The multi-media filter is a process that utilizes one or several filtration media to pass turbid water through a certain thickness of granular or non-granular material under a certain pressure, effectively removing suspended impurities and clarifying the water. Common filter materials include quartz sand, smokeless coal, and manganese sand, primarily used to remove suspended or colloidal impurities from water, particularly tiny particles and bacteria that sedimentation techniques cannot remove. It also offers some degree of removal for BOD5 and COD. It is mainly used for water treatment to remove turbidity, soften water, and as pre-treatment for pure water, with the effluent turbidity reaching below 3 degrees.
Multi-media filter materials can be glass fiber reinforced plastic, A3 steel with anti-corrosion coating or lined with rubber, or all stainless steel. Operating modes include fully automatic and manual options.