The methods of water treatment include physical treatment and chemical treatment. The way of human water treatment has a long history. The physical method includes the use of various filter materials with different pore sizes, and the use of adsorption or barrier methods to exclude impurities in the water. The most important adsorption method is activated carbon. The blocking method is to pass the water through the filter material, so that the larger impurities cannot pass through, so as to obtain relatively clean water. In addition, the physical method also includes the precipitation method, that is, the impurities with a small specific gravity are floated on the surface of the water to be fished out, or the impurities with a large specific gravity are precipitated below, and then obtained. The chemical method is to use various chemicals to convert the impurities in the water into substances that are less harmful to the human body, or to concentrate the impurities. The chemical treatment method with the longest history can be regarded as adding alum to the water. After the impurities in the water are collected, the volume changes. If it is large, the filtration method can be used to remove impurities.