Analysis Of Problems Related To Leather Industry And Pollution

< p > < strong > 1, < a target= "_blank" href= "http://www.91se91.com/" > leather < /a > the nature of wastewater < /strong > /p >

< p > leather industry is an industry which produces a lot of sewage. Tannery sewage is not only large, but also a complex and high concentration organic waste water. It contains a lot of toxic and harmful substances such as lime, dyestuff, protein, salt, oil, ammonia nitrogen, sulphide, chromate, and wool, pomace, mud and sand.

CODCr, BOD5, sulfide, ammonia nitrogen and suspended solids are very high. It is a kind of industrial wastewater which is difficult to control.

In leather making, due to the difference of raw material, processing technology and finished products, the quality of sewage is very different, especially the difference of COD. In terms of goat skin and sheepskin, the difference of COD is between 1800 and 6100mg/l. Due to the use of a lot of degreasing agents, fatliquoring agents and surfactants in tanning production, sewage is treated by conventional aeration aerobic activated sludge process, resulting in a large number of bubbles, and activated sludge will run away with the foam.

Therefore, when conventional activated sludge process is used in tannery sewage treatment, it is necessary to adjust the process appropriately.

< /p >

< p > 95% of the existing sewage treatment facilities in the tannery industry in China are all up to the two level emission standards in the national comprehensive wastewater discharge standards, which reach the first level discharge standards and few of them operate normally. Most of them are due to unreasonable processing technology, too high operating costs (the greater the amount of water in operation, the greater the burden of enterprises), the trouble of operation and management, and the failure to operate normally.

< /p >

< p > < strong > 2, leather industry's understanding of environmental protection < /strong > /p >

< p > in recent years, due to the gradual improvement of people's living standards, the gradual improvement of the state's policies and regulations on environmental protection, the increasing publicity on environmental protection, the continuous awareness of environmental protection by enterprises, the importance of environmental protection, and the fact that pollution control is not going to happen. Many private enterprises' sewage treatment is voluntary and voluntary investment, and has made pollution control facilities, and they can well operate the pollution control facilities.

The friendship leather factory in Xi'an, as early as 1998, invested 280 thousand yuan on its own and built a sewage treatment facility. However, because the enterprise did not understand the environmental protection policy, it did not set up a project and did not carry out environmental impact assessment.

Now leather industry has already realized the importance of pollution control. However, for enterprises, due to the lack of contact with sewage treatment technology, what technology and investment can be adopted to deal with the problem of pollution control in the end, there is no bottom in mind, and some environmental protection companies are making use of enterprises' ignorance to make enterprises spend a lot of money.

For example, there is a company's daily wastewater discharge of about 1000m3/d, and environmental protection companies cost 4 million 290 thousand yuan to make the sewage treatment result reach the two grade emission standard.

< /p >

< p > < strong > 3, China's leather industry pollution characteristics < /strong > < /p >

＜p＞　　皮革行業有句行話說“水里撈金”是非常形象的，由于制革生產的濕加工都是在水中進行的，很多的皮革化工原料都要加到水中，而制革生產中的原料皮又不可能將水中的化工原料吸收完全，而且有的化工原料吸收率特別低，如制革生產中的浸灰脫毛工序，所使用的石灰、硫化鈉和硫氫化鈉的吸收率只有約10～30%，從轉鼓中排出時硫化物有3000多mg/l，COD高達十幾萬mg/l;還有從原料皮中溶解下來的蛋白質能過分解以后，釋放出來的氨氮濃度也特別高，致使經處理過的污水中的氨氮含量比沒有處理前的氨氮含量還高;另外在加工皮革時所使用的表面活性劑被排放到廢水后，不但比較難去除，還影響到了微生物的生長;在制革過程中還使用了重金屬鉻，它回收回來后沒有人要，用到制革過程中影響成品革的質量，不回收隨著制革污泥排放到環境中又是危險廢棄物等等

。

< /p >

< p > addition of tannery wastewater is also due to the difference of raw material (cowhide, sheepskin, pig skin), processing technology and finished leather (< a target= "_blank" href= "http://www.91se91.com/" > shoes < /a > surface leather, a target= "_blank" href= "_blank" > clothing > leather, upholstery leather, luggage leather and so on). The quality of waste water varies greatly. These are the reasons why tannery wastewater is difficult to govern.

< /p >

< p > {page_break} < /p >

"P > < strong > 4. The problems related to pollution in the leather industry of China < /strong > < /p >

"P > 1) research on the clean production process of tannery so that the pollution is eliminated as much as possible in the production process, less or no pollution material, and the maximum output is obtained with its minimum input; < /p >

< p > 2) tannery sewage treatment technology, if the drainage is not surface water and municipal sewage treatment plant, the current sewage treatment technology should be able to solve the pollution problem of leather industry. The main reason is that some engineering and technical personnel of pollution control technology do not understand the nature of tannery wastewater. That is to say, the current domestic pollution control technology and tannery's economic capacity are not very coordinated, so long as there is economic capability, tannery wastewater treatment can reach the first level discharge standard, but the investment is too large.

< /p >

The problem of emission standard of < p > 3 is due to the particularity of tannery sewage and the difficulty in its treatment. Therefore, according to the development of the times and the development of science and technology, reasonable and timely discharge standards for sewage should be put forward, otherwise, the normal development of leather industry will be affected.

From this point, it is mainly reflected that the tannery industry is already a meager profit era, and the competition is fierce. If the sewage discharged by sewage treatment should meet the first grade standard, the investment will be too large and the burden on the back will be bigger, so it will be difficult to develop the technology and equipment of leather making.

< /p >

< p > 4) chromium recovery and utilization research shows that the resource of chromium metal is the largest in South Africa, and it is only enough for hundreds of years. The process of chrome used in leather making is about 1/3 of production, and in the process of leather making, 1/3 is discharged with sewage.

There is no problem in the recovery of waste chrome solution in sewage treatment. The problem is that tannery production is not willing to use after recycling. It will have certain effect on the quality of finished leather. There is a study on the processing of chromium from recycled chromium into tanning production or in other fields of research and development. In this regard, we need the government's policy and financial support.

< /p >

< p > 5. The comprehensive utilization of tannery sludge has been studied. The tannery sludge produced in the tanning industry is about 50 million tons.

In terms of environmental protection, there is almost no demand for tannery sludge discharge. Only the sewage discharge requirements of tannery industry reach the "comprehensive discharge standard for sewage". What can be found is the standard requirement for agricultural sludge, that is, the sludge with chromium content less than 1000mg/kg.

Tannery sludge contains about 70% of organic matter. If there is no chromium in tannery sludge, its utilization prospects will be very broad.

Each kg of dry sludge contains about 3000 calories of heat, which can be recycled. However, if chromium is used, the Cr3+ will be pformed into Cr6+ when burning, and Cr6+ will be more toxic. Tannery sludge can also be treated by anaerobic fermentation and biogas energy recovery. After the anaerobic fermentation, tannery sludge is also a very good agricultural fertilizer. It can be used in farmland to prevent the land from hardening, and can also be added directly to ferment as an agricultural fertilizer.

But if chromium is not recycled, the data we test are chromium containing 23000mg/kg dry sludge in tannery sludge, and in the field, the highest chromium content in the fruits of crops will directly affect the health of the human body.

Therefore, the premise is that chromium must be recycled.

< /p >

< p > < strong > 5, Leather Association has already done the work of pollution control < /strong > < /p >

< p > 1, the work has been done < /p >

< p > 1) pollution control work < /p >

< p > with the continuous improvement of people's living standards, people's demands for environmental awareness and environmental quality are getting higher and higher. With the continuous improvement of environmental protection policies and regulations, owners are willing to or not willing to do their own work. Now, about 80 to 90% of enterprises in tanning industry have been or are conducting pollution treatment.

< /p >

< p > 2) the role of trade associations in promoting leather making and environmental protection work < /p >

< p > industry associations are also promoting the environmental protection work of enterprises, such as leather signs and ecological leather activities, which are very strict with tannery enterprises in terms of environmental protection.

< /p >

< p > 3) promotion and training of leather cleaning process < /p >

< p > China Leather Association as early as 1995, with the help of the United Nations Technical and tannery cleaner production projects for the leather industry in China, the engineering and technical personnel of a group of tanning enterprises in the field of environmental protection and leather making, < /p >

< p > adopt the method of sending out, please send domestic personnel to the UK, Germany, etc. for environmental technology and tannery cleaner production training, and invite technical experts from Italy, Germany, Japan and other countries to come to the country to hold training courses for training or to hold seminars. Basically, once a year's training courses or seminars, the whole industry will benefit from environmental protection technology and cleaner production. 5 sample projects have been set up in Xi'an, Shanghai, Jiangsu and other places, and more than 30 leather processing plants have been directly supported and promoted by environmental protection technology.

In addition, the Holland government's assistance to China leather industry, which is directly implemented by the China Leather Research Institute, has achieved results in Henan shoe city, and is also actively promoting its work.

< /p >

< p > {page_break} < /p >

Experimental study on compost of tannery sludge < p > 4) < /p >

< p > U.N. assistance project was carried out in 1998 at Xuzhou Eagle ball leather group in Jiangsu. The composting test of tannery sludge was carried out. The composting experiment with tannery sludge and orange stalk was carried out. The results have been applied to the fertilization of rice and flowers, and the contrast test was carried out. The land was not tied up, the fertilizer efficiency lasted for a long time, and the crop yield increased by about 20%.

< /p >

< p > 2, problems existing in the process of pollution control < /p >

< p > (1) China's leather industry pollution control technology and deficiency < /p >

At present, in China's leather industry, pollution control technology is basically at the same level as that of foreign countries. There are not many technologies used in tannery industry, such as SBR, UASB, oxidation ditch and so on. Now, in the information age, some advanced environmental protection technologies abroad will soon be introduced into China. Why do the developed countries do not engage in tannery industry? Because the water quality in tanning industry is very complicated, the management is difficult, the investment in environmental protection is too large, the investment in the leather industry is too large, the tannery enterprises can not afford it, and the environmental protection requirements are very strict. This is the reason why the pollution is pferred to developing countries. This is the reason.

< /p >

< p > < strong > the existing shortcomings are as follows: < /strong > < /p >

< p > A, many environmental protection companies do not know enough about the complexity of tannery wastewater, resulting in a larger investment in tannery and less than expected results; < /p >

"P > b, large and state-owned tanning enterprises can also, small and medium-sized leather enterprises lack of environmental protection professional and technical personnel, some environmental protection professional technical personnel and their own industry pollution control aspects such as the nature of waste water.

< /p >

< p > C, and the fierce competition in the market economy makes the tannery enterprises lack the bottom gas, so it is difficult to invest large funds to thoroughly control the pollution.

< /p >

< p > D, tanning enterprises on pollution control facilities, but some environmental protection technology operation costs are too high, so that the more normal operation of the pollution control facilities, the heavier burden on the back, so that enterprises have to cope with environmental protection inspection, after inspection, no longer normal operation of the treatment facilities.

< /p >

< p >, therefore, the relevant departments should have an industry policy. We should affirm and popularize the environmental protection technologies for tannery wastewater pollution control, so as to make the tanneries less detours.

Tanning enterprises are also consulted by industry associations to meet environmental problems, so as to make their investment funds useful.

< /p >

< p > (2) main problems in the process of pollution control < /p >

< p > above all, the above deficiencies are also the problem here.

Leather waste water is very complex, and environmental protection industry is also developing in recent years, and the environmental protection work of tanning industry is also ongoing. As the emission standard of leather industry has been lagging behind, 90% of the pollution treatment facilities in leather industry are based on the two level emission standard in the comprehensive sewage discharge standard, or the design standard is based on the first level discharge standard. However, due to the complexity of tannery sewage, it is not up to the first level after completion of the operation. Now, if the leather industry is up to the first level emission standards (such as Sichuan province must meet the first level emission standards before the end of 2004), the whole industry is facing the technical pformation of environmental protection facilities. Here is only one point: making.

The enterprise has worked hard to achieve the two level emission standards. If we want to meet the first level emission standards, enterprises will have to invest billions of money and the effect is not yet achieved. Therefore, it is suggested that the emission standards of leather industry should be reduced.

< /p >