Aeration typically takes 50-80% of the total energy consumption of MBR based on submerged membranes. Optimizing aeration for membrane scouring and biological reaction is an essential part of energy conservation strategy in iMBR.Especially in MBR plant, where additional aerations are required for membrane scouring, the cost of running electric motors for pumping and blowing can be the largest fraction of a plant’s total operating costs (WEF 2009, — USEPA 2010).
Inefficiencies in pumping and blowing often come from a mismatch between the pump and the system it serves due to improper pump selection, changes in operating conditions, or the expectation that the pump will operate over a wide range of conditions (– USEPA, 2010). The mismatch also occurs when wastewater flow rate and strength changes even if the pumps and blowers were properly sized in the beginning. Following are the summary of common causes of efficiency loss in pumping and blowing.
- Flow control using flow control valves
- Flow control using bypass lines
- Frequent on/off cycling
- Cavitation at the pump or here in the system
- Overheated motor with overloading
- Pump/blower system with no flow, pressure, and power consumption monitoring
- Wear of seals in motor, pump, and blower