Full-scale validation of an air scour control system for energy savings in membrane bioreactors

Membrane aeration represents between 35-50% of the operational cost of membrane bioreactors (MBR). New automatic control systems and/or module configurations have been developed for aeration optimization. In this paper, we briefly describe an innovative MBR air scour control system based on permeability evolution and present the results of a full-scale validation that lasted over a 1-year period. An average reduction in the air scour flow rate of 13% was achieved, limiting the maximum reduction to 20%. This averaged reduction corresponded to a decrease in energy consumption for membrane aeration of 14% (0.025 kWh·m-3) with maximum saving rates of 22% (0.04 kWh·m-3). Permeability and fouling rate evolution were not affected by the air scour control system, as very similar behavior was observed for these variables for both filtration lines throughout the entire experimental evaluation period of 1 year.