A printing and dyeing wastewater treatment process

Abstract

The present application relates to the technical field of wastewater treatment, and specifically discloses a printing and dyeing wastewater treatment process, comprising the following steps: step 1) adding the printing and dyeing wastewater into a regulating tank, adjusting the pH to neutral, entering the flotation tank, adding flocculant A, removing suspended matter, and performing mud-water separation; step 2) adding the printing and dyeing wastewater treated in step 1) into an anaerobic tank for anaerobic bacteria treatment; then entering a deep well aeration tank for treatment; entering a sedimentation tank, adding flocculant B for treatment; step 3) the printing and dyeing wastewater treated in step 2) enters an ozone tank for treatment, and then performs multi-stage filtration in a sand filter tank, and the printing and dyeing wastewater meets the discharge standards; the printing and dyeing wastewater treatment process of the present application has simple steps, low cost, high efficiency, green environmental protection, and broad application prospects.

Description

Technical Field

[0001] The present application relates to the technical field of wastewater treatment, and more specifically, to a printing and dyeing wastewater treatment process. Background Art

[0002] With the increasing demand for textile and clothing patterns, many synthetic dyes have appeared, which has also caused a surplus of resources. A large amount of printing and dyeing wastewater needs to be discharged. Textile printing and dyeing wastewater is also a major source of problems hindering the development of the textile industry. Synthetic dyes have complex ingredients and are characterized by high pigment content, difficulty in degradation, high temperature, high toxicity, and large emissions. They may also be lethal to marine life.

[0003] At present, the existing printing and dyeing wastewater treatment technologies include physical treatment methods, chemical treatment methods, and biological treatment methods. The physical treatment method mainly transfers or concentrates pollutants between phases, and does not substantially degrade the pollutants; the chemical treatment method changes the molecular structure of pollutants through chemical reactions and degrades them into small molecules, which is easy to cause secondary pollution; the biological treatment method uses the metabolism of microorganisms to degrade pollutants, and the flocculation effect and use cost are not advantageous. As the composition of printing and dyeing wastewater becomes more and more complex, the existing treatment technology can no longer guarantee that its effluent water quality meets the discharge standards. Therefore, it is urgent to propose a low-cost, effective, green and environmentally friendly printing and dyeing wastewater treatment process, thereby reducing the multiple pressures of printing and dyeing wastewater discharge on the environment and humans, and achieving sustainable social development. Summary of the invention

[0004] In order to solve the problems of high cost and poor effect of existing printing and dyeing wastewater treatment processes, the present application provides a printing and dyeing wastewater treatment process.

[0005] The present application provides a printing and dyeing wastewater treatment process, which adopts the following technical solution:

[0006] A printing and dyeing wastewater treatment process comprises the following steps:

[0007] Step 1) adding the printing and dyeing wastewater into a regulating tank, adjusting the pH to neutral, and then entering an air flotation tank, adding flocculant A, removing suspended solids, and performing mud-water separation;

[0008] Step 2) the printing and dyeing wastewater treated in step 1) is added to an anaerobic tank for anaerobic bacteria treatment; then it is treated in a deep well aeration tank; then it is treated in a sedimentation tank and flocculant B is added for treatment;

[0009] Step 3) the printing and dyeing wastewater treated in step 2) enters an ozone tank for treatment, and then undergoes multi-stage filtration in a sand filter tank, so that the printing and dyeing wastewater meets the discharge standards;

[0010] The flocculant B is prepared by the following method:

[0011] The polyepichlorohydrin-dimethylamine modified starch is added to the cerium ammonium nitrate solution, mixed evenly, and then a biological flocculant is added to react to obtain flocculant B.

[0012] By adopting the above technical scheme, the printing and dyeing wastewater treatment method of the present application has simple steps, low cost, and is suitable for various printing and dyeing wastewater treatments. It can effectively degrade and remove organic matter in the printing and dyeing wastewater, has stable effect, high efficiency, high safety, low cost, and will not cause secondary pollution. The printing and dyeing wastewater treated by the above method can be directly discharged.

[0013] In addition, under the induction of cerium ions, polyepichlorohydrin-dimethylamine modified starch produces a large number of free radicals, which copolymerize with the active sites on the molecular chain of the biological flocculant to obtain flocculant B; flocculant B has both adsorption and bridging effects and good net capturing ability, which can increase the floc particle size, accelerate the sedimentation rate, and improve the decolorization effect, which is helpful for the deep purification of printing and dyeing wastewater, and also saves treatment costs.

[0014] Preferably, the reaction time is 10-30 min; the reaction temperature is 50-60°C.

[0015] Preferably, the mass ratio of the polyepichlorohydrin-dimethylamine modified starch, the cerium ammonium nitrate solution, and the bioflocculant is 6-10:10-15:20.

[0016] Preferably, the mass fraction of the ammonium cerium nitrate solution is 0.01-0.05wt%.

[0017] Preferably, the polyepichlorohydrin-dimethylamine modified starch is prepared by the following method:

[0018] Add starch and γ-chloropropyltrimethoxysilane to an ethanol aqueous solution, heat at 50-65° C. for reaction for 4-6 hours, and then freeze-dry to obtain chloropropylated starch;

[0019] Chloropropylated starch and polyepichlorohydrin-dimethylamine are added to a sodium hydroxide solution, stirred and reacted at 80-90° C. for 3-5 hours, filtered and dried to obtain polyepichlorohydrin-dimethylamine modified starch.

[0020] Preferably, the mass fraction of the ethanol aqueous solution is 20-25wt%.

[0021] Preferably, the mass fraction of the sodium hydroxide solution is 10-20wt%.

[0022] Preferably, the mass ratio of the starch, γ-chloropropyltrimethoxysilane, ethanol aqueous solution, polyepichlorohydrin-dimethylamine, and sodium hydroxide solution is 30:12-16:24-33:11-18:100.

[0023] Preferably, the molecular weight of the polyepichlorohydrin-dimethylamine is 150,000-250,000.

[0024] By adopting the above technical scheme, the present application first adopts silane coupling agent γ-chloropropyltrimethoxysilane to react with the hydroxyl group of starch to introduce chloropropyl groups on the surface of starch; then the chloropropyl groups react with the amine groups on polyepichlorohydrin-dimethylamine to graft polyepichlorohydrin-dimethylamine on the surface of starch to obtain polyepichlorohydrin-dimethylamine modified starch; the long chain structure of epichlorohydrin-dimethylamine is grafted on the surface of starch to form a giant network macromolecule, so that the polyepichlorohydrin-dimethylamine modified starch molecule has both the rigid structure of starch and the flexible structure of polymer; the polyepichlorohydrin-dimethylamine modified starch has excellent charge neutralization and adsorption bridging capabilities, has a good treatment effect on organic matter, dyes and impurities in printing and dyeing wastewater, significantly improves the purification capacity, shortens the onset time, effectively reduces the wastewater discharge, and is beneficial to environmental protection.

[0025] Preferably, the bioflocculant is prepared by the following method:

[0026] The Bacillus subtilis seed liquid is inoculated into the sterilized flocculent culture medium, and the culture is placed in a shaking incubator at 30-35°C and 150-190 r / min for 40-48 hours, and then centrifuged to obtain the supernatant; ethanol is added to the supernatant, and after being mixed evenly, the mixture is refrigerated for 3-5 days; the mixture is centrifuged, the precipitate is collected, and vacuum freeze-dried to obtain a bioflocculant.

[0027] Preferably, the Bacillus subtilis seed solution is prepared by the following method:

[0028] After being activated by slant, Bacillus subtilis was inoculated into a liquid culture medium and cultured at 30°C for 48 hours. The liquid culture medium was prepared by mixing 15g soybean powder, 10g starch, 2g yeast extract, 10g glucose and 1000mL water, and the pH was adjusted to 6.5 to obtain a Bacillus subtilis seed solution.

[0029] Preferably, the floc-producing culture medium is prepared by the following method:

[0030] Add 8-12 g of mannitol, 4-6 g of peptone, 4-6 g of K2HPO4, 1-3 g of KH2PO4, 0.05-0.25 g of MgSO4·7H2O, 0.01-0.2 g of NaCl, 0.4-0.6 g of urea and 0.4-0.6 g of yeast extract to 1000 mL of water, adjust the pH to 6.5-7.5, and obtain a flocculent culture medium.

[0031] By adopting the above technical scheme, Bacillus subtilis is used as a biological flocculant. Bacillus subtilis contains rich proteases, amylases, cellulases, lipases, etc., which can decompose organic matter such as polysaccharides and proteins, and can effectively degrade ammonia nitrogen, COD, total nitrogen, and BOD in printing and dyeing wastewater. During the preparation process of the biological flocculant, the present application controls various process parameters so that the biological flocculant has a stable flocculation effect.

[0032] Preferably, the flocculant A is obtained by mixing polyferric sulfate, polyacrylamide and chitosan in a mass ratio of 1:7-10:2-4.

[0033] By adopting the above technical scheme, the flocculant A of the present application is a mixture of polyferric sulfate, polyacrylamide and chitosan. The flocculant A has a color effect and a COD removal effect, and can provide a large amount of complex ions to electrically neutralize the colloid particles of suspended matter in the water, reduce the potential, and make the colloid particles in the water quickly condense into large particles; the colloidal particles quickly condense into large particles, and at the same time it also has an adsorption and bridging effect, so that the particles condense into large particles, accelerate the particle sedimentation, and achieve the purpose of purifying water quality.

[0034] Preferably, the anaerobic bacteria are obtained by mixing methanogens and denitrifying bacteria in a mass ratio of 2:1-4.

[0035] By adopting the above technical solution, the anaerobic bacteria of the present application are obtained by mixing methanogens and denitrifying bacteria in a specific ratio, which can consume the residual oxygen in the wastewater relatively quickly and improve the treatment effect of the wastewater.

[0036] In summary, this application has the following beneficial effects:

[0037] 1. The printing and dyeing wastewater treatment process of the present application mainly includes flotation flocculation, anaerobic bacteria treatment, deep well aeration, sedimentation flocculation, ozone treatment, multi-stage filtration and other steps. The steps are simple, low cost, high efficiency, and can effectively reduce COD, chromaticity, ammonia nitrogen, etc. in the wastewater, which is beneficial to environmental protection.

[0038] 2. In the sedimentation and flocculation process, the present application adopts flocculant B, and flocculant B is obtained by combining polyepichlorohydrin-dimethylamine modified starch and biological flocculant under the induction of ammonium cerium nitrate. Flocculant B can not only improve the decolorization effect, but also reduce the total nitrogen content of printing and dyeing wastewater, which is helpful for deep purification of printing and dyeing wastewater.

[0039] 3. In the flotation flocculation process, the present application uses flocculant A, which is obtained by mixing polyferric sulfate, polyacrylamide and chitosan. The three synergistically enhance the effect and have excellent color effect and COD removal effect. DETAILED DESCRIPTION

[0040] The present application is further described in detail below with reference to the embodiments.

[0041] Preparation Examples 1-3 provide methods for preparing polyepichlorohydrin-dimethylamine modified starch.

[0042] Preparation Example 1

[0043] Polyepichlorohydrin-dimethylamine modified starch is prepared by the following method:

[0044] 300g starch and 120g γ-chloropropyltrimethoxysilane were added to 240g 20wt% ethanol aqueous solution.

[0045] After heating at 50°C for 4 hours, freeze-drying at -24°C for 1 hour to obtain chloropropylated starch;

[0046] Chloropropylated starch and 110 g of polyepichlorohydrin-dimethylamine with a molecular weight of 150,000 were added to 1000 g of a 10 wt % sodium hydroxide solution, stirred and reacted at 80° C. for 3 h, then filtered and dried at 30° C. for 24 h to obtain polyepichlorohydrin-dimethylamine modified starch.

[0047] Preparation Example 2

[0048] Polyepichlorohydrin-dimethylamine modified starch is prepared by the following method:

[0049] 300g starch and 140g γ-chloropropyltrimethoxysilane were added to 280g 23wt% ethanol aqueous solution.

[0050] After heating at 60°C for 5 hours, freeze-drying at -10°C for 2 hours to obtain chloropropylated starch;

[0051] Chloropropylated starch and 150 g of polyepichlorohydrin-dimethylamine with a molecular weight of 200,000 were added to 1000 g of a sodium hydroxide solution with a mass fraction of 15 wt %, stirred and reacted at 85° C. for 4 h, then filtered and dried at 35° C. for 30 h to obtain polyepichlorohydrin-dimethylamine modified starch.

[0052] Preparation Example 3

[0053] Polyepichlorohydrin-dimethylamine modified starch is prepared by the following method:

[0054] 300g starch and 160g γ-chloropropyltrimethoxysilane were added to 330g 25wt% ethanol aqueous solution.

[0055] After heating at 65°C for 6 hours, freeze-drying at 0°C for 3 hours, chloropropylated starch was obtained;

[0056] Chloropropylated starch and 180 g of polyepichlorohydrin-dimethylamine with a molecular weight of 250,000 were added to 1000 g of a 20 wt % sodium hydroxide solution, stirred and reacted at 90° C. for 5 h, filtered, and dried at 40° C. for 48 h to obtain polyepichlorohydrin-dimethylamine modified starch.

[0057] Preparation Examples 4-6 and Comparative Preparation Examples 1-3 provide methods for preparing bioflocculants.

[0058] Preparation Example 4

[0059] Bioflocculant, prepared by the following method:

[0060] S1. Prepare Bacillus subtilis seed solution: activate Bacillus subtilis on a slant, inoculate in a liquid culture medium, and culture at 30° C. for 48 h. The liquid culture medium is prepared by mixing 15 g of soybean powder, 10 g of starch, 2 g of yeast extract, 10 g of glucose and 1000 mL of water, and the pH is adjusted to 6.5 to obtain Bacillus subtilis seed solution;

[0061] S2. Preparation of biological flocculant: inoculate the Bacillus subtilis seed liquid into the sterilized flocculant culture medium, place it in a shaker at 30°C and 150 r / min for 40 hours, centrifuge it at a speed of 3000 r / min for 10 minutes, and take the supernatant; add ethanol twice the volume of the supernatant to the supernatant, mix it evenly, and refrigerate it at -3°C for 3 days; centrifuge the mixture at a speed of 3000 r / min for 10 minutes, collect the precipitate, and perform vacuum freeze drying at a temperature of -20°C for 24 hours to obtain the biological flocculant;

[0062] The floc-forming medium is prepared by the following method: 8 g of mannitol, 4 g of peptone, 4 g of K2HPO4, 1 g of KH2PO4, 0.05 g of MgSO4·7H2O, 0.01 g of NaCl, 0.4 g of urea, and 0.4 g of yeast extract are added to 1000 mL of water, and the pH is adjusted to 6.5 to obtain a floc-forming medium.

[0063] Preparation Example 5

[0064] Bioflocculant, prepared by the following method:

[0065] S1. Prepare Bacillus subtilis seed solution: activate Bacillus subtilis on a slant, inoculate in a liquid culture medium, and culture at 30° C. for 48 h. The liquid culture medium is prepared by mixing 15 g of soybean powder, 10 g of starch, 2 g of yeast extract, 10 g of glucose and 1000 mL of water, and the pH is adjusted to 6.5 to obtain Bacillus subtilis seed solution;

[0066] S2. Preparation of biological flocculant: inoculating Bacillus subtilis seed liquid into sterilized flocculant culture medium, culturing in a shaking incubator at 33°C and 170 r / min for 45 h, centrifuging at 4000 r / min for 15 min, and taking the supernatant; adding ethanol twice the volume of the supernatant to the supernatant, mixing evenly, and refrigerating at 0°C for 4 days; centrifuging the mixture at 4000 r / min for 15 min, collecting the precipitate, and performing vacuum freeze drying at -15°C for 30 h to obtain the biological flocculant;

[0067] The floc-producing medium is prepared by the following method: 10 g of mannitol, 5 g of peptone, 5 g of K2HPO4, 2 g of KH2PO4, 0.15 g of MgSO4·7H2O, 0.1 g of NaCl, 0.5 g of urea, and 0.5 g of yeast extract are added to 1000 mL of water, and the pH is adjusted to 7 to obtain a floc-producing medium.

[0068] Preparation Example 6

[0069] Bioflocculant, prepared by the following method:

[0070] S1. Prepare Bacillus subtilis seed solution: activate Bacillus subtilis on a slant, inoculate in a liquid culture medium, and culture at 30° C. for 48 h. The liquid culture medium is prepared by mixing 15 g of soybean powder, 10 g of starch, 2 g of yeast extract, 10 g of glucose and 1000 mL of water, and the pH is adjusted to 6.5 to obtain Bacillus subtilis seed solution;

[0071] S2. Preparation of biological flocculant: inoculate the Bacillus subtilis seed liquid into the sterilized flocculant culture medium, place it in a shaker at 35°C and 190 r / min for 48 hours, centrifuge it at a speed of 5000 r / min for 20 minutes, and take the supernatant; add ethanol twice the volume of the supernatant to the supernatant, mix it evenly, and refrigerate it at 3°C ​​for 5 days; centrifuge the mixture at a speed of 5000 r / min for 20 minutes, collect the precipitate, and perform vacuum freeze drying at a temperature of -10°C for 48 hours to obtain the biological flocculant;

[0072] The floc-producing medium is prepared by the following method: 12 g of mannitol, 6 g of peptone, 6 g of K2HPO4, 3 g of KH2PO4, 0.25 g of MgSO4·7H2O, 0.2 g of NaCl, 0.6 g of urea, and 0.6 g of yeast extract are added to 1000 mL of water, and the pH is adjusted to 7.5 to obtain a floc-producing medium.

[0073] Comparative Preparation Example 1

[0074] Comparative Preparation Example 1 is the same as Preparation Example 4, except that mannitol is not added to the floc-producing culture medium.

[0075] Comparative Preparation Example 2

[0076] Comparative Preparation Example 2 is the same as Preparation Example 4, except that peptone is not added to the floc-producing medium.

[0077] Comparative Preparation Example 3

[0078] Comparative Preparation Example 3 is the same as Preparation Example 4, except that yeast extract is not added to the floc-producing medium. Preparation Examples 7-9 and Comparative Preparation Examples 4-8 provide methods for preparing polyepichlorohydrin-dimethylamine modified starch.

[0079] Preparation Example 7

[0080] Flocculant B is prepared by the following method:

[0081] 60g of polyepichlorohydrin-dimethylamine modified starch was added to 100g of 0.01wt% cerium ammonium nitrate solution, mixed uniformly at a speed of 600r / min for 30min, and then 200g of biological flocculant was added, and reacted at 50°C for 10min to obtain flocculant B;

[0082] Wherein, the polyepichlorohydrin-dimethylamine modified starch is prepared by Preparation Example 1; and the bioflocculant is prepared by Preparation Example 4.

[0083] Preparation Example 8

[0084] Flocculant B is prepared by the following method:

[0085] 80g of polyepichlorohydrin-dimethylamine modified starch was added to 120g of 0.03wt% cerium ammonium nitrate solution, mixed evenly at a speed of 800r / min for 50min, and then 200g of biological flocculant was added, and reacted at 55°C for 20min to obtain flocculant B;

[0086] Among them, the polyepichlorohydrin-dimethylamine modified starch is prepared by Preparation Example 2; and the biological flocculant is prepared by Preparation Example 5.

[0087] Preparation Example 9

[0088] Flocculant B is prepared by the following method:

[0089] 80g of polyepichlorohydrin-dimethylamine modified starch was added to 150g of 0.05wt% cerium ammonium nitrate solution, mixed uniformly at a speed of 1000r / min for 70min, and then 200g of biological flocculant was added, and reacted at 60°C for 30min to obtain flocculant B;

[0090] Among them, the polyepichlorohydrin-dimethylamine modified starch is prepared by Preparation Example 3; and the bioflocculant is prepared by Preparation Example 6.

[0091] Comparative Preparation Example 4

[0092] Comparative Preparation Example 4 is the same as Preparation Example 7, except that an equal mass of starch is used to replace the polyepichlorohydrin-dimethylamine modified starch.

[0093] Comparative Preparation Example 5

[0094] Comparative Preparation Example 5 is the same as Preparation Example 7, except that the bioflocculant is prepared by Comparative Preparation Example 1.

[0095] Comparative Preparation Example 6

[0096] Comparative Preparation Example 6 is the same as Preparation Example 7, except that the bioflocculant is prepared by Comparative Preparation Example 2.

[0097] Comparative Preparation Example 7

[0098] Comparative Preparation Example 7 is the same as Preparation Example 7, except that the bioflocculant is prepared by Comparative Preparation Example 3.

[0099] Comparative Preparation Example 8

[0100] Flocculant B is obtained by mixing polyepichlorohydrin-dimethylamine modified starch (Preparation Example 1) and biological flocculant (Preparation Example 4) in a mass ratio of 2:5.

[0101] Embodiment 1-3 provides a printing and dyeing wastewater treatment process.

[0102] Example 1

[0103] A printing and dyeing wastewater treatment process comprises the following steps:

[0104] Step 1) adding the printing and dyeing wastewater into a regulating tank, adjusting the pH to neutral, and then entering an air flotation tank, adding flocculant A, removing suspended solids, and performing mud-water separation;

[0105] Step 2) the printing and dyeing wastewater treated in step 1) is added to an anaerobic tank for anaerobic bacteria treatment; then it is treated in a deep well aeration tank; then it is treated in a sedimentation tank and flocculant B is added for treatment;

[0106] Step 3) the printing and dyeing wastewater treated in step 2) enters an ozone tank for treatment, and then undergoes multi-stage filtration in a sand filter tank, so that the printing and dyeing wastewater meets the discharge standards;

[0107] Among them, flocculant B is prepared by Preparation Example 7; anaerobic bacteria are obtained by mixing methanogens and denitrifying bacteria in a mass ratio of 2:1; flocculant A is obtained by mixing polyferric sulfate, polyacrylamide and chitosan in a mass ratio of 1:7:2.

[0108] Example 2

[0109] A printing and dyeing wastewater treatment process comprises the following steps:

[0110] Step 1) adding the printing and dyeing wastewater into a regulating tank, adjusting the pH to neutral, and then entering an air flotation tank, adding flocculant A, removing suspended solids, and performing mud-water separation;

[0111] Step 2) the printing and dyeing wastewater treated in step 1) is added to an anaerobic tank for anaerobic bacteria treatment; then it is treated in a deep well aeration tank; then it is treated in a sedimentation tank and flocculant B is added for treatment;

[0112] Step 3) the printing and dyeing wastewater treated in step 2) enters an ozone tank for treatment, and then undergoes multi-stage filtration in a sand filter tank, so that the printing and dyeing wastewater meets the discharge standards;

[0113] Wherein, flocculant B is prepared by Preparation Example 8; anaerobic bacteria are obtained by mixing methanogens and denitrifying bacteria in a mass ratio of 2:3; and flocculant A is obtained by mixing polyferric sulfate, polyacrylamide and chitosan in a mass ratio of 1:9:3.

[0114] Example 3

[0115] A printing and dyeing wastewater treatment process comprises the following steps:

[0116] Step 1) adding the printing and dyeing wastewater into a regulating tank, adjusting the pH to neutral, and then entering an air flotation tank, adding flocculant A, removing suspended solids, and performing mud-water separation;

[0117] Step 2) the printing and dyeing wastewater treated in step 1) is added to an anaerobic tank for anaerobic bacteria treatment; then it is treated in a deep well aeration tank; then it is treated in a sedimentation tank and flocculant B is added for treatment;

[0118] Step 3) the printing and dyeing wastewater treated in step 2) enters an ozone tank for treatment, and then undergoes multi-stage filtration in a sand filter tank, so that the printing and dyeing wastewater meets the discharge standards;

[0119] Among them, flocculant B is prepared by Preparation Example 9; anaerobic bacteria are obtained by mixing methanogens and denitrifying bacteria in a mass ratio of 1:2; and flocculant A is obtained by mixing polyferric sulfate, polyacrylamide and chitosan in a mass ratio of 1:10:4.

[0120] In order to verify the treatment effect of the printing and dyeing wastewater treatment process in Examples 1-3 of the present application, the applicant set up comparative examples 1-9, which are as follows:

[0121] Comparative Example 1

[0122] Comparative Example 1 is the same as Example 1, except that flocculant B is prepared from Comparative Preparation Example 4.

[0123] Comparative Example 2

[0124] Comparative Example 2 is the same as Example 1, except that flocculant B is prepared from Comparative Preparation Example 5.

[0125] Comparative Example 3

[0126] Comparative Example 3 is the same as Example 1, except that flocculant B is prepared from Comparative Preparation Example 6.

[0127] Comparative Example 4

[0128] Comparative Example 4 is the same as Example 1, except that flocculant B is prepared from Comparative Preparation Example 7.

[0129] Comparative Example 5

[0130] Comparative Example 5 is the same as Example 1, except that flocculant B is prepared from Comparative Preparation Example 8.

[0131] Comparative Example 6

[0132] Comparative Example 6 is the same as Example 1, except that the anaerobic bacteria are only methanogens.

[0133] Comparative Example 7

[0134] Comparative Example 7 is the same as Example 1, except that the anaerobic bacteria are only denitrifying bacteria.

[0135] Comparative Example 8

[0136] Comparative Example 8 is the same as Example 1, except that flocculant A is obtained by mixing polyferric sulfate and polyacrylamide in a mass ratio of 1:7.

[0137] Comparative Example 9

[0138] Comparative Example 9 is the same as Example 1, except that flocculant A is obtained by mixing polyferric sulfate and chitosan in a mass ratio of 1:2.

[0139] Comparative Example 10

[0140] Comparative Example 10 is the same as Example 1, except that flocculant A is obtained by mixing polyacrylamide and chitosan in a mass ratio of 7:2.

[0141] The treatment effects of the printing and dyeing wastewater treatment processes in Examples 1-3 and Comparative Examples 1-10 of the present application were respectively detected, and the following result parameters were obtained, as shown in Table 1:

[0142] COD of sewage: refer to HJ-T 399-2007 "Determination of Chemical Oxygen Demand of Water Quality - Rapid Digestion Spectrophotometry" for testing; Chroma of sewage: refer to GB11903-1989 "Determination of Chroma of Water Quality" for testing;

[0143] Ammonia nitrogen in sewage: refer to HJ 535-2009 "Determination of ammonia nitrogen in water - Nessler's reagent spectrophotometric method" for detection;

[0144] Total nitrogen in sewage: refer to HJ 636-2012 "Determination of total nitrogen in water quality - Alkaline potassium persulfate digestion ultraviolet spectrophotometry" for detection.

[0145] Table 1:

[0146]

[0147]

[0148] It can be seen from the data shown in Table 1 above that the treatment effect of the printing and dyeing wastewater treatment process in Examples 1-3 of the present application is significantly better than that in Comparative Examples 1-10. The COD content, chromaticity, total nitrogen content and ammonia nitrogen content of the printing and dyeing wastewater of the present application are significantly reduced after treatment, which has a good purification effect on the printing and dyeing wastewater, and is low in cost, high in efficiency and green and environmentally friendly.

[0149] It can be seen from Example 1 and Comparative Example 1 that the flocculant B of Example 1 is prepared by Preparation Example 7, and polyepichlorohydrin-dimethylamine modified starch is combined with a biological flocculant. Compared with Comparative Example 1, the printing and dyeing wastewater treated with starch in Example 1 has lower COD content, chroma, total nitrogen content and ammonia nitrogen content.

[0150] It can be seen from Example 1 and Comparative Examples 2-4 that the flocculant B of Example 1 is prepared by Preparation Example 7, the biological flocculant used is prepared by Preparation Example 4, and the flocculant production culture medium used contains mannitol, peptone, and yeast extract. Compared with Comparative Examples 2-4, the printing and dyeing wastewater treated by Example 1 has better indicators.

[0151] It can be seen from Example 1 and Comparative Example 5 that the flocculant B of Example 1 is prepared by Preparation Example 7, and polyepichlorohydrin-dimethylamine modified starch and a biological flocculant are combined under the induction of ammonium cerium nitrate. Compared with Comparative Example 5, polyepichlorohydrin-dimethylamine modified starch and a biological flocculant are physically blended. Example 1 can not only reduce the ammonia nitrogen content of printing and dyeing wastewater, but also effectively decolorize.

[0152] It can be seen from Example 1 and Comparative Examples 6 and 7 that the anaerobic bacteria in Example 1 are obtained by mixing methanogens and denitrifying bacteria. Compared with Comparative Examples 6 and 7, the treatment effect of printing and dyeing wastewater in Example 1 is better.

[0153] It can be seen from Example 1 and Comparative Examples 8-10 that the flocculant A of Example 1 is obtained by mixing polyferric sulfate, polyacrylamide and chitosan. Compared with Comparative Examples 8-10, the flocculant A of Example 1 has a better treatment effect on organic matter, dyes and impurities in wastewater, and effectively improves the treatment effect of printing and dyeing wastewater.

[0154] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A printing and dyeing wastewater treatment process, characterized in that: The following steps are involved: Step 1) adding the printing and dyeing wastewater into a regulating tank, adjusting the pH to neutral, and then entering an air flotation tank, adding flocculant A, removing suspended solids, and performing mud-water separation; Step 2) the printing and dyeing wastewater treated in step 1) is added to an anaerobic tank for anaerobic bacteria treatment; then it is treated in a deep well aeration tank; then it is treated in a sedimentation tank and flocculant B is added for treatment; Step 3) the printing and dyeing wastewater treated in step 2) enters an ozone tank for treatment, and then enters a sand filter tank for multi-stage filtration, and the printing and dyeing wastewater meets the discharge standards; The flocculant A is obtained by mixing polyferric sulfate, polyacrylamide and chitosan in a mass ratio of 1:7-10:2-4; The flocculant B is prepared by the following method: Adding polyepichlorohydrin-dimethylamine modified starch to cerium ammonium nitrate solution, mixing evenly, adding biological flocculant to react, and obtaining flocculant B; The polyepichlorohydrin-dimethylamine modified starch is prepared by the following method: Add starch and γ-chloropropyltrimethoxysilane to an ethanol aqueous solution, heat at 50-65° C. for reaction for 4-6 hours, and then freeze-dry to obtain chloropropylated starch; Chloropropylated starch and polyepichlorohydrin-dimethylamine are added to a sodium hydroxide solution, stirred and reacted at 80-90° C. for 3-5 hours, filtered and dried to obtain polyepichlorohydrin-dimethylamine modified starch.

2. The printing and dyeing wastewater treatment process according to claim 1, characterized in that: The mass ratio of the polyepichlorohydrin-dimethylamine modified starch, the cerium ammonium nitrate solution and the bioflocculant is 6-10:10-15:

20.

3. The printing and dyeing wastewater treatment process according to claim 1, characterized in that: The mass ratio of the starch, γ-chloropropyltrimethoxysilane, ethanol aqueous solution, polyepichlorohydrin-dimethylamine and sodium hydroxide solution is 30:12-16:24-33:11-18:

100.

4. The printing and dyeing wastewater treatment process according to claim 1, characterized in that: The biological flocculant is prepared by the following method: The Bacillus subtilis seed liquid is inoculated into the sterilized flocculent culture medium, and the culture is placed in a shaking incubator at 30-35°C and 150-190 r / min for 40-48 hours, and then centrifuged to obtain the supernatant; ethanol is added to the supernatant, and after being mixed evenly, the mixture is refrigerated for 3-5 days; the mixture is centrifuged, the precipitate is collected, and vacuum freeze-dried to obtain a bioflocculant.

5. The printing and dyeing wastewater treatment process according to claim 4, characterized in that: The flocculant-producing culture medium is prepared by the following method: Add 8-12 g of mannitol, 4-6 g of peptone, 4-6 g of K2HPO4, 1-3 g of KH2PO4, 0.05-0.25 g of MgSO4·7H2O, 0.01-0.2 g of NaCl, 0.4-0.6 g of urea, and 0.4-0.6 g of yeast extract to 1000 mL of water, adjust the pH to 6.5-7.5, and obtain a flocculent culture medium.

6. The printing and dyeing wastewater treatment process according to claim 1, characterized in that: The anaerobic bacteria are obtained by mixing methanogens and denitrifying bacteria in a mass ratio of 2:1-4.

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