Clogging Vs. Cake Layer Vs. Internal Pore Fouling
Fouling of the membrane is a major concern. There are multiple classifications of membrane fouling in MBR and why they occur. Understanding these fouling types helps to counter the problem, and have the filtration process running smoothly.
Among many reasons, the location of the fouling holds great significance.
There are three types of fouling when fouling is classified.
- Clogging
- Cake Layer
- Internal Pore Fouling
Clogging:
This type of fouling occurs in the outer space of the membrane bundle. It is typically formed between the membrane channels.
When sludge passes through the channels, the small particles of containments or debris are accumulated and stuck within the hollow fibers or flat sheet membranes inside a membrane module.
Hence, choking the membranes completely. This process is called clogging. When clogging happens, it blocks the flow of the wastewater and leads to the fouling of the membrane.
Cake Layer
Cake layering is the predominant fouling mechanism in MBR, irrespective of the membrane type when mixed liquors and SSs in the aeration basin start to deposit the convective flows from the bulk solution to the membrane.
Cake layer thickness ranges from several to hundreds of micrometers depending on the membrane pressure and the aeration intensity.
This cake layer formation occurs on the membrane surface and the entrance channels.
Internal Pore Fouling
Absorbed, dissolved, or fine particulate absorption to internal pore walls causes internal fouling. During the filtration stage, liquor begins to enter the pore entrance and the walls of the membrane. This accumulation over the period causes the pore diameter to narrow.
Hence, the cake layer is the buildup on the outside of the membrane.
In other words, when the particles are stuck in the membrane’s pores and blocking the flow of the activated sludge flocs. This results in the jammed particles in the pore, narrowing down the pore diameter.
