Discussion on the new technology of treating chlor

2022-09-21
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Talking about the new technology of treating chlorine containing bleaching wastewater

wastewater treatment in modern sulfate pulping workshop, Dr. Frank Henning, the head of lightweight research, has affirmed Hengrui's affirmation and put forward targeted countermeasures. It's not a problem to praise it. However, the situation of pulp bleaching workshop is different. If the new chlorine free bleaching process has been realized, the bleaching waste liquid can be treated in the alkali recovery system as the pulp waste liquid. However, if chlorine or chlorine dioxide is also used in the bleaching process of pulp, in addition to the traditional wastewater treatment method, there are many new technologies for reference, which are summarized as follows:

1. Ultrafiltration method because the bleaching wastewater contains high molecular weight parts, it is not easy to be decomposed by microorganisms. Therefore, ultrafiltration treatment is considered before biological treatment. Ultrafiltration can remove 50% - 90% of organic chlorides or AOX in the wastewater of section E. however, chlorophenols with low molecular weight are the most toxic components in AOX, so the efficiency of ultrafiltration is very low, but then biological treatment can remove 62% - 90% of AOX

2. Iron salt or aluminum salt by chemical sedimentation can precipitate organic chloride and remove AOX. The use of polyethyleneimine (PO should actively cultivate the new kinetic energy of green development lyethyleneiminc) can also settle the organic matter in the chlorination and alkali treatment stages, and the AOX removal rate in the chlorination section is 54%-84%. The alkali treatment stage is 50% - 73

3. Oxidation method

1 ultrasonic oxidation can remove 10%-60% of low molecular weight chlorinated organics such as monochlorophenol, dichlorophenol and trichlorophenol when aerating and ultrasonic treatment for 1H at the same time

2 "ozone, ultraviolet radiation and powdered activated carbon are oxidized alone or in combination. Using activated carbon alone to treat C-stage wastewater, e-Stage wastewater and mixed wastewater, the removal rates of low molecular weight tox are 32.2%-43.7%, 18.7%-78.7% and 10.2%-53.0% respectively, and the removal rates of total tox are 82%-86%, 47%-48% and 73%-74% respectively. The range of removal rates is related to the selection of powdered activated carbon. Oxidation irradiated by UV alone can be called photolysis, which is mainly the decomposition of high molecular weight AOX into c1-

3 "oxygen oxidation e-Stage bleaching wastewater can significantly remove TOCl and color quality by oxygen oxidation. The degradation of chlorinated lignin is mainly the strongest in the early stage of oxygen treatment, which plays an important role in the removal of TOCl and color quality

4. alkaline hydrolysis is the reaction of various alkaline compounds with chlorinated lignin. The method of promoting the reduction of AOX in waste liquid is due to different or different combinations of alkaline compounds. Its ability to reduce AOX in waste liquid is also different. Usually, NaOH/Ca (OH) 2 or the combination of Na2S, na0h and Ca (0h) 2 is used to reduce AOX. In the treatment, the treatment time, temperature, pH value and concentration have an impact on its effect. Generally, the pH value is certain, and the reaction time is long and good; The reaction time is certain, the pH value is high, and the removal rate of AOX in the mixture is high

5. Unconventional biodegradation waste liquid unconventional biodegradation. At present, fungi are basically used, especially those that decompose lignin. White rot fungi are commonly used. It can degrade chlorinated lignin, but carbon sources need to be added to produce peroxidase, so that the pH value of lignin degradation, nutrients, dissolved oxygen, and contact residence time all affect its effect

6. electrolytic treatment electrolytic treatment is to use electrodes with different compositions to conduct electrolysis for different times to obtain the required AOX removal rate. The highest AOX removal rate can reach more than 99%, but this situation has high energy consumption and is not worth the loss

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