Oxygen uptake rate (OUR) is the rate of oxygen transferred from the bulk liquid to microorganisms; it is sometimes referred to as the breathing or “respiration rate”.  This is typically measured as mgO2/L/hr. OUR is influenced by the amount of biomass and food available.  Generally, higher MLSS concentrations and higher pollutant loading conditions will result in a greater OUR. The MLSS you operate at, where in the aeration basin you feed raw influent, and the DO setpoint you maintain all impact the air demand across the basin. 

The aeration basins we operate are designed to run a certain way, i.e. designed deliver a certain amount of air in specific locations.  Sometimes as operators we need operate things a little differently.  When the systems aren’t designed to accommodate that new operation mode, we can run into challenges. How well does your current mode of operation align with the design?