Correlating numerical and experimental analysis for aeration in gravity driven membrane systems

Gravity driven membrane (GDM) is an alternative over conventional high energy-consuming water filtration systems. Especially in less-privileged communities with limited access to clean water or energy resources. Here, we optimize aeration mechanism for membrane recovery for GDM. Most contributions for aeration optimization focus on high pressure membrane operation, which differs for low pressure GDM. We propose a computationally efficient numerical model to be used for predicting the performance of different aeration regimes in GDM system. Time-averaged membrane shear from simulations is found to be inversely proportional to the experimental permeability drop. After validating, we present an empirically derived equation correlating shear stress for different scenarios to the expected permeability drop for GDM. The validated numerical model could predict permeability drop from CFD shear within acceptable error. To our knowledge, this is the first attempt to derive a predictive model for such application. Prolonged test using raw water was performed for the optimized aeration regime in the GDM system and the proposed empirical equation was validated for this case. Presented results provide a guide for development of anti-fouling aeration strategies for GDM systems and highlight a cost effective use of CFD for practical GDM system optimization through correlation with real membrane performance.