SINCE THE 1980's, Membrane Bioreactors (MBR) have been successfully used to treat municipal, commercial and industrial wastewaters for discharge and reuse applications. Today, with thousands of installations operating worldwide, MBR technology is shaping the way we view wastewater treatment and water conservation in the US and around the world.
Description of MBR technology
An MBR is a combination of the activated sludge process, a wastewater treatment process characterized by a suspended growth of biomass, with a micro- or ultra-filtration membrane system that rejects particles. The membrane system replaces the traditional gravity sedimentation unit (clarifier) in the activated sludge process. The turbidity and suspended solids concentration of the effluent is far lower than in conventional treatment. All biomass is retained and becomes returned activated sludge. Biological growth leaves the system as waste activated sludge. The figure shows an immersed MBR that is market by several vendors with various proprietary features.
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Advantages of MBR
1.High effluent quality
• Filtrate – free of suspended solids & fecal coliforms
2.Elimination of secondary clarification tank, small footprint
• Only half of the area of conventional activated sludge process is required, capital cost is reduced
• Solve the problem of poor sedimentation in conventional activated sludge process; especially for winter.
3.Long solid retention time, easy management
• Sludge wasting volume is greatly reduced
4.High biomass concentration and treatment efficiency
• Operate at biomass concentration of 10,000 – 20,000 mg/L, COD removal and denitrification occur simultaneously.
5.Easy to install in the existing aeration tank to become MBR
6.Easy for Operation & Maintenance
7.Greatly reduce the volume of aeration tank
8.Reduce fouling and increase water flux
Parameters |
Raw sewage |
Treated sewage |
| BOD |
300PPM |
<5PPM |
| COD |
800PPM |
<10PPM |
| TSS |
350PPM |
<2PPM |
| O&G |
50PPM |
<10PPM |
| Turbidity |
10 NTU |
<0.1 NTU |
| Fecal coli forms |
6 10 |
Not detectable |
| Total Phosphorous |
10PPM |
1PPM |
| Total nitrogen |
60PPM |
<3PPM |
| Total Ammonia |
10PPM |
Not detectable |
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