Alfa Laval PB-00479, System Manual

Page: 58 / 603

1.1 Preparations and conditions 1 Introduction
If stripping is performed with a low flow for a long period of time, we recommend that stripping is
performed from the ballast tanks to a “collection tank”. After that it is possible pump the water
from this tank with full flow using the ballast pump, and finally empty it by stripping.
Note
: The
driving water used for stripping must have been treated once, so that all water that is flushed
overboard has been treated twice.
This will reduce the power consumption and UV lamp runtime. If all tanks are stripped (with a low
flow) the power consumption per treated cubic meter will be unnecessary high, since the power
consumption will be high in relation to the low flow.
Example: If a process is run with a flow of 100 m 3 /h for 10 hours, it will give a power consumption
of 1000 kwh, not including the ballast water pump. But if the same amount of water is collected
and then processed with a flow of 1000 m 3 /h using the ballast water pump, the power consumption
will be 100 kWh.
1.1.2 Heeling (internal transfer)
Internal transfer of ballast water between tanks, for example during heeling procedures, does not
require the use of the PureBallast system. It is possible to perform heeling during standby ballast
or deballasting.
If external component signal for heeling mode is integrated between PureBallast and the vessel’s
ISCS, ongoing process will be paused and resumed automatically. The user is notified of started
and stopped heeling via warnings, and the event is logged.
If no external signal is integrated, the ongoing process must be paused manually. During pause,
cooling water is flushed through the AOT to cool the UV lamps. After completed heeling, the
operator must resume the paused process.
1.1.3 Ballast water handling in the event of malfunction
If the ballast water treatment system malfunctions, follow the procedures stated in the ship’s ballast
water management plan. This is valid both if the system malfunctions, for example mechanical
problems, or if full treatment cannot be guaranteed, for example a lamp failure or low UV intensity.
General recommendations are given blow.
PureBallast is equipped with a by-pass valve. The valve can be used in case of emergency to
secure the ship, by allowing ballast water operations (ballast, deballast and internal transfers)
without involving the ballast water treatment system. The valve is controlled by the ISCS, not
PureBallast’s control system, but all valve activities are logged in the event log. Such valve is
required by the
International convention for the control and management of ship’s ballast water
and sediments 2004
.
If the system malfunction in connection with general cargo operation, ballast and deballast
operations should be avoided. Note that the system requires treatment both during ballast and
deballast.
If untreated water is pumped to a ballast tank, this water shall primarily be discharged to a reception
facility. When this is not possible, other discharge possibilities must be agreed with the port state
responsible for the waters where the ship is sailing and most importantly be agreed with the flag
state administration of the ship; the procedures concerning emergency and malfunction of the
ballast water treatment system should be implemented in the ships Ballast Water Management
Plan which must be approved by the flag state administration.
8
Book No.9010183 02, rev. 2