The Membrane Bioreactor process (MBR) is a mechanism used to remove the sludge that emerges during the filtration of biological waste during wastewater treatment. The MBR system is a combination of biological filtration and microfiltration or ultrafiltration processes. The MBR is a much more efficient and shorter process than the conventional activated sludge mechanism.
In the traditional activated sludge process, the settling tank separates the sludge into solid and liquid, and the system then sends it for secondary clarification. The MBR system combines activated sludge treatment with slid-liquid separation using the micro-porous membranes instead of traditional separation by secondary clarification. In a standard setup, you can place the MBR module in a separate tank after the oxidation tank. The MBR modules can also be introduced directly into the oxidation tank. We call this setup a compact system. You can rearrange the MBR system in a variety of configurations.
How MBR in wastewater treatment works
Components of MBR in water treatment
- Rotary influence screen
- Anoxic tank
- Aerobic tank
- Anaerobic tank
- MBR modules
- Air blowers
- Pump set for permeate suction
- Chemical dosing systems
- Cleaning tank for backwash
Working
Step 1: The anoxic tank:
The system screens the wastewater to remove large solids and then sends it into the anoxic tank. Here, a submergible mixer mixes the process water with a mixed liquor coming back from the MBR tank to obtain the desired level of denitrification. Without dissolved oxygen, the bacteria in the tank convert nitrate into nitrogen gas.
Step 2: The anaerobic tank
From anoxic tank, the process water flows into the anaerobic tank. The anaerobic process triggers the discharge of phosphorus by microbes fueling anaerobic reaction.
Step 3: The aerobic tank
From the anaerobic tank, the process water flows into the aerobic tank. Here, oxygen is injected using air blowers and a diffused aeration system. The oxygen-rich environment aids in biologically oxidiging organic material and ammonical nitrogen from process water. What remains is carbon dioxide, nitrate, and water.
Step 4: The MBR membrane tank
The system sends the process water from the aerobic tank into the MBR tank for liquid–solid separation. Flat‑sheet MBR membranes operate fully submerged in the mixed liquor inside the MBR tank. The membranes have a pore size of 0.04 micrometers. They separate solids and microbes from activated sludge. The aeration system within the tank creates an upward flow of water and air flux. This prevents the fouling of membranes, and ensures up to 99% efficiency in the removal of suspended solids.
Advantages of MBR system
- Higher efficiency
- Shorter hydraulic retention time
- Longer solid retention time
- Smaller footprint due to lack of secondary clarifiers
- Suited for high-strength effluents
- Potential for simultaneous nitrification/denitrification in long SRTs
Conclusion
The MBR system offers more efficiency and flexibility in water treatment than conventional systems. It is the critical component that allows Inovar water treatment plant to have a smaller footprint. MBR system can be configured in a number of ways and can be easily integrated into the existing system. Along with design, manufacturing and installation of new STPs, Inovar also provides consultancy and retrofitting services to upgrade existing plants. TO further save your operating costs, all Inovar products are backed by annual maintenance contracts.
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