Water treatment methods include physical treatment, chemical treatment and biological treatment.
Physical methods include using various filter materials with different pore sizes to exclude impurities in the water by adsorption or blocking. The more important method of adsorption is to use activated carbon for adsorption. The blocking method is to pass the water through the filter materials so that larger impurities cannot pass through, thus obtaining cleaner water. In addition, the physical method also includes the precipitation method, that is, let the impurities with small specific gravity float on the water surface and fish out, or the impurities with large specific gravity settle down to obtain. The chemical method is to use various chemicals to convert impurities in water into substances that are less harmful to human body, or concentrate impurities. The chemical treatment method with a long history should be to add alum into water. After the impurities in water are collected, the volume becomes larger, and then the impurities can be removed by filtration.
Generally speaking, sewage treatment includes the following three levels: the first level treatment is to remove stones, sand and fat, iron ions, manganese ions, grease, etc. contained in sewage through mechanical treatment, such as grid, sedimentation or air flotation. The secondary treatment is biological treatment. The pollutants in the sewage are degraded and transformed into sludge under the action of microorganisms. The tertiary treatment is the advanced treatment of sewage, which includes the removal of nutrients and the disinfection of sewage through chlorine, ultraviolet radiation or ozone technology. Depending on the treatment objectives and water quality, some wastewater treatment processes do not include all the above processes.
The purified water treatment process depends on the quality of raw water.
If the raw water is municipal tap water, the general process is
Sand filtration -- activated carbon filter -- softening (optional) -- cartridge filter -- reverse osmosis -- ultraviolet disinfection -- water production
In case of ordinary surface water, sterilize and add flocculant before entering the above process.
If it is well water, add a filter to remove iron and manganese after sand filtration.