Systems and techniques for cleaning pressure membrane systems using a water-in-air cleaning stream

A system comprising:

• a membrane positioned in a housing that pressure isolates the membrane from an ambient environment, the membrane being configured to separate a feed stream into a permeate stream and a concentrate stream;
• a water metering device configured to provide a flow rate of water;
• an air metering device configured to provide a flow rate of air that combines with the flow rate of water to generate the feed stream supplied to the housing;
• an analyzer positioned to measure a concentration of at least one chemical species in the permeate stream;
• and
• a controller communicatively coupled to the water metering device, the air metering device, and the analyzer, wherein the controller is configured to:
• control the water metering device and the air metering device to generate the feed stream with a ratio of the flow rate of air divided by the flow rate of water is greater than 1, and
• control the analyzer to analyze the permeate stream and determine the concentration of that at least one chemical species in the permeate stream.