Water Reclamation Using a Ceramic Nanofiltration Membrane and Surface Flushing with Ozonated Water.

Area of Science:

• Environmental Science
• Water Treatment Technologies
• Membrane Science

Background:

• Membrane fouling is a significant challenge in direct nanofiltration (NF) of secondary wastewater effluent.
• Existing fouling control methods may not be sufficient for effective water recycling.
• Ceramic NF membranes show promise but require optimization for contaminant removal.

Purpose of the Study:

• To evaluate ozonated water flushing as a membrane fouling control technique for ceramic NF membranes.
• To assess the effectiveness of ozonated water in mitigating fouling and restoring membrane permeability.
• To highlight the importance of membrane development for removing pharmaceuticals and personal care products (PPCPs).

Main Methods:

• Direct nanofiltration of secondary wastewater effluent using a ceramic NF membrane.
• Surface flushing with clean water and ozonated water (4 mg/L dissolved ozone) at 44 L/m²h permeate flux.
• Monitoring transmembrane pressure increase over five filtration cycles to quantify fouling progression.

Main Results:

• Surface flushing with clean water was ineffective in removing foulants.
• Surface flushing with ozonated water effectively removed foulants and restored membrane permeability.
• Ozonated water flushing limited transmembrane pressure increase to 35% over five cycles.

Conclusions:

• Ozonated water flushing is a viable technique for controlling membrane fouling in NF of wastewater.
• Further development of ceramic NF membranes is needed for efficient removal of PPCPs.
• The developed fouling mitigation technique is particularly important for smaller-pore ceramic NF membranes with enhanced PPCP rejection.