Important Driving Forces in Various Membrane ProcessesMain Driving ForcePressure gradientConcentration gradientGradient in electrical potentialTemperature gradientTypical Transmembrane Pressures and Recoveries for Pressure Driven Membrane ProcessSystem RecoveryMolecularMacromolecularMicroparticleMacroparticleConventional processesCoagulation/flocculationSedimentation/dissolved air flotationGranular media filtrationA membrane array. Each module could contain from a few to several thousand membrane elements.