שאלה | Why is there a need for a recirculation stream between the aerated reactor and the anoxic step in the A2O process?

Why is there a need for a recirculation stream between the aerated reactor and the anoxic step in the A2O process?

		The recycling stream carries oxygen and organic matter from the aeration tank to the anoxic tanks, which is needed for nitrification.
		Bacteria consume more nitrogen when conditions are alternating between aerobic and anoxic.
		Anoxic conditions are required to remove the remaining ammonium before denitrification in the aerated tank.
		High concentration of organic matter is required for denitrification, as it removes the nitrate that is generated in the aeration tank.