Suzhou Hongyu Breaks Through The Four Major Problems Of Water Reuse In Dyeing And Printing Industry

In 2009, Hongyu energy saving and emission reduction company of Suzhou, Jiangsu, contracted the reclaimed water reuse project of Fuyi dyeing and finishing company in Changshu. After several months of stable operation, the water reuse rate of the project was more than 70%. This time, they won the bid in the new construction project of Fuxing textile and dyeing Co., Ltd. in May 2010. Hongyu company started construction of 6000 tons of printing and dyeing wastewater treatment project in May 2010, and the water reuse rate reached over 50%. At the moment, the water reuse project of Changshu Yongxin dyeing and printing plant was also put into operation, and the water reuse rate accounted for more than 70% of the wastewater discharge.

　　 Jiangsu economic and Trade Commission Textile printing and dyeing Experts said that the high concentration of printing and dyeing wastewater due to high concentration of pollutants, heavy color, water quality is very complex, can make the water reuse rate of 30%, has been quite good. Suzhou Hongyu company can raise the reuse rate of water to more than 50%. What is the "know-how" here?

Conquer four major difficulties New emission reduction Route

Suzhou Hongyu printing and dyeing Garments Co., Ltd. is a company engaged in dyeing cotton and polyester. Printing and dyeing enterprise The daily production capacity is 40 tons for printing and dyeing and finishing, and the daily printing and dyeing waste water has reached 7000 tons. As a printing and dyeing enterprise, Hongyu has become a large local wastewater discharge manufacturer. The wastewater generated by the company not only has large discharge capacity, but also has complex water quality, so it is difficult to deal with it.

In May 2007, the drinking water crisis caused by the outbreak of cyanobacteria in Taihu, located in Wuxi, raised an urgent proposition for the Taihu drainage Enterprises: how to create a new emission reduction path and further reduce the total amount of pollutants discharged on the basis of the standard discharge?

In the face of severe challenges, Suzhou Hongyu dyeing and printing company has been relying on pressure to make a good answer in the development of dyeing and cleaning technology and water reuse technology, allowing enterprises to occupy a high position in pollution reduction and win the initiative.

In the second half of 2007, Yao Peijun, chief executive of Suzhou Hongyu dyeing and printing company, organized the best troops and concentrated on the reform of production technology.

Hongyu company has encountered four difficult problems in the development of new technology for reclaimed water. But Yao Peijun led the tackling team and made great progress in research and development.

It is no easy task to reform the mature production technology and minimize the consumption of materials in the printing and dyeing process. Faced with the problem of "adjustment of alkali agents in the process of decolorization", the tackling group found that in the initial stage of operation of the reclaimed water reuse system, lime water was used as the neutralization and precipitation base of the bleaching and settling process, resulting in a low chromaticity and turbidity of the effluent. Using the reclaimed water in the printing and dyeing process, the white spots and fuzz appear on the cloth. After research and analysis, the reason is that the lime dosage is too large, so that the concentration of calcium ions in recycled water is too high. To solve this problem, after tackling the dosage of lime and caustic soda for many times, the tackling group successfully solved the problem after paying 1 million 800 thousand yuan for dyeing loss.

In the face of the problem of "interference of iron ions in reclaimed water", the decoloring agent and initial modified flocculant used by the tackling group in the reclaimed water treatment experiment are all pickling waste liquid. Although it is simple, easy to operate and easy to control, the effect of decolorization and flocculation after aeration is good. However, due to the high content of iron and manganese ions in water, the color of dyed products is seriously disturbed. At the same time, in the pretreatment of knitted fabric, iron ion is used as catalyst for hydrogen peroxide when oxygen bleaching, and it is easy to form holes in cloth. The emergence of this problem immediately attracted the attention of the tackling group. They will adjust immediately from two aspects: first, according to the principle of iron precipitation solubility product, adjust the variety and dosage of alkali agent, reduce the concentration of iron ion effluent, strengthen the decolorization and sedimentation effect; at the same time, adjust the dyeing process, most of them no longer do oxygen bleaching, and adopt refining agent high temperature refining technology; aiming at the problem that metal ions easily interfere with reactive dye dyeing, the tackling group also chooses chelating dispersant with high chelating force for metal ions, and shields metal ions as far as possible.

Faced with the problem of "excessive ionic strength and excessive salt", the tackling group found that due to the addition of a large amount of dyeing agents and fixing agents in dyeing of reactive dyes, the ions in the water will be saturated in the process of reclaimed water treatment, and the dyeing process with high salt concentration will also affect the fixation effect of dyeing cloth. In order to solve this problem, after a long period of research and repeated experiments, the team has adjusted the salt formula for promoting dyeing and fixing color, and tackled this problem, which not only reduced the amount of auxiliaries and saved the cost, but also solved the problem of high salinity. In response to the problem of "shielding against COD interference in water," the tackling group launched a fourth round of battle.

It turned out that in the whole study of reclaimed water reuse, after several dozens of experiments, the team found that as long as strict control of turbidity, chroma, hardness, pH and temperature of recycled water can effectively improve the reuse rate of reclaimed water. At the same time, the improvement of reclaimed water utilization rate has little to do with COD, total phosphorus and total nitrogen. To seize this characteristic, the tackling group also shielded COD and other pollutants by adjusting the formula of auxiliaries, so as to realize the efficient reuse of reclaimed water.

Sewage is reduced by 5000 tons a day.

After nearly a year's research, Hongyu company finally picked up the achievements of reclaimed water recycling technology. Subsequently, Hongyu invested about 8000000 yuan, and built a set of daily water treatment of 8000 tons of printing and dyeing wastewater reuse device. At present, the reclaimed water reuse system has been running normally and efficiently for over a year. After treatment, the production wastewater has met the requirements of dyeing production water steadily, so that the discharge volume of printing and dyeing wastewater has dropped from about 7000 tons in the past day to less than 1500 tons, and the rest is returned to the production process for recycling. At the same time, the quality of dyed fabrics has reached the level of international high quality products, and no complaints have been reported in cloth enterprises.

In the past, Hongyu was a major customer of the sewage treatment plant in the local town. After the completion of the reclaimed water reuse project, Hongyu company reduced more than 7000 tons of printing and dyeing wastewater to the town level sewage treatment plant and reduced more than 5000 tons at a time. The municipal sewage treatment plant did not believe that Hongyu company could complete the water reuse project, and even the environmental protection department suspected Hong Yu company suspected of stealing. As a result, Hongyu company carried out uninterrupted supervision and inspection all day and night, and carried out 24 hours of water sampling for the only outlet. In the 3 consecutive months of encryption supervision, the local environmental protection department did not find the phenomenon of stealing, only to believe in the efficiency of the reclaimed water reuse project.

Set up energy saving and emission reduction technology export company

When Suzhou Hongyu's reclaimed water reuse project was stable, they invited Jiangsu environmental protection and textile experts enthusiastically to consult the company's reclaimed water reuse system. In view of the experts' opinions on "consultation" at the scene, Hongyu company has adjusted and improved the reclaimed water reuse system and printing and dyeing process, resulting in a marked increase in the reuse rate of reclaimed water. At present, the utilization rate of reclaimed water has reached over 80%.

The new path of reusing the reclaimed water has made Hongyu company "a new world" in energy conservation, emission reduction, upgrading and improving efficiency, winning the initiative of enterprises to survive and develop.

Subsequently, Hongyu company developed a "homogenous printing and dyeing wastewater treatment and reuse technology", which was successfully passed at the provincial technical appraisal conference hosted by the Jiangsu economic and Trade Commission. Experts believe that this technology has reached the international advanced level and is the first creation at home and abroad.

The technology of printing and dyeing wastewater treatment and reuse developed by Hongyu company is not only high in gold content, but also effective in energy saving and emission reduction. In terms of saving water charges, Hongyu company had taken about 7000 tons of water per day, and now the reclaimed water volume is 5500 tons. The annual water saving is 495 thousand yuan. In the aspect of saving sewage charges, the cost of reclaimed water per ton in Hongyu company is 1.05 yuan, while the water treatment fee of one ton water treatment plant in the town sewage treatment plant is 3.2 yuan. In this way, Hongyu saves only 3 million 548 thousand yuan a year in saving sewage treatment charges. According to special statistics, Hongyu's homogenous dyeing and printing wastewater treatment and reuse technology reduces the dosage of dyeing agents and auxiliaries, and saves about 930 thousand yuan annually. In terms of energy saving, Hongyu company uses about 35 degrees of water for reclaimed water, and the higher water temperature has increased the dyeing production and dyeing temperature, and shortened the dyeing cycle. In this way, the heating up time and steam consumption of the reused water are greatly reduced, and the steam cost is reduced by about 1 million 300 thousand yuan a year. Several additivity, a year's return of 6 million 200 thousand yuan income; at the same time, in reducing COD emissions also significant benefit, a year COD emission reduction of 99 tons.

Another encouraging news is that after the water reuse rate of Hongyu company has reached 80%, the tonne of water has dropped from 180 tons to 60 tons, making the water rate per ton of cloth reach the international advanced level.

Suzhou Hongyu company has brought out the "remedial works" for the reuse of printing and dyeing wastewater. In order to increase the intensity of energy saving and emission reduction in the printing and dyeing industry, they set up Hongyu energy saving and emission reduction company to promote the technology of water reuse in the printing and dyeing industry. At present, a batch of prototype projects have been produced in the Taihu River Basin.