Membrane bioreactors (MBR) are becoming quite popular these days. I designed one. MBRs have the advantage of producing reuse quality effluent and have a small footprint. They have 2 BIG disadvantage:
1. The design to peak flows are usually just 2:1
2. They have a BIG energy demand because of the scour air needed to keep the membranes clean, and the low alpha of the fine bubble diffusers due to the high MLSS that the manufacturers tout. Additionaly, if you live in the cold weather part of the country, you will need to buy lots of extra membranes because low temperature adversely affects the membrane flux rate
I will propose a different solutioon: Put the membranes downstream of the secondary clarifiers. Why?
1. You only need 1/3 of the membranes compared to an MBR
2. The requirement for scouring air is much reduced, saving energy
3 The membranes can be bypassed, if necessary
4. You can still eliminate disinfectioin in some states, as the membranes remove the bacteria.
This makes a lot more sense to me.
A blog from a wastewater guy about various things
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