Technical Characteristics Of Wastewater Treatment In Tanning And Fur Industry

We should encourage the adoption of cleaner production processes, use pollution-free and less polluting raw materials, and adopt water-saving technologies to gradually eliminate backward technologies that seriously pollute the environment. We should completely ban 30 thousand scale sheets of leather (the scale of enterprises that break the cowhide and fine fur) should consider as appropriate, and carry out centralized tannery and centralized pollution control under the small leather making enterprises that are calculated according to natural sheets. The construction and improvement of sewage treatment facilities will lead to the comprehensive utilization of solid waste resources, and strive to make the leather and fur industry's environmental pollution problems better solved.

[trainees question]

And the characteristics of wastewater treatment technology in fur industry?

[answer] 1.3 control objectives

We should encourage the adoption of cleaner production processes, use pollution-free and less polluting raw materials, and adopt water-saving technologies to gradually eliminate backward technologies that seriously pollute the environment. We should completely ban 30 thousand scale sheets of leather (the scale of enterprises that break the cowhide and fine fur) should consider as appropriate, and carry out centralized tannery and centralized pollution control under the small leather making enterprises that are calculated according to natural sheets. The construction and improvement of sewage treatment facilities will lead to the comprehensive utilization of solid waste resources, and strive to make the leather and fur industry's environmental pollution problems better solved.

The new (expansion and expansion) tannery enterprises should adopt the two stage biochemical process to treat their process waste water and use the mature clean production process to make leather production. By the end of 2010, the existing tannery and fur wastewater should be treated by two stage biochemical treatment, and adopt the mature clean production technology and technology.

By the end of 2015, we must strive to adopt cleaner production technologies and processes in the whole industry to meet the basic requirements of cleaner production.

2. cleaner production technology and technology

Two point one

Preservation and recycling of salt

We should gradually eliminate the preservation technology of fresh skins preserved with salt and preserve the fresh skins. We should use drum impregnation salting method or dip salt pickling method.

Strictly control the use of halogenated organic preservatives, prohibit the use of arsenic, mercury, Lin Dan, pentachlorophenol, and promote the use of non-toxic and biodegradable preservatives.

2.2 freezing storage and direct processing

We should encourage the preservation of raw skins and encourage them to build tanneries near large slaughterhouses and directly process fresh skins.

2.3 low sulfur depilation and wool removal

According to the different production varieties, we gradually use the low sulfur, sulfur free enzyme depilation and low COD emission hair removal methods, and advocate the recycling of small liquid than hair removal and depilatory Liming waste liquor.

2.4 high efficiency Ash Leaching and low ammonia nitrogen deashing

Chemical and biological auxiliaries are used to improve the Liming effect, recycle the lime leaching liquid to replace the processing technology of lime, and gradually adopt the technology of no ammonium salt deashing.

2.5 salt free pickling and high PH tanning.

In the tanning process, salt free pickling (non expansion acid pickling) method and pickle chrome tanning process are gradually adopted.

2.6 low chromium high

Chrome free tanning

The white wet skin technology was popularized. The chemical tanning materials were pre tanned and pollution-free. The low chrome high absorption chrome tanning agent and chrome free tanning agent were recommended instead of chrome tanning. Retanning agents were not used or reused in the retanning process.

2.7 high efficiency fatliquoring and emission reduction

It is strictly prohibited to use internationally banned dyes containing carcinogenic aromatic amine groups, use new retanning and fatliquoring materials, improve the absorption of leather to fatliquors, and cautiously use the fatliquoring agents that can promote trivalent chromium oxidation to six valence chromium with double bonds.

2.8 environmental protection finishing, green products

Reduce the use of formaldehyde and other harmful volatile substances.

We advocate the use of new water-soluble or water emulsion finishing materials, and gradually replace solvent based finishing materials.

2.9 optimize the additives and facilitate degradation.

Non halide surfactants are used instead of halide surfactants, and biodegradable agents are used instead of non degradable additives.

3. water saving measures

3.1 accurate water consumption and elimination of waste

To strengthen the monitoring of water consumption, not only install the flowmeter at the total inlet of the enterprise, but also install the flowmeter at the entrance of the equipment with large water consumption, so as to achieve accurate water consumption according to the process, and eliminate the large opening, big rush, big washing, and no water metering, which seriously waste the extensive operation of water resources.

3.2 process water saving and source reduction

In the wet processing section, it is necessary to use the small liquid ratio process as much as possible, as far as possible to change the flow to wash the water for batch closed water washing. Under the premise of ensuring the processing needs, we should simplify and merge the water operations of the related processes, and reduce the water consumption of tonnes.

3.3 recycle water and improve water efficiency

We should strengthen the recycling of waste liquid in the process of Liming and chrome tanning, and replace the fresh water with the two level biochemical treatment as far as possible. It is used for production, environmental cleaning in factories and other production links which require less water quality, so as to improve the water reuse rate.

4. centralized leather making and centralized pollution control.

4.1 strictly prevent the tannery enterprises that have banned the annual production of 30 thousand sheets of leather under the law to resume production.

4.2 the existing tanning enterprises with an annual output of 3 to 100 thousand sheets of leather should focus on leather making and centralized pollution control.

The existing enterprises that have already concentrated on leather making should not be less than 100 thousand scale sheets, and build a centralized centralized sewage treatment facility.

4.3 new (expansion and expansion) of independent tannery enterprises, the annual output should be 100 thousand (including 100 thousand, below the same) marked above.

Encourage tannery enterprises with annual output of above 100 thousand sheets of leather to concentrate on leather making and centralized pollution control.

4.4 the areas with relatively concentrated leather making enterprises need to strengthen management and co-ordination arrangements, make plans when necessary, and carry out planning environmental impact assessment.

5. wastewater treatment process

5.1 wastewater classification treatment

5.1.1 promotes tannery wastewater classification.

Pretreatment of wastewater containing sulfide containing wastewater, defatted wastewater and chromium containing waste water can be carried out. Wastewater containing chromium must be pre treated.

5.1.2 recovery of hydrogen sulfide or oxidation of sulfide by catalytic oxidation can be achieved by acidizing process.

5.1.3 for the degreasing wastewater with high fat content, the waste oil can be recovered by acidification or air flotation can be used to separate oil from water and remove fat.

5.1.4 for the wastewater containing high chromium content in tanning workshop, suitable chromium base material and process can be used to produce chromium hydroxide precipitated by chromium. After being filtered, separated and recovered, the chromium will be treated according to the hazardous waste to prevent chromium from entering the sludge produced by the comprehensive wastewater treatment.

5.2 integrated wastewater treatment

Chromium containing wastewater must be pre treated and chromium removed before comprehensive wastewater treatment. The resulting chromium sludge is hazardous waste and can not be mixed with other wastewater treatment sludge.

For comprehensive wastewater treatment, PH should be adjusted first, then flocculant sedimentation or air floatation to remove suspended solids and filtered residues, and then treated by oxygen consumption and anaerobic biochemical treatment.

6. tannery solid waste disposal and comprehensive utilization technology

6.1 use wool to remove hair and recycle the wool. For the wool with no recycling value, the keratin can be further hydrolyzed and used to make leather chemical materials, moisturizing ingredients in cosmetics, hair nutrition agents or fertilizers.

6.2 the leather waste before tanning can be used to make gelatin and other products, such as hydrolyzing and recovering collagen, making cosmetics and making use of amino groups and carboxyl groups on their molecular chains to synthesize surfactants.

6.3 wet blue leather leftover material can be used to produce regenerated leather and remove the chromium and extract the protein, which is used as the raw material of industrial protein. Without dechroming, the leather chemicals can be reused in leather industry.

6.4 the chromic sludge recovered from the chrome containing wastewater during tanning process can be made into chrome tanning agent and can be used in tanning process after proper adjustment.

If it is not used, it must be disposed of by hazardous waste.

6.5 the chromium containing sludge produced by comprehensive wastewater treatment is identified as hazardous waste according to the disposal of hazardous waste, which is identified as solid waste disposal in general solid waste.

7. odor control

New (alteration, expansion) construction enterprises should keep away from residential areas and so on, and set up necessary protection distance; production workshop that can not meet the protection distance requirements should be closed and ventilated, and the waste gas in the workshop should be purified and discharged after reaching the standard.

The existing tannery enterprises that cause pollution of the surrounding air environment should be relocated or taken the above measures.

8. encourage research and development technologies.

8.1 encourage the development and development of cleaner production processes and equipment for tanning, especially the systematic cleaner production processes and equipment that are related to improving the quality of products, so as to achieve efficient cleaner production of leather.

8.2 encourage the development and development of floating ice preservation, radiation preservation and vacuum preservation technology in the preservation of raw leather; use of sodium sulfide instead of products in depilation process; use supercritical fluid technology and other physical processing technologies in the degreasing and other wet processing processes, such as ultrasonic technology; use high pH chrome tanning or non-toxic inorganic and organic tanning agents in tanning process; use powder coating in the finishing process, eliminate organic solvent finishing technology; use membrane technology in the process of wastewater treatment, waste water recycling, waste recovery and so on; use biotechnology in preparatory work and waste disposal process.

8.3 to encourage the development and development of low pollution, biodegradable multi species, multifunctional and series of surfactants, tanning agents, retanning agents, degreasing agents, fatliquoring agents, finishing agents and other leather chemicals.

8.4 encourage the development and development of water-saving technology and comprehensive utilization technology of solid waste in tannery production, especially the reuse technology of leather and leftover materials and the comprehensive utilization technology of sludge generated from tannery wastewater treatment.

8.5 encourage the development and development of tannery wastewater and sludge treatment technologies that are suitable for the tannery enterprises in China with low investment, low energy consumption, low operating cost and high treatment efficiency.

The above contents are compiled according to the problems encountered by the trainees in actual work, for reference. If there are any problems, please communicate with them in time.