Ballast Water Management Systems for Vessels - Global Maritime Transport and Ballast Water Management: Issues and Solutions - page 115

According to the Lloyd's Register review of BWMS (Lloyds Register 2011a , b ),
technical features of the products are not necessarily common to all of them and are
specifi c to generic types of process technologies. Deoxygenation is effective because
the deoxygenated water is stored in sealed ballast tanks. However the process takes
between 1 and 4 days to take effect, and thus represents the only type of technology
where longer voyage length is a factor in process effi cacy. This type of technology
is also the only one where, technically, a decrease in corrosion propensity would be
expected (and, according to one supplier, has been recorded as being suppressed by
50-85 %), since oxygen is a key component in the corrosion process. The water is
re-aerated on discharge to avoid any unwanted effects to the recipient environment.
However, the effi ciency of deoxygenation is of concern as some organism can
change their metabolism to another source than oxygen and other organisms are not
dependent on oxygen at all.
Essentially most UV systems operate using the same type of medium pressure
amalgam lamps. A critical aspect of UV effectiveness is the applied UV dose/power
of the lamp. This information has not been given by all suppliers. Another aspect of
UV effectiveness is the clarity of the water. In waters with a high turbidity or col-
loidal content, UV would not expected to be as effective as in very clear waters, but
it was shown that UV systems also under these conditions meet the D-2 standard.
Most of the busy ports in Europe (e.g., Rotterdam, Antwerp, Felixstowe and
Hamburg) are located in estuaries with high sediment content.
Ballast Water Management Systems Capacities
and Installation Requirements
Different BWMS have different capacities and technical profi les, which are mainly
related to the aspects of appropriate capacity of the ballast water system of a vessel,
as well as to the system space requirement and power consumption. For many
BWMS the information available was very limited, and for some BWMS no infor-
mation became known at all.
BWMS capacities range from 50 m 3 h −1 to more than 10,000 h −1 , while fi ve man-
ufacturers informed that their systems are (will be) able to treat 20,000 and more
h −1 . In terms of footprint space requirements the systems with the capacity 200 h −1
could occupy from even less than 1 m 2 and up to 30 m 2 , while the systems with the
capacity 2,000 m 3 h −1 would occupy from 1 m 2 and up to 145 m 3 . Systems operate
also with no electricity requirement, and others may consume up to 200 kW per
1,000 m 3 h −1 water to be treated.
Chemical dosing systems such as PeracleanOcean, SeaKleen and chlorine diox-
ide have low capital costs because only a dosing/mixing pump is required but these
systems require chemical storage facilities and availability of chemicals in all ports
visited. Should the active substance be transported in higher concentrations, as dur-
ing shipment to the vessel, some special regulations regarding the transport of dan-
gerous goods may apply in certain ports due to safety concerns.