Patent ID: 7455765

Claim:
A wastewater treatment system, comprising: a first biological treatment zone; a second biological treatment zone fluidly connected to the first biological treatment zone; a membrane module comprising a filter membrane fluidly connected to the second biological treatment zone; a recycle system fluidly connecting the membrane module to the first biological treatment zone; a source of biodegradable carbon fluidly connected to the recycle system; a sensor disposed to monitor a characteristic of a liquid exiting the second biological treatment zone; and a controller configured to allow introduction of the biodegradable carbon based on a signal from the sensor; wherein the controller is further configured to generate a first control signal that establishes a first liquid circuit from an outlet of the membrane module to an inlet of the second biological treatment zone, and further configured to generate a second control signal that establishes a second liquid circuit from an outlet of the second biological treatment zone to an inlet of the first biological treatment zone.