On the present situation of water resources and the present and future of sewage treatment technology.

Since ancient times, human survival has been closely related to "water". In the biochemical reactions carried out in the human body, water is the main medium, and water is also a participant in metabolic reactions, so it can be said that there is life only when there is water. Most of the area of the earth is covered by sea water, and there is a water circulation system in nature: sea water evaporates into the atmosphere and cools into clouds and rain, and the rain falls to the ground for human and all things to use, and the sewage after human social life, agriculture or industrial use is treated by sewage and returned to rivers or oceans.

In recent years, the extreme climate caused by the greenhouse effect has made the water circulation system rapidly change, frequent extreme floods and droughts, and serious imbalance between supply and demand of water resources. The frequency of heavy rainfall increased, and the turbidity of tap water soared after typhoon. The huge increase in population has also made the allocation of water resources around the world increasingly important.

The Food and Agriculture Organization of the United Nations also pointed out that the freshwater resources needed for daily drinking water, industrial development and agricultural use will face serious shortages in the future. Therefore, how to make good use of sewage treatment technology to solve the problem of water scarcity has become one of the most important issues in the 21st century.

Scientific sewage treatment technology to solve water scarcity

In view of this, countries around the world are currently investing resources in the research and development of sewage treatment technology, such as the development of advanced seawater desalination technology in Israel, the establishment of high-reuse sewage treatment recycling systems for agricultural irrigation and other uses. Singapore is also actively developing a variety of new water sources, including seawater desalination and the use of new water technology, which is the purification of domestic and industrial sewage after three layers of treatment (filter impurities, reverse osmosis, ultraviolet disinfection).

When the future sewage treatment technology standard discharge water becomes one of the important water resources, it is necessary to establish the concept of water recycling by science and technology to "use a drop of water at least twice". "Water regeneration and utilization" is the water regeneration and utilization after the treatment of domestic sewage, rainwater storage and utilization, agricultural irrigation return water, sea water, industrial sewage, etc. The theme of the United Nations World Water Day 2017 (22 March each year) is "wastewater", emphasizing the recycling of wastewater as an effective means to address the water shortage crisis in the face of climate change.

The evolution of sewage treatment technology

The water technology mentioned above, strictly speaking, should be sewage treatment technology. Sewage treatment technology can be divided into drinking water treatment and non-drinking water treatment, tap water treatment belongs to drinking water treatment, not the focus of this article, the other are non-drinking water treatment, the range is quite wide. The technology of non-drinking water treatment includes the treatment technology of people's livelihood sewage and industrial sewage, and the treatment and utilization technology of sewage recycling.

In the past, most waste and sewage treatment technologies only consider the removal of pollutants in sewage, pay attention to the quality of the discharged water after sewage treatment, and take the discharge water standard that can meet the technical specification index of sewage treatment as the main demand. These wastewater treatment technologies focus on the establishment of effective treatment procedures and the effective use of related equipment and materials.

When the recycling of useful substances in water recycling and industrial sewage treatment technology is paid attention to, the trace organic matter and inorganic matter remaining in the discharged water after traditional sewage treatment still need to be removed or recovered, then the sewage treatment plant will be transformed into a water and substance recycling plant. This involves more molecular level chemistry and chemical technology, need for different sewage treatment water quality applications and material recycling requirements, the use of different sewage treatment materials and process equipment water recycling technology, these are not only environmental engineering but also the scope of chemistry and chemical industry, is a highly integrated cross-field sewage treatment technology.

Comprehensive overview of sewage treatment technology

Sewage treatment technology research and development, in the development of sewage treatment related technologies and applications, focuses on the most complex industrial sewage treatment, from the early guidance of traditional industries for industrial sewage treatment, to now assist high-tech industries in plant sewage treatment technology and water-saving planning. In response to changes in the objective situation and future needs, we also actively establish water recycling and resource recycling technologies.