Recently, the national development and Reform Commission and other ten departments jointly issued the "guidance on promoting the utilization of sewage resources" (hereinafter referred to as the "guidance"), which clearly pointed out that the utilization of sewage resources should be systematically carried out in urban, industrial, agricultural and rural areas, focusing on water shortage areas and water environment sensitive areas, taking the utilization of urban domestic sewage resources as a breakthrough point, and taking the industrial and rural areas as an example In order to promote the utilization of sewage resources and achieve high-quality development, the utilization of sewage and ecological water supply are the main ways. The guidance is of great significance to promote the utilization of sewage resources and improve the efficiency of water resources utilization.

In recent years, China's sewage treatment and water pollution control have achieved remarkable results, but the proportion and level of sewage resource utilization is still low, and the amount of reclaimed water is less than 15% of urban sewage discharge. As the second water resource, sewage has the advantages of stable water quantity, controllable water quality and available nearby, which has great potential for development and utilization. Actively promoting the utilization of sewage resources can not only alleviate the contradiction between water supply and demand, but also reduce water pollution and restore water ecological security. It is a powerful measure to promote the green transformation of China's economy and society, and is of great significance to achieve high-quality development and build a new development pattern. However, from the reality, there are still many problems and bottlenecks to promote the utilization of sewage resources and realize the transformation of sewage into treasure. Especially in the stage of work deployment, we need to make careful planning.

The fourteenth five year plan and related special projects should be linked up with the guiding opinions as soon as possible. At present, all localities are working hard to draw up the "14th five year" plan, and drawing up a "roadmap" for urban population size, land use, industrial adjustment, key areas and key industries in the next five years. The key areas of sewage resource utilization proposed in the guidance include urban domestic sewage, industrial wastewater and agricultural and rural sewage. As an important means of production and living, the use of water resources is closely related to regional development. Therefore, during the preparation of the "fourteenth five year" plan, special plans for water supply and drainage, and industrial development plans should meet the requirements of the "guiding opinions" in a timely manner, analyze local weak links according to local conditions, and study the target of reclaimed water utilization rate and related major wastewater resources according to the priority The project of chemical utilization.

The application scenarios of sewage resource utilization should be excavated in time. According to the requirements of the guiding opinions, the major directions for the resource utilization of sewage after treatment include: the nearby recharge of natural water body for industrial production, municipal miscellaneous use and ecological make-up water use. When determining the utilization of water resources in different regions, it is mainly determined by the water supply quantity, water supply structure and water demand of three industries. However, after the implementation of sewage resource utilization measures, the water consumption of regions and industries will change. Some units and regions with large water consumption and low water quality requirements will give priority to the use of treated sewage, which will greatly reduce the supply of tap water and have a great impact on the local water supply structure and total water supply. The implementation of this policy during the "14th five year plan" period will lead to more application scenarios in daily life and production. For example, Tokyo encourages government buildings, schools, hospitals, hotels and other new public facilities and large buildings to install rainwater collection and utilization system. Rainwater collection and filtration facilities are set on the roof for toilets, air-conditioning equipment and watering, car washing, house cleaning, etc., greatly reducing the supply of tap water.

Urban infrastructure construction and operation should be updated. To give full play to the application value of sewage recycling in various scenarios, the construction of pipe network should keep up with it in time. At present, the "double pipe water supply system" is mostly used in international cities. For example, St. Petersburg, Florida, as a big city that fully realizes the recycling of sewage, implements the double pipe water supply system. One system transports fresh fresh water for residents' drinking and domestic use; the other system transports reclaimed water to areas with lower water use standards, and its price is about 40% of the price of tap water, which is used to irrigate parks, green spaces, lawns and clean vehicles. Another example, Tokyo, Japan has also set up two systems of drinking water and reclaimed water. The reclaimed water pipeline of reclaimed water system is famous for transporting reclaimed water for miscellaneous use, 40% of which is used for environmental water, 40% for industrial water and 8% for greening irrigation. It can be seen from the international experience that the recycling of reclaimed water puts forward higher requirements for the construction and management of urban infrastructure. In the construction of new urban areas and development zones in China, the reclaimed water treatment facilities and reuse pipe network can be arranged in advance in the planning stage, and the short pipelines can be used to supply water to the surrounding industrial water users.

To solve the problem of regulations and standards of reclaimed water quality and the problem of user payment. According to the requirements of the guidance, the local government should transfer the tail water to the surrounding water using enterprises in the nearby drainage pipe near the sewage treatment plant. In this way, the tail water discharged by the urban sewage treatment plant will be discharged to the natural water body by the reuse enterprise after resource utilization, and the responsibility subject of the drainage water quality will be changed, which will bring a series of legal problems. According to the regulations on urban drainage and sewage treatment, the operation unit of urban sewage treatment facilities shall ensure that the effluent quality meets the national and local discharge standards, and shall not discharge substandard sewage. However, it is necessary to make clear through relevant laws and regulations whether there is a problem of "responsibility transfer" after using the tail water of the sewage plant. In addition, the waste water that can be used as resources is also a factor of production, so the cost regulation should be calculated. At present, the price mechanism of reclaimed water is not perfect, and there is a lack of reasonable charging and incentive mechanism, which leads to the low enthusiasm of enterprises for the use of reclaimed water in ecological environment. The guidance requires "establishing a user payment system" and liberalizing government pricing, in order to encourage more enterprises to develop related technologies, innovate more application scenarios, and stimulate greater resource utilization market.

Source: China Environment News