Process and apparatus for treating wastewater from pulping papermaking

Abstract

The invention discloses a process for treating paper-making sewage, which comprises the following steps: 1. sewage in a water collecting pond is lifted to a fiber recovering tank for fiber recovery; 2. the discharged water is guided in a hydrolysis acidification tank for hydrolysis acidification reaction; 3. the discharged water is pretreated; 4. the sewage after pretreatment is guided in an anaerobic tank to degrade organic pollutants by anaerobic microorganism; 5. the discharged water at the step 4 is guided in a destabilization tank for improving biodegradability of the sewage; 6. the discharged water is guided in an aerobic biological tank for treatment; 7. the discharged water is guided in a secondary sedimentation tank for mud-water separation; and 8. the discharged water is sterilized and disinfected to meet the discharge standard and discharge into a clean water tank, and pressurized by a water pump and sent to a reuse water pipe network. The process has simple process and lower cost, and the discharged water directly meets the new standards, and the treating capabilities of the anaerobic tank and the aerobic biological tank are greatly improved simultaneously; moreover, the process only uses a small quantity of medicaments, and generates relatively less sludge.

Description

technical field [0001] The invention relates to a sewage treatment process and its device, in particular to a pulping and papermaking sewage treatment process and its device. Background technique [0002] Pulping and papermaking wastewater is a difficult industrial wastewater with high chroma, high alkalinity, high organic pollutants, and low biodegradability. Sewage comes from raw material preparation, cooking, bleaching, papermaking and other workshops. Sewage contains a variety of alkanes, hydrocarbons, phenols, acids, benzene, alcohols, aldehydes, ketones, ethers, anthracene, quinones, sugars, amines, cellulose, hemicellulose And lignin and other organic substances and their derivatives, polymers, halogenated substances. After alkali recovery, pulp and paper enterprises usually adopt conventional anaerobic plus aerobic treatment process. Under the condition of reasonable design and good operation of sewage treatment facilities, the effluent can basically meet the requir...

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Problems solved by technology

However, these conventional processes have certain defects: the adsorption method needs to add a large amount of adsorbent, which will fail after the adsorption is saturated, the cost is high, and a large amount of sludge is produced; the oxidation method (ozone, hydrogen peroxide, hypochlorous acid, etc.) has a decolorization effect It is not obvious, and the treatment cost is high; the conditions required for efficient decolorization engineering bacteria are harsh, and it is difficult to apply in engineering; the electrolysis method and photocatalysis have better effects, but the power consumption is high, resulting in unacceptable operating costs; although the UF+RO membrane method treats The effect is good, but a very strict pretreatment system is required, and its high construction cost and operating cost are very high; acid analysis of lignin requires a large amount of acid to be added to the water quality, and after the lignin is precipitated, alkali is used to adjust the pH value, and the treatment cost High, and a large number of ions are added to the water

[0004] At the same time, in the existing secondary biochemical treatment process, the removal rate of chemical oxygen demand (COD) in the anaerobic tank is generally between 45% and 55%, while the effluent from the aerobic tank is very turbid after precipitation and separation. Its COD is generally 400-450mg / L, and the treatment efficiency of anaerobic and aerobic pools is low

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