Earthtek - Pressure Sand Filter

Adsorption differs from the occlusion in that occluded particles are removed from the flow because they are too large to pass through a physical restriction in the media. Occluded particles are held in place by the flow of the water as they are trapped against a restrictive surface.

The term “depth filtration” generally refers to filtration that occurs by the adsorption of suspended particles onto the surface of the media, throughout the media layer. The entire thickness of the media layer is used, instead of just the media bed surface (surface filtration or occlusion). During surface filtration, only the influent surface of the media bed is actually removing particles.

In order to achieve efficient filtration, particles must slow down enough to be held on the surface of a substance. High flows can prevent adsorption due to a lack of surface interaction time. Secondly, sufficiently high flow can shear adsorbed particles off the filtering media.

High rate automatic backwashing sand media filters are designed for general-purpose water filtration of relatively moderate flows. These permanent media automatic backwashing filters will remove organic and/or inorganic suspended solids down to 5 microns in size depending on the type of media used.

Pressure vessels are made of carbon steel or FRP with sand or other filtration media. These filters are cleaned using a backwash flow. During a backwash cycle, the filter bed is lifted and fluidized to remove accumulated particles. After the backwash cycle, the filter bed is allowed to settle. While it settles, the filter bed media will classify with the heaviest media particles settling first, and the lightest particles settling on the top.

Our standard single media sand filters utilize a vertical side shell depth of 24”. Deep bed sand media filters with are also available.

EarthTek sand media filters feature fusion bonded epoxy linings, automatic valves, solid-state automatic controls and stainless-steel underdrains.

Standard systems are shipped assembled on structural steel skids for easy installation and start-up. Standard inlet and outlet connections are solvent-weld PVC socket or flanges.