Membrane filter system and method for membrane filtering a liquid

A membrane filter system comprising:

• a storage tank;
• a ring line for connecting consumers;
• at least one stage comprising:
• a membrane module connected to a concentrate line for delivering a concentrate volume flow and a permeate line for delivering a permeate volume flow;
• a feed line to the membrane module;
• at least one booster pump for pumping liquid into the membrane module;
• and
• at least one circulation pump for returning concentrate from the membrane module to the feed line:
• at least two sensors, each sensor configured to measure a process variable;
• and
• at least one control and regulation unit,
• each of the at least two sensors being connected on an signal input side to the at least one control and regulation unit, and
• the at least one control and regulating unit configured to regulate the at least one booster pump and at least one circulation pump based on sensor signals of the at least two sensors.