ballast Water - Great Lakes Bulk Carrier Field Trials

The Glosten Associates; Reynolds, Kevin

Marine vessels of all types move not only people and goods, but also move ballast water in order to maintain stability and trim, control hull stresses, and assure propeller immersion. Ballast water is often taken up by a ship in a port in one geographic location and discharged into the harbor of a port in a different geographic location. Ballast water may be considered high risk if it suspected or known to contain harmful aquatic organisms and/or pathogens. When such high risk ballast water is transferred from one port to another, it could result in a non-native species invasion or result in fish mortality from the release of harmful pathogens. Ballast water management efforts to minimize such transfers include mandatory ballast water exchange for transoceanic and some inter-coastal voyages and, more recently, the development of water treatment capabilities on the vessels themselves; however, many gaps remain in this management approach. Of those vessels currently required to manage ballast water, equipment failures or human error could result in the arrival of high risk ballast water. In addition, a vessel that has not managed its ballast water could go aground; this creates an incident where potentially high risk ballast water may be pumped off the vessel for purposes of refloating. Vessels operating on the U.S. Great Lakes, inland waterways systems, and on some near coastal voyages are not currently required to manage their ballast water discharges. There is concern that transfer of organisms and pathogens between the lakes could be harmful. In particular, recent pathogen outbreaks have occurred in some parts of the Great Lakes, but not others. Methods to treat ballast water from affected locations are particularly desired by management at Isle Royal National Park in the State of Michigan. To address the need to have strategies that can be implemented to manage high risk ballast water, the National Park Service (NPS) has developed an Emergency Response Guide for Handling Ballast Water to Control Non-Indigenous Species (hereafter referred to as Guide). The Guide assumes that there are suitable biocides that can inactivate the harmful organisms and pathogens. The Guide outlines several methods for mixing such biocides into the ballast tanks of marine vessels. This report outlines the field work performed in the development of suitable methods to address a fundamental challenge for an emergency responder; e.g., how to mix biocides into large, complex ballast tanks that are already full of water.

Mixing Biocides into Ship's Ballast Water - Great Lakes Bulk Carrier Field Trials

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