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Anonymous users2024-02-12The paper mill discharges three streams of water according to the process, one is the pulp cooking waste liquid, commonly known as papermaking black liquor; the second is the washing, sorting and bleaching of pulp after separating black liquor, also known as middle water; The third is the white water on the papermaking machine, which can be reused after treatment. The middle section of water is the part left over from the incomplete extraction of black liquor, which should account for less than 10% of the total amount. The pollutants contained in the black liquor account for more than 90% of the total pollution discharge of the whole plant.
As a result, black liquor emissions are a major source of pollution in paper mills. It is well established that the plant raw materials used in papermaking contain cellulose, lignin and hemicellulose (i.e., glycans). Papermaking mainly uses cellulose, and cellulose is removed by cooking and pulping, and lignin, hemicellulose and caustic soda (or ammonium) are added together into black liquor and discarded, that is, one is discarded and two are discarded.
In terms of quantity, taking wheat straw as an example, cellulose accounts for only 40%, lignin about 25%, and hemicellulose about 28%, that is, the pulp mill only uses 40% of the raw materials, and discards 60% of the raw materials, and the amount of pollutants emitted by the paper mill is very staggering. Since these pollutants flow into the river water in the form of fluids through underground pipes or ditches, their quantities are not noticeable, and if the pollutants are converted into solids and poured into the rivers in bags, people will perceive the large amount and the serious damage to water quality. It can be seen that the pollution of papermaking pulp waste liquid is not harmful and toxic, but caused by the artificial discharge of two resources that are not needed in the papermaking industry, on the contrary, if these two resources are taken out and effectively utilized, the pollution will be eliminated naturally.
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Anonymous users2024-02-11The pollutants of the paper mill are mainly generated in the cooking process, that is, during the cooking process, the organic matter (mainly lignin, and a small amount of hemicellulose and cellulose) is degraded and dissolved in the waste liquid to form the black liquor commonly known as the paper mill; The bleaching section is also a major source of pollution, and when chlorine-containing bleaching such as chlorine bleaching is used, chlorine-containing harmful substances will be produced in the bleaching wastewater; The washing section will also produce pollution, the pollutants are mainly the residual part of the pulp in the cooking section, and the white water is formed in the papermaking section, which is easier to deal with, and can be reused after treatment.
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Anonymous users2024-02-10The direct impact is that the sewage discharged from the sewage discharge flows into the sea, which is a major threat to all life in the sea. This is the most directly affected and most directly affected organism. In the ocean, we know that there are a lot of marine life, if you have dived into the water, you will know that the bottom of the sea is very beautiful, and all the fish and shrimp, all the marine creatures are very energetic, they do not walk on land, do not appear on the earth, only live in the water generation after generation, which is actually a state of life in harmony with nature for us.
But if we humans discharge sewage, it will directly affect their homes and will be a big threat to marine life. If the sewage discharge is severe, it will affect our drinking water.
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Anonymous users2024-02-09Several aspects:
1. Sewage discharge of cooling water of crusher in material preparation workshop;
2. The pulping workshop has cooking wastewater, washing and screening wastewater, and bleaching wastewater;
3. Process wastewater from pulp board workshop;
4. Alkali ** workshop wastewater;
5. Chemical plant production wastewater;
6. Thermal power station wastewater;
7. Wastewater from public facilities.
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Anonymous users2024-02-08A: The main pollutants in paper mill effluent, including BOD5, SS ammonia nitrogen, oil, color;
Treatment methods that can be adopted: oxidation pond method
This problem is relatively big, the traditional papermaking method is more polluting, the pollution is mainly water pollution, you can choose the best papermaking additives to reduce the concentration of white water, you can also take DMC clean pulping technology, no sewage discharge, water saving 98%, in addition to the more traditional pollution control methods, which index exceeds the standard plus the corresponding thing to reduce, waste not to say, pollution is greater!
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The wastewater produced by the alkali (caustic soda and sulfate process) pulping process in the paper industry contains a large amount of lignin and is black-brown, so it is called black liquor. Black liquor contains a large number of suspended solids, organic pollutants and toxic substances, and direct discharge into the water body will cause serious pollution. >>>More
1. The lignin in the papermaking raw material is soluble in strong acids and alkalis, and the lignin can be removed as long as it is in this environment. Do you refer to pulping or fiber analysis? If it is pulping, it is possible as long as it is under the above conditions. >>>More