This paper describes a complete simulation package for simulation of granular membranes and membrane filtration/backflushing processes. It consists of two basic models, one (the sphere packing model) for the structure of granular membranes, and the other (the random network model) for the morphology of the interconnected pores in the membrane media; and procedures to use the generated model structure to simulate filtration/backflushing processes in three distinct cases, namely cake filtration (alpha much greater than alpha(p)), internal fouling (alpha much greater than alpha(p)) and a transient case (alpha similar to alpha(p)) where both internal fouling and cake build-up are important.