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The Role of MBRs in Reducing Wastewater Treatment Costs

Membrane Bioreactors (MBRs) have emerged to be the newest and most widely used technology for municipal and industrial wastewater treatment processes. Integrating membrane separation technology like ultrafiltration or microfiltration with suspended growth biological treatment technology or the activated sludge process, an MBR system is built with a biochemical reaction system and membrane components for effective solid-liquid separations, essential in obtaining the highest quality of reusable water. 

The MBR Technology has gained popularity over the years because of its advantages including high effluent quality to meet the most demanding water quality requirements, high loading capability and therefore can drain water quickly, high removal efficiency for pollutants, and less sludge production. Since secondary clarifiers and tertiary filtration methods are ruled out with MBRs, plant footprint is greatly reduced, saving space compared to a Conventional Activated Sludge (CAS) facility. 

Wastewater treatment efficiency of MBRs and the cost of sewage treatments greatly depend on the choice of membrane materials and membrane modules in an MBR system. One of the most favored membrane materials used in MBRs is polyvinylidene fluoride (PVDF) as it comes with unique material properties.

Why Choose PVDF Membrane Material for MBRs? 

 

PVDF sheet has good chemical stability and the characteristics of both fluororesin and general resin. Moreover, it also features piezoelectric, electrical, dielectric, and thermoelectric properties. Aside from offering excellent chemical resistance, PVDF is also resistant to high temperatures, oxidation, and radiation. These characteristics are essential for chemical cleaning of membranes that typically involve high temperatures, PH levels, and oxidant concentration. Frequent chemical cleaning is critical to block pollutants on the membrane surface and is necessary for stable MBR operations.

Another main reason why PVDF membranes are widely used in MBRs is its superior mechanical properties that can ensure integrity of the MBR structure. PVDF is an excellent polymer that can be utilized in a hollow fiber (outside-in) configuration with air PVDF fibers bent and stretched. Even if PVDF has a low pore density, its outside-in structure largely makes up for it. 

In general, the membrane material used in MBRs should offer resistance to fouling. Since PVDF is highly hydrophobic, it has an innate tendency to be fouled by similarly hydrophobic organic matter in the mixed liquor. This is one of the reasons why hydrophilic modification of PVDF membrane material has been a critical point of discussion in recent years. Modifying PVDF to be hydrophilic can effectively improve membrane flux and reduce membrane fouling, in turn making MBR membrane modules anti-fouling.  

Membrane Solutions’ MBR Systems as Cost-Effective Wastewater Treatment Solutions