What'S The Way For Japan'S Printing And Dyeing Industry To Face Pollution

How does the Japanese printing and dyeing industry deal with the pollution problem of printing and dyeing? What is there to draw lessons from? The reporter recently interviewed Araki Hirohikaru, the technical department of Japan dyeing Association.

Araki Hirohikaru said that the biochemical oxygen demand (BOD) and chemical oxygen demand (COD) of the effluent from Japanese dyeing factories were relatively large, and generally reached 300 ~ 500ppm.

As for how to dispose of waste water, Araki Hirohikaru said: "the biological treatment method represented by activated sludge is usually used in dyeing and finishing wastewater treatment.

Activated sludge process is an economical and cheap processing method, which can remove BOD components, but sometimes it is not necessary to clean up COD components.

For this kind of waste water, it is sometimes necessary to treat it with agglutination sedimentation and pressurized floating method.

In order to carry out advanced treatment such as decolorization, some enterprises have also introduced activated carbon adsorption tower and ozone treatment device.

Current issues and new technology development

Consciously decolorizing wastewater

In introducing the decolorization link, Araki Hirohikaru said: "as is known to all, the effluent from dyeing factories is colored.

In recent years, with the development of the urban river embankment road to the public pedestrian street, the public is hoping to remove Kawa Kawazu's color.

At present, although the relevant laws and regulations have not been formulated in areas other than Wakayama, some dyeing enterprises have begun to decolorizing wastewater independently according to the wishes of residents.

When removing the color of dyeing wastewater, it is necessary to use activated carbon adsorption tower and ion treatment device.

Although technically feasible, the cost of processing is very high.

Therefore, the development of a reasonable cost of microbial decolorization technology has been highly anticipated.

In Japan, because of the difficulty of building drainage facilities, some dyeing factories in cities and towns turn dye waste water into public sewer pipes.

Landfill disposal after disposal of waste sludge

"At present, waste sludge discharged by activated sludge process and other wastewater treatment equipment is generally disposed of by landfill, resulting in a shortage of landfill sites in Japan.

As a countermeasure, more and more factories dehydrate and dry waste sludge, reduce the volume of waste sludge through combustion treatment, and then adopt landfill mode.

It is also discussed that the waste sludge can be pformed into a road paving material with water absorption after high temperature treatment above 1000 degree.

Araki Hirohikaru said, "in addition, improve the efficiency of basic activated sludge treatment.

Technological development of waste sludge volume is also advancing.

About air pollution

Countermeasures for soot control

The fuel used in boilers is the source of soot in dyeing factories.

A heavy oil, C heavy oil, city gas, LPG, coal and biofuels are all used as fuel.

"In Japan, boiler manufacturers have designed coal soot treatment equipment that meets the standards of air pollution prevention and control according to the characteristics of fuel utilization.

As dyeing factories have introduced such equipment, there will be no major problems. "

When it comes to air pollution control, Araki Hirohikaru said.

In addition, in recent years, with the increase of oil prices and changes in production load, enterprises are encouraged to replace large heavy oil boilers with small gas-fired boilers.

For example, replacing C heavy fuel oil with city gas will not only reduce carbon dioxide emissions, but also do not require flue gas desulfurization equipment.

This proves that the soot control strategy is developing in a good direction.

How to reduce (VOC) emissions

Araki Hirohikaru said that Japan made some changes to the air pollution control law in 2006, requiring that factories must combine relevant laws and regulations and the industry's independent action plan, and the total emissions of volatile organic compounds (VOC) discharged by 2010 will be reduced by about 30%.

Conversion (coating,

The toluene, two methyl formamide and other solvents used in the equipment, the resin used in printing and dyeing equipment (carbohydrates as the main component) and the ethanol used in the processing equipment as the penetrant are the main volatile organic compounds (VOC) in the dyeing and finishing industry.

Only the conversion equipment is stipulated in laws and regulations.

The Japanese dyestuff association has been involved in the VOC emission reduction initiative for a long time. It has made positive contributions to the emission reduction of volatile organic compounds (VOC), and achieved a target of 64% reduction in 2010.

As a major countermeasure, volatile organic compound (VOC) recovery equipment and incineration equipment were introduced into large-scale conversion equipment.

Other devices also actively replace solvent reagents with solution reagents.

Prohibition on chemical substances

There are no regulations to prohibit enterprises from taking the initiative to stop.

Araki Hirohikaru said that China and South Korea have already formulated relevant laws and regulations regarding the use of azo pigments to produce aromatic amines.

Japan mainly adopts the independent standards of the Federation for the prevention and control of industry. At present, relevant laws are under consideration.

The Japanese dyeing association has voluntarily ceased the use of azo pigments producing specific aromatic amines.

On the six brominated twelve alkane (HBCD), Araki Hirohikaru said: "at the meeting of the States parties to the Stockholm Convention held in April 2013, it was decided to discard (prohibit the manufacture, use and import) of the flame retardant polyester processing agent - six bromo ring twelve alkane (HBCD).

Therefore, Japan also banned the manufacture, use and import of six bromo ring twelve alkane (HBCD) in April 2014.

The Japanese dyeing association has jointly implemented six bromine ring twelve alkane (HBCD) reduction initiative since 5 years ago, and has stopped using six bromo ring twelve alkane (HBCD) as of December 2012.

In introducing the industry's suspicion of mixing PFOA and its waterproof and oil repellency agent, Araki Hirohikaru said that the Stockholm convention issued in May 2009 stipulates that waste (forbidden to manufacture, use and import) perfluorooctanoic acid is prohibited.

Therefore, Japan banned the manufacture, use and import of perfluorooctanoic acid from April 2010.

Since the structure of perfluorooctanoic acid is similar to that of PFOS, the environmental protection agency of the United States proposed in 2006 to 8 enterprises that produce fluorinated resins and fluorine-containing waterproofing and oil repellent agents. As a whole, the production of PFO class a pharmaceutical was abandoned in 2015, and the approval of 8 enterprises was obtained.

In December 2012, Japan's 2 main production enterprises stopped the production of PFO class a pharmaceutical.

In the Japanese dyeing and finishing industry, on the basis of respecting the will of manufacturers, efforts are being made to discuss with the relevant industries the replacement of pesticides.

Energy saving countermeasures and global warming

Various measures have been taken to change fuel types.

Araki Hirohikaru said that because of the close relationship between energy conservation and fuel cost reduction, Japan adopted various countermeasures, such as changing fuel types, miniaturization and decentralization of boilers, and introducing low bath ratio dyeing machines.

Every major dyeing enterprise that meets the requirements of the energy conservation law designated by the energy management plant is obliged to submit periodic energy reports every year to promote energy efficiency.

After the promulgation of the global warming act, Japan has designated the cause to report greenhouse gas emissions to the executive authorities.

In addition, the Japanese industry and the executive authorities jointly formulated the global warming action plan of self action, in accordance with the Kyoto Protocol, and strive to achieve the goal of cutting carbon dioxide emissions by 6%.

The Japanese dyestuff has been involved in the initiative in the early days and has been working to reduce carbon dioxide emissions.