Oil and Water Recovery from Palm Oil Mill Effluent: A Comparative Study of PVDF and α-AlO Ultrafiltration Membranes.

Recovering oil and water from palm oil mill effluent reduces environmental pollution and promotes sustainable practices. An effective method to achieve this is ultrafiltration (UF), which uses semi-permeable membranes to separate oil, solids, and other contaminants from wastewater under pressure. To assess the most effective recovery method, an experimental comparison was conducted between PVDF and α-AlO UF membranes at constant permeate of 20-50 LMH for PVDF and 20-70 LMH for α-AlO membranes. Both membranes achieved 99.8% chemical oxygen demand (COD) rejection, with oil concentration factor (F) of 186.8% and 253.0%, and water recovery (R) of 46.6% and 60.5%, respectively. The permeate water quality was superior to the Malaysian discharge standards, and the fat, oil, and grease (FOG) content was suitable for phase separation processes. The optimal permeate fluxes, with stable transmembrane pressures (TMP), were observed at 40 LMH (PVDF) and 60 LMH (α-AlO). Total resistance (R) values were 1.30 × 10 m (PVDF) and 1.59 × 10 m (α-AlO). The ratio of irreversible to total resistances (R/R) was 0.02 (PVDF) and 0.06 (α-AlO), indicating minimal irreversible fouling. Overall, the α-AlO membrane demonstrated superior performance in oil and water recovery with more stable operation compared to the PVDF membrane. UF membrane technology emerges as an efficient technique for recovering oil and water compared to conventional methods.