Discussion on the new technology of treating chlor

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A brief talk on the new technology of treating chlorine containing bleaching wastewater the wastewater treatment of modern sulfate pulping workshop is no longer a problem. However, the situation in the 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 pulp bleaching to summarize and exchange the research results, product information and field utilization experience in the field of oilfield chemicals, in addition to the traditional wastewater treatment methods, there are also many new technologies for reference, which are briefly described as follows:

1. ultrafiltration method because the bleaching wastewater contains high molecular weight, It is not easy to be decomposed by microorganisms. Therefore, ultrafiltration treatment is considered before biological treatment. Ultrafiltration can remove 50%-90% of the 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. However, biological treatment can remove 62%-90% of AOX

2. the iron salt or aluminum salt can precipitate the organic chloride to remove AOX. The use of polyethyleneiminc 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 monochlorophenol, dichlorophenol, trichlorophenol and other low molecular weight chlorinated organics during aeration and ultrasonic treatment for 1H

2. Ozone, ultraviolet radiation and powdered activated carbon are oxidized alone or in combination. Where activated carbon is used alone, such as wastewater from rigid differential treatment section C, wastewater from section E 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. The removal rates of total tox are 82%-86%, 47%-48% respectively. Now the conditions are so good and 73%-74%. The range of removal rates is related to the selection of powdered activated carbon. Oxidation by ultraviolet irradiation 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 be significantly oxidized with oxygen to remove TOCl and color quality. The degradation of chlorinated lignin is the strongest at the initial 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. A method for promoting the reduction of AOX in waste liquid 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; The reaction time is constant, the pH value is high, and the AOX removal rate in the mixed solution is high

5. unconventional biodegradation waste liquid unconventional biodegradation. At present, fungi are basically used, especially those that decompose lignin. White rot is commonly used. It can degrade chlorinated lignin, but it needs to add carbon source to produce peroxidase, so that the pH value, nutrient, dissolved oxygen and contact residence time of degraded lignin will affect its effect

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

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