The Sand Filter is a new-generation model made of carbon steel, stainless steel or fiberglass filter tank (depending on application) that uses a permanent sand and gravel filter media. The sand filter will remove contaminants with a specific gravity higher than 1.2, with a spherical size greater than 10 microns, up to 98.9% efficiency and with contaminants concentration from 2% by weight. Essentially, processed waste water enters tangentially or circumferentially at the top of the filter then passes through a cyclonic piping mechanism (VORTICYCLO) designed to ensure dynamic rotation of the water and to prevent any solids from settling at the top of the sand media, and agglomerating. Side diffuser plates are used in strategic locations with their leading edges angled towards the mid-point of the vessel, ensuring continuous agitation of top of media. The system is self flushing.