the IHS Ballast Water Guide - RWO Marine Water Technology

Sponsored by IHS Fairplay Solutions Guide to Ballast Water Treatment Systems
required efficacy. Biocide dosing level
is variable and depends on ballast water
conditions – the physical, chemical, and
biological characteristics that, cumulatively,
are called chlorine demand.
The SiCURE system treats ballast water
only on intake, allowing the system to be
sized for ballast water flows while discharge
can be done with higher flow rates. This is
suitable for those vessels that use only one
pump on intake and two pumps on discharge.
Ozone
(Mitsui) Special Pipe
Hybrid 5 8
The Special Pipe Hybrid system (Ozone
version) from the Japanese shipbuilder Mitsui
Engineering is a two-stage system based on
cavitation by high shear and ozonation. In the
ballasting phase, water is taken into the pretreatment
unit before passing to a unit that
injects ozone, which has been generated on
board, into the water.
This method of treatment starts with
inline pre-treatment to preventing blockage
of the disinfecting unit followed by a more
complex mechanical treatment via a “special
pipe” which is inserted into a section of
the normal ballast pipe run and then ends
by adding the produced ozone which is
considered as an active substance by the IMO.
After addition of the ozone to the water, for
the treatment to be effective it is necessary
for the ballast to be stored in the tank for at
least 48 hours.
This minimum amount of storage time is
needed to allow for the strong oxidising and
disinfecting properties of bromate, which
is generated from the reaction of ozone and
seawater, to become ineffective. The halflife
period of the bromate ion is, on average,
around 12 hours.
A discharging unit decomposes the oxidant
remaining in the ballast water at the time
of discharge. The ozone generator contains
multiple electrodes that convert a part of the
oxygen in the gas to ozone.
A power supply unit converts the power
type from commercial frequency and low
voltage to medium frequency and high voltage
most suitable to ozone generation.
A gas/liquid separation unit is employed
to prevent ozone that does not react from
flowing into the ballast tank.
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