Comparisons of interdisciplinary ballast water treatment systems and operational experiences from ships.

Goran Bakalar

doi:10.1186/s40064-016-1916-z

Abstract

There are high functioning and low functioning ballast water treatment systems on board ships. In this study, five systems were analysed so as to methodically examine the operational difficulties for ship crew members while giving important consideration to sustainable environment practices. Multi-criteria analysis, a questionnaire, survey and interviews were used as the research method so as to ascertain and corroborate existing problems on board ships, and the reliability of the systems was calculated. The co-insistency, maintenance and the efficiency of the systems, were shown as being the major problem as there are no systems for tracking ship ballast operations from land. The treatment system that used oxidants was, through multi criteria analysis, evaluated as being the best and was ranked first. However, the survey results showed that the ship’s crew had serious problems with this system which difficult to solve during the ship’s operations with cargo. The deoxygenation system was the most appropriate according to ballast water treatment criteria in the port or at sea. The treatment system which used electrolysis with oxidant was better in terms of efficacy and the treatment system electrolysis with ultra violet light was better in terms of the criterion environment pollution footprint. During further research, it was shown that 7 % of the surveyed crew members had major problems with operating ballast water treatment systems, including the system which was ranked first through multi criteria analysis. They by-passed these systems while continuing to ballast or de-ballast. It was calculated that of the total time needed for the ballast water treatment system operation, 9 % of this time was used for repairs or maintenance of the systems. Some examples are changing a used UV bulb, cleaning the filter or controlling the amount of oxidant which would be discharged into the sea. A conclusion was made and solution was suggested. The study results emphasised taking action in the interest of protecting the natural world, with particular attention being given to environmental protection to support human life.

Highlights

When large ships offload their cargo, they flood ballast tanks with seawater for stability on the return trip
Of the 5 ship captains who were surveyed and during the interview confirmed that they had problems with the operating of the BWTS, one of the surveyed captains worked on a ship with an installed BWTS using the treatment method of electrolysis and oxidant
The multi-criteria analysis parameters and scenarios did not consider the functional and operational problems of the systems. It can be clearly concluded from the survey result of 7.3 % from all participants and interviews that ship officers by-pass ballast water treatment systems due to lack of time for rectifying malfunctions, failures, maintenance or spare parts replacement in ballast water treatment systems

Summary

Introduction

When large ships offload their cargo, they flood ballast tanks with seawater for stability on the return trip. Ballast water is widely used on ships to ensure manoeuvrability and stability when cargoes are unloaded (La Carbona et al 2010). At the cargo loading port, the ballast water is pumped into the harbour in order to load more cargo. When ballast water is pumped overboard it may carry with it aquatic nuisance species that can seriously harm indigenous species in ports and coastal waters. These nuisance species may include unwanted bacteria such as Escherichia coli or Vibrio cholerae and animals such as zebra mussels. Ballast water will have to be treated once this convention comes into effect (Gregg et al 2009)

Objectives

Methods

Results

Conclusion