Impurities in the water include heavy substances, suspended solids, colloids and solutes.
Heavy materials such as water grass, garbage, large aquatic organisms, gravel in waste water, and large amounts of dirt.
In the water supply engineering, the coarse impurities are removed from the facilities of the water intake structure and are not included in the water treatment range.
In wastewater treatment, the removal of large impurities generally belongs to the pretreatment part of water.
Suspensions and colloids include sediment, algae, bacteria, viruses, and insoluble materials that are present in water and in the process of water treatment.
Solvents have inorganic salts, organic compounds and gases.
There are many ways to remove impurities in water, and the application scope of the main method can be roughly divided according to the granularity of impurities (figure 1).
The water treatment process is very different because the impurities contained in the original water are very different from that of the finished water.