Dissolved Oxygen (DO) is one of the most critical measurements in a wastewater treatment plant. DO is the measure of oxygen dissolved in a solution, typically expressed in parts per million (ppm) or milligrams per liter (mg/l). Measuring DO levels is a typical practice in aerobic wastewater treatment since biochemical breakdown is performed by bacterial microorganisms in the presence of oxygen. Maintaining an appropriate concentration of DO in an aeration basin of a wastewater treatment plant is necessary to keep the microorganisms alive and to allow for the break down of organic wastes. Aerobic bacteria require dissolved oxygen and “food” to live. When proper levels of DO are not maintained in a wastewater treatment plant, troublesome microbes proliferate- causing sludge settling problems. Aeration is a large operating expense because of the associated power requirements; and, properly measuring and managing DO levels can lead to process efficiencies and subsequent cost savings.

Reprinted with Permission from Severn Trent Services