Factors responsible for membrane fouling

Factors responsible for membrane fouling
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Factors responsible for membrane fouling: Membrane fouling in almost all membrane processes is normally caused by precipitation and deposition of molecules or particulates on the membrane surface or membrane pores. The consequences of membrane fouling are increased membrane separation resistances, reduced productivity, and/or altered membrane selectivity. These factors can be grouped into three categories, namely: membrane characteristics, operating conditions, and feed and biomass characteristics.


A. Membrane Characteristics:


1. Membrane Material 

The material the membrane is made of has an impact on its fouling propensity in MBRs. Based on the membrane material, membranes can be classified into: ceramic membranes, polymeric membranes, and composite membranes. Ceramic membranes exhibit good filtration performance due to their high chemical resistance, integrity, inert nature and ease of cleaning leading to low operating costs Ceramic membranes are also highly hydrophilic which makes them more fouling resistant 


2. Water affinity 

The water affinity (hydrophilicity or hydrophobicity) property of the membrane material affects fouling in MBRs.


3. Membrane surface roughness

The surface roughness of the membrane material also has some influence on membrane fouling in MBRs. Membranes with homogeneous surfaces are less subject to be fouled than those with uneven surfaces.


4. Membrane surface charge 

The membrane surface charge is another property of importance in relation to membrane fouling especially if there are charged particles in the feed. 


5. Membrane pore size

Generally, membranes used in wastewater treatment are broadly grouped into two: porous membranes and non-porous membranes. 


B. Operating conditions:

1. Operating mode

2. Rate of aeration

3.Solid retention time

4. Hydraulic retention time

5.Food-microorganisms ratio

6.Organic loading rate

7. COD/N ratio

8. Temperature

C. Feed and biomass characteristics:

1.Mixed liquor suspended solids

2.Sludge apparent viscosity

3.Extra cellular polymeric substances

4.Floc size

5. Alkalinity and pH

6.Salinity


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