If I told you that the seemingly harmless piece of paper you just pulled out of the tissue bag was actually doing a lot of damage to the environment, you would probably tell me, yes, it hurts the forest, but it just some tree, nothing to worry about, right?
Is it really that simple?
Paper in modern industry is very complex, and paper for different uses has very different production processes. For example, toilet paper has completely different performance requirements than printed paper, and some high-end toilet paper or facial tissue even contains some plastic fibers and cotton, so modern paper production is more than just cutting down some trees.
Now the paper production process can be simply divided into several steps. First, the paper is recycled or trees are cut, then the recycled paper or trees are washed, and then the recycled paper or trees are crushed to make pulp, and then the pulp is washed and bleached. The pulp is then fed into a paper machine, where a portion of the water is removed from the pulp and turned into a wet pulp tape in which the fibers are gently pressed together by rollers; these pulp tapes are then moved along the belt Moving, squeezing and then draining, getting tighter; ironing is next. The smooth-surfaced rollers are heated and the surface of the paper is ironed smooth; the final step is cutting. Put the paper into the machine and cut it to the standard size.
After the above steps, modern paper is completed and can be sent to various industries that need it for further processing to obtain the final product.
It sounds simple and straightforward, there are no complicated parts, and there seems to be nothing that can cause pollution, does it?
However, things are far from simple. Modern paper causes a lot of water pollution in the manufacturing process. Let's take a closer look.
As mentioned above, the manufacture of paper in a paper mill consumes a lot of water, and this process can cause serious water and gas pollution.
In the papermaking process, a large amount of organic matter other than cellulose and part of hemicellulose will enter the wastewater, and even after sufficient waste liquid recycling, there will still be more or less loss of cellulose and hemicellulose. into waste water. Papermaking wastewater containing a large amount of organic matter is discharged into the water body, causing different degrees of pollution to the water body. At the same time, it is usually necessary to add some necessary chemicals and chemical additives in the papermaking process, and the loss of these substances into the water body will aggravate the water pollution. In the bleaching section of the paper industry, chlorine-containing compounds are usually used for bleaching, resulting in a large amount of chlorinated organic compounds in the discharged bleaching wastewater. Organisms in the environment are highly toxic, teratogenic, and cause polyneuropathy. Therefore, how to effectively remove chlorine-containing organic compounds in papermaking wastewater has become a major problem in wastewater treatment.
If the waste water of the paper industry is discharged into the river without effective treatment, the organic matter in the waste water will be fermented, oxidized and decomposed, which will consume the oxygen in the water and cause the death of aquatic organisms such as fish and shellfish due to lack of oxygen; some fine fibers are suspended. In water, it is easy to block fish gills and also cause fish death; bark chips, wood chips, grass clippings, rot grass, sap, etc. in the wastewater sink to the bottom of the water, silting up the river bed, and continuously producing toxic odors during anoxic fermentation. There are some substances in the wastewater that are not easy to ferment and decompose, which are suspended in the water, absorb light, reduce the penetration of sunlight into the river water, and hinder the photosynthesis of aquatic plants; in addition, there are some toxic and harmful substances that are carcinogenic, teratogenic and mutagenic. substance. Eventually, the water is cloudy and black, foul smelling, water plants are not growing, fish and shrimp are wiped out, mosquitoes and flies are overgrown, and maggots are everywhere, which seriously threatens the health of coastal residents, causing diseases such as sputum, enteritis, and scabies to prevail. At the same time, it is not conducive to farmland irrigation. Human and animal drinking water.
In addition to the characteristics of large flow, serious pollution and difficult treatment, papermaking wastewater also has the following characteristics: high pollutant concentration, containing a large amount of raw material leaching substances and chemical additives; many refractory organic components, poor biodegradability, lignin, Cellulose and other substances are difficult to degrade by activated sludge method; the composition of wastewater is complex, in addition to raw material leaching substances, some also contain sulfides, inks, flocculants and other chemicals that are unfavorable for biochemical treatment; wastewater flow and load fluctuate greatly , and accompanied by fiber and chemical spillage, the fluctuation of water volume and load is very unfavorable to the stable operation of the biochemical treatment system.
The waste gas pollution generated by the paper industry is mainly dust odor, sulfur dioxide and nitrogen oxides. Most of the dust is generated in the material preparation process, and the odor is generated in the process of cooking, washing, and black liquor evaporation. Sulphur dioxide and oxides mostly appear in the alkali recovery furnace. According to data, the paper industry in China, in 2015, the dust emissions reached 138,000 tons, sulfur dioxide was 371,000 tons, and nitrogen oxides were 220,000 tons. Excessive dust will cause fog, high concentrations of sulfur dioxide and nitrogen oxides will cause air pollution, and it is easy to generate acid rain, which will cause many adverse effects on the ecological environment.
In addition to water and gas pollution, papermaking also leads to the problem of over-exploitation of forest resources, so the next time you take out a paper towel, you can seriously think about it again, whether you really need this A tissue?
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