Fouling represents a bottleneck problem for promoting the use of membranes in filtration and separation applications. It becomes even more persistent when it comes to the filtration of fluid emulsions. In this case, a gel-like layer that combines droplets, impurities, salts, and other materials form at the membrane’s surface, blocking its pores. It is, therefore, a privilege to combat fouling by minimizing the accumulation of these droplets that work as seeds for other incoming droplets to cluster and coalesce with. In this work, we explore the use of the newly developed and novel periodic feed pressure technique (PFPT) in combating the fouling of ceramic membranes upon the filtration of oily water systems. The PFPT is based on alternating the applied transmembrane pressure (TMP) between the operating one and zero. A PFPT cycle is composed of a filtration half-cycle and a cleaning half-cycle. Permeation occurs when the TMP is set at its working value, while the cleaning occurs when it is zero. Three PFPT patterns were examined over two feeds of oily water systems with oil contents of 100 and 200 ppm, respectively. The results show that the PFPT is very effective in minimizing the problem of fouling compared to a non-PFPT normal filtration. Furthermore, the overall drops in permeate flux during the cleaning half-cycles are compensated by appreciable enhancement due to the significant elimination of fouling development such that the overall production of filtered water is even increased. Inspection of the internal surface of the membrane post rinsing at the end of the experiment proves that all PFPT cycles maintained the ceramic membranes as clean after a 2-h operation. This can ensure a prolonged lifespan of the ceramic membrane use and a continuous greater permeate volume production. The advantage of the PFPT is that it can be implemented on existing units with minimal modification, ease of operation, and saving energy.

A comprehensive study using a novel aluminum oxide microfiltration (MF) membrane and a thorough analysis of the effects of various operating conditions on the treatment of produced water were carried out. To set up the experiments and optimize the process parameters, an L9 orthogonal array of the Taguchi method and the larger-the-better target group analysis method was used. The impacts on filtrate flux and fouling control of operating conditions such as pH, temperature, crossflow velocity (CFV), and transmembrane pressure (TMP) were examined. Optimum operating conditions were determined to be 50°C, 1.8 bar, $1.8\mathrm{m}/\mathrm{s}$ , and a pH of 5 and allowing for a maximum flux of $975\mathrm{L}/\mathrm{h}·{\mathrm{m}}^2$ . The microfiltration (MF) membrane showed an oil-rejection rate of 98.25%, and the CFV was considered to be the most significant operating variable contributing to the regulation of the flux. Furthermore, 97% recovery was achieved with a mixture of cleaning solutions combining NaOH and ${\mathrm{HNO}}_3$ . Two flux decline models were used to interpret the data including the Hermia and an artificial neural network (ANN). Hermia’s cake-forming process had the average highest correlation with permeate flux decline data for the nine experiments ($\mathrm{R}2=0.83$ ). Using ANN simulation, the best results were obtained with two hidden layers and 25 neurons in each layer. Its performance in terms of the mean squared error as a percentage of the maximum flux was 0.4%.

In this comprehensive study, a seven-channel ultrafiltration (UF) titania membrane was used to investigate the impact of the pulsatile cleaning process on the crossflow filtration system. Seventeen experimental runs were performed for different operating conditions with a transmembrane pressure (TMP) varying from 0.5 to 1.5 bar, a crossflow velocity (CFV) ranging from 0.5 to 1 m/s, and pulsatile parameters within an interval varying from 60 to 120 s with a duration of 0.8 s, and collecting membrane permeate flux and volume data. The optimized operating conditions revealed that a TMP of 1.5 bar, a CFV of 0.71 m/s, and a pulsatile cycle of 85 s were the best operating conditions to reach the highest steady permeability flux and volume of 302 LMH and 8.11 L, respectively. The UF ceramic membrane under the optimized inputs allowed for an oil-rejection ability of 99%. The Box–Behnken design (BBD) model was used to analyze the effect of crossflow operating conditions on the permeate flux and volume. The analysis of variance (ANOVA) indicated that the quadratic regression models were highly significant. At a 95% confidence interval, the optimum TMP significantly enhanced the flux and permeate volume simultaneously. The results also demonstrated a positive interaction between the TMP and the pulsatile process, enhancing the permeate flux with a slight impact on the permeate volume. At the same time, the interaction between the CFV and pulsatile flow improved the permeability and increased the permeate volume.