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Application of ozone nanobubbles in ballast water treatment and analysis of bromated formation

Kotzia Eleftheria

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Year 2022
Type of Item Diploma Work
Bibliographic Citation Eleftheria Kotzia, "Application of ozone nanobubbles in ballast water treatment and analysis of bromated formation", Diploma Work, School of Chemical and Environmental Engineering, Technical University of Crete, Chania, Greece, 2022
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Ballast water consists of sea water and the floating matter found in it. It is pumped into the special tanks on a ship with the purpose of regulating its draught, as well as providing transverse stability and reducing the stress on the hull, especially when the ship is empty of cargo. Discharging untreated ballast water poses a great threat to the marine biodiversity, as it allows the transfer of non – native aquatic organisms. Therefore, the water ballast treatment is a major issue for the shipping industry, as the introduction of international maritime regulations with a world – wide implementation has determined that ballast water must meet specific quality criteria, prior to its discharging.The International Maritime Organization (IMO) was the pillar of addressing this issue, by setting environmental criteria for the control and management of ballast water and its sediments, first in 2004, when the International Convention for the Control and Management of Ship’s Ballast Water and Sediment (BWM) was adopted, and then again in 2017, when the final modifications of the Convention were put in place. It was, thus, the acknowledgment of the need for treatment methods that lead to the development of a large number of systems, which through natural, chemical, and biological processes eliminate or suspend the development of microorganisms.This dissertation examines the efficiency of Ozonation, the method of chemically decontaminating ballast water with ozone, an oxidizing biocide. It was applied with the use of Ozone Nanobubbles, and the efficiency of the method was determined in comparison to the conventional Ozonation with Macrobubbles. Additionally, the percentage of the bacteria elimination, so that it complies to the standardsof the D2 rule as set by the IMO, was determined with the assistance of the Escherichia Coli bacterium.

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