Cloth media filtration and membrane microfiltration: serial operation

Area of Science:

• Environmental Engineering
• Water Treatment Technologies

Background:

• Secondary effluent requires advanced treatment to meet quality standards.
• Membrane microfiltration is a key technology for water purification.
• Prefiltration can impact the performance and economics of membrane systems.

Purpose of the Study:

• To evaluate the impact of premembrane filtration on membrane microfiltration performance.
• To determine the effect on maximum sustainable flux, transmembrane pressure, and effluent quality.
• To assess the economic benefits of a combined filtration system.

Main Methods:

• A series system combining a cloth media filter and a membrane microfilter was employed.
• Secondary effluent was treated under defined operating and cleaning cycles.
• Key performance indicators including flux, pressure, and water quality were monitored.

Main Results:

• The combined system achieved a maximum sustainable time-averaged flux of 127 L/m(2)xh.
• Effluent water quality was consistently high, with low turbidity (0.04 NTU) and BOD (1.4 mg/L).
• No total or fecal coliforms were detected in the final effluent.

Conclusions:

• Prefiltration effectively enhances membrane microfiltration performance for secondary effluent treatment.
• The combined system delivers superior effluent quality independent of flux or influent variations.
• Implementing prefiltration offers significant annualized cost savings of about 12%.