The Inactivation of Non-Indigenous Microorganisms by Ballast Water Treatment Systems

Abstract

Ballast water is home to many different organisms many of which are not visible to the naked eye. Although a great majority of these species are naturally present and are part of the marine ecosystem, disturbing their order can affect the marine habitat of which they are introduced to. Around 80% of global trade is through shipping, and an estimate of 3 to 5 billion tons of ballast water is annually transferred and discharged across different parts of the globe. The Purpose of this research is to develop a ballast water treatment system which uses a combination of 40 micron filtration module, followed by a 100 (mJ/cm2) UV bank, and finally into an ozone production and injection bank rated at a dosage of 5 (mg/L) to successfully treat a fleet of 22 ships divided into 9 types owned by ADNATCO and NGSCO in the UAE. The research proceedings will require a mathematical modelling of the UV/O3 prototype versus two other systems (UV and O3) in terms of the energy consumption and the overall dosage to surpass the IMO D2 standards for ballast water purification. The Research outcome shows that the Protozoa Giardia Lamblia and Cryptosporidium Parvum can be easily reduced from 106 counts to 0 in a single pass through the UV system, with viruses being more resilient to a 100 (mJ/cm2) rated UV lamp. The O3 system shows a remarkable inactivation effect on viruses, whilst C. Parvum being more resistant to the NK-O3 5 (mg/L) dosage. The result of the research highlights that the UV system is more energy intensive and has a relatively high footprint when viruses are to be treated, and the O3 system requires an unrealistic number of units for a complete ballast treatment. The UV/O3 system proved less energy demanding for all ships whilst achieving the required treatment standard. The number of units is reduced to a sizable limit compared to the O3 and UV systems during ballasting and deballasting.

Date of Award	Jul 2014
Original language	American English
Supervisor	Hector Hernandez (Supervisor)