Method for treating high-concentration filtrate of chemi-mechanical pulp

Abstract

The invention discloses a method for treating high-concentration filtrate of chemi-mechanical pulp, and relates to the technical field of papermaking wastewater treatment. The method comprises the steps of S1, pretreatment, S2, neutralization treatment, S3, biochemical treatment, S4, deep treatment and S5, purification treatment. According to the method, the high-concentration filtrate in the chemi-mechanical pulp production line is subjected to pretreatment, neutralization treatment, biochemical treatment, deep treatment and purification treatment, so that impurities in the high-concentration filtrate are removed, organic matters in the high-concentration filtrate are degraded into inorganic matters, and meanwhile, harmful substances in the high-concentration filtrate are separated out under the action of magnetization and mimic enzyme catalysis; the method has the advantages that harmful substances in the high-concentration filtrate are sufficiently treated, the COD (chemical oxygen demand) value of the high-concentration filtrate is reduced, the high-concentration filtrate reaches the emission standard, the process is simple, the operation is convenient and fast, the equipment investment is low, and the operation cost of treatment enterprises is reduced; and magnetization and mimic enzyme catalysis can recover the mimic enzyme type magnetic catalyst, so that the medicament cost of high-concentration filtrate treatment is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of papermaking wastewater treatment, in particular to a method for treating high-concentration filtrate of a chemical-mechanical pulp. Background Art

[0002] The pollutants in the high-concentration filtrate of chemical-mechanical pulp mainly come from organic compounds dissolved in the fiber raw materials, residual chemicals in the process and lost fine fibers. The high-concentration filtrate has a brown-red color. The main chemical components of its organic pollutants are lignin degradation products, polysaccharides and organic acids, among which lignin degradation products account for 20%~30%, polysaccharides account for 15%~20%, and organic acids account for 30%~35%. Due to the high temperature and heavy pollution load of high-concentration filtrate of chemical-mechanical pulp, most of the existing technologies currently use biological treatment technology with anaerobic as the core to treat high-concentration filtrate of chemical-mechanical pulp. However, there are still some defects in treating high-concentration filtrate of chemical-mechanical pulp by anaerobic technology: When the high-concentration filtrate of chemical-mechanical pulp is treated by anaerobic technology, the anaerobic treatment cannot be carried out throughout the entire treatment process, resulting in insufficient treatment of harmful substances in the high-concentration filtrate of chemical-mechanical pulp. Therefore, the COD value of the high-concentration filtrate of chemical-mechanical pulp is high and cannot meet the discharge standard; At the same time, the anaerobic treatment method in the existing technology is completed by processes such as fiber recovery, precipitation, hydrolysis, anaerobic, concentration, aerobic, coagulation and dehydration. The equipment investment in the process is large, which leads to high operating costs for the treatment company.

[0003] In view of the above problems, the inventors proposed a method for treating high-concentration filtrate of chemical-mechanical pulp to solve the above problems. Summary of the invention

[0004] In order to solve the above problems, the purpose of the present invention is to provide a method for treating high-concentration filtrate of chemical-mechanical pulp.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solution: a method for treating high-concentration filtrate of chemical-mechanical pulp, comprising the following steps: S1. Preprocessing First, the high-concentration filtrate of the chemical-mechanical pulp production line is pretreated by filtering equipment and sedimentation equipment to remove suspended solids, grease and other solid impurities in the high-concentration filtrate; S2. Neutralization The pretreated high-concentration filtrate is added to the biochemical pool, and a buffer solution is added to the high-concentration filtrate to adjust the pH value of the high-concentration filtrate, reduce the alkalinity of the high-concentration filtrate, and maintain the pH value of the high-concentration filtrate at 4.5-5.5; S3. Biochemical treatment Adding microorganisms to the high-concentration filtrate in the biochemical pool, the organic matter in the high-concentration filtrate is degraded into stable inorganic matter by the action of the microorganisms, thereby reducing the concentration of pollutants in the high-concentration filtrate; S4. Deep processing A: Magnetization treatment The high-concentration filtrate after the biochemical treatment is added to the magnetization treatment equipment, and the content in the high-concentration filtrate acquires magnetism under the action of the magnetic field through the magnet of the magnetization treatment equipment; B: Enzyme-like catalytic treatment The high-concentration filtrate after the magnetization treatment is catalytically treated by using an enzyme-mimicking magnetic catalyst, and the enzyme-mimicking magnetic catalyst and the treated filtrate are separated by a separation method; S5. Purification The treated filtrate obtained after the deep treatment is added to the purification tank, and an activated carbon adsorbent is added to perform adsorption and purification treatment on the treated filtrate to obtain a filtrate that meets the emission standards.

[0006] Preferably, in S1, the precipitation time of the high-concentration filtrate is 1 to 1.5 hours.

[0007] Preferably, in S2, the buffer solution is any one of sodium hydroxide and calcium hydroxide.

[0008] Preferably, in S3, the microorganism includes any one of bacteria, fungi and algae.

[0009] Preferably, in S4, the specific steps of the enzyme-like catalytic treatment are as follows: B1, adding the enzyme-mimicking magnetic catalyst to the high-concentration filtrate after magnetization treatment, and adding H2O2, the mass ratio of the enzyme-mimicking magnetic catalyst to H2O2 is 1:1.5~5.5; B2. Stir the high-concentration filtrate at 30-50°C for 80-100 minutes to obtain a suspension; B3, adding the suspension into an enzyme-mimicking magnetic catalyst separation column, standing for 30 to 50 minutes under the action of a magnetic field, and separating the enzyme-mimicking magnetic catalyst at the bottom layer and the treated filtrate at the top layer; B4. The separated lower enzyme-mimicking magnetic catalyst is recovered for recycling in the treatment of high-concentration filtrate.

[0010] Preferably, in S5, the purification treatment of the treated filtrate also includes ozone oxidation and disinfection to ensure that the treated filtrate meets the discharge standard.

[0011] Compared with the prior art, the present invention has the following beneficial effects: 1. In the present invention, the high-concentration filtrate in the chemical-mechanical pulp production line is subjected to pretreatment, neutralization treatment, biochemical treatment, deep treatment and purification treatment to remove impurities in the high-concentration filtrate, degrade organic matter in the high-concentration filtrate into inorganic matter, and separate harmful substances in the high-concentration filtrate under the action of magnetization and enzyme-like catalysis, and the final purification treatment fully removes harmful substances in the high-concentration filtrate, reduces the COD value of the high-concentration filtrate, and makes the high-concentration filtrate meet the discharge standard; 2. In the present invention, during the deep treatment of high-concentration filtrate, magnetization and enzyme-mimicking catalysis can recover the enzyme-mimicking magnetic catalyst, thereby reducing the reagent cost of high-concentration filtrate treatment; 3. In the present invention, the high-concentration filtrate in the chemical-mechanical pulp production line is treated through the processes of pretreatment, neutralization treatment, biochemical treatment, deep treatment and purification treatment. The process is simple, the operation is convenient, the equipment investment is low, and the operating cost of the processing enterprise is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0013] Figure 1 The present invention is a process flow chart of a method for treating high-concentration filtrate of chemical-mechanical pulp. DETAILED DESCRIPTION

[0014] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] Embodiment 1: Figure 1 As shown, the present invention provides a method for treating high-concentration filtrate of chemical-mechanical pulp, comprising the following steps: S1. Preprocessing Firstly, the high-concentration filtrate of the chemical-mechanical pulp production line is pretreated by filtering equipment and sedimentation equipment. The high-concentration filtrate is precipitated for 1 hour to remove suspended solids, grease and other solid impurities in the high-concentration filtrate. S2. Neutralization The pretreated high-concentration filtrate is added to the biochemical pool, and sodium hydroxide is added to the high-concentration filtrate to adjust the pH value of the high-concentration filtrate and reduce the alkalinity of the high-concentration filtrate. The pH value of the high-concentration filtrate is 5; S3. Biochemical treatment Add fungi to the high-concentration filtrate in the biochemical pool, and degrade the organic matter in the high-concentration filtrate into stable inorganic matter through the action of fungi, thereby reducing the concentration of pollutants in the high-concentration filtrate; S4. Deep processing A: Magnetization treatment The high-concentration filtrate after the biochemical treatment is added to the magnetization treatment equipment, and the content in the high-concentration filtrate acquires magnetism under the action of the magnetic field through the magnet of the magnetization treatment equipment; B: Enzyme-like catalytic treatment The enzyme-mimetic magnetic catalyst is added to the high-concentration filtrate after the magnetization treatment, and H2O2 is added, the mass ratio of the enzyme-mimetic magnetic catalyst to H2O2 is 1:3, and then the high-concentration filtrate is stirred at 30°C for 90 minutes to obtain a suspension, and the suspension is added to an enzyme-mimetic magnetic catalyst separation column, and the suspension is allowed to stand for 30 minutes under the action of a magnetic field to separate the enzyme-mimetic magnetic catalyst in the lower layer and the treated filtrate in the upper layer, and the separated enzyme-mimetic magnetic catalyst in the lower layer is recovered for recycling in the treatment of the high-concentration filtrate; S5. Purification The treated filtrate obtained after the deep treatment is added to the purification tank, and an activated carbon adsorbent is added to perform adsorption purification treatment on the treated filtrate. At the same time, the treated filtrate is subjected to ozone oxidation and disinfection treatment to obtain a filtrate that meets the emission standards.

[0016] Embodiment 2: The present invention provides a method for treating a high-concentration filtrate of a chemical-mechanical pulp, comprising the following steps: S1. Preprocessing First, the high-concentration filtrate of the chemical-mechanical pulp production line is pretreated by filtering equipment and sedimentation equipment. The high-concentration filtrate is precipitated for 1.2 hours to remove suspended solids, grease and other solid impurities in the high-concentration filtrate. S2. Neutralization The pretreated high-concentration filtrate is added to the biochemical pool, and calcium hydroxide is added to the high-concentration filtrate to adjust the pH value of the high-concentration filtrate and reduce the alkalinity of the high-concentration filtrate. The pH value of the high-concentration filtrate is 4.5; S3. Biochemical treatment Add bacteria to the high-concentration filtrate in the biochemical pool, and degrade the organic matter in the high-concentration filtrate into stable inorganic matter through the action of bacteria, thereby reducing the concentration of pollutants in the high-concentration filtrate; S4. Deep processing A: Magnetization treatment The high-concentration filtrate after the biochemical treatment is added to the magnetization treatment equipment, and the content in the high-concentration filtrate acquires magnetism under the action of the magnetic field through the magnet of the magnetization treatment equipment; B: Enzyme-like catalytic treatment The enzyme-mimetic magnetic catalyst is added to the high-concentration filtrate after the magnetization treatment, and H2O2 is added, the mass ratio of the enzyme-mimetic magnetic catalyst to H2O2 is 1:2, and then the high-concentration filtrate is stirred at 30°C for 80 minutes to obtain a suspension, the suspension is added to an enzyme-mimetic magnetic catalyst separation column, and the suspension is allowed to stand for 30 minutes under the action of a magnetic field to separate the enzyme-mimetic magnetic catalyst in the lower layer and the treated filtrate in the upper layer, and the separated enzyme-mimetic magnetic catalyst in the lower layer is recovered for recycling in the treatment of the high-concentration filtrate; S5. Purification The treated filtrate obtained after the deep treatment is added to the purification tank, and an activated carbon adsorbent is added to perform adsorption purification treatment on the treated filtrate. At the same time, the treated filtrate is subjected to ozone oxidation and disinfection treatment to obtain a filtrate that meets the emission standards.

[0017] Embodiment 3: The present invention provides a method for treating a high-concentration filtrate of a chemical-mechanical pulp, comprising the following steps: S1. Preprocessing First, the high-concentration filtrate of the chemical-mechanical pulp production line is pretreated by filtering equipment and sedimentation equipment. The high-concentration filtrate is precipitated for 1.5 hours to remove suspended solids, grease and other solid impurities in the high-concentration filtrate. S2. Neutralization The pretreated high-concentration filtrate is added to the biochemical pool, and calcium hydroxide is added to the high-concentration filtrate to adjust the pH value of the high-concentration filtrate and reduce the alkalinity of the high-concentration filtrate. The pH value of the high-concentration filtrate is 5.5; S3. Biochemical treatment Adding algae to the high-concentration filtrate in the biochemical pool, the algae degrade the organic matter in the high-concentration filtrate into stable inorganic matter, thereby reducing the concentration of pollutants in the high-concentration filtrate; S4. Deep processing A: Magnetization treatment The high-concentration filtrate after the biochemical treatment is added to the magnetization treatment equipment, and the content in the high-concentration filtrate acquires magnetism under the action of the magnetic field through the magnet of the magnetization treatment equipment; B: Enzyme-like catalytic treatment The enzyme-mimicking magnetic catalyst is added to the high-concentration filtrate after the magnetization treatment, and H2O2 is added, the mass ratio of the enzyme-mimicking magnetic catalyst to H2O2 is 1:4, and then the high-concentration filtrate is stirred at 50° C. for 100 minutes to obtain a suspension, and the suspension is added to an enzyme-mimicking magnetic catalyst separation column, and the suspension is allowed to stand for 50 minutes under the action of a magnetic field to separate the enzyme-mimicking magnetic catalyst in a lower layer and the treated filtrate in an upper layer, and the separated enzyme-mimicking magnetic catalyst in the lower layer is recovered for recycling in the treatment of the high-concentration filtrate; S5. Purification The treated filtrate obtained after the deep treatment is added to the purification tank, and an activated carbon adsorbent is added to perform adsorption purification treatment on the treated filtrate. At the same time, the treated filtrate is subjected to ozone oxidation and disinfection treatment to obtain a filtrate that meets the emission standards.

[0018] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for treating high-concentration filtrate of chemical-mechanical pulp, characterized in that: The following steps are involved: S1. Preprocessing First, the high-concentration filtrate of the chemical-mechanical pulp production line is pretreated by filtering equipment and sedimentation equipment to remove suspended solids, grease and other solid impurities in the high-concentration filtrate; S2. Neutralization The pretreated high-concentration filtrate is added to the biochemical pool, and a buffer solution is added to the high-concentration filtrate to adjust the pH value of the high-concentration filtrate, reduce the alkalinity of the high-concentration filtrate, and maintain the pH value of the high-concentration filtrate at 4.5-5.5; S3. Biochemical treatment Adding microorganisms to the high-concentration filtrate in the biochemical pool, the organic matter in the high-concentration filtrate is degraded into stable inorganic matter by the action of the microorganisms, thereby reducing the concentration of pollutants in the high-concentration filtrate; S4. Deep processing A: Magnetization treatment The high-concentration filtrate after the biochemical treatment is added to the magnetization treatment equipment, and the content in the high-concentration filtrate acquires magnetism under the action of the magnetic field through the magnet of the magnetization treatment equipment; B: Enzyme-like catalytic treatment The high-concentration filtrate after the magnetization treatment is catalytically treated by using an enzyme-mimicking magnetic catalyst, and the enzyme-mimicking magnetic catalyst and the treated filtrate are separated by a separation method; S5. Purification The treated filtrate obtained after the deep treatment is added to the purification tank, and an activated carbon adsorbent is added to perform adsorption and purification treatment on the treated filtrate to obtain a filtrate that meets the emission standards.

2. A method for treating high-concentration filtrate of chemical mechanical pulp according to claim 1, characterized in that: In S1, the precipitation time of the high-concentration filtrate is 1 to 1.5 hours.

3. The method for treating high-concentration filtrate of chemical mechanical pulp according to claim 1, characterized in that: In S2, the buffer solution is any one of sodium hydroxide and calcium hydroxide.

4. A method for treating high-concentration filtrate of chemical mechanical pulp according to claim 1, characterized in that: In S3, the microorganism includes any one of bacteria, fungi and algae.

5. The method for treating high-concentration filtrate of chemical-mechanical pulp according to claim 1, characterized in that: In S4, the specific steps of the enzyme-like catalytic treatment are as follows: B1, adding the enzyme-mimicking magnetic catalyst to the high-concentration filtrate after magnetization treatment, and adding H2O2, the mass ratio of the enzyme-mimicking magnetic catalyst to H2O2 is 1:1.5~5.5; B2. Stir the high-concentration filtrate at 30-50°C for 80-100 minutes to obtain a suspension; B3, adding the suspension into an enzyme-mimicking magnetic catalyst separation column, standing for 30 to 50 minutes under the action of a magnetic field, and separating the enzyme-mimicking magnetic catalyst at the bottom layer and the treated filtrate at the top layer; B4. The separated lower enzyme-mimicking magnetic catalyst is recovered for recycling in the treatment of high-concentration filtrate.

6. The method for treating high-concentration filtrate of chemical-mechanical pulp according to claim 1, characterized in that: In S5, the purification treatment of the treated filtrate also includes ozone oxidation and disinfection to ensure that the treated filtrate meets the discharge standard.

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