Fouling Behavior of Direct Microfiltration for Wastewater Up-Concentration

In the context of rapid urbanization and increasing demand for decentralized wastewater treatment, membrane-based technologies offer high effluent quality with a reduced footprint. Direct microfiltration (DMF) is a promising approach for simplified wastewater treatment. In this study, a lab-scale DMF system was operated for 65 h at an initial flux of 20 LMH to evaluate membrane fouling behavior with actual sewage. The results showed that the trans-membrane pressure (TMP) followed a typical three-stage fouling pattern, with a TMP jump between hours 10 and 15 at a fouling rate of 16 kPa/hour, sharply reducing permeate flux. Analysis of fouling resistance revealed that cake resistance (Rc) accounted for 94% of the total resistance, while membrane (Rm) and irreversible fouling (Rf) contributed only 2% and 4%, respectively, highlighting the dominant role of cake formation. These findings suggest that DMF systems are feasible for municipal sewage treatment at fluxes around 20 LMH. Finally, mitigation strategies such as backflushing, pretreatment and chemical cleaning to control early-stage fouling should be further investigated.