Advanced treatment method of papermaking wastewater

Abstract

The invention belongs to the technical field of sewage treatment, and particularly relates to an advanced treatment method of papermaking wastewater. According to the method, the coagulant and the coagulant aid are added into the papermaking wastewater, so that suspended matter particles or colloids in the wastewater are coagulated into floccules, most suspended matters in the wastewater are separated and removed from the wastewater, COD (Chemical Oxygen Demand) and chromaticity are reduced, and an organic load of a subsequent Fenton-like reaction is reduced; then hydrogen peroxide and a heterogeneous Fenton-like catalyst are added into flocculation supernate, under the action of the heterogeneous Fenton-like catalyst, the hydrogen peroxide generates hydroxyl free radicals with a strong oxidation effect, organic matter and ammonia nitrogen in the wastewater are oxidized and decomposed, COD and ammonia nitrogen in the wastewater are reduced, and finally Fenton-like reaction effluent is subjected to aeration biological oxidation treatment. By utilizing the adsorption effect of the filler and the degradation effect of microorganisms attached and grown on the surface of the filler, pollutants such as residual organic matters and ammonia nitrogen in the wastewater are further reduced, the treatment effect is enhanced, and the effluent chromaticity and the effluent quality are stabilized.

Description

technical field [0001] The invention belongs to the technical field of sewage treatment, and in particular relates to a method for advanced treatment of papermaking wastewater. Background technique [0002] The paper industry is a major water user in various industries. According to statistics, every 1 ton of pulp produced by a papermaking enterprise will produce 60-100m 3 of wastewater. The wastewater produced in the papermaking process contains a large amount of pollutants, mainly lignin, chloride, hemicellulose and inorganic fillers, etc. It has the characteristics of complex water quality, many refractory components and strong stability. [0003] The secondary biological treatment method can effectively remove most of the suspended solids, macromolecules and easily degradable organic matter in the wastewater, and can greatly reduce the COD, BOD, etc. Processing efficiency is low. At present, the commonly used advanced treatment processes include flocculation, adsorpti...

AI Technical Summary

Problems solved by technology

[0003] The secondary biological treatment method can effectively remove most of the suspended solids, macromolecules and easily degradable organic matter in the wastewater, and can greatly reduce the COD and BOD of the wastewater, but its effect on lignin and its degradation fragments and derivatives Processing efficiency is very low

The traditional Fenton oxidation method has problems such as large dosage, narrow pH range, large amount of iron sludge, and poor impact load resistance. The adsorption capacity of the adsorbent used in the adsorption method is low, and the energy consumption of the subsequent regeneration process is high; the investment and operation costs of the ozone oxidation and Fenton oxidation methods are relatively high; the biological filter has limited ability to remove pollutants in the tail water, and often needs to add carbon Source or combined with other processes; membrane treatment process has problems such as membrane fouling and membrane cleaning

[0004] At present, the existing advanced treatment of papermaking wastewater adopts the method of flocculation + Fenton oxidation. The reaction needs to add acid and alkali to adjust the pH value, and add ferrous sulfate. There are problems of large consumption of chemicals and large output of iron sludge, resulting in operating costs. At the same time, there are also problems such as unstable chromaticity of the effluent, which cannot guarantee that the effluent quality is stable and up to standard

[0005] Patent CN201110092690.4 discloses an advanced treatment method for papermaking wastewater. The effluent from the secondary settling tank after biochemical treatment is first treated by flocculation treatment, and then treated by ultra-efficient shallow air flotation + sand filtration combined process, but the average of the treatment process The influent water is only 100mg / L, which cannot withstand a large organic load. For the biochemical effluent with a high concentration of organic matter (COD>1000mg / L), it is difficult to meet the national first-level discharge standard through this treatment method

[0006] Patent CN202010775057.4 discloses an advanced treatment method for papermaking wastewater, which uses photocatalytic degradation of COD, and the COD removal rate reaches 95.5-97.6%. However, some papermaking wastewater has a darker chroma, which will affect the catalytic effect, and the light transmittance needs to be solved. problems, and the catalyst is easily deactivated after exposure to light, with short service life and high cost

[0007] The existing technology "Ozone + Fenton Combined Technology Advanced Treatment of Papermaking Wastewater Test" (Xu Junyuan. Energy Saving and Environmental Protection, 2021(9): 62-63. DOI: 10.3969 / j.issn.1009-539X.2021.09.019) uses ozone Oxidation + Fenton oxidation method is used to treat the effluent of the secondary sedimentation tank of papermaking wastewater. The COD effluent is lower than 50mg / L, but the ozone oxidation process consumes a lot of energy and the treatment cost is high, while the Fenton oxidation process requires a lower pH value, The reaction produces a large amount of iron sludge, and the effluent contains Fe 2+ Cause secondary pollution, while increasing the difficulty and cost of subsequent treatment

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