Water pretreatment is the primary treatment carried out before water purification to achieve good purification results. Since most water contains a large amount of impurities such as sediment, clay, organic matter, and microorganisms, the presence of these impurities seriously affects the purification effect of water quality. To reduce or remove them, these methods are called pretreatment. Due to multiple factors such as different water quality conditions in various regions, different uses of pure water machines, different production capacities, and different system designs, the filter materials used in pretreatment also vary. The main purpose is to create a good environment before purifying water. The main methods of pretreatment are:  

1.Sedimentation: Treatment by natural sedimentation methods with large volume and low flow rate, such as sedimentation tanks. 

2.Filtration: The water to be treated flows through a device filled with special filtering materials to intercept impurities in the water and remove them. For example: multi-media filters, fiber ball filters, precision filters. 

3.Coagulation: By using coagulants such as iron, aluminum, and high-molecular substances, they react with impurities in water through flocculation and bridging to form large particle precipitates, which are then removed by other equipment. 

4.Softening: By using chemical agents or cation exchange resin methods, calcium, magnesium and iron ions in water are removed. For example: fully automatic water softeners, diaphragm valve type water softening equipment. 

5.Add chemicals or use methods such as ultraviolet light and ozone to eliminate microorganisms in water, etc. For example: ultraviolet water purifiers, ozone generators .