Abstract: Disclosed are a configuration system and a method for configuring a ballast water treatment system for treating ballast water of one or more ballast tanks in a vessel. The ballast water treatment system is configured to circulate ballast water between a tank outlet and a tank inlet of a first ballast tank. The method includes obtaining structural parameters of the first ballast tank. These structural parameters include a compartment number parameter indicative of a number of compartments in the first ballast tank. Control data for the ballast water treatment system based on the structural parameters is then determined. The control data includes a first volume parameter indicative of a first ballast water volume to be circulated. The control data is provided to the ballast water treatment system.

Abstract: A process plant comprises a tank (1), an outlet conduit (2), a reservoir of cleaning agent (12), or feedstock(s) of additive(s) (13), a loop conduit (3) for returning liquid into the tank, valve means (9) for controlling admission of liquid into the loop conduit and a pump (4) for driving liquid through the loop conduit. Returning of the liquid takes place through a jetting device (5) adapted for introducing jets of liquid into the body of liquid inside the tank in order to cause stirring to the body of liquid. The jet nozzle is adapted for powered rotation about a first axis and about a second axis perpendicular, or non-perpendicular, to the first axis. The jet nozzles may be embodied in a flat jet rotating around one axis only. Upon emptying the tank, the jetting device may serve for cleaning the tank by spraying liquid onto the tank walls. The invention provides a method for treating liquid as well as a process plant.