Modelling of particle deposition in a submerged membrane microfiltration system

• Experiments on permeate flux, and aeration rate on particle deposition
• Modelling of particle deposition in submerged membrane with flat sheet membrane.
• Relationship of cake resistance, permeate flux, particle deposition was derived.

In this study, microfiltration of a concentrated suspension of kaolin clay was performed in an aerated tank with submerged flat sheet membranes. Particle deposition was correlated with cake resistance based on experimental results. The effects of air flow rate and permeate flux on transmembrane pressure (TMP) and on membrane resistance were studied. The experimental results show that the filtration resistance due to cake formation plays a dominant role in the total filtration resistance. An increase in permeate flux caused higher TMP development due to an increased amount of particle deposition. Conversely, an increase in air flow rate reduced TMP by detaching deposited layers back into suspension. The particle deposition under different filtration flux and air flow rates was correlated to establish an empirical formula. Based on the experimental results, a general relationship between the cake resistance, permeate flux and particle deposition was derived as Rc = 1.01 × 1012 J·wc that suggests that the cake resistance is proportional to the multiplication of flux and cake deposition. Moreover, the effect of air flow on cake porosity was observed to be more significant at low permeate flux.