Water treatment refers to the physical and chemical measures taken to make the water quality meet a certain use standard. The minimum standard for drinking water is formulated by the environmental protection department, and industrial water has its own requirements. 

 The temperature, color, transparency, smell, taste and other physical characteristics of water are the basic criteria for judging the quality of water. Water treatment includes physical, chemical, physicochemical and biological treatment processes and operations, and the removal of solids, organic matter, pathogens and bacteria in wastewater, and sometimes the removal of nutrients. The physical method is mainly based on filtration, precipitation, etc.; the chemical method is represented by neutralization, oxidation reaction, etc.; and the physical and chemical methods such as adsorption method and ion exchange method are mixed applications.