AERATION SYSTEMS CONTROLS; WHAT ARE THEY? DO THEY WORK?

The aeration process consumes upwards of 60% of the total power consumption of an activated sludge wastewater treatment plant.1, 11 Thus, it is of critical importance to optimize the operation of this process to reduce power consumption. The literature has presented advancements of the art to optimize the control of aeration blowers, and optimization of the aeration cells via automated process (dissolved oxygen) control, most open valve control, and air header pressure control.2, 3, 4, 5 Since about 1994, this optimization has been incorporated in scores of wastewater treatment plant designs and upgrades. But does it work? Has the expenditure of additional first cost dollars really improved the operational (power and labor) cost savings? What new maintenance problems have surfaced? Turblex has been at the forefront of design and equipment supply of completely instrumented and automated aeration systems since the mid 1990's. This paper will first present the concept of the completely instrumented aeration system, with a brief overview including:The aeration blowersComponents of the aeration system, i.e., DO probes, air flow control valves, flow meters, other instruments, and the Master Control PanelBlower on-line control (air header pressure control)Process (dissolved oxygen or other) control to minimize air volumeMost open valve control, i.e., keep air flow control valves in their most open position to minimize the system air pressure.6Use of fine bubble air diffusersThe substance of the paper will present the results of a survey of operating wastewater treatment plants using integrated aeration systems control, some dating to the mid 1990's. We received several comments that lead us to place greater emphasis on more reliable instruments and "bulletproof" back-up control modes. The objective of this study being the incorporation of long-term operating experience to provide a more reliable and maintenance free aeration system, operating at the lowest possible cost.