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The strictest sewage discharge standards in history have arrived! "Textile printing and dyeing wastewater treatment is about to enter hell mode?
Time：
2025-04-01
The Ministry of Ecology and Environment is preparing to introduce new standards for the discharge of water pollutants in the textile industry, and further control the discharge of wastewater from the textile industry.
There is not much time left for polluting enterprises to upgrade and transform!
Recently, it has been reported that the Ministry of Ecology and Environment is preparing to introduce new standards for the discharge of water pollutants in the textile industry, further controlling the discharge of textile industry wastewater, and planning to reserve a 2-year transition period for existing polluting units.
01
Why does the Ministry of Ecology and Environment insist on "cutting" textile printing and dyeing wastewater?
Textile printing and dyeing is a traditional pillar industry of China's national economy, as well as a typical high energy and high water consuming industry. The printing and dyeing process of 1 ton of textile requires 100-200 tons of water, and it is also a major emitter of wastewater, with an annual discharge of up to 2 billion tons. The wastewater generated during the printing and dyeing process accounts for more than 70% of the wastewater discharged by textile printing and dyeing enterprises.
According to the compilation instructions of the "Textile Industry Water Pollutant Discharge Standards (Second Draft for Soliciting Opinions)", the discharge of textile industry wastewater accounts for 9.22% of the total industrial wastewater discharge, chemical oxygen demand emissions account for 7.02% of the total industrial wastewater discharge, and ammonia nitrogen emissions account for 6.91% of the total industrial wastewater discharge.
That is to say, with the continuous development of textile enterprises in China, the current emission standards have encountered some problems in the implementation process, and it is necessary to further control the discharge of textile industry wastewater. Specifically, it includes——
Implementing standards separately is not conducive to law enforcement inspections;
Some indicators have unclear scope of application and weak standard operability;
The issue of toxic and harmful pollutants and biological toxicity risks has not received attention;
Some indicator limits and unit product benchmark drainage do not match the actual production in the industry;
The requirements for indirect discharge management cannot meet the current development model of centralized pretreatment of industrial wastewater.
In the second draft of the "Emission Standards for Water Pollutants in the Textile Industry" for soliciting opinions, it is clearly stipulated that:
Requirements for water pollutant control, monitoring, and supervision management in the textile industry;
Requirements for emission limits, monitoring, and supervision of water pollutants generated by textile industry enterprises, textile production facilities, and centralized treatment of textile industry wastewater.
Industry insiders have stated that the introduction of the "Textile Industry Water Pollutant Discharge Standards" will help promote technological progress in the textile printing and dyeing industry.
In the process of standardization, it is necessary to continuously introduce and develop new wastewater treatment technologies and equipment to meet the constantly changing environmental requirements and market demands. This helps to enhance the technological level and competitiveness of the entire industry, and promote the sustainable development of the industry
02
How to come up with the best solution for comparing four types of wastewater treatment technologies?
At present, the treatment processes for textile printing and dyeing wastewater mainly include the following four categories:
One is biological treatment processes, such as activated sludge process, biofilm process, biological contact oxidation process, etc.
The second is chemical treatment processes, such as oxidation, reduction, precipitation, etc.
The third is physical processing techniques, such as air flotation, adsorption, membrane separation, etc.
The fourth is the combination treatment process, which compensates for the shortcomings of single methods, such as biodegradation and chemical oxidation. Chemical oxidation can be used as a pre-treatment or as a deep treatment after biological methods to remove non biodegradable pollutants from wastewater.
03
How should enterprises respond under the new standards? What is the cost of upgrading and renovating?
Although according to the online monitoring data of textile dyeing and finishing enterprises in 2024, the proportion of textile dyeing and finishing enterprises directly discharging sewage is less than 5%, the basic situation of China's printing and dyeing industry is still characterized by high energy consumption, high material consumption, and high pollution.
How to achieve energy conservation, emission reduction, and clean production in the textile printing and dyeing industry has become the primary issue, and the treatment of textile printing and dyeing wastewater is particularly important.
1. Sort out the production process, control the source, and reduce pollution
The key to treating textile printing and dyeing wastewater lies in source control. For textile printing and dyeing enterprises:
One is to comprehensively sort out various energy-saving and environmental protection measures that can be taken in each production process, fundamentally reducing energy consumption and pollutant emissions.
The second is to upgrade and transform technology and equipment, such as introducing advanced foreign continuous rolling dyeing machines, rotary drum dyeing machines, overflow dyeing machines, etc., to reduce the use of dyes and additives; Alternatively, intelligent systems can be used to control the entire production process, reduce resource consumption and waste generation, and control wastewater discharge.
The third is to actively cooperate with the local ecological environment supervision department, install automatic online monitoring equipment, and actively handle alarms to ensure that various environmental monitoring indicators of the effluent are discharged in compliance with regulations.
2. Optimize end of pipe treatment to achieve good quality results
In addition to controlling from the source, efforts also need to be made in end of pipe management.
Firstly, textile printing and dyeing enterprises introduce and apply more advanced processing technologies, such as high-capacity anti pollution membrane separation technology, high-capacity, low-cost, and highly renewable adsorption technology, as well as advanced oxidation technology, biological treatment technology, etc.
Secondly, due to the advantages and disadvantages of various treatment technologies, in order to further improve the efficiency of wastewater treatment, a comprehensive combination treatment process can be adopted (which will not be elaborated here, see Chapter 02 of the article).
3. Optimize wastewater reuse and resource utilization application schemes
Textile printing and dyeing enterprises can optimize the reuse plan of printing and dyeing wastewater. Some of the water with good quality can be evaluated and reused in the production system, while the other untreated water can be used for site greening and cleaning.
For example, a textile printing and dyeing wastewater reuse project in Jiangsu adopts a hydrolysis acidification A/O ultrafiltration reverse osmosis treatment process. After the implementation of the project, the operating cost of deep treatment is 3.2 yuan/m3, which can reduce COD, ammonia nitrogen, and total phosphorus by about 780t/a, 189t/a, and 21t/a respectively each year, saving 825000 m3/a of water.
In addition, the thermal energy in printing and dyeing wastewater can be recovered through a heat pump system to heat the water that needs to be preheated at the front end, saving energy consumption and reducing operating costs for enterprises.
It is worth mentioning that regarding the cost of upgrading and transformation, the drafting team of the "Textile Industry Water Pollutant Discharge Standards" stated that——
With the development trend of industrial enterprises withdrawing from cities and entering parks, the direct discharge of sewage will be further reduced, and the change in direct discharge limits will result in relatively low upgrading and renovation costs for polluting units. Indirect discharge polluting units do not need to increase environmental protection investment to implement this standard
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