Study on the Control of Membrane Fouling by Pulse Function Feed and CFD Simulation Verification.

Area of Science:

• Membrane science and technology
• Fluid dynamics
• Water treatment

Background:

• Membrane fouling remains a significant challenge in water treatment, reducing efficiency and increasing operational costs.
• Controlling feed fluid velocity is crucial for mitigating membrane fouling.
• Traditional steady-flow feeding methods often lead to substantial fouling.

Purpose of the Study:

• To investigate the impact of various functional feeding strategies on membrane flux and fouling.
• To compare the effectiveness of sine, square wave, reciprocal, and power function feeding against steady-flow feeding.
• To elucidate the mechanisms behind fouling reduction using Computational Fluid Dynamics (CFD) simulations.

Main Methods:

• Utilizing a complex-function fluid controller to implement different feeding functions (square wave, sine, reciprocal, power).
• Conducting experiments with humic acid as a simulated pollutant in a membrane filtration system.
• Analyzing membrane flux, employing Scanning Electron Microscopy (SEM) for surface analysis, and performing CFD simulations.

Main Results:

• Sine function feeding achieved the highest membrane-specific flux, maintained above 0.85 at an intermittent frequency of 9 s.
• Functional feeding significantly reduced membrane fouling compared to steady-flow feeding (final flux of 0.55).
• CFD simulations indicated sine function feeding generated approximately three times the shear force of steady flow (6 × 10^5 N), leading to reduced fouling.

Conclusions:

• Functional feeding, especially sine function feeding, is a highly effective strategy for reducing membrane fouling.
• The enhanced shear force generated by functional feeding plays a key role in mitigating fouling on the membrane surface.
• This approach offers a promising method for improving the longevity and efficiency of membrane filtration systems.