Energy Reduction and Optimisation in Membrane Bioreactor Systems

One of the major components of MBR operating expenditure is energy consumption. This paper presents our six-year journey of energy reduction and optimization in MBR systems through various pilot and demonstration studies. Through comprehensive and systematic MBR optimisation studies, the specific energy consumption was reduced from 1.3 kWh m⁻³ to less than 0.8 kWh m⁻³ by increasing membrane flux and reducing aeration at 300 m³ per day pilot scale plants. Through energy audit, the key energy consumption components including process aeration, membrane scouring rate, SRT, MLSS level, MLSS recirculation, and energy efficient equipment selection were identified, and these were optimised one by one at 23,000 m³ per day municipal scale MBR demonstration plant after the baseline had been set up. The specific energy consumption was further reduced to 0.37 kWh m⁻³.