Wastewater treatment controls that maintain the ORP of a mixed liquor at a relatively stable value during a wastewater treatment process such as an aerated-anoxic wastewater treatment process. The wastewater treatment control may compare a setpoint value of ORP and a measured value of ORP of the mixed liquor, generate a control signal based at least in part on the comparison, and control a biological nutrient removal control parameter using the control signal. Values corresponding to the control signal may be acquired and utilized to adjust the setpoint value of ORP to maintain stable operating conditions of the wastewater treatment process.