About printing and dyeing wastewater

      In the industrial industries, textile printing and dyeing industry COD emissions ranked fourth.

Among the four major COD emission industries in China’s industrial industry, from 1998 to 2003, the proportion of COD emission in papermaking and food industry decreased year by year, while the proportion of COD emission in textile printing and dyeing and chemical industry increased year by year, among which the proportion of textile printing and dyeing industry increased from 4.7% to 5.6% in 2003, rising by 0.9% in five years.

According to statistics, in 2003, the total amount of textile industry wastewater discharge is 1.413 billion tons, of which printing and dyeing wastewater is about 1.13 billion tons (accounting for 80% of the textile printing and dyeing wastewater), due to the dyeing and finishing process produced a large amount of wastewater, generally up to 70% ~ 90% of the water consumption of printing and dyeing enterprises.

At present, our country produces 4 ~ 5 tons of wastewater for every 100 meters of cloth dyed.

And with the growth of China’s textile export output is bound to bring an increase in the amount of wastewater.

The printing and dyeing wastewater is composed of additives, dyes and slurry discharged from the dyeing and finishing process, and is not toxic.

Due to printing and dyeing wastewater chroma is emitted from dye, printing and dyeing processing process, about 10% ~ 20% of dye waste water discharge, the dye wastewater can absorb light, reduce the water transparency, and microbial effects to aquatic organisms, is not conducive to water self-purification, caused the pollution on the vision at the same time, serious can affect human body health.

And with the increase of design and variety, dyeing and finishing technology is constantly updated, some of which lead to the aggravation of pollution.

For example, in recent years the popular alkali reduction process, due to a large number of terephthalic acid in the fiber is dissolved, resulting in a significant increase in COD content, the COD in the wastewater can reach 20000 ~ 80000mg/L;

On the same principle, the COD in the wastewater of island silk process is as high as 20000 ~ 100000 mg/L.

The adoption of these new processes for printing and dyeing wastewater treatment increased the difficulty.

Some enterprises have poor quality environmental protection facilities and despise operation and management.

Due to the unwillingness of enterprises to invest in sewage treatment facilities reasonably, some sewage treatment facilities have poor quality in design and construction, short process flow and poor equipment performance.

Wastewater treatment is a high technical content of the system engineering, from the design, construction, equipment selection, commissioning to the production and operation of each link all need professional knowledge and strict standards, and in the production process according to the change of water quality at any time to adjust, need specialized technical personnel practice.

But because the enterprise does not pay attention to this, so the technical personnel are equipped with basic vacancy, more lack of due training and management.

Therefore, the printing and dyeing wastewater treatment industry is in urgent need of formal professional environmental protection companies, guided by the scientific concept of development, the full implementation of the printing and dyeing industry operation management technology, improve the overall level of printing and dyeing water treatment in China.

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