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Cleaner production in leather industry
发布日期:2017-01-05 浏览次数:1608

1, the main characteristics of China's leather industry


Chinese pigskin leather industry, production accounted for about 62%, ranking first in the world.


90% of tanneries are small and medium enterprises.


70% of tannery wastewater treatment, wastewater emissions accounted for about 0.3% of the total industrial wastewater emissions.


At present, the leather industry has a great demand for technology, high added value and environmental pollution.


According to the 97 year Economic Yearbook, the leather industry's annual output value of the industry and product sales in fell by 6.5% and.


2, enterprise status


China's leather industry is mostly small and medium enterprises, large leather enterprises accounted for only 10% of the total number of enterprises.


In order to promote the development of leather industry, China has established a relatively complete scientific research, personnel training, consulting services, industry management system.


The use of raw materials in leather tanning China pigskin, its output accounts for 62% of the total production, followed by cowhide, sheepskin and other soft skins.


3, production process evaluation


The tanning process mainly comprises soaking ash (soft, degreasing, unhairing), tanning, and finishing process. Most of the waste and pollutants in the wet process (liming, tanning) produced. In our country, most of the tanning factories adopt the technology of lime unhairing and chrome tanning.


4, environmental conditions


Leather industry emissions of 70 million tons of waste each year, accounting for about 0.3% of the total industrial wastewater emissions. The characteristics of tannery wastewater are as follows: the color is deep, the oxygen consumption is high, the suspended matter is more, and it contains toxic chromium and sulfide. According to the survey, at present, only 30% of the tannery enterprises to different degrees of simple treatment of waste water, other enterprises integrated wastewater directly into rivers or water bodies. Solid waste tanning industry which includes waste dander and tannery sludge. Tannery sludge has not been a good solution, still stacked or buried.


All tannery enterprises are responsible for the implementation of the policy of pollution charge and pollution punishment. However, the implementation of the standard fees vary with different regions.


According to the comprehensive wastewater discharge standards promulgated by the state (GB897888), standard of wastewater and pollutants emission China leather industry is divided into two levels. The first grade standard is used for the newly built, expanded and rebuilt tanning enterprises. The two grade standard is aimed at the existing tanning enterprises. With the increasingly severe environmental situation, in order to adapt to the new economic development model of China's industry, the State Environmental Protection Administration and the State Bureau of Technical Supervision issued a new national integrated wastewater discharge standard GB8978 - 96 in 1996, and began to perform in 1998. The new standard puts forward the annual limit standard, with the annual limit instead of the original standard to existing enterprises and new expansion of enterprise classification. It is divided into two time periods from December 31, 1997. At the same time, it replaces the national standards for the discharge of pollutants from other 17 industries, including the tanning industry.


5, market prospects and financial status:


China is an important part of the international leather market, China leather and leather products production has accounted for 10% of total world production and 11%, demand for leather products is increasing at an average annual rate of 15%, becoming the world's important leather producer and consumer.


But in recent years, some leather enterprises, especially those state-owned large and medium-sized enterprises in the economic decline, mainly due to change, can not adapt to the planned economy system to market economy system, enterprise management mechanism behind the new small and medium-sized enterprises in raw materials and market to participate in competition, pigskin tax policy change, and corporate social burden etc..


6, technical level and EST needs


China's leather technology is equivalent to the level of the world in 80s. The main difference lies in the poor quality of leather chemicals, and some even use homemade materials, seriously affecting the quality of leather, but also increased the burden of water pollution. China's leather technology update is relatively slow. The majority of small and medium-sized enterprises lack of technical personnel, low production efficiency, poor professional collaboration.


For the leather industry, the technology of environmental protection should pay attention to reduce the consumption of water in the production process, toxic substances in the waste water, as well as the following three aspects: comprehensive utilization and disposal of solid waste.


At the present stage, the recommended list of environmentally sound technologies


* saturated brine pickled fresh preservation technology of leather drum;


* environment-friendly leather chemicals (including various additives, depilatories, de ashing material, chemical material and new tanning retanning finishing material application materials, etc.);


By using a special enzyme preparation research and development production of new tanning modern microbial technology;


This new water soluble coating materials;


Hair removal technology security;


Ash removal technology of clean;


High chromium absorption technology;


No chrome retanning technology;


The circulation of water immersion;


Water recycling and reuse of wastewater from hair removal;


* with precipitation to recover waste chromium chromium, reuse;


Recycle of waste chrome liquor;


This recovery of fatty acid from defatted wastewater;


This cycle of tannery wastewater after treatment and comprehensive utilization;


The treatment of Tannery Wastewater by oxidation ditch;


Waste recycling. The comprehensive treatment technology of dander;