A practical classification of membrane fouling includes:
Organic fouling
Caused by natural organic matter, oils, proteins, and polymers. Organic fouling often leads to pore blocking or adsorption onto the membrane surface, gradually reducing flux and increasing transmembrane pressure. It is highly influenced by membrane surface chemistry and hydrophobicity.
Inorganic fouling (Scaling)
Occurs when dissolved salts precipitate and deposit on or within the membrane structure. Scaling is commonly driven by high recovery operation, temperature changes, and unfavorable feedwater chemistry. Once established, it can be difficult to remove without chemical intervention.
Biofouling
Results from microbial attachment and biofilm formation on membrane surfaces. Biofouling is particularly persistent because biological growth continuously regenerates, often leading to rapid pressure increase and reduced cleaning effectiveness over time.
Why differentiation matters
Each fouling type:
- Develops under different operating conditions
- Responds differently to cleaning
- Has a different impact on membrane lifespan
Treating all fouling as the same problem often leads to ineffective mitigation strategies.
