In conventional activated sludge processing, solid-liquid separation is performed in a settling tank. However, in the MBR system it is performed in a membrane module. Consequently, a settling tank is not required in MBR systems, a high MLSS concentration can be maintained, and 100% separation of SS larger than the membrane pore diameter is possible.
Conventional activated sludge
Membrane bio reactor (MBR)
There are two types of MBR system:
- Integrated MBR systems which place membrane modules in aeration tanks.
- Separated MBR systems which place membrane modules in seprate membrane tanks.
Integrated MBR system
Separate MBR system
Characteristics and Applications
Space saving, high quality of treated water and ease of maintenance are unique properties of this MBR system. Appling this MBR system will reduce footprint to 1/3 space that have being used in conventional methods. MBR can treat a sludge that is 5 times thicker compared to conventional methods. For this reason, it can treat more water even with smaller biological tank.
MBR can be used the only treatment unit before RO plant to not only decrease the TSS but also it can remove notable amount of COD, BOD and total nitrogen and phosphorous.
another example of using MBR in when oily waste water is required to treated with better final effluent quality in terms of BOD and SS.
for domestic wastewater with the concern of efficient nitrogen and phosphorous removal.
The benefits of low footprint
Ultra Hollow fiber specification:
• Fineness: 0.05 micron
• Material: PVDF
• Advantageous over flat sheet:
o More membrane surface area
o Membrane tank size reduction
o Reduced aeration demand
o Reduced energy consumption
o Reduced Capital and Operational costs.
Performance mechanism:
There is no need to backwash just 7-minute filtration and 1-minute relaxation is required
Wuxi Xincheng wastewater treatment plant
Challenge:
On June 5, 2008, the newly revised Taihu Lake Water Pollution
Prevention Regulation was brought into effect. However, the footprint
of this facility was too small to comply with the stringent regulation by
increasing of the existing conventional activated sludge process
capability without overloading.
Solution:
Apply membrane bioreactor (MBR) to meet the effluent standard with
the limited land.
Benefits:
Apply membrane bioreactor (MBR) to meet the effluent standard with
the limited land.
| Treated water | Influent | |
| 33.2 | 360 | CODCr mg/L |
| <5 | 400 | SS mg/L |
| 0.3 | 5 | T-P mg/L |
| 1.3 | 38 | NH3-N mg/L |
| 11.1 | 43 | T-N mg/L |