With the rapid development of society and economy and the acceleration of urbanization, the problem of water pollution is becoming more and more serious, and the human living environment is facing unprecedented challenges. In this context, sewage treatment, as an important part of environmental protection, is becoming more and more important.

　　1. Protect water resources and promote ecological balance. Sewage not only contains a lot of harmful substances such as organic matter and heavy metals, but also may carry pathogenic microorganisms. Direct discharge into natural water bodies will cause irreversible damage to water quality. The treated sewage can effectively remove these pollutants, reduce the pressure on surface water sources such as rivers and lakes and underground water systems, provide clean and safe living space for animals and plants, maintain biodiversity and maintain the stable operation of ecosystems.

　　Second, save water and promote circular economy. Through scientific and reasonable technological process and technical means, urban domestic wastewater that was originally abandoned or difficult to use can be transformed into renewable resources. For example, after deep purification, it can be used for industrial cooling, green irrigation and even drinking water supplement, which greatly relieves the contradiction between supply and demand, realizes the recycling of water resources, reduces production costs and improves economic benefits.

　　Third, improve the living environment and improve people's health. Untreated sewage gives off a pungent and unpleasant smell, which breeds pests such as mosquitoes and flies and seriously affects the appearance of the city; However, discharging into the sewer system may lead to pipeline blockage and waterlogging disaster. Therefore, strengthening the investment in facilities construction, improving the collection rate and meeting the discharge standards can not only beautify the urban and rural areas, but also prevent the outbreak of infectious diseases and protect people's health.

　　Fourth, help reduce carbon emissions and deal with climate change. A certain amount of greenhouse gases, such as methane, will be produced in the process of sewage treatment, but anaerobic digestion technology can be used to convert it into clean energy-biogas for power generation and heating, thus reducing fossil fuel consumption and carbon dioxide emission intensity, actively responding to the call of the national "double carbon" goal and jointly guarding beautiful homeland.

　　To sum up, sewage treatment is a great cause that benefits the present and the future, and it is related to the overall situation of national economy and people's livelihood and social sustainable development. We should fully understand its far-reaching significance, take active actions, start from me, start from dribs and drabs, and work together to make every drop of water the most precious gift of Mother Earth!