Thinking and suggestions on the problem of wastewater treatment resource utilization



Industrial wastewater has the characteristics of complex types, strong pollution, difficult treatment, and great harm, and has always been a headache for environmental protection management departments. The wastewater mainly comes from petrochemical industry, coal mining, paper industry, iron and steel industry, etc. In 2019, the total discharge of industrial wastewater in China was about 25.2 billion tons, and the overall reuse rate was not high, and basically it was a standard discharge.

In 2015, the "Environmental Access Conditions for Modern Coal Chemical Construction Projects" strengthened water-saving measures, reduced the amount of fresh water, and gave priority to the use of mine drainage water and recycled water in areas where conditions were met, and prohibited the use of groundwater as production water. Sea water should be used as circulating cooling water in coastal areas, and water-saving technologies such as air cooling and closed cycle should be preferred in water-scarce areas. The salt sludge produced by wastewater treatment which cannot be used as resources shall be temporarily managed as hazardous waste; Products sold as by-products shall meet the requirements of applicable product quality standards and ensure that they do not create environmental problems when used as products.

From the level of policy control, in November 2016, The General Office of the State Council issued the "Implementation Plan for the Control of Pollutant Emission Permit System", marking the official launch of the reform of China's emission permit system. Since December 2016, The Ministry of Ecology and Environment has successively issued the "Notice on the Implementation of the Comprehensive Emission Plan for Industrial Pollution Sources to meet the Standards", the "Interim Provisions on the Management of Emission Permits", and the "Close thousands of thermal power plants, The paper industry and the Beijing-Tianjin-Hebei pilot city overhead source emission permit management Notice ", "Fixed Pollution Source Emission Permit Classification Management List (2017 edition)", "Emission permit Management Measures (Trial)" and other documents, improve the relevant provisions of the emission permit application, issuance, implementation, supervision of the whole process, and further improve the operability. On April 7, 2017, the first national unified code of pollutant discharge permit was issued by the Ecological Environment Protection Department of Hainan Province. Pollutant discharge permit is the only administrative permit for enterprises and institutions to discharge pollutants during the production and operation period, enterprises and institutions must be certified to discharge pollutants, one enterprise one certificate, and industrial wastewater discharge tends to be standardized. China is accelerating the construction of a new environmental management system based on emission permits, and more than 330,000 certificates will be issued by the end of 2020. The emission permit system will clarify the responsibilities of all parties, strengthen supervision, implement the integrity responsibility of enterprises and the responsibility of law-abiding subjects, and promote enterprises to shift from passive governance to active prevention, thus promoting the development of environmental protection industry and the research and development of new technologies.

In 2017, the Ministry of Industry and Information Technology of the National Development and Reform Commission issued the "Modern Coal Chemical Industry Innovation and Development Layout Plan", "Strengthen the management of the whole water system, encourage the use of waste water, water, mine water reuse technology and air cooling, closed cycle cooling water system and other water-saving technologies, implement strict water quota standards, and constantly reduce the intensity of water resources consumption. Improve utilization efficiency."

In October 2017, the Ministry of Ecology and Environment, the National Development and Reform Commission, and the Ministry of Water Resources jointly issued the "Key River Basin Water Pollution Prevention and Control Plan (2016-2020)", which decomposed the "Ten water quality goals" into each river basin, clarified the key directions of pollution prevention and control in each river basin and the water environment protection priorities in the Beijing-Tianjin-Hebei region and the Yangtze River Economic Belt, and implemented the land control unit. Based on the 341 water ecological control areas and 1,784 control units, 580 priority control units have been selected and further subdivided into 283 water quality improvement units and 297 units to prevent degradation, and refined management has been implemented by classification and classification. In accordance with the "Water Ten" deployment, the former Ministry of Environmental Protection and the provincial people's governments signed a water pollution prevention target responsibility letter, and formulated protection targets by river basin and sub-region. In 2017, the Law on the Prevention and Control of Water Pollution was revised, the Regulations on the Implementation of the Environmental Protection Tax Law were officially promulgated, the emission permit system and the "front-runner system" for resources and the environment were implemented, and the reform of environmental monitoring continued to advance, strengthening the environmental quality responsibility of governments at all levels, increasing the enthusiasm of local governments to protect the environment, and encouraging enterprises to shift from passive governance to proactive prevention. Forcing the green transformation of enterprises, thereby promoting the development of environmental protection industry and the research and development and application of new technologies.

In the report to the 19th National Congress of the Communist Party of China, it was proposed to promote green development, build a market-oriented green technology innovation system, and develop and expand clean production and clean energy industries. The "13th Five-Year Plan" energy conservation and environmental protection Industry Development Plan also proposed to accelerate the development of energy conservation and environmental protection industry into a pillar industry of China's national economy. The recycling of industrial wastewater is the mainstream and the trend of The Times.

In September 2019, the National Development and Reform Commission, the Ministry of Ecology and Environment, and the Ministry of Industry and Information Technology jointly issued the "Cleaner Production Evaluation Index System for Sewage Treatment and Recycling Industry", which put forward a clear evaluation index system for cleaner production in sewage treatment and recycling industry, guiding and promoting enterprises in sewage treatment and recycling industry to implement cleaner production according to law and improve resource utilization rate. Reduce and avoid the production of pollutants, protect and improve the environment.

On January 11, 2021, the National Development and Reform Commission, the Ministry of Ecology and Environment, the Ministry of Science and Technology, the Ministry of Industry and Information Technology and other ten ministries and commissions jointly issued the "Guiding Opinions on Promoting the Resource Utilization of Sewage" (referred to as the "Opinions"), which put forward specific requirements for the resource utilization of industrial wastewater. The "Opinions" pointed out that: to carry out enterprise water audit, water efficiency standard and water-saving transformation, promote the recycling of industrial water within enterprises, and improve the reuse rate. Promote the integration and optimization of water use systems among enterprises in the park, and realize serial water use, differentiated water use, multi-use of one water and cascade utilization. We will improve the construction of wastewater treatment facilities in industrial enterprises and parks, improve operation and management, and ensure that industrial wastewater is discharged up to standards. We will carry out water quality monitoring, evaluation and water management for the recycling of industrial wastewater, and encourage local and key water enterprises to build smart management platforms for the recycling of industrial wastewater.

At present, China's sewage resource utilization is still in the initial stage, the development is insufficient and unbalanced, the overall utilization level is not high, and there is still a large gap with the requirements of building a beautiful China, and there are also problems such as imperfect standards, imperfect policies, and the level of technical equipment to be further improved. The Opinions put forward that the systematic utilization of sewage resources in urban, industrial, agricultural and rural areas should be carried out to comprehensively promote the utilization of sewage resources in China and achieve high-quality development. The key areas of sewage resource utilization include urban domestic sewage, industrial wastewater, agricultural and rural sewage, etc.

It is clear that by 2025, the national sewage collection efficiency will be significantly improved, the county and urban sewage treatment capacity will basically meet the needs of local economic and social development, and the sewage treatment in water environment sensitive areas will basically be upgraded; The utilization rate of recycled water in water-scarce cities at the prefecture level and above has reached more than 25%, and that in the Beijing-Tianjin-Hebei region has reached more than 35%. The reuse of industrial water, manure of livestock and poultry and the utilization of tail water resources in fishery and breeding have been significantly improved. A policy system and market mechanism for the utilization of sewage resources have been basically established. By 2035, a systematic, safe, environmentally friendly and economical sewage resource utilization pattern will be formed.

In order to ensure the effective implementation of the resource utilization of sewage in key areas, the "Opinions" also deployed and implemented key projects such as the construction of sewage collection and resource utilization facilities, regional recycled water recycling projects, industrial wastewater recycling projects, agricultural and rural sewage use promotion and treatment projects, sewage near-zero discharge scientific and technological innovation pilot projects, and comprehensive demonstration of sewage resource utilization pilot projects. It is proposed to improve the system and mechanism of sewage resource utilization from five aspects: perfecting laws and regulations, constructing policy system, perfecting price mechanism, perfecting financial policy and strengthening scientific and technological support.

The "Opinions" proposed that conditional industrial parks should be encouraged to plan the comprehensive treatment and resource utilization of wastewater, establish point-to-point water use systems between enterprises, and realize the recycling and graded reuse of industrial wastewater. Focusing on high-water consumption industries such as thermal power, petrochemical, iron and steel, nonferrous metals, paper making, printing and dyeing, organize the utilization of wastewater within enterprises, create a number of industrial wastewater recycling demonstration enterprises and parks, and drive enterprises to improve water efficiency through typical demonstrations.

We will encourage the implementation of scientific and technological innovation pilot projects for near-zero sewage discharge. Select representative national high-tech industrial development zones to carry out comprehensive integration and demonstration of technologies, develop and integrate low-cost, high-performance industrial wastewater treatment technologies and equipment, and create demonstration models of sewage resource technology, engineering and services, management, and policies.

Basic principles of sewage resource utilization

Sewage resource utilization includes renewable water utilization, resource recycling and energy conversion and utilization, which needs overall research, overall planning and coordinated promotion. The utilization of recycled water should adhere to the basic principles of "water saving priority, overall promotion" and "according to local conditions, classified policies".

1. Give priority to water saving and promote it as a whole.

The utilization of recycled water is an important part of water-saving work, and it should be included in the unified allocation of water resources, the formation of a scientific and reasonable price mechanism and incentive policies, and the overall promotion of the utilization of sewage resources.

2. Adopt policies according to local conditions and categories.

Different from the drinking water system that supplies water according to unified water quality, the utilization of recycled water should adhere to the quality, quality, demand, and quality control. Different regions should scientifically and accurately determine key areas, ways and modes of utilization according to their respective water resources, water environmental endowments, development needs and economic and technological levels.