A clutch actuator for an electromechanical clutch having a solenoid actuating coil initially provides power to the solenoid at a high rate by using a high duty cycle pulse with a modulated controller. The information processing unit compares a program that is set based on a newly-input ID with a program that is set based on an already-input ID, and ends the currently-executed program when the two programs are different from each other. The vessel defines a free settling zone, a hindered settling zone intermediate, an upper clarification zone and a lower compaction zone.