The methods of water treatment include physical treatment and chemical treatment. 干净 的水。 Humans have been treating water for many years. Physical methods include the use of various filter materials with different pore sizes, and adsorption or blocking methods to exclude impurities in water. The more important of the adsorption methods is activated carbon adsorption. The barrier method is to pass water through the filter material, so that larger impurities cannot pass through, and then cleaner water is obtained. In addition, the physical method also includes a precipitation method, that is, impurities with a small specific gravity are floated on the water surface to be removed, or impurities with a large specific gravity are precipitated underneath, and then obtained. The chemical method is to use various chemicals to convert impurities in the water into substances that are less harmful to the human body, or to concentrate the impurities. The oldest chemical treatment method can be regarded as adding alum to the water. After the impurities in the water are collected, the volume changes. Large, you can use the filtration method to remove impurities.