A Model to Predict Granular Activated Carbon Backwash Curves

A mathematical model that produces curves for predicting the expansion of granular activated carbon (GAC) filter beds has been developed and applied to several widely used commercial GAC products. Initially, the hydraulic load required to produce a given bed expansion was assumed to be inversely proportional to the viscosity. This assumption was then modified by assuming a power law for the dependence on viscosity. The errors were sufficiently small to allow practical application of the formulae presented in this paper. The potential for application of the method was tested and is illustrated by an example.