High frequency back-pulsing for fouling development control in ceramic microfiltration for treatment of produced water

Produced water is a mixture of dispersed oil in water, dissolved organic, and inorganic particles. Membrane technology is a potential process to meet future discharge standards and regulations on the Norwegian Continental Shelf (NCS). Fouling minimization with backpulsing technique was assessed in this study. The influence of produced water properties i.e., oil concentration, oil types, particles and membrane flux during the back-pulsing was investigated. α-Al₂O₃ MF membranes (nominal pore sizes; 0.1, 0.2 and 0.5 μm) were tested. Results show that control of fouling rates is better at low oil concentrations, low flux, larger oil droplet size and no fine oil/particles. Selection of membrane pore sizes depends on the feed properties. At low oil concentration (i.e., 50 ppm) and low flux (i.e., 250 l.m^–2.hr^–1 (LMH), a pore size of 0.5 μm resulted in the lowest fouling rates, whereas for higher oil concentrations and low flux and presences of fi ne particles the 0.2 μm pore size performed better. At high flux (i.e., 500 LMH), high oil concentrations and presences of particles the 0.1 μm membrane had the lowest fouling rates. A permeate quality of <5 ppm could be achieved even though the oil in the feed was increased from 50 to 350 ppm of oil in water.