Social and environmental protection and sustainable development have become a global issue, and the protection and rational utilization of water resources is an important part of it. With the acceleration of industrialization and urbanization, sewage discharge is increasing day by day, which brings severe challenges to the water supply environment. Therefore, it is of great significance to explore efficient, economical and environmentally friendly sewage treatment technology for improving water quality and ensuring human health.

1. Physical treatment method

Physical treatment is a method to remove suspended solids from water by physical action, which mainly includes grid interception, precipitation, flotation and other processes. These methods can effectively remove large solid wastes and some organic pollutants, and provide basic conditions for subsequent treatment. For example, the sedimentation tank can settle substances with density greater than water to the bottom to realize preliminary purification; The air flotation method is suitable for removing light oil and other low-density impurities.

2. Chemical treatment method

Chemical treatment refers to the technical means to change the state or properties of some components in sewage by chemical reaction, so as to achieve the purpose of purification. Coagulation and sedimentation, redox and acid-base neutralization are commonly used. For example, in the treatment of heavy metal wastewater, special chemicals are added to promote the deposition of insoluble compounds formed by metal ions and reduce their toxicity; Or use ozone to carry out advanced oxidation treatment on refractory organic matter to improve the quality of effluent.

3. Biological treatment method

Biological treatment is the most cost-effective and natural way, which decomposes organic substances in sewage with the help of microbial metabolism. Activated sludge process, biofilm process and wetland system are all mature application forms. They can not only efficiently remove BOD (biochemical oxygen demand), COD (chemical oxygen demand) and other indicators, but also simultaneously realize the functions of nitrogen and phosphorus removal and promote the restoration of ecological balance.

4. Resource recovery and reuse

With the progress of science and technology, people begin to pay attention to extracting valuable resources from wastewater and recycling them. For example, biogas produced by anaerobic digestion can be used as clean energy; The concentrated brine concentrated by reverse osmosis membrane technology can be used in industrial production; After proper treatment, domestic sewage can also be used as agricultural irrigation water source to maximize the utilization of water resources.

In a word, in the face of complex and changeable pollution problems, we should take comprehensive measures, choose appropriate sewage treatment technologies and schemes in combination with local actual conditions, and at the same time strengthen public education, raise the awareness of water conservation among the whole people, and jointly protect the blue planet on which we depend.