A filter press uses increased pump pressure to maximize the rate of filtration and produce a final filter cake with a water content under 65%. This is more efficient than regular filtration because of the increased filtration pressure applied by the pump that can reach anywhere between 50-200 PSI.

In addition to the filter plate filtration medium, the growing filter cake enhances removal of fine particles in the slurry. The solution coming through the filter press water bibs, called the filtrate, will be pure.

The filtrate can be drained away for safe disposal, or it can be kept in a water tank for recycled use. At the end of filtration, the solid filter cake can be removed. The whole filtration process is often controlled by electronics to make it automatic or semi-automatic.