Ballast water treatment

1
CREATING SHARED VALUE WITH ECO-EFFICIENT AND
GREEN CHEMICAL SYSTEMS IN SHIP OPERATIONS
AND IN BALLAST WATER MANAGEMENT
Konstantinos Aravossis1 and Yanna Pavlopoulou1,*
1 2 National Technical University of Athens (NTUA) , School of Mechanical Engineering, Sector of Industrial Management and Operations Research,
Enviromental Economics and Sustainability Unit, 9, Iroon Polytehniou Street, 15780 Zografou, Athens, Greece
Presented at the 3rd International Symposium on Green Chemistry for
Environment, Health and Development, October 3-5, 2012, Skiathos island, Greece
ABSTRACT
Green systems in ship operations and in ballast water
management are needed to enhance marine sustainability.
There is a challenging debate between regulators and the
shipping business over the pragmatism of forthcoming environmental
legislation. This is an overview study of arguments
over the sustainability transition to actual „shared
value‟ growth of global stakeholders. Re-ballasting in the
high seas currently provides the best-available measure to
reduce transfer risk of harmful aquatic organisms, but is
subject to serious ship-safety and other practical and financial
concerns. Corporate Social Responsibility (CSR)
strategy could assist the shipping sector in tackling operational
issues, re-conceiving innovative methods, despite
global financial crisis. According to European Commission‟
s renewed strategy on Corporate Social Responsibility
for 2011-2014, enterprises should integrate social, environmental,
ethical and consumer concerns into their business
operations, shifting focus from “values” to “value”
(from a morals-driven to a business-driven approach). At
a global scale the issue at stake is how to maximize the
creation of shared value (CSV) for the marine business,
stakeholders and society at large. In times of serious downturn,
shipping may endorse shared value solutions, linking
eco-efficiency in ship treatment operations (e.g. discharges
of wastewater and ballast water), with strategic social partnerships.
Aligned to its economic and environmental objectives,
the industry may support scientific research and
development of alternative treatment systems that serve
local communities & emerging societal needs e.g. water
shortage. The shipping community could proactively lead
social progress, beyond regulatory and administrative
global efforts, as a collective effective response to global
sustainable growth.

Hydrodynamic cavitation has been effectively proven to be an efficient advanced oxidation process on an
industrial scale. The utility of hydrodynamic cavitation for microbial disinfection of seawater has been
reported in this work. Seawater is used as cooling water in refineries and nuclear power plants or as ballast
water in the shipping industry. Various norms and regulations of the International Maritime
Organization (IMO) make it compulsory for ship owners to treat the ballasting seawater before discharging
it into the sea. Also, if the seawater is not properly treated, it causes biofouling which affects the performance
of cooling tower and other heat transfer equipments. It has been observed through our study
that, hydrodynamic cavitation can be effectively used for microbial disinfection of seawater. Effectiveness
of different types of cavitating devices for the extent of disinfection was studied. It was conclusively
proved that, slit type of geometry consumes 40% less energy compared to cylindrical geometry for similar
extent of seawater disinfection. A combination of the conventional treatments of water disinfection such
as chlorination and thermal treatment with hydrodynamic cavitation was found to increase the overall
rate of disinfection significantly. Rate of reaction almost doubles when 5 ppm hypochlorite was used
as disinfectant with the combination of cavitation compared to when only 5 ppm of hypochlorite was
used. Similarly the rate of disinfection increases 2.5 times at 50 C in combination with cavitation compared
to when, only 50 C was maintained and disinfection was carried out.

We examined methods for verifying whether or not ships have performed mid-ocean ballast water exchange (BWE) on four commercial vessels operating in the Pacific and Atlantic Oceans. During BWE, a ship replaces the coastal water in its ballast tanks with water drawn from the open ocean, which is considered to harbor fewer organisms capable of establishing in coastal environments. We measured concentrations of several naturally occurring chemical tracers (salinity, six trace elements, colored dissolved organic matter fluorescence and radium isotopes) along ocean transects and in ballast tanks subjected to varying degrees of BWE (0-99%). Many coastal tracers showed significant concentration changes due to BWE, and our ability to detect differences between exchanged and unexchanged ballast tanks was greatest under multivariate analysis. An expanded dataset, which includes additional geographic regions, is now needed to test the generality of our results.