The Discharge Of Textile Printing And Dyeing Wastewater Is Large, Such As Recycling, And 20% Of The Total Domestic Water Consumption Can Be Saved.

"There will always be one less clothing in your wardrobe."

This does not seem to be a joke.

With the gradual improvement of living standards, shopping, buying, buying and buying has become a common occurrence in our daily life.

Especially women, buying clothes has become a big hobby. As long as they have time and ability, they will go shopping together in groups.

But when you marvel at the colourful clothes in the mall, you know that behind it is a huge pollution discharge.

Taking printing and dyeing as an example, it is understood that a ton of traditional dyes can produce more than 15 tons of waste water, and if there are other circumstances, it will be more.

The printing and dyeing industry is absolutely the "big household" in the textile industry. The daily discharge of dyeing wastewater is only 3 million to 4 million cubic meters.

If all the waste water is recycled, it is equivalent to saving 20% of the daily water consumption of the whole country.

Recently, a research report entitled "pollution should not be a new label for textile printing and dyeing industry" released by green Jiangnan found that textile printing and dyeing enterprises had a large amount of sewage discharge, low reuse rate of wastewater and difficult to deal with, and there was regional agglomeration phenomenon, mainly concentrated in two provinces in Jiangsu and Zhejiang provinces.

At the same time, in Jiangsu and Zhejiang provinces where the concentration of textile printing and dyeing enterprises is relatively high, the rate of report recovery is lower than the average value. There are many textile printing and dyeing enterprises that steal and drain pollutants and avoid supervision.

"The high degree of regional concentration is a prominent feature of the printing and dyeing industry."

Fan Yanting, a member of the research report, said: "China's printing and dyeing enterprises are mainly distributed in Southern China and East China.

Zhejiang, Jiangsu, Shandong, Guangdong and Fujian are five main producing areas of printing and dyeing in China. These areas are rich in water resources and well-developed in upstream and downstream industries.

From the perspective of the development and scale of textile printing and dyeing enterprises, Jiangsu and Zhejiang are more prominent.

Take Jiangsu Wujiang as an example, textile is not only a traditional dominant industry in Wujiang, but also an important pillar industry. It has reached 100 billion level.

The textile and dyeing industry is the earliest and internationally competitive traditional advantage industry in China, but it is also a typical high energy consumption and high water consumption industry.

The energy consumption of textile printing and dyeing industry accounts for 4.4% of the total industrial output of the country, and water consumption accounts for about 8.5%.

Traditional textile dyeing and printing not only pollutes the environment, but also produces all kinds of harmful chemical substances that cause damage to our bodies.

"The pollutants produced by textile printing and dyeing enterprises are mainly industrial waste water and industrial waste gas."

Fan Yanting explained that textile printing and dyeing wastewater has the characteristics of large quantity of water, high content of organic pollutants, large variation of water quality and low reuse rate of wastewater. It is one of the refractory industrial waste water.

At the same time, printing and dyeing wastewater contains a large number of organic pollutants, and easy to consume dissolved oxygen into the water, resulting in the destruction of water ecological balance. The effluent into the field will also make the salinization of the land.

Heavy metal salts such as chromium, lead and mercury in wastewater are difficult to be degraded by general biochemical methods.

Typical pollutants from the textile printing and dyeing industry are soot, sulfur dioxide, nitrogen oxides and VOCs (volatile organic compounds).

In this regard, fan Yan Ting explained, "spinning process will release hydrogen sulfide, carbon disulfide and sulfur dioxide as the main harmful gas substances.

In typical dyeing and finishing processes, all nodes such as weaving, dry cloth, printing drying, steaming and finalization will produce lampblack, particulates and VOCs.

VOCs emissions from China's textile and dyeing industry account for 8.8% of the total VOCs emissions from different sources, accounting for more than 30% of VOCs emissions from industrial processes.

Lack of regulations in textile printing and dyeing industry

It is undeniable that under the circumstances of the lack of regulations in the textile and dyeing industry, both water pollution and air pollution are becoming increasingly severe.

The utilization efficiency of water resources in China's textile and dyeing industry is relatively low, and the unit water consumption is 3~4 times that of foreign countries. The average content of pollutants in wastewater is 2~3 times higher than that in foreign countries.

As early as 1992, China issued and implemented the "discharge standard for water pollutants in textile dyeing and finishing industry", and strictly controlled the discharge of wastewater from textile printing and dyeing industry.

In 2012, the former Ministry of environmental protection completed the first revision of the standard. The revised standards are more stringent than before, and some new pollutant emission limits have been added.

However, Li Jia, a member of the research report, said: "the entire legal system does not cover the pollution of toxic and harmful substances. Some substances, even at very low concentrations, can also damage the aquatic ecosystem and human health."

Wastewater from textile printing and dyeing enterprises is usually discharged through centralized treatment of sewage treatment plants, but when the capacity of sewage treatment plants is limited, it becomes a "source of pollution".

The 3 phase report of green choice textile industry released by the seven environmental protection organizations such as green Jiangnan, "the new standard tests brand responsibility", has recorded a few years ago that the Linjiang sewage treatment plant in Xiaoshan exceeded the standard and discharged directly to the Qian Tang river.

There are many textile printing and dyeing enterprises in Xiaoshan Linjiang Industrial Park close to the sewage treatment plant, many of which are suppliers of international clothing brands.

"At present, the printing and dyeing exhaust emissions from the industry are mainly from the high temperature setting machine. The energy utilization rate of the domestic high-temperature setting machine is about 40% ~ 50%, far below the advanced level of 70% abroad, and there is a big space for reducing pollution."

Li Jia admitted that, compared to the particularity of the textile and dyeing industry, the existing "comprehensive emission standards for atmospheric pollutants" and "odor pollutants emission standards" set a limited number of indicators, did not fully cover the types of textile exhaust pollutants, and the national textile printing and dyeing industry air pollutants emission standards have not yet been promulgated.

In recent years, central and local governments have promulgated a series of policies and regulations to limit pollution conditions and standardize green production.

In June 2017, the discharge standard of pollutants for textile dyeing and finishing industry was assessed and passed.

In October 2018, the seminar on emission standards for air pollutants in textile and dyeing industry was held.

Enterprises have begun to explore ways to improve the efficiency of energy and equipment utilization, and adopt clean production technology to invest in wastewater reuse projects.

With the continuous improvement of information disclosure, the public is more and more involved in environmental protection activities, providing strong support for environmental information disclosure from the source.

Research report found that from the number of public reports, textile printing and dyeing enterprises exceeded the standard was reported mainly concentrated in Jiangsu and Zhejiang two provinces, which is precisely consistent with China's textile printing and dyeing industry regional concentration of high characteristics.

From the recovery rate, the average value is above 80%, and the recovery rate is 100% in areas where the number of reported cases is less than that in Fujian, Jiangxi, Hebei, Hubei and Shanxi, but the recovery rates in Jiangsu and Zhejiang are only 44% and 66% respectively.

In Li Jia's view, this shows that environmental protection in textile printing and dyeing industry is still a difficult task in the gathering areas of textile and dyeing enterprises. In addition to setting up special operations, we should constantly increase the frequency of law enforcement, crack down on illegal activities such as stealing, drain, drain, avoid supervision, and seriously exceed the standard, so as to form a high-pressure situation.

At the same time, the research report also found that in the textile and dyeing industry, the number of cases reported due to excessive water quality accounted for 97% of the total number of reports, and exhaust accounted for only 3%.

In fact, emissions from textile printing and dyeing are more subtle and difficult to monitor than wastewater discharge.

Li Jia believes that there are two reasons for the huge number of reports on waste water and waste gas reporting. One is the low emission factor (usually only soot, sulphur dioxide and nitrogen oxides) detected on the monitoring platform. The two is that the existing "comprehensive emission standards for atmospheric pollutants" and "odor pollutants emission standards" have limited targets, which fail to completely cover the types of textile exhaust pollutants, and the relevant standards are not perfect to bring resistance to public supervision.

To reduce pollution, we should develop a new mode of cooperation between NGO and environmental protection departments, enterprises and the public.

For the environmental protection department, it is suggested to strengthen and perfect the construction of key monitoring and controlling information release platform for enterprises, increase the channels for solving environmental problems, improve classification guidance and service level, and strengthen green supply chain management.

For textile printing and dyeing enterprises, it is suggested to improve the quality of pollution sources monitoring, strengthen the internal management of enterprises, actively promote technological pformation of enterprises, explore innovative development mode, and create a supply chain collaboration mechanism.