Patent ID: 7459083

Claim:
A method for controlling fouling of a membrane filter in a biological wastewater treatment process, comprising: directing wastewater influent into one or more reactors and treating the wastewater; directing the wastewater into and through one or more membrane tanks having one or more membrane filters therein; filtering the wastewater by directing the wastewater through the membrane filters and producing a permeate; cleaning the membrane filters with air scouring; measuring trans-membrane pressures and a liquid level in at least one of the membrane tanks; executing multiple control cycles to control scouring air flow rate, flux, permeation phase duration, and relaxation phase duration; in at least one of the control cycles, optionally adjusting each of scouring air flow rate and flux as a function of the measured trans-membrane pressures and of the measured liquid level in the membrane tank; in at least one of the control cycles, optionally adjusting each of relaxation phase duration and flux as a function of the measured trans-membrane pressures and of the measured liquid level in the membrane tank; and in at least one of the control cycles, optionally adjusting each of flux and permeation phase duration as a function of the measured liquid level in the membrane tank.