Polyaluminum chloride treatment 0.3-5μm fine particle coagulation effect in the treatment of fine particles of 0.3-5μm coagulation effect, in the treatment of similar size impurities, the filter can be selected with 5μm filter accuracy, but for 0.3 ~ 5μm between Fine particles and colloids are difficult to remove using conventional filtration techniques described above. Although ultrafiltration of these particles and colloids have an absolute removal, but the hollow fiber ultrafiltration membrane is extremely serious harm. In particular, colloidal particles with a charge, is a polymer of molecules and ions, so colloids can exist stably in water, mainly due to the same-sex colloidal particles mutually exclusive results. Charged material (flocculant), which is opposite to colloidal particles, is added to the raw water to break the stability of the colloidal particles, so that the charged colloidal particles are neutralized into electricity and the dispersed colloidal particles are condensed into large lumps , And then use the filter or settlement can be relatively easy to remove. In the polyaluminum chloride added at the same time, can be added coagulant, such as the PH regulator lime, sodium carbonate, chlorine and bleach oxidant, water and cement coagulant sub-class polymerization of aluminum chloride, etc., to improve the coagulation effect. When the water contains suspended solids, colloids, microorganisms and other impurities, will make the water a certain degree of opacity, the opacity of the opacity of the light transmission will have an impediment, this optical effect and the number of impurities, size and shape related. Measurement of water turbidity is generally expressed as degree of corrosion, and provides 1mg / lSiO2 turbidity produced by 1 degree, the greater the degree, indicating more impurity. In different areas of the turbidity of water have different requirements, for example, for general domestic water, turbidity should not exceed 5 degrees. Because the measurement of turbidity is to measure the light quantity, color, opacity, the size, quantity and shape of the light reflected by the water particles through the raw water through the raw water, the relationship between the turbidity and the suspended solids is random, for less than A few microns of particles, turbidity and can not be reflected.