Abstract: A control algorithm for operating a fluid disinfecting system by UV radiation, wherein the UV radiation is generated by at least one UV lamp including a pair of heating cathodes having a discharge voltage (UD), the UV lamp is operated by an electronic ballast unit equipped with the control algorithm for adjusting the UV power of the UV lamp by pulse-width-modulation to reduce UV power. The control algorithm decreases the current to a level (Ikmin), increases the voltage amplitude (U) above the discharge voltage (UD) until a desired UV power level is reached. The pulse width (PW) is decreased with increasing voltage amplitude (U) until PWmin is reached. The decrease in current and the increase in voltage generate an ineffective current-voltage-ratio in which excess current heats the cathode. An electronic ballast equipped with the algorithm and systems equipped with such ballasts are also disclosed.

Abstract: A method for controlling a treatment apparatus arrangement in a treatment plant, the treatment plant including a basin housing a liquid and solid matter. The operating condition in the basin is anoxic and/or anaerobic, and the treatment apparatus arrangement includes at least one mixer machine located in the basin and a variable speed drive operatively connected to the mixer machine. The variable speed drive operates the mixer machine alternately in a Normal Operation Mode, in which an operational speed of the mixer machine is at least the greater of a suspension speed and a process speed, and a Reduced Operation Mode, in which the operational speed of the mixer machine is below the suspension speed. Also described is a treatment apparatus arrangement and a treatment plant, respectively.

Abstract: A guide rail assembly for a submersible machine as well as a guide rail holder for such a guide rail assembly is described herein. The guide rail holder includes a radially extending support body and an axially extending post, which is rigidly connected to the support body and which is adapted to be inserted into an end of the guide rail. An engagement head is connected to the post at a distance from the support body and has a greater radial extension than the post. The engagement head includes a radially expandable member that is adapted to be reversibly manipulated between an active state, in which the expandable member is in engagement with the guide rail, and an inactive state, in which the expandable member is disengaged from the guide rail.