Thread Content
I. Generation of printing and dyeing wastewater abroad In regions where the textile printing and dyeing industry is well-developed, such as Busan in South Korea, Osaka in Japan, Milan in Italy, and Mexico, printing and dyeing enterprises are concentrated, resulting in a relatively large amount of printing and dyeing wastewater. At the same time, industrial chains have naturally formed in these areas, with raw material production and supply facilities located in these regions and their surrounding areas to serve as upstream suppliers； Production and market sales of downstream products such as textiles, clothing, and accessories ； The three together form a relatively complete industrial chain. This type of \"sectoral\" economy, characterized by relatively concentrated production, large output, a large market scale, and significant sales influence both domestically and internationally, holds great importance for the development of the dyeing and finishing industry. This is also similar in the domestic market. 1. Regarding the handling methods, there are mainly two types. Countries such as Italy and Japan use a combination of plant-based treatment and integrated municipal wastewater treatment for the treatment of printing and dyeing wastewater. After preliminary treatment of the printing and dyeing wastewater to meet certain standards, it is mixed with urban sewage and sent to a wastewater treatment plant for further processing. This can improve the effectiveness of subsequent treatment; if there are many dyeing and printing factories, centralized treatment can be used to meet the emission standards. Due to the lack of industry concentration in Germany, a single plant-based processing approach is generally used. A wastewater treatment plant is built in the printing and dyeing factory to treat the wastewater generated there. Thanks to the relatively good practices in clean production and water resource recycling, the treated water meets the discharge standards. Furthermore, Germany also has low levels of discharge of dyeing and printing wastewater, and its treatment technologies are quite advanced; some factories even achieve \"zero discharge\". 2. Regarding treatment technologies, printing and dyeing wastewater is primarily characterized by organic pollution; therefore, biochemical methods are the main approach used for its treatment. Sulfur dyes are banned abroad. For wastewater volumes that are small, mechanical equipment is employed, while for larger volumes, structural facilities are used. From a theoretical perspective of treatment technologies, there doesn’t seem to be much difference, but the level of technical sophistication, degree of automation, and quality of equipment are higher than those in domestic settings. II. Differences in the treatment of printing and dyeing wastewater between China and other countries Based on what is known, in developed countries, printing and dyeing wastewater is treated effectively, so no major problems have arisen. There are no reports of severe pollution in rivers and seas; then why is pollution from dyeing and printing wastewater so serious in China? The differences in the treatment of dyeing and printing wastewater at home and abroad mainly lie in the following aspects: 1. Differences in environmental protection legislation and enforcement. Environmental protection legislation is very strict abroad, with severe penalties imposed on companies and individuals who pollute the environment. Our country’s environmental protection legislation is not yet sufficiently developed and has not reached the standards of developed countries. Moreover, various factors interfere with the enforcement process, resulting in insufficient enforcement efforts. 2. Different product grades result in different profits, and therefore different investments in environmental protection. China is a developing country; its printing and dyeing products are of relatively low quality, focusing on mid-to-low-end products, with very low profits. For example, in our country, the processing cost for dyeing one meter of fabric is only 0.4–0.5 yuan, with some rates even lower. In contrast, the printing and dyeing products manufactured in developed countries are of higher quality, carrying a greater added value, which results in higher profits for those products. Take a certain foreign-owned dyeing factory in China as an example: the processing cost there for one meter of fabric is over 10 yuan. Therefore, developed countries invest more in the treatment of printing and dyeing wastewater; in contrast, China allocates relatively less funding to this area. In China, the investment required for urban sewage treatment plants is, in principle, 3,000 yuan per ton of water treated. Thus, building a sewage treatment plant with a capacity of 100,000 tons per day requires an investment of around 100 million yuan. For printing and dyeing wastewater treatment plants, which are much more complex to operate, the cost per ton of water treated is only 1,000–1,200 yuan. As a result, there are significant differences in terms of standards, quality, level of automation, and operating costs. 3. Differences in concepts and understanding of clean production and resource recycling At present, the concept of clean production is being applied more and more in enterprises, with the aim of implementing it throughout the entire production process in order to minimize environmental pollution and damage. However, looking at the development situation in our country, there are few enterprises that truly implement clean production in an effective manner; on the contrary, resource waste occurs from time to time. Abroad, the effort and scope put into implementing clean production are significant; activities to promote clean production in enterprises have been carried out nationwide, yielding excellent results. Resource waste in the production process has been significantly reduced, the utilization rate of recycled water has increased, useful resources from waste materials are recovered, and product costs have been lowered. All these demonstrate the importance and necessity of implementing clean production. 4. Different management levels: Due to differences in awareness of environmental protection, economic constraints, and local protectionism, there are significant variations in management practices between domestic and foreign entities. 5. Highly polluting processes are being introduced in developing countries from abroad. The alkali reduction process causes particularly severe pollution, with COD levels as high as 20,000–80,000 mg/l ； "The production of island silk causes very little pollution, but when it is used, the COD level of the wastewater generated can reach 20,000–100,000 mg/l. Other countries push those processes that cause high levels of pollution to developing countries, while they themselves produce high-quality products that generate less pollution and thus yield higher profits. Taking all of the above into account, the differences in the treatment of domestic and foreign textile printing and dyeing wastewater are caused by various factors such as technical, cognitive, managerial, and economic aspects. Therefore, solving this problem is a systematic task that requires collaboration among governments, enterprises, research institutions, schools, and other parties. True resolution of the pollution problem caused by printing and dyeing wastewater requires cooperation among the **Development and Reform Commission**, environmental protection agencies, industry associations, and manufacturing enterprises.