Substances in tap water classified by particle size mainly are suspended matter, colloidal matter, dissolved matter (ions and molecules), organic matter and water molecules themselves.
Suspended matter in tap water: particles with a diameter of 0.1μm－100μm. It can be seen to the naked eye that these particles are mainly composed of sediment, clay, protozoa, algae, bacteria, viruses and high molecular organic matters, which are often suspended in the water flow. The turbidity produced by water is also caused by such substances. Suspended matter is the main source of turbidity, chroma and odor.
Colloidal material in tap water: the particles with a diameter of 1nm-100nm are the aggregation of many molecules and ions. The inorganic mineral colloids in natural water are mainly the compounds of iron, aluminum and silicon; the organic colloidal material is mainly the humus generated by the decomposition and rottenness of animal and plant limbs. Due to the large surface area of colloidal substance per unit volume, its surface has a large adsorption capacity.
Soluble substances in tap water: the dissolved substances in water are small particles, including the total amount of various ions, molecules and compounds dissolved in groundwater (including various organic and inorganic substances), but excluding suspended substances and dissolved gases. Dissolved substances can be removed by ion exchange or desalination.
Organic matter in tap water: mainly refers to the pollutants of humic acid and acid compound in water, domestic sewage and industrial wastewater. It contains animal and plant fibers, oils, grains, dyes, organic raw materials, etc. There is a common feature of organic matter in water, that is, to oxidize and decompose, it needs to consume dissolved oxygen in water, which leads to anoxia in water, at the same time, it will produce putrefaction and fermentation, make bacteria grow, deteriorate water quality and destroy water body. Organic matter is one of the main causes of water pollution.
There are many substances in tap water, which is not suitable for direct drinking. It is recommended to use it with tap water filter.
