The design, build and preliminary testing of a ballast water treatment plant prototype

• Main Author: Moloney, Shane Richard
• Published: University of Newcastle Upon Tyne 2012
• Subjects: 628.96
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.580318

Ballast water is indispensable for maritime trade as it is required to operate ships successfully and safely through its various evolutions over the course of a voyage. Ships taking on ballast water also take on the marine organisms present in the water such as phytoplankton, zooplankton and micro organisms. It is estimated that 10 billion tonnes of ballast water is transferred around the world annually and ballast water has been identified as one of the key vectors for the introduction of non-indigenous species The introduction of non-indigenous species can have critical economic, industrial, human health and ecological consequences. Invasive aquatic species are classified as one of the four greatest threats to the world's oceans. The preferred solution is to treat or manage the water itself. The International Maritime Organisation's Ballast Water Management Convention details a performance standard to which ballast water must be treated to. The variability of seawater around the world (e.g. salinity, turbidity) as well as the organisms that are required to be inactivated makes achieving this performance standard technologically challenging. The primary aim of the European Union, Framework Programme 6 funded Sustainable Ballast Water Treatment Plant (BaWaPla) project was "To provide a safe, economically viable, and technically competitive alternative for onboard ballast water management". The concept was to create a hybrid treatment plant utilising filtration, ultraviolet light and an electrochemically generated chlorine based active substance. To investigate the feasibility of the system concept a prototype was developed and tested. The development of the design was aided by the application of engineering design methods. These methods guided the decision making process and made the reasoning behind these decisions traceable. 3-dimensional surface modelling software was used to develop the engineering design, and to reduce the time required for design and construction. The prototype was tested to measure its biological efficacy. The electrochemical system was not included in these tests. Testing was conducted using sea water from the North Sea to mimic the conditions encountered by ships pumping ballast water on board. The results of the tests were inconclusive primarily due to the low number of organisms present in the water. This is believed to be a result of the tests being conducted in winter. However, the data and subsequent statistical analysis indicate that the treatments have an effect on the organisms present and encourage further testing.