Filtration is the process of removing all pollutants causing sediment, turbidity, color, taste and odor from the water through filters.
Sediment and Turbidity: Sediment and turbidity in water are caused due to suspended solids. The source is sand, mud and collapsed salts. They have different particle sizes and are suspended in water. They precipitate in boilers, making heat transfer difficult and causing blockages in pipes. They can be easily removed from the water by physical processes such as filtration and precipitation. Turbidity is expressed in NTU (Nephalometric Turbidity Units), JTU or FTU units. Its permitted value is 5 NTU in Turkey Drinking Water Standards (TS-266).
Color: the color formation in water is caused by iron (Fe) and manganese (Mn) in addition to organic substances. Water containing Fe and Mn make stains on fabrics, clothes and porcelain articles. Iron makes brownish while manganese makes gray-black stain. Fe and Mn are precipitated with chlorine and can be easily removed from the water. In addition, organic substances also cause a yellowish appearance in water. Color is measured in Pt-Co (Plain- Cobalt) unit. The permissible value according to TS-266 is 5 Pt-Co .
Taste and odor: The most important active substances causing taste and odor formation in water are active organic substances followed by chlorine. Organic substances are generally formed by decomposition and degrading of organisms such as algae, viruses, bacteria and algae in water and cause undesirable taste and odor in water. Chlorine is used for disinfection and precipitation of heavy metals (such as Fe and Mn). It has its own smell and taste. After these procedures, it must be removed from the water. Chlorine can react with organic substances in water to form harmful compounds. (such as chloramine , chlorophenols and etc.) It also has a corrosive effect and lowers the pH of the water. According to TS-266, water should be odorless and tasteless.