Process for combined deep treatment of coking wastewater

Abstract

The application relates to a process for jointly deep treating coking wastewater, which comprises pretreatment, adsorption in an adsorption tower, biochemical treatment and filtration of the treated water; wherein a composite biological filler is used in the biochemical treatment process, and the composite biological filler is made of activated sludge, fly ash, polystyrene-polyethylene block, microbial flora, polyurethane foam carrier and modified cellulose solution. In the treatment process, the wastewater is first subjected to an adsorption tower containing porous carbon materials, so that the difficult-to-treat impurities in the wastewater can be effectively reduced, and the organic load of the biochemical treatment can be reduced; nitrification and denitrification reactions are carried out in an anoxic tank and an aerobic tank, and the composite biological filler is filled in the aerobic tank, the filler is formed by embedding and adsorbing a certain microbial flora in activated sludge and then fixing the activated sludge on a polyurethane foam carrier, the filler has good microbial fixing effect and strong mechanical stability, can effectively remove residual organic matter and ammonia nitrogen and the like, has high removal rate, has short operation cycle in the whole coking wastewater treatment process, has low equipment investment and high economic benefit.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment, in particular to a process for combined deep treatment of coking wastewater. BACKGROUND

[0002] At present, the common methods of water treatment technology mainly include physical and chemical methods such as coagulation sedimentation, adsorption and chemical precipitation method, biological treatment method mainly using the oxidation and adsorption of microorganisms such as anaerobic digestion method, aerobic degradation method, activated sludge method and biological fluidized bed, and membrane separation method and advanced oxidation method. When the biological treatment method is used, due to the difficulty of microorganisms to tolerate high organic matter and ammonia nitrogen in coking wastewater, about one time of defoaming water is added as dilution water during treatment, which greatly increases the amount of coking wastewater. Based on this, the wastewater is first pretreated by the adsorption tower before the biological treatment method, and then the biochemical treatment is carried out by the composite biological filler after the special fixed microorganism, which can greatly improve the water treatment effect, has few treatment process steps, low operation cost, and the effluent can reach the national discharge standard. SUMMARY

[0003] In view of the deficiencies in the prior art, the present application provides a process for combined deep treatment of coking wastewater.

[0004] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0005] A process for combined deep treatment of coking wastewater, comprising the following steps:

[0006] 1) Pretreatment

[0007] The coking wastewater is transported from the adjusting tank to the primary sedimentation tank to remove the suspended solids in the water body;

[0008] 2) Adsorption by adsorption tower

[0009] The coking wastewater from the primary sedimentation tank is transported to the adsorption tower filled with porous carbon material to reduce the content of pollutants in the coking wastewater;

[0010] 3) Biochemical treatment

[0011] The water discharged from the adsorption tower is sequentially transported to the anoxic tank and the aerobic tank, and the aerobic tank is filled with composite biological filler;

[0012] 4) Filtration of effluent;

[0013] The composite biological filler comprises the following raw materials by weight: 20-30 parts of activated sludge, 10-20 parts of fly ash, 4-8 parts of polystyrene-polyethylene block, 15-20 parts of microbial flora, 40-60 parts of polyurethane foam carrier, and 80-100 parts of modified cellulose solution.

[0014] The activated sludge is collected from a coking aerobic tank and an anaerobic tank, and the collected sludge is concentrated to obtain the activated sludge.

[0015] The polyurethane foam carrier is prepared by the following method:

[0016] S1, the chitosan powder is added to the chloroethylamine hydrochloride, heated and stirred in a constant temperature water bath until the chitosan is dissolved; then sodium hydroxide solution is slowly added dropwise under stirring, after the dropwise addition is completed, the temperature is raised to 80℃ and stirring is continued overnight, after cooling, dialysis, and freeze-drying, the amino-modified chitosan is obtained and reserved;

[0017] S2, polyether polyol, isophorone diisocyanate, 2,2-dimethylol propionic acid, 1,4-butanediol and stannous octoate are added to the reaction vessel, and reacted at 80-100℃, after cooling, deionized water is added and dispersed at high speed to obtain a polyurethane prepolymer with a solid content of 35wt%, which is reserved;

[0018] S3, the amino-modified chitosan is dissolved in deionized water and then mixed with the polyurethane prepolymer, a foaming agent, a surfactant, and a catalyst are added to the mixture and stirred until uniform; then isocyanate is added and continued to stir, and then poured into a foaming mold, foamed and shaped, and cured at room temperature for 48h;

[0019] S4, the prepared polyurethane foam is cut and placed in a sealed high-pressure box, hydrogen gas is injected to open the pores, and a polyurethane foam carrier is prepared;

[0020] The preparation process of the modified cellulose solution is as follows:

[0021] In the reaction bottle, hydroxyethyl cellulose and water are stirred and dissolved, then epichlorohydrin is added, the pH is adjusted to alkaline, the temperature is raised to 70℃ and reacted for 5h, then cooled to room temperature, amino-functionalized graphene is added, ultrasonic treatment is carried out for 30-60min, centrifugal separation is carried out, and then washed with ethanol and water for three times, after which it is ultrasonic dispersed in deionized water again, dodecyl alcohol polyoxyethylene ether acrylate is added, and grafting reaction is carried out under ultrasonic irradiation.

[0022] Further, the porous carbon material is prepared by using N-carboxymethyl chitosan as a carbon source and a nitrogen source, thiophene as a sulfur source, and 2-acrylamido-2-methylpropanesulfonic acid as a supplementary nitrogen source and a sulfur source to obtain an N / S-doped chitosan precursor, and then by using sodium chloride and sodium silicate as hard templates and potassium acetate as an activator, the N / S-doped porous carbon material is obtained by calcination.

[0023] Further, in step S2, the mass ratio of polyether polyol, isophorone diisocyanate, 2,2-dimethylol propionic acid, and 1,4-butanediol is 1-2:1-2:0.5-1:0.3-0.5.

[0024] Further, in the step S3, the weight parts of the amino-modified chitosan, the polyurethane prepolymer, the foaming agent, the surfactant and the catalyst are 20-30 parts, 70-100 parts, 2-5 parts, 1-4 parts and 1-5 parts respectively.

[0025] Further, in the step S3, the foaming agent is one of n-hexane, n-pentane, isopentane and petroleum ether; the surfactant is silicon oil or stearic acid; and the catalyst is N,N-dimethylcyclohexylamine or triethylenediamine.

[0026] Further, in the preparation of the modified cellulose solution, the mass ratio of the hydroxyethyl cellulose, the epichlorohydrin and the aminated graphene is 2-3:1:1.

[0027] Further, the ultrasonic irradiation condition is that the ultrasonic frequency is 20kHZ-1MHz, the irradiation intensity is 20-50W / cm 2 , and the irradiation time is 1-3h.

[0028] Compared with the prior art, the coking wastewater treatment process has the advantages that: the adsorption treatment is performed in advance before the biochemical treatment, the wastewater is treated by the adsorption tower containing the porous carbon material, the suspended organic matter, the refractory phenolic aromatic compounds and the metal ions and other impurities in the wastewater can be effectively reduced, and the organic load of the biochemical treatment is reduced; the nitrification and denitrification reactions are performed in the anoxic tank and the aerobic tank, the composite biological filler is filled in the aerobic tank, the filler is formed by embedding and adsorbing a certain microbial flora in the active sludge and then being fixed on the polyurethane foam carrier, the fixing effect of the filler on the microorganism is good, the mechanical stability is strong, the residual organic matter and ammonia nitrogen and the like in the coking wastewater can be effectively removed, the removal rate is high, the effluent reaches the national first emission standard, the operation cycle in the whole coking wastewater treatment process is short, the equipment investment is small, and the economic benefit is high. DETAILED DESCRIPTION

[0029] The technical solutions of the present application will be described clearly and completely below in conjunction with the embodiments, obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by the ordinary skilled in the art without creative labor belong to the protection scope of the present application.

[0030] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0031] Embodiment:

[0032] 1. A process for combined advanced treatment of coking wastewater, characterized in that it comprises the following steps:

[0033] 1) Pretreatment

[0034] The coking wastewater is transported from the conditioning tank to the primary sedimentation tank to remove suspended solids in the water body;

[0035] 2) Adsorption tower adsorption

[0036] The coking wastewater from the primary sedimentation tank is transported to an adsorption tower filled with porous carbon material to reduce the content of pollutants in the coking wastewater;

[0037] 3) Biological treatment

[0038] The water discharged from the adsorption tower is transported to the anoxic tank and the aerobic tank in turn, and the aerobic tank is filled with composite biological filler;

[0039] 4) Filtered water;

[0040] The nitrogen and sulfur doped porous carbon material is prepared by using N-carboxymethyl chitosan as the carbon source and nitrogen source, thiophene as the sulfur source, and 2-acrylamido-2-methylpropanesulfonic acid as the supplementary nitrogen source and sulfur source to obtain an N / S doped chitosan precursor, and then calcining under the condition of sodium chloride and sodium silicate as hard templates and potassium acetate as an activator to obtain the nitrogen and sulfur doped porous carbon material. Refer to Example 1 of application number 2023104803253.

[0041] The composite biological filler includes the following raw materials by weight: 20 parts of activated sludge, 10 parts of fly ash, 4 parts of polystyrene-polyethylene block, 15 parts of microbial flora, 40 parts of polyurethane foam carrier, and 80 parts of modified cellulose solution.

[0042] 1) A measured amount of microbial flora nitrifying bacteria, bacillus, denitrifying bacteria, and yeast (mass ratio 3:2:4:1) are cultured separately and then mixed to obtain a microbial flora suspension;

[0043] 2) A measured amount of fly ash and polystyrene-polyethylene block are mixed and calcined at 600-800°C for 1-2h, and then mixed with activated sludge after cooling for standby use;

[0044] 3) The product obtained in step 2) is immersed in the microbial flora suspension of step 1) for 2-10h;

[0045] 4) The polyurethane foam carrier is immersed in the modified cellulose solution for 12-48h, dried after removal, then placed in the suspension of step 3) and shaken in a constant temperature shaker at 25°C for 24-48h, and dried after removal to obtain the product.

[0046] The activated sludge is collected from the coking aerobic tank and anaerobic tank microbial sludge, and the collected sludge is concentrated to obtain the activated sludge.

[0047] The polyurethane foam carrier is prepared by the following method:

[0048] S1, 10 g of chitosan powder is added to 500 ml of 1 mol / L chloroethylamine hydrochloride, heated and stirred under constant temperature water bath conditions until the chitosan is dissolved; then equal volume of 1 mol / L sodium hydroxide solution is slowly added dropwise under stirring conditions, after the dropwise addition is completed, the temperature is raised to 80℃ and stirring is continued overnight, after cooling, dialysis, freeze-drying to obtain amino-modified chitosan, which is ready for use;

[0049] S2, 100 parts of polyether polyol, 100 parts of isophorone diisocyanate, 50 parts of 2,2-dimethylol propionic acid, 30 parts of 1,4-butanediol and stannous octoate are added to a reaction vessel, and reacted at 80-100℃, after cooling, deionized water is added and dispersed at high speed to obtain a polyurethane prepolymer with a solid content of 35wt%, which is ready for use;

[0050] S3, 20 parts of amino-modified chitosan is stirred and dissolved in deionized water, then mixed with 100 parts of polyurethane prepolymer, 3 parts of n-pentane, 2 parts of silicone oil surfactant and 3 parts of N,N-dimethylcyclohexylamine are added to the mixture and stirred and dispersed uniformly; then an appropriate amount of isocyanate is added, and after continuous stirring, it is poured into a foaming mold, foamed and shaped, and cured at room temperature for 48h;

[0051] S4, the prepared polyurethane foam is cut and placed in a sealed high-pressure box, hydrogen gas is injected, and the hydrogen gas in the sealed state is detonated to open the holes, and a polyurethane foam carrier with a honeycomb structure is prepared;

[0052] The preparation process of the modified cellulose solution is as follows:

[0053] In a reaction bottle, 20 parts of hydroxyethyl cellulose and 100 parts of water are stirred and dissolved, then 10 parts of epoxy chloropropane is added, the pH is adjusted to alkaline, the temperature is raised to 70℃ and reacted for 5h, then cooled to room temperature, 10 parts of amino graphene is added, ultrasonic for 30-60min, centrifugal separation, washed with ethanol and water for three times, then ultrasonic dispersed in deionized water again, add dodecyl alcohol polyoxyethylene ether acrylate, grafting reaction under ultrasonic irradiation, ultrasonic irradiation conditions: ultrasonic frequency is 50kHZ, irradiation intensity is 30W / cm 2 , irradiation time is 3h.

[0054] Example 2:

[0055] The same as example 1, the difference is that the composite biological filler includes the following raw materials by weight: 25 parts of activated sludge, 10 parts of fly ash, 4 parts of polystyrene-polyethylene block, 20 parts of microbial flora, 50 parts of polyurethane foam carrier, 90 parts of modified cellulose solution.

[0056] Example 3:

[0057] The same as example 1, except that the composite biofiller comprises the following raw materials by weight: 30 parts of activated sludge, 20 parts of fly ash, 8 parts of polystyrene-polyethylene block, 20 parts of microbial flora, 60 parts of polyurethane foam carrier, and 100 parts of modified cellulose solution.

[0058] Effect evaluation:

[0059] The main water quality indexes of the coking wastewater influent are as follows: COD 3450 mg / L, ammonia nitrogen 240 mg / L, volatile phenol 1140 mg / L, cyanide 30 mg / L, and sulfide 100 mg / L.

[0060] The coking wastewater discharge standard GB 16171-2012: COD≤80 mg / L, ammonia nitrogen≤10 mg / L, volatile phenol≤0.3 mg / L, cyanide≤0.2 mg / L, and sulfide≤0.5 mg / L.

[0061] The treatment of the coking wastewater by each example is shown in Table 1

[0062] Table 1

[0063] COD mg / L ammonia nitrogen mg / L volatile phenol mg / L cyanide mg / L sulfide mg / L Example 1 51 7.9 0.2 0.2 0.3 Example 2 48 7.3 0.2 0.1 0.2 Example 3 43 7.2 0.1 0.1 0.1

[0064] As shown in Table 1, the effluent quality of the coking wastewater treated by the process of the present application meets the requirement of the direct discharge standard.

[0065] Although the embodiments of the present application have been disclosed as above, it is not limited to the application listed in the specification and the embodiments, and can be fully applied to various fields suitable for the present application, and other modifications can be easily realized by those skilled in the art, and therefore the present application is not limited to specific details, but falls within the general concept defined by the claims and the equivalent scope.

Claims

1. A process for combined deep treatment of coking wastewater, characterized in that, It comprises the following steps: 1) pretreatment The coking wastewater is transported from the conditioning tank to the first sedimentation tank to remove suspended solids in the water body; 2) adsorption tower adsorption The coking wastewater from the first sedimentation tank is transported to the adsorption tower filled with porous carbon material to reduce the content of pollutants in the coking wastewater; 3) biochemical treatment The water discharged from the adsorption tower is transported to the anoxic tank and the aerobic tank in turn, and the aerobic tank is filled with composite biological filler; 4) filtered water; The composite biological filler comprises the following raw materials by weight: 20-30 parts of activated sludge, 10-20 parts of fly ash, 4-8 parts of polystyrene-polyethylene block, 15-20 parts of microbial flora, 40-60 parts of polyurethane foam carrier, and 80-100 parts of modified cellulose solution. The activated sludge is collected from the coking aerobic tank and anaerobic tank sludge, and the collected sludge is concentrated to obtain the activated sludge. The polyurethane foam carrier is prepared by the following method: S1, add chitosan powder to chloroethylamine hydrochloride, heat and stir under constant temperature water bath conditions until chitosan is dissolved; then slowly add sodium hydroxide solution under stirring conditions, after the completion of dropwise addition, heat to 80℃ and continue to stir overnight, cool down, dialysis, freeze-drying to obtain amino-modified chitosan, ready for use; S2, add polyether polyol, isophorone diisocyanate, 2,2-dimethylol propionic acid, 1,4-butanediol and stannous octoate to the reaction container, react at 80-100℃, after cooling, add deionized water and disperse at high speed to obtain a polyurethane prepolymer with a solid content of 35wt%, ready for use; S3, dissolve the amino-modified chitosan in deionized water by stirring, then mix it with the polyurethane prepolymer, add a foaming agent, a surfactant and a catalyst to the mixture and stir to disperse uniformly; then add isocyanate and continue to stir, then pour into a foaming mold, foam and shape, and mature at room temperature for 48h; S4, cut the prepared polyurethane foam into a sealed high-pressure box, inject hydrogen to open the pores, and obtain the polyurethane foam carrier; The preparation process of the modified cellulose solution is as follows: In the reaction bottle, add hydroxyethyl cellulose and water to stir and dissolve, then add epichlorohydrin, adjust the pH to alkaline, heat to 70℃ and react for 5h, cool to room temperature, add amino-functionalized graphene, ultrasonic for 30-60min, centrifugal separation, wash with ethanol and water for three times, then ultrasonic dispersion in deionized water again, add dodecyl alcohol polyoxyethylene ether acrylate, and graft reaction under ultrasonic irradiation.

2. The process for combined depth treatment of coking wastewater as claimed in claim 1 wherein, The porous carbon material is prepared by using N-carboxymethyl chitosan as carbon source and nitrogen source, thiophene as sulfur source, and 2-acrylamido-2-methylpropane sulfonic acid as supplementary nitrogen source and sulfur source to obtain N / S doped chitosan precursor, then calcine under the condition of sodium chloride and sodium silicate as hard template and potassium acetate as activator to obtain nitrogen and sulfur doped porous carbon material.

3. The process for combined depth treatment of coking wastewater as claimed in claim 1 wherein, In step S2, the mass ratio of polyether polyol, isophorone diisocyanate, 2,2-dimethylol propionic acid, 1,4-butanediol is 1-2:1-2:0.5-1:0.3-0.

5.

4. The process for co-treatment of coking wastewater by advanced processes as claimed in claim 1 wherein, The weight parts of the amino-modified chitosan, the polyurethane prepolymer, the foaming agent, the surfactant and the catalyst in the step S3 are 20-30 parts, 70-100 parts, 2-5 parts, 1-4 parts and 1-5 parts respectively.

5. The process for co-treatment of coking wastewater by advanced processes as claimed in claim 1 wherein, The foaming agent in the step S3 is one of n-hexane, n-pentane, iso-pentane and petroleum ether; the surfactant is silicone oil or stearic acid; and the catalyst is N,N-dimethylcyclohexylamine or triethylenediamine.

6. The process for co-treatment of coking wastewater by advanced processes as claimed in claim 1 wherein, In the preparation process of the modified cellulose solution, the mass ratio of the hydroxyethyl cellulose, the epichlorohydrin and the amino-graphene is 2-3:1:

1.

7. The process for co-treatment of coking wastewater by advanced processes as claimed in claim 1 wherein, The ultrasonic irradiation conditions are: ultrasonic frequency of 20-1 MHz, irradiation intensity of 20-50 W / cm 2 , and irradiation time of 1-3 h.