A stable and efficient process for treating phosphorus reduction

Abstract

The present invention provides a stable and efficient phosphorus removal process treatment method, which relates to the technical field of phosphorus removal from wastewater. The specific method includes: first, primary treatment: the phosphorus-containing wastewater is introduced into a primary reaction tank, and a primary metal salt solution is added to the primary reaction tank for reaction; after the reaction, it flows to a primary flocculation tank, and a flocculant solution is added to the primary flocculation tank for flocculation reaction; finally, it flows to a sedimentation tank for sedimentation separation to obtain the primary treated wastewater; the primary treated wastewater is introduced into a secondary reaction tank, and a secondary metal salt solution is added to the secondary reaction tank for reaction; after the reaction, it flows to a secondary flocculation tank, and a flocculant solution is added to the secondary flocculation tank for flocculation reaction; finally, it flows to a sedimentation tank for sedimentation separation to obtain the treated wastewater. The obtained treated wastewater has low contents of phosphorus, solids, and magnesium ammonium phosphate that is not easily degraded, and has excellent effects.

Description

Technical Field

[0001] The present invention relates to the technical field of phosphorus removal from wastewater, and particularly to a stable and efficient phosphorus removal process treatment method. Background Art

[0002] In wastewater, phosphorus exists in the form of phosphate. Appropriate amounts of phosphate can play an anti-corrosion role and are also essential substances for most aquatic plants and animals. However, when there is an excessive amount of phosphate in water, it will cause water eutrophication. If the phosphorus content in water cannot be controlled within the standard range, this water eutrophication will have a great negative impact on human survival and the environment. In recent years, with the rapid development of the electronic semiconductor industry, the electronics industry has become one of the main sources of phosphorus-containing wastewater. With the increasingly strict environmental protection discharge standards, the conventional treatment method for phosphorus-containing wastewater is to use a chemical precipitation process to remove phosphorus. The removal rate of a single chemical precipitation process is not high, and it is difficult to stably meet the requirements of low phosphorus discharge. Therefore, there is an urgent need for a treatment method that can reduce the phosphorus content in phosphorus-containing wastewater to improve water utilization. Summary of the Invention

[0003] The purpose of the present invention is to provide a stable and efficient phosphorus removal process treatment method to better degrade phosphorus-containing wastewater, meet the requirements of low phosphorus discharge, and improve water utilization.

[0004] To solve the above technical problems, the present invention specifically provides the following technical solutions:

[0005] The present invention discloses a stable and efficient phosphorus removal process treatment method, including:

[0006] S1: The phosphorus-containing wastewater is introduced into the first-stage reaction tank to react with the first-stage metal salt solution; after the reaction, it flows to the first-stage flocculation tank to react with the flocculant solution; finally, it flows to the first-stage sedimentation tank for sedimentation separation to obtain the first-stage treated wastewater;

[0007] S2: The first-stage treated wastewater obtained in S1 is introduced into the second-stage reaction tank to react with the second-stage metal salt solution; after the reaction, it flows to the second-stage flocculation tank to react with the flocculant solution; finally, it flows to the second-stage sedimentation tank for sedimentation separation to obtain the treated wastewater; the flocculant solution is obtained by adding a flocculant to water, and the flocculant is at least one of polyacrylamide and a composite flocculant. The use of the composite flocculant can better combine with the phosphate particles generated in the phosphorus-containing wastewater to form larger particles, improve the sedimentation efficiency, reduce the phosphorus content of the treated wastewater, reduce the solid content in the treated wastewater, and the content of magnesium ammonium phosphate that is not easily degraded.

[0008] Preferably, the first-stage reaction tank in S1 includes a first-stage reaction tank 1 and a first-stage reaction tank 2.

[0009] Preferably, the phosphorus value of the phosphorus-containing wastewater in S1 is 2000 - 2200 mg / L; the primary metal salt solution is a calcium salt solution, and the volume ratio of the usage amount of the calcium salt solution in the primary reaction tank 1 to the amount of the phosphorus-containing wastewater is 1:35 - 48, and the volume ratio of the usage amount of the calcium salt solution in the primary reaction tank 2 to the amount of the phosphorus-containing wastewater is 1:245 - 300.

[0010] Preferably, the primary metal salt solution in S1 is a calcium salt solution, and the volume ratio of the usage amount of the calcium salt solution to the amount of the phosphorus-containing wastewater is 1:35 - 48.

[0011] Preferably, the phosphorus value of the primary treated wastewater in S2 is 10 - 20 mg / L.

[0012] Preferably, the secondary metal salt solution in S2 is at least one of an aluminum salt solution, an iron salt solution, a polyaluminum ferric solution, or a lanthanum salt solution.

[0013] Preferably, the volume ratio of the usage amount of the aluminum salt solution in S2 to the amount of the primary treated wastewater is 1:1100 - 1850, the volume ratio of the usage amount of the iron salt solution to the amount of the primary treated wastewater is 1:1100 - 1800, the volume ratio of the usage amount of the polyaluminum ferric solution to the amount of the primary treated wastewater is 1:9000 - 15000, and the volume ratio of the usage amount of the lanthanum salt solution to the amount of the primary treated wastewater is 1:2100 - 2800.

[0014] Preferably, the flocculant solution in S1 or S2 is obtained by adding a flocculant to water, and the amount of the flocculant added to water is 0.7 - 1.3 g / L; the volume ratio of the usage amount of the flocculant solution in S1 to the amount of the phosphorus-containing wastewater is 1:0.3 - 0.6, and the volume ratio of the usage amount of the flocculant solution in S2 to the amount of the primary treated wastewater is 1:32 - 55.

[0015] Preferably, the reaction time in S1 is 10 - 50 min, and the reaction pH is adjusted to 7 - 10 by sodium hydroxide and sulfuric acid; the flocculation reaction time is 8 - 15 min.

[0016] Preferably, the reaction time in S2 is 10 - 20 min, and the reaction pH is adjusted to 7 - 10 by sodium hydroxide, sulfuric acid, and an aluminates solution; the flocculation reaction time is 8 - 15 min.

[0017] The present invention discloses a stable and efficient phosphorus reduction process treatment method, including:

[0018] S1: Primary treatment: The phosphorus-containing wastewater is introduced into the primary reaction tank, and a primary metal salt solution is added to the primary reaction tank for reaction; after the reaction, it flows to the primary flocculation tank, and a flocculant solution is added to the primary flocculation tank for flocculation reaction; finally, it flows to the sedimentation tank for sedimentation separation to obtain the primary treated wastewater;

[0019] S2: Secondary treatment: The primary treated wastewater obtained from S1 is introduced into the secondary reaction tank, and a secondary metal salt solution is added to the secondary reaction tank for reaction; after the reaction, it flows to the secondary flocculation tank, and a flocculant solution is added to the secondary flocculation tank for flocculation reaction; finally, it flows to the sedimentation tank for sedimentation separation to obtain the treated wastewater.

[0020] Preferably, the phosphorus value of the phosphorus-containing wastewater is 2000 - 2200 mg / L.

[0021] Preferably, the primary reaction tank in S1 includes primary reaction tank 1 and primary reaction tank 2.

[0022] More preferably, the primary metal salt solution in S1 is a calcium salt solution. The volume ratio of the usage amount of the calcium salt solution in primary reaction tank 1 to the amount of the phosphorus-containing wastewater is 1:35 - 48, and the volume ratio of the usage amount of the calcium salt solution in primary reaction tank 2 to the amount of the phosphorus-containing wastewater is 1:245 - 300.

[0023] More preferably, the calcium salt solution is obtained by adding a calcium salt to water. The amount of the calcium salt added to water is 200 - 400 g / L, and the calcium salt is calcium chloride.

[0024] Preferably, the phosphorus value of the primary treated wastewater in S2 is 10 - 20 mg / L.

[0025] Preferably, the metal salt solution in S2 is at least one of an aluminum salt solution, an iron salt solution, a polyaluminum ferric solution, or a lanthanum salt solution.

[0026] More preferably, the aluminum salt solution is obtained by adding an aluminum salt to water. The amount of the aluminum salt added to water is 100 - 400 g / L, and the aluminum salt is at least one of a polyaluminum chloride solution and an aluminum sulfate solution.

[0027] More preferably, the iron salt solution is obtained by adding an iron salt to water. The amount of the iron salt added to water is 100 - 300 g / L, and the iron salt is at least one of a ferric chloride solution and a polyferric sulfate solution.

[0028] More preferably, the polyaluminum ferric solution is obtained by adding polyaluminum ferric to water. The amount of polyaluminum ferric added to water is 100 - 300 g / L, and the polyaluminum ferric is at least one of polyaluminum ferric chloride, polyaluminum ferric sulfate, and polyaluminum bisacid ferric.

[0029] More preferably, the lanthanum salt solution is obtained by adding a lanthanum salt to water. The amount of the lanthanum salt added to water is 250 - 350 g / L, and the lanthanum salt is lanthanum chloride.

[0030] More preferably, the volume ratio of the usage amount of the aluminum salt solution to the amount of the primary treated wastewater is 1:1100 - 1850.

[0031] More preferably, the volume ratio of the usage amount of the iron salt solution to the amount of the primary treated wastewater is 1:1100 - 1800.

[0032] More preferably, the volume ratio of the usage amount of the polyaluminum-ferric solution to the amount of the primary treated wastewater is 1:9000 - 15000.

[0033] More preferably, the volume ratio of the usage amount of the lanthanum salt solution to the amount of the primary treated wastewater is 1:2100 - 2800.

[0034] Preferably, in S1 or S2, the flocculant solution is obtained by adding a flocculant to water, and the amount of the flocculant added to water is 0.7 - 1.3 g / L.

[0035] Preferably, the flocculant is at least one of polyacrylamide and a composite flocculant.

[0036] Preferably, the volume ratio of the usage amount of the flocculant solution in S1 to the amount of the phosphorus-containing wastewater is 1:0.3 - 0.6.

[0037] Preferably, the volume ratio of the usage amount of the flocculant solution in S2 to the amount of the primary treated wastewater is 1:32 - 55.

[0038] Preferably, in S1, the reaction time is 10 - 50 min, the reaction pH is adjusted to 7 - 10 with sodium hydroxide and sulfuric acid; the flocculation reaction time is 8 - 15 min.

[0039] Preferably, in S2, the reaction time is 10 - 20 min, the reaction pH is adjusted to 7 - 10 with sodium hydroxide, sulfuric acid and an aluminosilicate solution; the flocculation reaction time is 8 - 15 min.

[0040] The present invention also discloses the preparation of a composite flocculant, including:

[0041] First, chitosan is added to an acetic acid solution for mixing, and N,N-bis(2-hydroxyethyl)methacrylamide and sodium methallylsulfonate are added. Ceric ammonium nitrate is added under nitrogen conditions for reaction. After the reaction ends, precipitation, washing and vacuum drying are carried out to obtain a chitosan polymer; then polyaluminum chloride and water are added to the chitosan polymer for mixing to obtain a composite liquid, and the composite liquid is dried and ground to obtain a composite coagulant.

[0042] Preferably, the acetic acid solution is composed of acetic acid and water, and the volume ratio of the usage amount of water to the usage amount of acetic acid is 1:0.00026.

[0043] Preferably, the amount of chitosan added to the acetic acid solution is 1.8 - 2.3 g / L.

[0044] Preferably, the mass ratio of the usage amount of chitosan to the usage amount of N,N-bis(2-hydroxyethyl)methacrylamide is 1:0.2 - 0.3.

[0045] Preferably, the mass ratio of the usage amount of chitosan to the usage amount of sodium methallylsulfonate is 1:0.2 - 0.3.

[0046] Preferably, the mass ratio of the usage amount of chitosan to the usage amount of ammonium cerium nitrate is 1:0.0002 - 0.0004.

[0047] Preferably, the mass ratio of the usage amount of chitosan polymer to the usage amount of polyaluminum chloride is 1:4 - 5.5.

[0048] Preferably, the amount of polyaluminum chloride in water is 48 - 51 g / L.

[0049] Preferably, the reaction temperature is 55 - 65 °C and the reaction time is 4.5 - 6 h.

[0050] More preferably, in the secondary treatment process, on the basis of using the composite flocculant solution, a carboxylic acid organosilicate solution can also be used. The addition of the carboxylic acid organosilicate solution can be used in synergy with the composite flocculant solution to enhance the adhesion to phosphate particles in the wastewater, make them further agglomerate, and the agglomerates are more compact, thereby promoting precipitation, further reducing the phosphorus content in the treated wastewater, reducing the solid content in the treated wastewater and the content of magnesium ammonium phosphate that is not easily degraded, and having excellent effects.

[0051] Preferably, the carboxylic acid organosilicate solution is obtained by adding a carboxylic acid organosilicate to water. The amount of the carboxylic acid organosilicate added to water is 0.7 - 1.3 g / L, and the volume ratio of the usage amount of the carboxylic acid organosilicate solution to the usage amount of the composite flocculant solution is 1:1.5 - 5.

[0052] The present invention discloses the preparation of a carboxylic acid organosilicate, including:

[0053] First, vinylmethyldichlorosilane and trimethylchlorosilane are mixed and added dropwise to isopropanol for reaction, then water is added dropwise and the reaction continues. After the reaction ends, the organic layer is separated, and the organosilicon precursor is obtained through washing to remove water and vacuum distillation. The organosilicon precursor, mercaptoacetic acid, and tetrahydrofuran are mixed, 2,2 - dimethoxy - phenylacetophenone is added, and the reaction is carried out under ultraviolet light. Then sodium carbonate is added and the reaction continues. After the reaction ends, the carboxylic acid organosilicate is obtained through rotary evaporation, washing, and drying.

[0054] Preferably, vinylmethyldichlorosilane and trimethylchlorosilane are mixed in a mass ratio of 1:3.5 - 4.5.

[0055] Preferably, the mass ratio of the usage amount of isopropanol to the usage amount of vinylmethyldichlorosilane is 1:0.3 - 0.43.

[0056] Preferably, the mass ratio of the usage amount of water to the usage amount of vinylmethyldichlorosilane is 0.8 - 0.92.

[0057] Preferably, the mass ratio of the usage amount of the silicone precursor to the usage amount of mercaptoacetic acid is 1:1 - 1.8.

[0058] Preferably, the mass ratio of the usage amount of the silicone precursor to the usage amount of tetrahydrofuran is 1:0.3 - 0.5.

[0059] Preferably, the mass ratio of the usage amount of the silicone precursor to the usage amount of 2,2 - dimethoxy - phenylacetophenone is 1:0.02 - 0.034.

[0060] Preferably, the mass ratio of the usage amount of the silicone precursor to the usage amount of sodium carbonate is 1:0.17 - 0.25.

[0061] Preferably, after adding isopropanol, the reaction temperature is 2 - 5°C and the reaction time is 0.8 - 1.2 h.

[0062] Preferably, after adding water, the continuous reaction time is 1 - 2 h.

[0063] Preferably, after adding 2,2 - dimethoxy - phenylacetophenone, the reaction time is 15 min.

[0064] Preferably, after adding sodium carbonate, the reaction time is 1.5 - 2.3 h.

[0065] The present invention has the following beneficial effects compared with the prior art:

[0066] The present invention provides a stable and efficient phosphorus - reducing process treatment method. First, primary treatment is carried out: the phosphorus - containing wastewater is introduced into the primary reaction tank, and a primary metal salt solution is added to the primary reaction tank for reaction; after the reaction, it flows to the primary flocculation tank, and a flocculant solution is added to the primary flocculation tank for flocculation reaction; finally, it flows to the sedimentation tank for sedimentation separation to obtain the primary treated wastewater; the primary treated wastewater is introduced into the secondary reaction tank, and a secondary metal salt solution is added to the secondary reaction tank for reaction; after the reaction, it flows to the secondary flocculation tank, and a flocculant solution is added to the secondary flocculation tank for flocculation reaction; finally, it flows to the sedimentation tank for sedimentation separation to obtain the treated wastewater. The phosphorus content, solid content, and the content of magnesium ammonium phosphate that is not easily degraded in the finally obtained treated wastewater are all low, showing excellent effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only exemplary, and for those of ordinary skill in the art, without creative efforts, other implementation drawings can also be obtained according to the provided drawings.

[0068] Figure 1It is the infrared spectrum characterization and analysis diagram of the chitosan polymer;

[0069] Figure 2 It is the result diagram of the phosphorus content determination of the treated wastewater;

[0070] Figure 3 It is the result diagram of the solid content determination of the treated wastewater;

[0071] Figure 4 It is the diagram of the struvite content determination of the treated wastewater. Detailed implementation mode

[0072] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0073] First, the concepts involved in the present application will be described in conjunction with the accompanying drawings. It should be noted here that the following descriptions of each concept are only for making the content of the present application easier to understand, and do not represent a limitation on the protection scope of the present application; at the same time, without conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0074] Example 1:

[0075] Primary treatment: The phosphorus-containing wastewater is introduced into the primary reaction tank 1, and a calcium chloride solution is added to the primary reaction tank 1 for reaction for 15 minutes; after the reaction, it flows to the primary reaction tank 2, and a calcium chloride solution is added to the primary reaction tank 2 for reaction for another 15 minutes; then it flows to the primary flocculation tank, and a polyacrylamide solution is added to the primary flocculation tank for flocculation reaction for 10 minutes; finally, it flows to the sedimentation tank for sedimentation separation to obtain the primary treated wastewater. Among them, the phosphorus value of the phosphorus-containing wastewater is 2000 mg / L; the calcium chloride solution is obtained by adding calcium chloride to water, the amount of calcium chloride added to water is 300 g / L, the volume ratio of the amount of calcium chloride solution added to the primary reaction tank 1 to the amount of phosphorus-containing wastewater is 1:45.71, and sodium hydroxide and sulfuric acid are added to the primary reaction tank 1 to adjust the pH to 9; the volume ratio of the amount of calcium chloride solution added to the primary reaction tank 2 to the amount of phosphorus-containing wastewater is 1:320, and sodium hydroxide and sulfuric acid are added to the primary reaction tank 2 to adjust the pH to 8; the polyacrylamide solution is obtained by adding polyacrylamide to water, the amount of polyacrylamide added to water is 1 g / L, and the volume ratio of the amount of polyacrylamide solution added to the primary flocculation tank to the amount of phosphorus-containing wastewater is 1:0.5; when the phosphorus value after the reaction of the phosphorus-containing wastewater in the primary reaction tank 1 is ≤20 mg / L, it directly flows to the primary flocculation tank.

[0076] Secondary treatment: The primary-treated wastewater is introduced into the secondary reaction tank, and an aluminum sulfate solution is added to the secondary reaction tank for 15 minutes of reaction; after the reaction, it flows to the secondary flocculation tank, and a polyacrylamide solution is added to the secondary flocculation tank for 10 minutes of flocculation reaction; finally, it flows to the sedimentation tank for sedimentation separation to obtain the treated wastewater. Among them, the phosphorus value of the primary-treated wastewater is 20 mg / L; the aluminum sulfate solution is obtained by adding aluminum sulfate to water, the amount of water added to aluminum sulfate is 300 g / L, and the volume ratio of the amount of aluminum sulfate solution added to the secondary reaction tank to the amount of primary-treated wastewater is 1:1699; sodium hydroxide, sulfuric acid, and aluminate solutions are added to the secondary reaction tank to adjust the pH to 6.8; the polyacrylamide solution is obtained by adding polyacrylamide to water, the amount of polyacrylamide added to water is 1 g / L, and the volume ratio of the amount of polyacrylamide solution added to the secondary flocculation tank to the amount of primary-treated wastewater is 1:50.

[0077] Example 2:

[0078] The primary treatment is the same as that in Example 1.

[0079] Secondary treatment: The primary-treated wastewater is introduced into the secondary reaction tank, and a ferric chloride solution is added to the secondary reaction tank for 15 minutes of reaction; after the reaction, it flows to the secondary flocculation tank, and a polyacrylamide solution is added to the secondary flocculation tank for 10 minutes of flocculation reaction; finally, it flows to the sedimentation tank for sedimentation separation to obtain the treated wastewater. Among them, the phosphorus value of the primary-treated wastewater is 20 mg / L; the ferric chloride solution is obtained by adding ferric chloride to water, the amount of water added to ferric chloride is 200 g / L, and the volume ratio of the amount of ferric chloride solution added to the secondary reaction tank to the amount of primary-treated wastewater is 1:1675; sodium hydroxide, sulfuric acid, and aluminate solutions are added to the secondary reaction tank to adjust the pH to 6.8; the polyacrylamide solution is obtained by adding polyacrylamide to water, the amount of polyacrylamide added to water is 1 g / L, and the volume ratio of the amount of polyacrylamide solution added to the secondary flocculation tank to the amount of primary-treated wastewater is 1:50.

[0080] Example 3:

[0081] The primary treatment is the same as that in Example 1.

[0082] Secondary treatment: The primary treated wastewater is introduced into the secondary reaction tank, and an aluminum sulfate solution and a polyaluminum chloride - ferric chloride solution are added to the secondary reaction tank and reacted for 40 minutes; after the reaction, it flows to the secondary flocculation tank, and a polyacrylamide solution is added to the secondary flocculation tank, and the flocculation reaction is carried out for 4 hours; finally, it flows to the sedimentation tank for sedimentation separation to obtain the treated wastewater. Among them, the phosphorus value of the primary treated wastewater is 20 mg / L; the aluminum sulfate solution is obtained by adding aluminum sulfate to water, the amount of water added to aluminum sulfate is 300 g / L, and the volume ratio of the amount of aluminum sulfate solution added to the secondary reaction tank to the amount of primary treated wastewater is 1:1699; the polyaluminum chloride - ferric chloride solution is obtained by adding polyaluminum chloride - ferric chloride to water, the amount of polyaluminum chloride - ferric chloride added to water is 300 g / L, and the volume ratio of the amount of polyaluminum chloride - ferric chloride solution added to the secondary reaction tank to the amount of primary treated wastewater is 1:12000; sodium hydroxide, sulfuric acid and aluminate solution are added to the secondary reaction tank to adjust the pH to 6.8; the polyacrylamide solution is obtained by adding polyacrylamide to water, the amount of polyacrylamide added to water is 1 g / L, and the volume ratio of the amount of polyacrylamide solution added to the secondary flocculation tank to the amount of primary treated wastewater is 1:50.

[0083] Example 4:

[0084] The primary treatment is the same as that in Example 1.

[0085] Secondary treatment: The primary treated wastewater is introduced into the secondary reaction tank, and an aluminum sulfate solution and a lanthanum chloride solution are added to the secondary reaction tank and reacted for 15 minutes; after the reaction, it flows to the secondary flocculation tank, and a polyacrylamide solution is added to the secondary flocculation tank, and the flocculation reaction is carried out for 10 minutes; finally, it flows to the sedimentation tank for sedimentation separation to obtain the treated wastewater. Among them, the phosphorus value of the primary treated wastewater is 20 mg / L; the aluminum sulfate solution is obtained by adding aluminum sulfate to water, the amount of water added to aluminum sulfate is 300 g / L, and the volume ratio of the amount of aluminum sulfate solution added to the secondary reaction tank to the amount of primary treated wastewater is 1:1699; the lanthanum chloride solution is obtained by adding lanthanum chloride to water, the amount of lanthanum chloride added to water is 300 g / L, and the volume ratio of the amount of lanthanum chloride solution added to the secondary reaction tank to the amount of primary treated wastewater is 1:2560; sodium hydroxide, sulfuric acid and aluminate solution are added to the secondary reaction tank to adjust the pH to 6.8; the polyacrylamide solution is obtained by adding polyacrylamide to water, the amount of polyacrylamide added to water is 1 g / L, and the volume ratio of the amount of polyacrylamide solution added to the secondary flocculation tank to the amount of primary treated wastewater is 1:50.

[0086] Example 5:

[0087] Preparation of composite flocculant: Chitosan was added to an acetic acid solution and mixed. After mixing, N,N-bis(2-hydroxyethyl)methacrylamide and sodium methallylsulfonate were added. Then, ammonium cerium nitrate was added under nitrogen conditions, and the reaction was carried out at 60°C for 5 h. After the reaction, the chitosan polymer was obtained through precipitation washing and vacuum drying. Then, polyaluminum chloride and water were added to the chitosan polymer and mixed to obtain a composite solution, and the composite solution was dried and ground to obtain the composite coagulant. The acetic acid solution was composed of acetic acid and water, and the volume ratio of the amount of water used to the amount of acetic acid used was 1:0.00026. The amount of chitosan added to the acetic acid solution was 1.95 g / L. The mass ratio of the amount of chitosan used to the amount of N,N-bis(2-hydroxyethyl)methacrylamide used was 1:0.25. The mass ratio of the amount of chitosan used to the amount of sodium methallylsulfonate used was 1:0.25. The mass ratio of the amount of chitosan used to the amount of ammonium cerium nitrate used was 1:0.0003. The mass ratio of the amount of chitosan polymer used to the amount of polyaluminum chloride used was 1:5. The amount of polyaluminum chloride in water was 50 g / L.

[0088] The primary treatment was the same as that in Example 1.

[0089] Secondary treatment: In this example, compared with Example 1 in the secondary treatment, the difference was that the polyacrylamide solution was replaced with the composite flocculant solution. The composite flocculant solution was obtained by adding the composite flocculant prepared in this example to water. The amount of the composite flocculant added to water was 1 g / L. The volume ratio of the amount of the composite flocculant solution added to the secondary flocculation tank to the amount of the primary treated wastewater was 1:50. Other conditions and parameters were the same as those in Example 4.

[0090] Example 6:

[0091] The preparation of the composite flocculant was the same as that in Example 5.

[0092] The primary treatment was the same as that in Example 1.

[0093] Secondary treatment: In this example, compared with Example 5 in the secondary treatment, the difference was that the volume ratio of the amount of the composite flocculant solution added to the secondary flocculation tank to the amount of the primary treated wastewater was 1:40. Other conditions and parameters were the same as those in Example 5.

[0094] Example 7:

[0095] The preparation of the composite flocculant was the same as that in Example 5.

[0096] Preparation of Carboxylic Acid Organosilicate: Vinylmethyldichlorosilane and trimethylchlorosilane were mixed and added dropwise to isopropanol for reaction at 4 °C for 1 h. Then, water was added dropwise and the reaction continued for 1.5 h. After the reaction, the organic layer was separated, washed to remove water, and distilled under reduced pressure to obtain the organosilicon precursor. The organosilicon precursor, mercaptoacetic acid, and tetrahydrofuran were mixed, and 2,2 - dimethoxy - phenylacetophenone was added. The reaction was carried out under ultraviolet light for 15 min. Then, sodium carbonate was added and the reaction continued for 2 h. After the reaction, rotary evaporation, hexane washing, and drying were performed to obtain the carboxylic acid organosilicate. Among them, vinylmethyldichlorosilane and trimethylchlorosilane were mixed at a mass ratio of 1:3.85, the mass ratio of the amount of isopropanol used to the amount of vinylmethyldichlorosilane used was 1:0.39, the mass ratio of the amount of water used to the amount of vinylmethyldichlorosilane used was 0.87, the mass ratio of the amount of organosilicon precursor used to the amount of mercaptoacetic acid used was 1:1.3, the mass ratio of the amount of organosilicon precursor used to the amount of tetrahydrofuran used was 1:0.41, the mass ratio of the amount of organosilicon precursor used to the amount of 2,2 - dimethoxy - phenylacetophenone used was 1:0.028, and the mass ratio of the amount of organosilicon precursor used to the amount of sodium carbonate used was 1:0.214.

[0097] The primary treatment was the same as in Example 1.

[0098] Secondary treatment: The primary - treated wastewater was introduced into the secondary reaction tank, and an aluminum sulfate solution was added to the secondary reaction tank for reaction for 15 min. The primary - treated wastewater after the reaction flowed to the secondary flocculation tank, and a composite flocculant solution and a carboxylic acid organosilicate solution were added to the secondary flocculation tank for flocculation reaction for 10 min. Finally, it flowed to the sedimentation tank for sedimentation separation to obtain the treated wastewater. Among them, the phosphorus value of the primary - treated wastewater was 20 mg / L; the aluminum sulfate solution was obtained by adding aluminum sulfate to water, the amount of water added to aluminum sulfate was 300 g / L, and the volume ratio of the amount of aluminum sulfate solution added to the amount of primary - treated wastewater in the secondary reaction tank was 1:1699; sodium hydroxide, sulfuric acid, and an aluminate solution were added to the secondary reaction tank to adjust the pH to 6.8; the composite flocculant solution was obtained by adding a composite flocculant to water, the amount of the composite flocculant added to water was 1 g / L, and the volume ratio of the amount of composite flocculant solution added to the amount of primary - treated wastewater in the secondary flocculation tank was 1:50; the carboxylic acid organosilicate solution was obtained by adding carboxylic acid organosilicate to water, the amount of carboxylic acid organosilicate added to water was 1 g / L, and the volume ratio of the amount of carboxylic acid organosilicate solution added to the amount of composite flocculant solution in the secondary flocculation tank was 1:2.

[0099] Example 8:

[0100] The preparation of the composite flocculant was the same as in Example 5.

[0101] The preparation of the carboxylic acid organosilicate was the same as in Example 7.

[0102] The primary treatment was the same as in Example 1.

[0103] Secondary treatment: In this embodiment, compared with Example 7, the difference in the secondary treatment is that the volume ratio of the amount of carboxylic acid organosilicate solution to the amount of composite flocculant solution added in the secondary flocculation tank is 1:3, and other conditions and parameters are the same as those in Example 7.

[0104] Comparative Example 1:

[0105] The composite flocculant was prepared in the same manner as in Example 5.

[0106] The primary treatment was the same as in Example 1.

[0107] Secondary treatment: In this embodiment, compared with Example 5, the difference in the secondary treatment is that the volume ratio of the amount of composite flocculant solution to the amount of primary treated wastewater added in the secondary flocculation tank is 1:60, and other conditions and parameters are the same as those in Example 5.

[0108] Comparative Example 2:

[0109] The composite flocculant was prepared in the same manner as in Example 5.

[0110] The primary treatment was the same as in Example 1.

[0111] Secondary treatment: In this embodiment, compared with Example 5, the difference in the secondary treatment is that the volume ratio of the amount of composite flocculant solution to the amount of primary treated wastewater added in the secondary flocculation tank is 1:28, and other conditions and parameters are the same as those in Example 5.

[0112] Experimental Example 1:

[0113] The chitosan polymer was characterized, and the composite flocculant prepared in Example 1 was subjected to infrared spectroscopic characterization analysis, with the scanning range being 400 - 4000 cm -1 . The results are as Figure 1 shown. 3200 - 3500 cm -1 is the characteristic absorption peak of O - H, 2800 - 3000 cm -1 is the characteristic absorption peak of - CH3 and - CH2, and 1651 cm -1 is the characteristic absorption peak of C = O, 1553 cm -1 is the characteristic absorption peak of N - H, 1265 cm -1 is the characteristic absorption peak of S = O, and 1074 cm -1 is the characteristic absorption peak of C - N.

[0114] Experimental Example 2:

[0115] The phosphorus content of the treated wastewater obtained in Examples 1 - 8 and Comparative Examples 1 - 2 was measured. The results are as Figure 2As shown, the phosphorus content in the treated wastewater of Example 1 of the present invention is higher than that of Examples 3 and 4, indicating that on the basis of using polyaluminum chloride, adding polyaluminum ferric chloride or lanthanum chloride can further reduce the phosphorus content in the treated wastewater and improve the phosphorus removal effect; comparing Example 4 with Example 5 shows that using a composite flocculant for flocculation treatment can improve the phosphorus removal effect and reduce the phosphorus content in the treated wastewater; comparing Example 5 with Example 6 shows that even with a reduction in the dosage of the composite flocculant within a certain range, the phosphorus content in the resulting treated wastewater is still relatively low; comparing Example 5 with Example 7 shows that on the basis of using the composite flocculant, adding carboxylic acid organosilicate can synergistically reduce the phosphorus content in the treated wastewater; comparing Example 7 with Example 8 shows that a decrease in the dosage of carboxylic acid organosilicate within a certain range will increase the phosphorus content in the treated wastewater; comparing Example 5 with Comparative Examples 1 and 2 shows that the dosage of the composite flocculant needs to be within a suitable range. Too low a dosage will inhibit the reduction of the phosphorus content in the treated wastewater, and when the dosage exceeds a certain range, increasing the dosage will not result in a significant improvement in the phosphorus removal effect.

[0116] Experimental Example 3:

[0117] The solid content of the treated wastewater obtained from Examples 1 - 8 and Comparative Examples 1 - 2 was measured. The results are as Figure 3 shown. The solid content of the treated wastewater in Example 1 of the present invention is higher than that of Examples 3 and 4, indicating that on the basis of using polyaluminum chloride, adding polyaluminum ferric chloride or lanthanum chloride can promote the formation of stable precipitates and reduce the solid content in the treated wastewater after separation; comparing Example 4 with Example 5 shows that using a composite flocculant for flocculation treatment can improve the flocculation effect, promote sediment settlement, and reduce the solid content in the treated wastewater after separation; comparing Example 5 with Example 6 shows that even with a reduction in the dosage of the composite flocculant within a certain range, the solid content in the treated wastewater after sediment separation is still relatively low; comparing Example 5 with Example 7 shows that on the basis of using the composite flocculant, adding carboxylic acid organosilicate can synergistically promote sedimentation and reduce the solid content in the treated wastewater after separation; comparing Example 7 with Example 8 shows that a decrease in the dosage of carboxylic acid organosilicate within a certain range will increase the solid content in the treated wastewater; comparing Example 5 with Comparative Examples 1 and 2 shows that the dosage of the composite flocculant needs to be within a suitable range. Too low a dosage will reduce the coagulation and precipitation effect, thus affecting the solid content of the treated wastewater, and when the dosage exceeds a certain range, increasing the dosage will not have a significant effect on reducing the solid content.

[0118] Experimental Example 4:

[0119] The magnesium ammonium phosphate particles are fine in particle size, have a density close to that of water, do not sink after being placed in water for a long time, and are difficult to treat. The magnesium ammonium phosphate content in the primary treated wastewater without secondary treatment in Example 1 and the treated wastewater obtained in Examples 1-8 and Comparative Examples 1-2 was measured, and the results are as Figure 4 shown. The magnesium ammonium phosphate content in the primary treated wastewater without secondary treatment in Example 1 was used as a control; the magnesium ammonium phosphate content in the treated wastewater of Example 1 of the present invention is higher than that in Examples 3 and 4, indicating that on the basis of using polyaluminum chloride, adding polyaluminum ferric chloride or lanthanum chloride can promote the reduction of the magnesium ammonium phosphate content and effective removal; comparing Example 4 with Example 5 shows that using a composite flocculant for flocculation treatment can better reduce the magnesium ammonium phosphate content; comparing Example 5 with Example 6 shows that a decrease in the dosage of the composite flocculant within a certain range will lead to an increase in the magnesium ammonium phosphate content; comparing Example 5 with Example 7 shows that on the basis of using a composite flocculant, adding a carboxylic acid organosilicate can synergistically promote the reduction of the magnesium ammonium phosphate content; comparing Example 7 with Example 8 shows that a decrease in the dosage of the carboxylic acid organosilicate within a certain range will increase the magnesium ammonium phosphate content; comparing Example 5 with Comparative Examples 1 and 2 shows that the dosage of the composite flocculant needs to be within a suitable range. Too low a dosage will reduce the removal effect on magnesium ammonium phosphate, and when the dosage exceeds a certain range, increasing the dosage will not significantly improve the removal effect on magnesium ammonium phosphate.

[0120] The above-mentioned embodiments and / or implementation manners are only used to illustrate the preferred embodiments and / or implementation manners for realizing the technology of the present invention, and do not impose any formal restrictions on the implementation manners of the technology of the present invention. Any person skilled in the art, without departing from the scope of the technical means disclosed in the content of the present invention, may make some changes or modifications to other equivalent embodiments, but should still be regarded as the same technology or embodiment as the present invention in essence.

[0121] In this article, specific examples are used to elaborate on the principles and implementation manners of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application. The above is only the preferred implementation manner of the present application. It should be noted that due to the limited nature of written expression and the objectively infinite specific structures, for those of ordinary skill in the art in this technical field, without departing from the principle of the present application, several improvements, refinements or changes can also be made, or the above technical features can be combined in an appropriate manner; these improvements, refinements, changes or combinations, or directly applying the concept and technical solution of the invention to other occasions without improvement, should all be regarded as the protection scope of the present application.

Claims

1. A stable and efficient phosphorus removal process treatment method, comprising: S1: Passing the phosphorus-containing wastewater into a primary reaction tank to react with a primary metal salt solution; After the reaction, flowing to a primary flocculation tank to react with a flocculant solution; Finally, flowing to a primary sedimentation tank for sedimentation separation to obtain primary treated wastewater; S2: Passing the primary treated wastewater obtained in S1 into a secondary reaction tank to react with a secondary metal salt solution; after the reaction, flowing to a secondary flocculation tank to react with a flocculant solution; finally, flowing to a secondary sedimentation tank for sedimentation separation to obtain treated wastewater; the flocculant solution in the secondary reaction tank is obtained by adding a flocculant to water, the flocculant is a composite flocculant, and the composite flocculant is prepared from chitosan, N,N-bis(2-hydroxyethyl)methacrylamide, sodium methallylsulfonate, ammonium cerium nitrate and polyaluminum ferric chloride; the mass ratio of the usage amount of chitosan to the usage amount of N,N-bis(2-hydroxyethyl)methacrylamide is 1:0.2 - 0.3, the mass ratio of the usage amount of chitosan to the usage amount of sodium methallylsulfonate is 1:0.2 - 0.3, and the mass ratio of the usage amount of chitosan polymer to the usage amount of polyaluminum chloride is 1:4 - 5.5; The flocculant solution in S1 or S2 is obtained by adding a flocculant to water, and the amount of the flocculant added to water is 0.7 - 1.3 g / L; the volume ratio of the usage amount of the flocculant solution in S1 to the amount of the phosphorus-containing wastewater is 1:0.3 - 0.6, and the volume ratio of the usage amount of the flocculant solution in S2 to the amount of the primary treated wastewater is 1:32 - 55; The reaction time in S1 is 10 - 50 min, and the reaction pH is adjusted to 7 - 10 by sodium hydroxide and sulfuric acid; the flocculation reaction time is 8 - 15 min.

2. The method for treating by a stable and efficient phosphorus reduction process according to claim 1, wherein: The primary reaction tank in S1 includes primary reaction tank 1 and primary reaction tank 2.

3. A stable and efficient phosphorus reduction process treatment method according to claim 1, characterized in that: The phosphorus value of the phosphorus-containing wastewater in S1 is 2000 - 2200 mg / L; the primary metal salt solution is a calcium salt solution, and the volume ratio of the usage amount of the calcium salt solution in primary reaction tank 1 to the amount of the phosphorus-containing wastewater is 1:35 - 48, and the volume ratio of the usage amount of the calcium salt solution in primary reaction tank 2 to the amount of the phosphorus-containing wastewater is 1:245 - 300.

4. A stable and efficient phosphorus reduction process treatment method according to claim 1, characterized in that: The phosphorus value of the primary treated wastewater in S2 is 10 - 20 mg / L.

5. The treatment method of a stable and efficient phosphorus reduction process according to claim 1, characterized in that: The secondary metal salt solution in S2 is at least one of an aluminum salt solution, an iron salt solution, a polyaluminum ferric solution or a lanthanum salt solution.

6. The method for treating by a stable and efficient phosphorus reduction process according to claim 5, wherein: The volume ratio of the usage amount of the aluminum salt solution in S2 to the amount of the primary treated wastewater is 1:1100 - 1850, the volume ratio of the usage amount of the iron salt solution in S2 to the amount of the primary treated wastewater is 1:1100 - 1800, the volume ratio of the usage amount of the polyaluminum ferric solution in S2 to the amount of the primary treated wastewater is 1:9000 - 15000, and the volume ratio of the usage amount of the lanthanum salt solution in S2 to the amount of the primary treated wastewater is 1:2100 - 2800.

7. A stable and efficient phosphorus reduction process treatment method according to claim 1, characterized in that: The reaction time in S2 is 10 - 20 min, and the reaction pH is adjusted to 7 - 10 by sodium hydroxide, sulfuric acid and a sodium aluminate solution; the flocculation reaction time is 8 - 15 min.

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