A method for deep decolorization treatment of sodium sulfate evaporation mother liquor from coking wastewater

Abstract

The present invention discloses a method for deep decolorization treatment of sodium sulfate evaporation mother liquor of coking wastewater, belonging to the technical field of coking wastewater decolorization, including S1. Iron-carbon oxidation decolorization: Using the self-electrolysis reaction of iron-carbon particles to electrolyze organic substances in the wastewater; S2. Biological treatment: Degrading organic substances in the wastewater through the degradation effects of microorganisms and plants; S3. Ozone decolorization: Using the oxidizing property of ozone to oxidize and degrade organic substances in the wastewater; S4. Reagent decolorization: Adjusting the pH to generate precipitates of sodium hydroxide and inorganic metal ions such as iron and copper to remove the colored inorganic metal ions in the wastewater; S5. Membrane filtration treatment: Passing mother liquor D into a reverse osmosis membrane filtration device for reverse osmosis membrane filtration. The present invention conducts decolorization treatment on the sodium sulfate evaporation mother liquor of coking wastewater through multiple channels, and has good treatment effects.

Description

Technical Field

[0001] The present invention relates to the technical field of coking wastewater decolorization, and specifically relates to a method for deep decolorization treatment of sodium sulfate evaporation mother liquor of coking wastewater. Background Art

[0002] Coking wastewater is a typical toxic and difficult-to-degrade organic wastewater. It mainly comes from the primary cooling of coke oven gas, production water during the coking production process, and steam condensate wastewater.

[0003] Coking plants mainly produce chemical products such as coke, commercial gas, ammonium sulfate, and light benzene. The tar recovery system in this plant adopts the ammonium sulfate process, the tar processing uses a two-tower continuous distillation with a tubular furnace, and the industrial naphthalene production process is a double-furnace and double-tower continuous distillation, washing, and refining. During the cooling, washing, crude benzene processing, and tar processing of coke oven gas, industrial wastewater containing phenols, cyanides, oils, ammonia, and a large amount of organic matter is generated.

[0004] Coking wastewater is a kind of industrial organic wastewater with high CODcr, high phenol value, high ammonia nitrogen and is very difficult to treat. The COD of coking wastewater is mainly composed of three parts: organic components, inorganic components, and suspended solids. Among them, the organic COD is mainly composed of phenolic compounds, heterocyclic compounds, and naphthalene substances. The phenolic compounds mainly include phenol, o-cresol, p-cresol, o,p-cresol, xylenol, catechol and its homologues, etc. The heterocyclic compounds include naphthalene, anthracene, phenanthrene, m-benzopyrene, etc.; phenolic compounds account for about 85% of the total organic matter, and the COD of phenolic compounds accounts for about 30% of the total COD. The inorganic COD components include SCN-, CN-, S2—, NO, etc., and SCN is the main component of the inorganic COD components. The suspended solid COD is mainly composed of coal dust, coke dust, and water-insoluble oils. In addition to COD, coking wastewater also contains ammonia nitrogen and salt components.

[0005] Sodium sulfate crystals are usually extracted from coking wastewater. Taking coking wastewater as raw material, after decolorization and impurity removal, it is concentrated and crystallized to recover and utilize sodium sulfate. However, coking wastewater contains complex organic colored substances. When the existing technologies treat coking wastewater, the methods are single and cannot deeply remove the colored substances in coking wastewater. Therefore, a method for deep decolorization of organic and inorganic colored substances in coking wastewater is needed. Summary of the Invention

[0006] To solve the above technical problems, the present invention provides a method for deep decolorization treatment of sodium sulfate evaporation mother liquor of coking wastewater.

[0007] The technical solution of the present invention is: a method for deep decolorization treatment of sodium sulfate evaporation mother liquor of coking wastewater, including the following steps:

[0008] S1. Iron-carbon oxidation decolorization:

[0009] Construct an iron-carbon adsorption tank. Then, first filter the sodium sulfate evaporation mother liquor of coking wastewater through an industrial filter cloth. The filtered mother liquor is introduced into the iron-carbon adsorption tank. Add iron-carbon adsorption particles to the iron-carbon adsorption tank. The solid-liquid mass ratio between the iron-carbon adsorption particles and the filtered mother liquor is 1:5. Then, carry out stirring with a stirring speed of 20 - 30 r / min and a stirring duration of 10 - 24 h. After the stirring is completed, let it stand for 2 - 3 days. After the activated sludge in the iron-carbon adsorption tank naturally settles, let the supernatant flow out of the iron-carbon adsorption tank. The outflowing supernatant is filtered through an industrial filter cloth again to obtain mother liquor A;

[0010] S2. Biological treatment:

[0011] Construct a biological tank and lay activated sludge at the bottom of the biological tank with a laying thickness of 20 - 30 cm. Then, add a microbial inoculant to the activated sludge with an addition amount of 50 - 100 g / m 3 , then plant green plants on the activated sludge, and then introduce the mother liquor A obtained in step S1 into the biological tank. The mass ratio of the microbial inoculant to the mass of the mother liquor A flowing into the biological tank is 1:80 - 100. Let the mother liquor A circulate in the biological tank for 1 - 2 days and then flow out to obtain mother liquor B;

[0012] S3. Ozone decolorization:

[0013] Construct an ozone aeration tank, lay a microporous ozone pipeline at the bottom of the ozone aeration tank. Then, after filtering the mother liquor B through a filter screen with a mesh number of 80 - 90 meshes, introduce it into the ozone aeration tank. The micropores on the microporous ozone pipeline have a diameter of 2 - 5 mm. After aeration, let it stand and precipitate for 1 - 2 days, and then let the supernatant of the ozone aeration tank flow out to obtain mother liquor C;

[0014] S4. Reagent decolorization:

[0015] Construct two reagent tanks, and then introduce the mother liquor C into the first reagent tank. Add activated carbon and sodium hydroxide solution at 20 - 30 °C. The mass concentration of the sodium hydroxide solution is 30 - 40%, and carry out stirring with a stirring duration of 2 - 3 h. After the stirring is completed, let it stand for 1 - 2 days. Then, introduce the supernatant into the second reagent tank and add a decolorizing agent with a stirring speed of 60 - 80 r / min. Continue to stir for 2 - 3 h and then let it stand for 24 - 36 h. Let the supernatant flow out of the second reagent tank to obtain mother liquor D;

[0016] S5. Membrane filtration treatment:

[0017] Introduce the mother liquor D into a reverse osmosis membrane filtration device for reverse osmosis membrane filtration. After the filtration is completed, obtain the decolorized mother liquor.

[0018] Further, in the step S1, the mesh number of the industrial filter cloth is 300-500 meshes, and the particle size of the iron-carbon particles is 1-3 cm.

[0019] Note: The industrial filter cloth filters the scum in the sodium sulfate evaporation mother liquor of coking wastewater, and the iron-carbon particles can electrolytically oxidize colored organic substances.

[0020] Further, biomass activated carbon particles are also added to the activated sludge in the step S2. The addition amount of the biomass activated carbon particles is 1.5-2.0% of the mass of the activated sludge. The particle size of the biomass activated carbon particles is 0.5-1.0 mm. The biomass activated carbon is made by mixing and stirring activated carbon and chitosan in a mass ratio of 1:1.

[0021] Note: Adding biomass carbon to the activated sludge can improve the adsorption capacity of the activated sludge. The functional groups of chitosan can bind organic substances and heavy metals in the sodium sulfate evaporation mother liquor of coking wastewater.

[0022] Further, the microbial inoculum in the step S2 is composed of the following components in mass percentages: 3-8% Bacillus amyloliquefaciens, 5-15% Bacillus subtilis, 5-13% Aerococcus viridans, 7-16% Pleurotus citrinopileatus mycelium residue, 10-16% Citrobacter H-3, and the balance is Novosphingobium TH-5.

[0023] Note: The purpose of decolorization is achieved by biological self-degradation of colored organic substances.

[0024] Further, the water temperature of the biological pond in the step S2 is 25-30 °C, the pH is 6.3-6.6, and the dissolved oxygen content is 8-10%.

[0025] Note: The above conditions are beneficial to the growth of the inoculum and microorganisms.

[0026] Further, the green plants in the step S2 are composed of cattail, water hyacinth, and duckweed. The planting area ratio of cattail, water hyacinth, and duckweed is 1:1:2. The planting density of cattail is 3-5 plants / m 2 and the planting density of water hyacinth is 4-5 plants / m 2 and the planting density of duckweed is 7-9 plants / m 2 .

[0027] Note: The purpose of decolorization is achieved by ecological purification of colored substances in the wastewater.

[0028] Further, the decolorant in the step S4 is composed of the following components in parts by weight: 2-8 parts of plant ash, 7-16 parts of activated carbon particles, 5-8 parts of boric acid, 9-12 parts of clay, 12-15 parts of aluminum sulfate, 5-11 parts of polyacrylamide, 3-5 parts of sodium metabisulfite, 8-14 parts of sodium chlorate, 6-11 parts of dimethyldiallylammonium salt, and 5-9 parts of titanium sol.

[0029] Description: The decolorizer has an adsorption effect to form flocculants, achieving the effect of decolorization.

[0030] Further, in the reverse osmosis membrane filtration in step S5, the aperture of the reverse osmosis membrane used is 1 - 2 nm, and the working pressure of the reverse osmosis membrane is 4 - 10 MPa.

[0031] Description: Through reverse osmosis membrane filtration, the suspended substances and sediment in the sodium sulfate evaporation mother liquor of coking wastewater are filtered to obtain a pure sodium sulfate evaporation mother liquor of coking wastewater.

[0032] Further, in step S4, the wall pressure of the microporous ozone pipeline in the aeration tank is 0.1 - 0.3 Mpa, the ozone aeration duration is 24 - 36 h, and the unit aeration volume per square meter in the aeration tank is 7 - 10 m 3 / h.

[0033] Description: The oxidation effect of ozone is beneficial to the oxidation and decomposition of colored substances in the sodium sulfate evaporation mother liquor of coking wastewater.

[0034] Further, the addition amount of sodium hydroxide in step S4 is 50 - 100 g / m 3 , the addition amount of activated carbon is 100 - 125 g / m 3 , and the addition amount of the decolorizer is 100 - 150 g / m 3 .

[0035] Description: After the addition of sodium hydroxide, it reacts with non-ferrous metal ions to form precipitate substances, which are adsorbed by activated carbon and then precipitated to remove inorganic colored ions.

[0036] The beneficial effects of the present invention are:

[0037] Since the colored substances in coking wastewater are complex and diverse, including colored organic and inorganic substances, the present invention conducts decolorization treatment on the sodium sulfate evaporation mother liquor of coking wastewater through multiple channels, with good treatment effects, and can effectively oxidize organic colored substances and colored inorganic components that show color, enabling the sodium sulfate evaporation mother liquor of coking wastewater to achieve the purpose of decolorization. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a schematic process flow diagram of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0039] Example 1:

[0040] As Figure 1 shown, a method for deep decolorization treatment of the sodium sulfate evaporation mother liquor of coking wastewater includes the following steps:

[0041] S1. Iron-carbon oxidation decolorization:

[0042] Construct an iron-carbon adsorption tank. Then, first filter the sodium sulfate evaporation mother liquor of coking wastewater through an industrial filter cloth. The filtered mother liquor is introduced into the iron-carbon adsorption tank. Add iron-carbon adsorption particles to the iron-carbon adsorption tank. The solid-liquid mass ratio between the iron-carbon adsorption particles and the filtered mother liquor is 1:5. Then, stir at a stirring speed of 20 r / min for 10 h. After stirring is completed, let it stand for 2 days. After the activated sludge in the iron-carbon adsorption tank naturally settles, let the supernatant flow out of the iron-carbon adsorption tank. The outflowing supernatant is filtered again through an industrial filter cloth to obtain mother liquor A.

[0043] S2. Biological treatment:

[0044] Construct a biological tank, lay activated sludge at the bottom of the biological tank with a laying thickness of 20 - 30 cm. Then, add microbial inoculum to the activated sludge, with the addition amount of the microbial inoculum being 50 g / m 3 , then plant green plants on the activated sludge. Then, introduce the mother liquor A obtained in step S1 into the biological tank. The mass ratio of the microbial inoculum to the mass of the mother liquor A flowing into the biological tank is 1:80. Let the mother liquor A circulate in the biological tank for 1 day and then flow out to obtain mother liquor B.

[0045] S3. Ozone decolorization:

[0046] Construct an ozone aeration tank, lay a microporous ozone pipeline at the bottom of the ozone aeration tank. Then, filter the mother liquor B through a filter screen with a mesh number of 80 meshes and introduce it into the ozone aeration tank. The micropores on the microporous ozone pipeline have a diameter of 2 mm. After aeration, let it stand and precipitate for 1 day, and then let the supernatant of the ozone aeration tank flow out to obtain mother liquor C.

[0047] S4. Reagent decolorization:

[0048] Construct two reagent tanks. Then, introduce the mother liquor C into the first reagent tank, add activated carbon and sodium hydroxide solution at 20 - 30 °C. The mass concentration of the sodium hydroxide solution is 30%, and stir for 2 h. After stirring is completed, let it stand for 1 day. Then, introduce the supernatant into the second reagent tank and add a decolorizing agent, with a stirring speed of 60 r / min. Continue to stir for 2 h, and then let it stand for 24 h. Let the supernatant flow out of the second reagent tank to obtain mother liquor D.

[0049] S5. Membrane filtration treatment:

[0050] Introduce the mother liquor D into a reverse osmosis membrane filtration device for reverse osmosis membrane filtration. After filtration is completed, obtain the decolorized mother liquor.

[0051] In step S1, the mesh number of the industrial filter cloth is 300 meshes, the particle size of the iron-carbon particles is 1 - 3 cm. The industrial filter cloth filters the scum in the sodium sulfate evaporation mother liquor of coking wastewater, and the iron-carbon particles can electrolytically oxidize colored organic substances.

[0052] In step S2, the microbial inoculum consists of the following components by mass percentage: 3% Bacillus amyloliquefaciens, 5% Bacillus subtilis, 5% Aerococcus viridans, 7% Pleurotus citrinopileatus residue, 10% Citrobacter sp. H-3, and the balance is Sphingobacterium thalpophilum TH-5, achieving the purpose of decolorization by biodegradation of colored organic substances.

[0053] In step S2, the water temperature of the biological pool is 25 °C, the pH is 6.3, and the dissolved oxygen content is 8%, which is beneficial to the growth of the inoculum and microorganisms.

[0054] In step S2, the green plants consist of cattail, water hyacinth, and duckweed. The planting area ratio of cattail, water hyacinth, and duckweed is 1:1:2, and the planting density of cattail is 3 plants / m 2 , the planting density of water hyacinth is 4 plants / m 2 , the planting density of duckweed is 7 plants / m 2 , achieving the purpose of decolorization by ecological purification of colored substances in wastewater.

[0055] In step S4, the decolorant consists of the following components by weight: 2 parts of plant ash, 7 parts of activated carbon particles, 5 parts of boric acid, 9 parts of clay, 12 parts of aluminum sulfate, 5 parts of polyacrylamide, 3 parts of sodium metabisulfite, 8 parts of sodium chlorate, 6 parts of dimethyldiallylammonium salt, and 5 parts of titanium sol. The decolorant has an adsorption effect to form flocs, achieving the decolorization effect.

[0056] In step S5, the aperture of the reverse osmosis membrane used in reverse osmosis membrane filtration is 1 - 2 nm, and the working pressure of the reverse osmosis membrane is 4 MPa. Through reverse osmosis membrane filtration, the suspended substances and sediment in the sodium sulfate evaporation mother liquor of coking wastewater are filtered to obtain pure sodium sulfate evaporation mother liquor of coking wastewater.

[0057] In step S4, the wall pressure of the microporous ozone pipeline in the aeration tank is 0.1 Mpa, the ozone aeration duration is 24 h, and the unit aeration volume per square meter in the aeration tank is 7 m 3 / h. The oxidation effect of ozone is beneficial to the oxidation and decomposition of colored substances in the sodium sulfate evaporation mother liquor of coking wastewater.

[0058] The addition amount of sodium hydroxide in step S4 is 50 g / m 3 , the addition amount of activated carbon is 100 g / m 3 , the addition amount of decolorant is 100 g / m 3 , after the addition of sodium hydroxide, it reacts with non-ferrous metal ions to form precipitate substances, which are adsorbed by activated carbon and precipitated to remove inorganic colored ions.

[0059] Example 2:

[0060] As Figure 1As shown, a method for deep decolorization treatment of sodium sulfate evaporation mother liquor of coking wastewater includes the following steps:

[0061] S1. Iron-carbon oxidation decolorization:

[0062] Build an iron-carbon adsorption tank. First, filter the sodium sulfate evaporation mother liquor of coking wastewater through an industrial filter cloth. The filtered mother liquor is introduced into the iron-carbon adsorption tank. Add iron-carbon adsorption particles to the iron-carbon adsorption tank. The solid-liquid mass ratio between the iron-carbon adsorption particles and the filtered mother liquor is 1:5. Then stir at a stirring speed of 25 r / min for 20 h. After stirring is completed, let it stand for 2.5 days. After the activated sludge in the iron-carbon adsorption tank naturally settles, make the supernatant flow out of the iron-carbon adsorption tank. The outflowing supernatant is filtered through an industrial filter cloth again to obtain mother liquor A;

[0063] S2. Biological treatment:

[0064] Build a biological pond, lay activated sludge at the bottom of the biological pond with a laying thickness of 25 cm. Then add microbial inoculant to the activated sludge. The addition amount of the microbial inoculant is 80 g / m 3 , then plant green plants on the activated sludge. Then introduce mother liquor A obtained in step S1 into the biological pond. The mass ratio of the microbial inoculant to the mass of mother liquor A flowing into the biological pond is 1:90. Let mother liquor A circulate in the biological pond for 1.5 days and then flow out to obtain mother liquor B;

[0065] S3. Ozone decolorization:

[0066] Build an ozone aeration tank, lay a microporous ozone pipeline at the bottom of the ozone aeration tank. Then filter mother liquor B through a filter screen with a mesh number of 85 meshes and introduce it into the ozone aeration tank. The micropore diameter on the microporous ozone pipeline is 4 mm. After aeration, let it stand and precipitate for 1.5 days. Then make the supernatant on the upper layer of the ozone aeration tank flow out to obtain mother liquor C;

[0067] S4. Reagent decolorization:

[0068] Build two reagent tanks. Then introduce mother liquor C into the first reagent tank. Add activated carbon and sodium hydroxide solution at 25 °C. The mass concentration of the sodium hydroxide solution is 35%. Stir for 2.5 h. After stirring is completed, let it stand for 1.5 days. Then introduce the supernatant into the second reagent tank and add a decolorizing agent. Stir at a stirring speed of 70 r / min and continue to stir for 2.5 h. Then let it stand for 30 h. Make the supernatant flow out of the second reagent tank to obtain mother liquor D;

[0069] S5. Membrane filtration treatment:

[0070] Introduce mother liquor D into a reverse osmosis membrane filtration device for reverse osmosis membrane filtration. After filtration is completed, obtain decolorized mother liquor.

[0071] In step S1, the mesh number of the industrial filter cloth is 400 meshes, the particle size of the iron-carbon particles is 1-3 cm. The industrial filter cloth filters the scum in the sodium sulfate evaporation mother liquor of coking wastewater, and the iron-carbon particles can electrolytically oxidize colored organic substances.

[0072] In step S2, the microbial inoculant is composed of the following components by mass percentage: 4% Bacillus amyloliquefaciens, 10% Bacillus subtilis, 10% Aerococcus viridans, 10% Pleurotus citrinopileatus residue, 13% Citrobacter sp. H-3, and the balance is Sphingobacterium novum TH-5. The colored organic substances are decolorized through biodegradation.

[0073] In step S2, the water temperature of the biological pond is 28 °C, the pH is 6.5, and the dissolved oxygen content is 9%, which is beneficial to the growth of the inoculant and microorganisms.

[0074] In step S2, the green plants are composed of cattail, water hyacinth, and duckweed. The planting area ratio of cattail, water hyacinth, and duckweed is 1:1:2. The planting density of cattail is 4 plants / m 2 , the planting density of water hyacinth is 5 plants / m 2 , the planting density of duckweed is 8 plants / m 2 , and the colored substances in the wastewater are decolorized through ecological purification.

[0075] In step S4, the decolorant is composed of the following components by weight: 7 parts of plant ash, 14 parts of activated carbon particles, 7 parts of boric acid, 10 parts of clay, 13 parts of aluminum sulfate, 8 parts of polyacrylamide, 4 parts of sodium metabisulfite, 10 parts of sodium chlorate, 10 parts of dimethyldiallyl quaternary ammonium salt, 8 parts of titanium sol. The decolorant has an adsorption effect to form flocs, achieving the decolorization effect.

[0076] In step S5, the pore size of the reverse osmosis membrane used in the reverse osmosis membrane filtration is 1-2 nm, and the working pressure of the reverse osmosis membrane is 5 MPa. Through the reverse osmosis membrane filtration, the suspended substances and sediment in the sodium sulfate evaporation mother liquor of coking wastewater are filtered to obtain pure sodium sulfate evaporation mother liquor of coking wastewater.

[0077] In step S4, the wall pressure of the microporous ozone pipeline in the aeration tank is 0.2 Mpa, the ozone aeration duration is 30 h, and the unit aeration volume per square meter in the aeration tank is 8 m 3 / h. The oxidation effect of ozone is beneficial to the oxidation and decomposition of the colored substances in the sodium sulfate evaporation mother liquor of coking wastewater.

[0078] The addition amount of sodium hydroxide in step S4 is 80 g / m 3 , the addition amount of activated carbon is 110 g / m 3 , the addition amount of the decolorant is 125 g / m 3 , after the addition of sodium hydroxide, it reacts with non-ferrous metal ions to form precipitate substances, which are adsorbed by activated carbon and precipitated to remove inorganic colored ions.

[0079] Example 3:

[0080] As Figure 1 shown, a method for deep decolorization treatment of sodium sulfate evaporation mother liquor of coking wastewater includes the following steps:

[0081] S1. Iron-carbon oxidation decolorization:

[0082] Build an iron-carbon adsorption tank, then filter the sodium sulfate evaporation mother liquor of coking wastewater through an industrial filter cloth first, and the filtered mother liquor is introduced into the iron-carbon adsorption tank. Add iron-carbon adsorption particles to the iron-carbon adsorption tank, and the solid-liquid mass ratio between the iron-carbon adsorption particles and the filtered mother liquor is 1:5. Then stir at a stirring speed of 30 r / min for 24 h. After stirring, let it stand for 3 days. After the activated sludge in the iron-carbon adsorption tank naturally settles, make the supernatant flow out of the iron-carbon adsorption tank, and the outflowing supernatant is filtered through an industrial filter cloth again to obtain mother liquor A;

[0083] S2. Biological treatment:

[0084] Build a biological tank, lay activated sludge at the bottom of the biological tank, and the laying thickness of the activated sludge is 30 cm. Then add microbial inoculant to the activated sludge, and the addition amount of the microbial inoculant is 100 g / m 3 , then plant green plants on the activated sludge, and then introduce mother liquor A obtained in step S1 into the biological tank. The mass ratio of the microbial inoculant to the mass of mother liquor A flowing into the biological tank is 1:100. Let mother liquor A circulate in the biological tank for 2 days and then flow out to obtain mother liquor B;

[0085] S3. Ozone decolorization:

[0086] Build an ozone aeration tank, lay a microporous ozone pipeline at the bottom of the ozone aeration tank, and then filter mother liquor B through a filter screen with a mesh number of 90 meshes and introduce it into the ozone aeration tank. The micropore diameter on the microporous ozone pipeline is 5 mm. After aeration, let it stand and precipitate for 2 days, and then make the supernatant on the upper layer of the ozone aeration tank flow out to obtain mother liquor C;

[0087] S4. Reagent decolorization:

[0088] Build two reagent tanks, then introduce mother liquor C into the first reagent tank, add activated carbon and sodium hydroxide solution at 30 °C, and the mass concentration of the sodium hydroxide solution is 40%. Then stir for 3 h. After stirring, let it stand for 2 days. Then introduce the supernatant into the second reagent tank and add a decolorizing agent, and stir at a stirring speed of 80 r / min for another 3 h. Then let it stand for 36 h, and make the supernatant flow out of the second reagent tank to obtain mother liquor D;

[0089] S5. Membrane filtration treatment:

[0090] The mother liquor D is passed into a reverse osmosis membrane filtration device for reverse osmosis membrane filtration, and the decolorized mother liquor is obtained after filtration is completed.

[0091] In step S1, the mesh number of the industrial filter cloth is 500 meshes, the particle diameter of the iron-carbon particles is 3 cm. The industrial filter cloth filters the scum in the sodium sulfate evaporation mother liquor of coking wastewater, and the iron-carbon particles can electrolytically oxidize colored organic substances.

[0092] In step S2, the microbial inoculant is composed of the following components by mass percentage: 8% Bacillus amyloliquefaciens, 15% Bacillus subtilis, 13% Aerococcus viridans, 16% Pleurotus citrinopileatus residue, 16% Citrobacter H-3, and the balance is Sphingobacterium novum TH-5. The colored organic substances are biodegraded to achieve the purpose of decolorization.

[0093] In step S2, the water temperature of the biological pool is 30 °C, the pH is 6.6, and the dissolved oxygen content is 10%, which is beneficial to the growth of the inoculant and microorganisms.

[0094] In step S2, the green plants consist of cattail, water hyacinth, and duckweed. The planting area ratio of cattail, water hyacinth, and duckweed is 1:1:2. The planting density of cattail is 5 plants / m 2 , the planting density of water hyacinth is 5 plants / m 2 , and the planting density of duckweed is 9 plants / m 2 , and the colored substances in the wastewater are ecologically purified to achieve the purpose of decolorization.

[0095] In step S4, the decolorant is composed of the following components by weight: 8 parts of plant ash, 16 parts of activated carbon particles, 8 parts of boric acid, 12 parts of clay, 15 parts of aluminum sulfate, 11 parts of polyacrylamide, 5 parts of sodium metabisulfite, 14 parts of sodium chlorate, 11 parts of dimethyldiallyl quaternary ammonium salt, and 9 parts of titanium sol. The decolorant has an adsorption effect to form flocs, achieving the effect of decolorization.

[0096] In step S5, the aperture of the reverse osmosis membrane used in the reverse osmosis membrane filtration is 1-2 nm, and the working pressure of the reverse osmosis membrane is 10 MPa. Through reverse osmosis membrane filtration, the suspended substances and sediment in the sodium sulfate evaporation mother liquor of coking wastewater are filtered to obtain pure sodium sulfate evaporation mother liquor of coking wastewater.

[0097] In step S4, the wall pressure of the microporous ozone pipeline in the aeration tank is 0.3 Mpa, the ozone aeration duration is 24-36 h, and the unit aeration volume per square meter in the aeration tank is 10 m 3 / h. The oxidation effect of ozone is beneficial to the oxidation and decomposition of the colored substances in the sodium sulfate evaporation mother liquor of coking wastewater.

[0098] In step S4, the addition amount of sodium hydroxide is 50-100 g / m 3 , and the addition amount of activated carbon is 125 g / m 3, the dosage of the decolorizer is 100 - 150 g / m 3 , after the addition of sodium hydroxide, it reacts with non-ferrous metal ions to form precipitate substances, which are adsorbed by activated carbon and then precipitated to remove inorganic colored ions.

[0099] Comparing Example 1 - Example 3, in actual application, Example 3 has the best decolorization effect, so Example 3 is the best example.

[0100] Example 4:

[0101] Based on Example 3, the difference between Example 4 and Example 3 is that in step S2, biomass activated carbon particles are further added to the activated sludge. The dosage of the biomass activated carbon particles is 1.5% of the mass of the activated sludge, and the particle size of the biomass activated carbon particles is 0.5 mm. The biomass activated carbon is made by mixing and stirring activated carbon and chitosan in a mass ratio of 1:1. Adding biomass carbon to the activated sludge can improve the adsorption capacity of the activated sludge, and the functional groups of chitosan can bind the organic substances and heavy metals in the sodium sulfate evaporation mother liquor of coking wastewater.

[0102] Example 5:

[0103] Based on Example 3, the difference between Example 5 and Example 3 is that in step S2, biomass activated carbon particles are further added to the activated sludge. The dosage of the biomass activated carbon particles is 1.8% of the mass of the activated sludge, and the particle size of the biomass activated carbon particles is 0.8 mm. The biomass activated carbon is made by mixing and stirring activated carbon and chitosan in a mass ratio of 1:1. Adding biomass carbon to the activated sludge can improve the adsorption capacity of the activated sludge, and the functional groups of chitosan can bind the organic substances and heavy metals in the sodium sulfate evaporation mother liquor of coking wastewater.

[0104] Example 6:

[0105] Based on Example 3, the difference between Example 6 and Example 3 is that in step S2, biomass activated carbon particles are further added to the activated sludge. The dosage of the biomass activated carbon particles is 2.0% of the mass of the activated sludge, and the particle size of the biomass activated carbon particles is 1.0 mm. The biomass activated carbon is made by mixing and stirring activated carbon and chitosan in a mass ratio of 1:1. Adding biomass carbon to the activated sludge can improve the adsorption capacity of the activated sludge, and the functional groups of chitosan can bind the organic substances and heavy metals in the sodium sulfate evaporation mother liquor of coking wastewater.

[0106] Comparing Example 4 - Example 6, in actual decolorization treatment, Example 6 has the best effect, so Example 6 is the best example.

Claims

1. A method for the deep decolorization treatment of sodium sulfate evaporation mother liquor of coking wastewater, characterized in that, It includes the following steps: S1. Iron-carbon oxidation decolorization: Construct an iron-carbon adsorption tank. Then, first filter the coking wastewater sodium sulfate evaporation mother liquor through an industrial filter cloth. The filtered mother liquor is introduced into the iron-carbon adsorption tank. Add iron-carbon adsorption particles to the iron-carbon adsorption tank. The solid-liquid mass ratio between the iron-carbon adsorption particles and the filtered mother liquor is 1:

5. Then, stir at a stirring speed of 20 - 30 r / min for a stirring duration of 10 - 24 h. After stirring is completed, let it stand for 2 - 3 days. After the activated sludge in the iron-carbon adsorption tank naturally settles, make the supernatant flow out of the iron-carbon adsorption tank. The outflowing supernatant is filtered through an industrial filter cloth again to obtain mother liquor A; S2. Biological treatment: Construct a biological pond, lay activated sludge at the bottom of the biological pond, with the laying thickness of the activated sludge being 20 - 30 cm, then add microbial inoculant into the activated sludge, and the addition amount of the microbial inoculant is 50 - 100 g / m 3 , then plant green plants on the activated sludge, and then introduce the mother liquor A obtained in step S1 into the biological pond. The ratio of the mass of the microbial inoculant to the mass of the mother liquor A flowing into the biological pond is 1:80 - 100, and let the mother liquor A circulate in the biological pond for 1 - 2 days and then flow out to obtain mother liquor B; S3. Ozone decolorization: Construct an ozone aeration tank. Lay the microporous ozone pipeline at the bottom of the ozone aeration tank. Then, after filtering the mother liquor B through a filter screen with a mesh number of 80 - 90 meshes, introduce it into the ozone aeration tank. The micropores on the microporous ozone pipeline have a diameter of 2 - 5 mm. After aeration, let it stand and precipitate for 1 - 2 days, and then make the supernatant of the ozone aeration tank flow out to obtain mother liquor C; S4. Reagent decolorization: Construct two reagent tanks. Then, introduce mother liquor C into the first reagent tank. Add activated carbon and sodium hydroxide solution at 20 - 30 °C. The mass concentration of the sodium hydroxide solution is 30 - 40%. Stir for a stirring duration of 2 - 3 h. After stirring is completed, let it stand for 1 - 2 days. Then, introduce the supernatant into the second reagent tank and add a decolorizing agent. Stir at a stirring speed of 60 - 80 r / min and continue to stir for 2 - 3 h. Then, let it stand for 24 - 36 h, and make the supernatant flow out of the second reagent tank to obtain mother liquor D; S5. Membrane filtration treatment: Introduce mother liquor D into a reverse osmosis membrane filtration device for reverse osmosis membrane filtration. After filtration is completed, obtain the decolorized mother liquor; In step S1, the mesh number of the industrial filter cloth is 300 - 500 meshes, and the particle size of the iron-carbon particles is 1 - 3 cm; In step S2, biomass activated carbon particles are also added to the activated sludge. The addition amount of the biomass activated carbon particles is 1.5 - 2.0% of the mass of the activated sludge. The particle size of the biomass activated carbon particles is 0.5 - 1.0 mm. The biomass activated carbon is made by mixing activated carbon and chitosan at a mass ratio of 1:1 and stirring; The microbial inoculant in step S2 is composed of the following components by mass percentage: 3 - 8% Bacillus amyloliquefaciens, 5 - 15% Bacillus subtilis, 5 - 13% Aerococcus viridans, 7 - 16% Pleurotus citrinopileatus mycelium residue, 10 - 16% Citrobacter sp. H-3, and the balance is Novosphingobium sp. TH-5; In step S2, the water temperature of the biological tank is 25 - 30 °C, the pH is 6.3 - 6.6, and the dissolved oxygen content is 8 - 10%; 2. The method for deep decolorization treatment of sodium sulfate evaporation mother liquor from coking wastewater according to claim 1, characterized in that, The green plants described in step S2 are composed of cattails, water hyacinths, and duckweeds. The planting area ratio of cattails, water hyacinths, and duckweeds is 1:1:2, and the planting density of cattails is 3 - 5 plants / m 2 , the planting density of water hyacinths is 4 - 5 plants / m 2 , and the planting density of duckweeds is 7 - 9 plants / m 2 .

3. A method for deep decolorization treatment of sodium sulfate evaporation mother liquor from coking wastewater as claimed in claim 1, characterized in that, The decolorizing agent in step S4 is composed of the following components by weight: 2 - 8 parts of plant ash, 7 - 16 parts of activated carbon particles, 5 - 8 parts of boric acid, 9 - 12 parts of clay, 12 - 15 parts of aluminum sulfate, 5 - 11 parts of polyacrylamide, 3 - 5 parts of sodium metabisulfite, 8 - 14 parts of sodium chlorate, 6 - 11 parts of dimethyldiallyl quaternary ammonium salt, 5 - 9 parts of titanium sol.

4. A method for deep decolorization treatment of sodium sulfate evaporation mother liquor from coking wastewater according to claim 1, characterized in that, In the reverse osmosis membrane filtration in step S5, the aperture of the reverse osmosis membrane used is 1-2 nm, and the working pressure of the reverse osmosis membrane is 4-10 MPa.

5. The method for deep decolorization treatment of sodium sulfate evaporation mother liquor from coking wastewater according to claim 1, characterized in that, In the step S4, the wall pressure of the microporous ozone pipeline in the aeration tank is 0.1-0.3 Mpa, the ozone aeration duration is 24-36 h, and the unit aeration volume per square meter in the aeration tank is 7-10 m 3 / h.

6. The method for deep decolorization treatment of sodium sulfate evaporation mother liquor of coking wastewater according to claim 1, characterized in that, The addition amount of sodium hydroxide in the step S4 is 50 - 100 g / m 3 , the addition amount of activated carbon is 100 - 125 g / m 3 , the addition amount of decolorizing agent is 100 - 150 g / m 3 .

Images