Chlorine dioxide as a treatment for ballast water to control invasive species: Shipboard testing

Document Type

Article

Date of Original Version

10-15-2013

Abstract

The efficacy of chlorine dioxide (ClO2) in eliminating organisms present in estuarine ballast water of a containership was determined under actual operating conditions by comparing the survival of planktonic communities present in waters of treated and control ballast tanks. Sampling was via ballast-tank hatches. The treatment (5mgL-1ClO2 without pre-filtration) delivered by a prototype ClO2-generating system was generally effective against planktonic assemblages, although bacterial communities rebounded after a few days. Regardless of temperature, ClO2 was very effective against phytoplankton; the effect was immediate, without resurgence. Some zooplankters in the ≥50-μm fraction may survive the biocide, especially those able to find refuge within a protective coating (e.g., cysts, resting eggs, and shells) or in sediment. In order to boost efficacy, a pre-filtration step is recommended (now installed as standard equipment) to lower the intake of the ≥50-μm fraction and lessen the challenge posed by this size class. © 2013 Elsevier Ltd.

Publication Title, e.g., Journal

Marine Pollution Bulletin

Volume

75

Issue

1-2

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