Читать книгу Automation of Water Resource Recovery Facilities - Water Environment Federation - Страница 255

The main control strategy for aeration control is to vary the individual air valve’s position in each reactor or reactor area to maintain the dissolved oxygen level in that area at a setpoint. As dissolved oxygen drops below the setpoint, the valve is opened, and, as dissolved oxygen rises above the setpoint, the valve closes. In some instances, airflow to each reactor is monitored and used to modulate the individual air valve’s position. Dissolved oxygen, in this instance, is used in a cascade loop to modify the airflow setpoint.