With a tremendous amount of surface area, granular media filters are very adept at removing turbidity in water due to the adherence of colloidal particles to the granule surfaces by various mechanisms such as van der Waals forces. However, media filters need to come off-line and use a high volume of water when backwashing. Orival filters preceding granular media filters will remove a majority of suspended solids and keep the granular media filters on–line longer; thus, wasting much less water. Orival filters installed downstream of granular media filters prevent media particles from plugging process nozzles.