Abstract
Fouling constitutes one of the main issues challenging the application of membranes in reverse osmosis processes. Serious results of fouling are decrease of the permeation flux through time, decreased lifetime of membranes, more usual washings, and therefore more important use of chemical products and extra energy costs to balance out the decline in membrane permeability. A short discussion of investigations realized on fouling parameters and experiments established is given. This work aims to attract the attention on a dimensionless grouping of a restricted number of parameters that may ultimately play a role of a fouling index upon a wide span of working situations. This is done by a convenient non-dimensionalization of the equation of Ruth. The dimensionless number which is attained is named dimensionless fouling index (DFI) and may be explained as the ratio of the membrane resistance to that of the cake due to the concentration of the raw water. The validation of DFI requires doing tests subject to different conditions of membrane type and an extent of particulate and/or dissolved material. Unfortunately, the lack of appropriate equipment and the lack of all needed data to realize the necessary transformations using experimental results found in the literature make this step unattainable at this stage. (c) 2018 The Authors. Published by IASE.