Evaluation of Venturi Oxygen Stripping (trademark) as a Ballast Water Treatment to Prevent Aquatic Invasions and Ship Corrosion

摘要

Invasions by non-native species have resulted in significant ecological changes and enormous economic cost. Although there are several vectors that can transport aquatic invaders, by far the most important is through ship ballast water. Currently, however, there is no environmentally friendly ballast water treatment that is truly effective at reducing introductions and yet also acceptable to the shipping industry in terms of safety, time, and cost. Deoxygenation may however be such a treatment with benefit for ship owners through corrosion prevention, while simultaneously limiting the number of aquatic organisms surviving transport in ballast tanks. Our current investigations are providing the critical information required to evaluate the efficacy and feasibility of deoxygenation as a ballast water treatment to prevent aquatic invasions and tank corrosion. Specifically, we are: (1) evaluating the Venturi Oxygen Stripping (trademark) system developed by NEI Treatment Systems, Inc. to optimize the deoxygenation process, (2) examining the impact of this oxygen stripping technique on the immediate and long-term survival of natural Chesapeake Bay planktonic organisms, and (3) quantifying corrosion rates and establishing the corrosion mechanism under deoxygenated conditions (with particular emphasis on microbiologically influenced corrosion and the production of hydrogen sulfide). These results will ultimately lead to a full-scale shipboard evaluation of deoxygenation as a cost-saving ballast water treatment.