Printing and Dyeing Sewage Treatment Equipment Matters Needing Attention

The sewage produced by printing and dyeing is relatively complex, and it is a type of industrial sewage with a large amount of change. Therefore, when using printing and dyeing sewage treatment equipment, attention should be paid to:
1. The common problems in printing and dyeing sewage treatment are that the amount of aerobic microorganisms in biochemical treatment is too small, and the amount of flocculant is not well controlled. In order to achieve the ideal effect of printing and dyeing sewage treatment, we must pay attention to reducing the amount of sewage from dyeing and washing as much as possible from the dyeing and finishing process.
2. The second is to pay attention to the diversion and discharge of printing and dyeing sewage. The production water consumption in dyeing and finishing is high, but the discharge is not seriously polluted sewage.
Therefore, the printing and dyeing sewage should be separated and discharged, the seriously polluted sewage will be discharged up to the standard after being treated by the sewage station, and the lightly polluted sewage will be directly discharged or sent to a suitable water place for reuse after simple treatment.

At present, there are two methods for the treatment of printing and dyeing wastewater: one is to carry out advanced treatment of printing and dyeing wastewater, and the treated wastewater can meet the standard, but the treatment cost is high, and the treatment cost of 1m3 printing and dyeing wastewater is as high as 3.5 yuan; the other is to treat The depth is not enough, and the treated wastewater fails to meet the standard. The high treatment cost limits the effective treatment of printing and dyeing wastewater and restricts the survival of printing and dyeing enterprises. Therefore, the use of treatment technologies with good treatment effect and low operating costs (such as Daquan printing and dyeing sewage treatment equipment) is of great significance for the treatment of printing and dyeing wastewater.

Based on the particularity of the water quality of printing and dyeing sewage, the traditional treatment methods generally have the following two methods:
1. Coagulation method: Coagulation method is the most widely used method in the treatment of printing and dyeing wastewater, including coagulation sedimentation method and coagulation air flotation method. Commonly used coagulants are basic aluminum chloride, polymeric ferric sulfate, etc. Coagulation has a good effect on removing COD and chroma.
When the coagulation method is set before biological treatment, the dosage of coagulant is large and the amount of sludge is large, which is easy to increase the treatment cost and increase the difficulty of sludge treatment and final treatment. The COD removal rate of coagulation method is generally 30% to 60%, and the BOD5 removal rate is generally 20% to 50%.
As the advanced treatment of wastewater, the coagulation method is installed after the biological treatment structure, which has the advantage of flexible operation. When the influent concentration is low and the biochemical operation effect is good, no coagulant can be added to save costs; when the biological contact oxidation method is adopted, it can be considered to not set up a secondary sedimentation tank, so that the effluent of the biological treatment structure directly enters the mixing Condensation treatment facility. In the treatment of printing and dyeing wastewater, most of the coagulation methods are set after biological treatment. The COD removal rate is generally 15% to 40%.
When the concentration of pollutants in the original wastewater is low, and only the coagulation method can meet the discharge standard, only the coagulation method can be considered to be installed.

2. Chemical oxidation method: One of the characteristics of textile printing and dyeing wastewater is that it has a darker color. Mainly caused by dyes remaining in wastewater. In addition, some suspensions, slurries and additives can also produce color. Decolorization of wastewater is to remove the above-mentioned color organic matter in wastewater. After the printing and dyeing wastewater is treated by biological method or coagulation method, with the removal of BOD and some suspended solids, the chromaticity is also reduced to a certain extent. Under normal circumstances, the decolorization rate of biological methods is low, only 40% to 50%. The decolorization rate of the coagulation method is slightly higher, but there are great differences due to the different types of dyes and coagulants, and the decolorization rate is between 50% and 90%.
Therefore, after the above method is used, the effluent still has a dark color, which is unfavorable for discharge and reuse. For this reason, further decolorization treatment is necessary. Commonly used decolorization treatment methods are oxidation method and adsorption method. There are three kinds of oxidation decolorization methods: chlorine oxidation method, ozone oxidation method and photooxidation method.

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