What are the primary reasons for change in the performance of all membranes over time?

The primary reasons for changes in the performance of all membranes over time are primarily compaction and fouling.

Compaction refers to the gradual decrease in the membrane's thickness and porosity as it undergoes pressure or hydraulic stress during operation. This can reduce the membrane's permeability and its efficiency in separating contaminants from water, leading to diminished performance over time.

Fouling is a process where particles, organic matter, or biological growth accumulate on the membrane surface or within its structure, forming a barrier to flow. This can severely hinder the membrane's ability to function effectively, leading to increased resistance to water flow, requiring higher pressures to maintain the same flow rates, and ultimately reducing the quality of the permeate produced.

While temperature fluctuations, regular cleaning, and changes in pH or chemical composition can also impact membrane performance, compaction and fouling are the most direct and significant factors leading to long-term performance degradation. Regular maintenance and appropriate operational practices can mitigate fouling and compaction, but they remain intrinsic challenges inherent to membrane technology over time.