Siemens Water Technologies’ new MemPulse membrane bioreactor (MBR) uses a mechanical device that supplies irregular pulses of air to the MBR module. This is said to decrease operation and maintenance costs, reduce energy consumption, and increase scouring effectiveness. The process can be used with a wide range of municipal and industrial wastewater treatment applications and can easily be retrofitted to existing plants wishing to replace conventional clarification processes with membrane separation. The MemPulse device introduces air and mixed liquor into the bottom of the membrane modules through an “airlift effect.” The air bubbles blend with the mixed liquor and rise up into membrane fibers, providing effective scouring to the membrane surface and refreshing the membrane surface to prevent solids concentration polarization. The two-phase cross-flow reduces scour air energy dramatically. No moving parts are added to the system and there are no mixed liquor jet laterals.