Clean and safe water is important in our daily lifes. It affects the health, hygiene and productivity of humans. Water treatment is a process that improves water quality in order to be able to use it in the end. This can be for drinking water, industrial water or irrigation. Water treatment reduced or removed contaminants and components. There are different water treatment methods. The methods range from natural processes to human and forced ways of water treatment. We distinguish physical processes as filtration and sedimentation, biological processes, such as sand filters and activated silt, chemical processes as flocculation and chlorination and the use of electromagnetic radiation as ultra violet. Coagulation ensures that floating particles coagulate on the surface. Flocculation binds particles together to form larger flakes that can be removed by sedimentation or filtration. Pathogenic micro-organisms are removed together with the flakes during sedimentation and filtration. As a final step, the water is disinfected. Disinfection aims to inactivate or kill pathogenic micro-organisms.
Water purification is the removal of organic and chemical substances from water. It is necessary to keep the surface water clean and to ensure the quality of the water. In case of water treatment for drinking water, substances are removed, including suspended matter, bacteria, algae, viruses, fungi and minerals. This action ensures that the water becomes pure enough for human consumption. Drinking water must be clear, colorless, odorless, completely safe and good taste. Water treatment is needed to make drinking water from water. The water comes from nature and can be polluted. After the water treatment, it is usual to keep residual disinfectants in the treated water to kill bacteria that cause contamination during distribution. Another water treatment is done in wastewater treatment. During this water treatment process, the contaminants are removed from wastewater or sewage water and liquid waste water is produced. This liquid waste water is then again suitable as a sludge in nature.