Optimization of membrane physical and chemical cleaning by a statistically designed approach

Membrane cleaning efficiency depends on many parameters such as hydrodynamic conditions, concentration and temperature of chemical cleaning solution, as well as sequence of cleaning. Various studies and industrial applications show that factorial design is an efficient method in optimization of operational parameters. In this study, a statistical factorial design was employed to identify more accurately the key factors as well as their interactions in both physical and chemical cleaning of ultrafiltration (UF) and reverse osmosis (RO) membranes in municipal wastewater reclamation. It was found that significant factors affecting physical cleaning of both UF and RO membranes are production interval between cleans, duration of backwash and pressure during forward flush. In chemical cleaning of both membranes, temperature and concentration of high pH cleaning solution and backwash after chemical cleaning play important roles. By using the optimized membrane cleaning methods, the cleaning efficiency was significantly improved, which can cause higher membrane filtration capacity and efficiency.