Sludge conditioning and dewatering composite agent and preparation method thereof

Abstract

The invention relates to a sludge conditioning and dewatering composite agent and a preparation method thereof. The sludge conditioning and dewatering composite agent comprises a high-molecular polymer, wherein the high-molecular polymer comprises a 1-vinyl-2-pyrrolidone copolymerization unit and a copolymerization unit comprising an alkenyl group and an amino group or an acylamino group; and a tannic acid-inorganic salt complex. The sludge conditioning and dewatering composite agent can efficiently flocculate fine particles, increase the particle size of sludge, improve the sludge-water separation speed and promote deep dewatering of sludge.

Description

Technical Field

[0001] The invention relates to the technical field of sludge treatment and disposal, and in particular to a sludge conditioning and dehydration composite agent and a preparation method thereof. Technical Background

[0002] Sludge is an inevitable product of the biological treatment process of urban sewage treatment plants. The annual production of concentrated sludge (with a water content of 98%) in my country has reached more than 300 million tons, and the pressure on sludge treatment and disposal is enormous. Among them, sludge dehydration is an important link in sludge treatment and disposal, which can effectively reduce the sludge volume and reduce the subsequent transportation, treatment and disposal costs of sludge.

[0003] Usually, mechanical dehydration is used to reduce the moisture content of sludge. However, due to the presence of a large number of hydrophilic substances in the sludge and the high moisture content, it is very difficult to dehydrate it directly. Therefore, before dehydrating the sludge, pretreatment measures are generally required to adjust the sludge dehydration performance in order to effectively dehydrate it. At present, the main methods for dehydration and conditioning of sludge in urban sewage treatment plants include physical conditioning, chemical conditioning, microbial flocculation conditioning, etc., in order to improve the dehydration performance of sludge. However, the above methods still have some shortcomings in practical applications:

[0004] (1) Physical conditioning generally consumes a lot of energy. After conditioning, the sludge dewatering liquid contains a large amount of chemical oxygen demand (COD) and ammonia nitrogen, which increases the treatment burden of the dewatering liquid;

[0005] (2) Although chemical conditioning can significantly improve the dewatering performance of sludge, the introduction of a large amount of inorganic matter will reduce the organic matter content in the sludge, which is not conducive to the later resource utilization of sludge and is likely to cause potential secondary pollution to the environment;

[0006] (3) Although microbial flocculation conditioning technology has broad development prospects, it has problems such as large amount of flocculants and high cost, which seriously restrict the large-scale production of microbial flocculants and greatly limit their widespread application in industry.

[0007] At present, most urban sewage treatment plants in my country use polyelectrolytes to condition sludge. Although chemical agents such as polyelectrolytes can greatly improve the dewatering performance and solid recovery rate of sludge, there are many types of agents and the proportioning and dosing process is complicated, and it is difficult to ensure the best effect. Moreover, the existing technology uses a single organic matter for conditioning, which will result in poor results, and the moisture content of the dewatered sludge cake is still as high as 80%.

[0008] Therefore, a new sludge conditioning and dehydration composite agent is needed, which can efficiently flocculate fine particles to increase the sludge particle size, increase the mud-water separation speed, and promote the deep dehydration of sludge. Summary of the invention

[0009] In view of the defects in the above-mentioned prior art, the purpose of the present invention is to provide a sludge conditioning and dehydration composite agent and a preparation method thereof. In view of the difficulty in dehydrating the residual sludge generated by urban sewage treatment plants and the potential secondary pollution to the environment caused by subsequent treatment, a sludge conditioning and dehydration composite agent is proposed, which utilizes the adsorption and bridging effect of tannic acid and inorganic salt complexes to promote sludge floc aggregation and increase the mud-water separation rate, and utilizes the specific adsorption between 1-vinyl-2-pyrrolidone and tannic acid to connect tannic acid into a polymer, reduce tannic acid hydrolysis, and at the same time acts as a coprecipitant to enhance the flocculation effect after tannic acid complexes with organic matter.

[0010] In one aspect, the present invention provides a composite agent for sludge conditioning and dehydration, wherein the composite agent comprises:

[0011] (1) a high molecular weight polymer comprising a copolymerization unit of 1-vinyl-2-pyrrolidone and a copolymerization unit comprising an alkenyl group and an amine group or an amide group; and

[0012] (2) Tannic acid-inorganic salt complex.

[0013] In one embodiment of the present invention, the copolymerization unit comprising alkenyl and amine or amido is selected from vinylamine copolymerization unit, N-vinylformamide copolymerization unit, vinylacrylamide copolymerization unit, N,N-dimethylenebisacrylamide copolymerization unit or one or more combinations thereof.

[0014] In one embodiment of the present invention, the high molecular polymer comprises vinylamine copolymer units, N-vinyl formamide copolymer units and vinyl acrylamide copolymer units.

[0015] In one embodiment of the present invention, the tannic acid-inorganic salt complex includes a tannic acid-aluminum salt complex, a tannic acid-iron salt complex or a combination thereof.

[0016] In one embodiment of the present invention, the composite pharmaceutical composition further comprises 1-vinyl-2-pyrrolidone.

[0017] In one embodiment of the present invention, the composite pharmaceutical agent further comprises an oxidant.

[0018] In one embodiment of the present invention, the oxidant comprises hydrogen peroxide, peracetic acid, persulfate, calcium peroxide, ferrate, sodium hypochlorite or a combination thereof.

[0019] On the other hand, the present invention provides a method for preparing the sludge conditioning and dehydration composite agent, the method comprising:

[0020] (1) reacting 1-vinyl-2-pyrrolidone with a copolymer containing an alkenyl group and an amine group or an acylamino group to form a high molecular weight polymer;

[0021] (2) contacting tannic acid with an inorganic salt to form the tannic acid-inorganic salt complex; and

[0022] (3) Mixing the high molecular polymer and the tannic acid-inorganic salt complex to form a sludge conditioning and dehydration composite agent.

[0023] In one embodiment of the present invention, the high molecular polymer is formed by reacting at 50-80° C. for 3-5 hours in the presence of an initiator and a cross-linking agent. Preferably, the initiator includes potassium persulfate, cerium sulfate, ammonium persulfate, hydrogen peroxide or a combination thereof; the cross-linking agent includes N,N-methylenebisacrylamide, divinylbenzene, diisocyanate or a combination thereof.

[0024] In one embodiment of the present invention, step (3) further comprises adding a stabilizer. Preferably, the stabilizer comprises isopropanol, thiourea, triethanolamine or a combination thereof.

[0025] In the present invention, the tannic acid-inorganic salt complex has an adsorption bridging effect, which can promote the aggregation of sludge flocs and increase the speed of mud-water separation, which is conducive to the net capture and sweeping of flocs in the sludge. At the same time, 1-vinyl-2-pyrrolidone and tannic acid have specific adsorption, which can connect tannic acid to form a polymer, which can reduce the hydrolysis of tannic acid; and 1-vinyl-2-pyrrolidone itself is also a coprecipitant, which can strengthen the flocculation effect after tannic acid complexes organic matter, so that there is no residue in the filtrate. In addition, 1-vinyl-2-pyrrolidone is easy to copolymerize with other ethylene compounds to form a high molecular long-chain polymer. In addition, adding an oxidant (for example, peracetic acid, potassium persulfate, calcium peroxide, ferrate, etc.) can pre-oxidize sludge flocs and cells, promote the decomposition of biological organic matter in sludge flocs and the release of bound water, and the sludge conditioning and dehydration composite agent of the present invention can be used to achieve deep dehydration of sludge. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of preparing a composite agent for sludge conditioning and dehydration according to one embodiment of the present invention is shown. DETAILED DESCRIPTION

[0027] The present application is described in detail below, and the features of the present application will be further revealed in the following specific description.

[0028] "Scope" disclosed herein is defined in the form of lower limit and upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a particular range. The scope defined in this way can be including end values ​​or not including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a particular parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following scope can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In this application, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0029] In this application, if there is no special description, all embodiments and preferred embodiments mentioned herein can be combined with each other to form a new technical solution. In this application, if there is no special description, all technical features and preferred features mentioned herein can be combined with each other to form a new technical solution.

[0030] In this application, unless otherwise specified, the terms "include" and "comprising" mentioned herein may be open-ended or closed-ended. For example, the terms "include" and "comprising" may mean that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0031] In the description herein, unless otherwise specified, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0032] In the prior art, a single organic conditioning agent has poor effect, and the moisture content of the dehydrated mud cake is still as high as 80%. Treatment with an oxidant alone will lead to deterioration of the sludge dewatering performance. The present invention replaces acrylamide polymer with a copolymer of ethyleneamine / N-vinylformamide / vinylacrylamide, which can reduce secondary pollution. At the same time, it integrates the characteristics of dense aluminum salt flocs, large iron salt flocs, and good organic-inorganic polymer adsorption bridging net capture effect. In the present invention, the use of the conditioning and dehydration composite agent (10-200 mg / gTS) and optionally supplemented with an oxidant (0-120 mg / gTS) can achieve deep dehydration of sludge (mud cake moisture content <60%).

[0033] High molecular weight polymer

[0034] In the present invention, the sludge conditioning and dehydration composite agent comprises a high molecular polymer, wherein the high molecular polymer comprises a copolymerization unit of 1-vinyl-2-pyrrolidone and a copolymerization unit comprising an alkenyl group and an amine group or an acylamino group. The copolymerization unit comprising an alkenyl group and an amine group or an acylamino group comprises a copolymerization unit comprising an alkenyl group and an amine group, a copolymerization unit comprising an alkenyl group and an acylamino group, or a copolymerization unit comprising an alkenyl group, an amine group and an acylamino group.

[0035] In a specific embodiment of the present invention, the copolymerization unit containing alkenyl and amine or amido is selected from vinylamine copolymerization unit, N-vinylformamide copolymerization unit, vinylacrylamide copolymerization unit, N,N-dimethylenebisacrylamide copolymerization unit or one or more combinations thereof.

[0036]

[0037] In a specific embodiment of the present invention, the high molecular polymer comprises vinylamine copolymer units, N-vinyl formamide copolymer units and vinyl acrylamide copolymer units.

[0038] In the present invention, the content of the high molecular polymer in the dehydration composite agent can be comprehensively evaluated and adjusted according to factors such as the water content of the sludge, the type and concentration of the pollutants, the molecular weight of the polymer itself, the charge density, the characteristics of the process equipment, the operational stability, the treatment effect, the economic cost, etc. In an embodiment of the present invention, the content of the high molecular polymer in the dehydration composite agent can be 5% by weight to 25% by weight, 10% by weight to 20% by weight, or 13% by weight to 17% by weight.

[0039] Tannic acid-inorganic salt complex

[0040] In the present invention, the sludge conditioning and dehydration composite agent comprises a tannic acid-inorganic salt complex. In a specific embodiment of the present invention, the tannic acid-inorganic salt complex comprises a tannic acid-aluminum salt complex, a tannic acid-iron salt complex or a combination thereof.

[0041]

[0042] In the formula, each R is independently selected from an alkyl group or an aryl group. In some embodiments of the present invention, each R is independently selected from a C1-C20 alkyl group or a C6-C18 aryl group.

[0043] In an embodiment of the present invention, the content of the tannic acid-inorganic salt complex in the sludge conditioning and dehydration composite agent may be 0.5 wt %-5.0 wt %, 1.0 wt %-4.0 wt %, or 2.0 wt %-3.0 wt %.

[0044] Optional additives

[0045] In the present invention, the sludge conditioning and dehydration composite agent further comprises one or more optional additives. In a preferred embodiment, the sludge conditioning and dehydration composite agent further comprises 1-vinyl-2-pyrrolidone. The 1-vinyl-2-pyrrolidone itself acts as a coprecipitant, which can enhance the flocculation effect after tannic acid complexes organic matter, so that there is no residue in the filtrate. Moreover, 1-vinyl-2-pyrrolidone is easy to copolymerize with other vinyl compounds to form high molecular long-chain polymers.

[0046] In the present invention, the content of 1-vinyl-2-pyrrolidone in the sludge conditioning and dehydration composite agent can be comprehensively evaluated and adjusted according to many factors such as sludge properties, treatment objectives, treatment conditions, etc. In an embodiment of the present invention, the content of 1-vinyl-2-pyrrolidone in the sludge conditioning and dehydration composite agent can be 0.5 wt%-10.0 wt%, 1.0 wt%-8.0 wt%, 2.0 wt%-6.0 wt%, or 3.0 wt%-5.0 wt%.

[0047] In a preferred embodiment, the sludge conditioning and dehydration composite agent further comprises an oxidant. In a specific embodiment of the present invention, the oxidant comprises hydrogen peroxide, peracetic acid, persulfate, calcium peroxide, ferrate, sodium hypochlorite or a combination thereof. In the present invention, the oxidant (e.g., ozone, peracetic acid, potassium persulfate, etc.) can pre-oxidize the sludge flocs and cells, promote the decomposition of biological organic matter in the sludge flocs and the release of bound water, and the sludge conditioning and dehydration composite agent of the present invention can be used in combination to achieve deep dehydration of the sludge.

[0048] In the present invention, the oxidant is used to enhance the oxidation and decomposition of sludge flocs and promote the release of bound water. In an embodiment of the present invention, the content of the oxidant in the dehydration composite agent can be 1.0 wt%-8.0 wt%, 2.0 wt%-7.0 wt%, 3.0 wt%-6.0 wt%, or 4.0 wt%-5.0 wt%.

[0049] Preparation method

[0050] The method for preparing the sludge conditioning and dehydration composite agent of the present invention comprises: reacting 1-vinyl-2-pyrrolidone with a copolymer containing alkenyl and amine or acylamino groups to form a high molecular polymer.

[0051] In a specific embodiment, in the presence of an initiator and a cross-linking agent, the reaction is carried out at a temperature of 50-80°C, 50-70°C, 50-60°C, 60-80°C or 60-70°C for 3-5 hours, 3-4 hours to form the high molecular polymer. In a preferred embodiment, the initiator includes potassium persulfate, cerium sulfate, ammonium persulfate, hydrogen peroxide or a combination thereof. In a preferred embodiment, the cross-linking agent includes N,N-methylenebisacrylamide, divinylbenzene, diisocyanate or a combination thereof.

[0052] In the present invention, the initiator is mainly used for the cross-linking reaction of the polymer to increase the stability and durability of the polymer. In an embodiment of the present invention, the amount of the initiator is generally 0.1 wt %-0.5 wt %, 0.2 wt %-0.4 wt %, or 0.3 wt %-0.4 wt %, based on the total weight of the reactants.

[0053] The cross-linking agent is used to form a cross-linked structure of the polymer, increasing its stability in the sludge and the dehydration effect. The amount of the cross-linking agent can be adjusted according to the type and properties of the specific high molecular polymer. In an embodiment of the present invention, the amount of the cross-linking agent is generally 0.5% by weight to 5% by weight, 1.0% by weight to 4.0% by weight, or 2.0% by weight to 3.0% by weight, based on the total weight of the reactants.

[0054] The method for preparing the sludge conditioning and dehydration composite agent of the present invention comprises: contacting tannic acid with inorganic salt to form the tannic acid-inorganic salt complex.

[0055] In a specific embodiment, the inorganic salt is selected from iron salt or aluminum salt.

[0056] In a specific embodiment, the ratio of tannic acid to inorganic salt (iron salt / aluminum salt) is between 1:1 and 3:1 or between 1:1 and 2:1.

[0057] In specific embodiments, the reaction temperature may be between 25-60°C, between 30-50°C, or between 35-45°C.

[0058] In specific embodiments, the reaction time may be between 15 minutes and 2 hours or between 30 minutes and 1 hour.

[0059] The method for preparing the sludge conditioning and dehydration composite agent of the present invention comprises: mixing the high molecular polymer and tannic acid-inorganic salt complex to form the sludge conditioning and dehydration composite agent.

[0060] In some embodiments, the amount of high molecular weight polymer used is in the range of 50-300 mg / L, depending on the sludge characteristics, dewatering equipment and the requirements for the final dewatering effect.

[0061] In some embodiments, considering the complexing capacity and cost of the complex, the tannic acid-inorganic salt complex is used in a range of 100-500 mg / L.

[0062] In a specific embodiment, the mixing step further includes adding a stabilizer to improve the stability of the high molecular weight polymer and the tannic acid-inorganic salt complex and improve the storage stability of the final product, the sludge conditioning and dehydration composite agent. In a preferred embodiment, the stabilizer includes isopropanol, thiourea, triethanolamine or a combination thereof.

[0063] application

[0064] The application field of sludge conditioning and dehydration compound agents is very wide, mainly including various engineering treatment sites, not limited to urban sewage treatment plants, petrochemical enterprises, food industry, pulp and paper manufacturing industry, mining, metallurgical industry, river restoration, etc., and is used to treat sludge generated by industry, domestic sewage, river management, etc.

[0065] The sludge conditioning and dehydration compound agent is mainly used in the sludge conditioning and dehydration stage. Sludge is the solid residue in the sewage treatment process, containing a large amount of water and harmful substances. In this stage, the compound agent can effectively improve the filterability of the sludge, enhance its dehydration effect, and reduce the difficulty and cost of subsequent treatment.

[0066] The sludge conditioning and dehydration compound agent strengthens the coagulation of particles in the sludge through complexation, improves the structure of the sludge, changes it from a sparse state to a compact state, and maintains its stability, which is conducive to the subsequent filter pressing and dehydration. At the same time, it can also improve the solid-liquid separation efficiency during the sludge dehydration process, thereby reducing the sludge burden and the cost of sludge treatment, and also greatly reduces the concentration of some toxic and harmful substances, reducing the harm to the environment and human body.

[0067] Example

[0068] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0069] In the following examples, sludge was taken from Changzhou Shenshui Chengbei Sewage Treatment Plant; polyvinylamine was purchased from Hubei Shiteng Chemical Technology Co., Ltd.; polyacrylamide was purchased from Shanghai Yuanye Biotechnology Co., Ltd.; poly N-vinyl formamide was purchased from Shanghai Yaji Biotechnology Co., Ltd.; 1-vinyl-2-pyrrolidone was purchased from Guangzhou Ruiyue Trading Co., Ltd.; sodium persulfate was purchased from Fujian Minglin Technology Co., Ltd.; hydrogen peroxide was purchased from Anhui Andeno Chemical Products Sales Co., Ltd.; N,N-methylenebisacrylamide was purchased from Hubei Linyang Chemical Co., Ltd.; tannic acid was purchased from Hebei Yaxin Biotechnology Co., Ltd.; ferric chloride was purchased from Tianjin Chemical Reagent Co., Ltd.; and thiourea was purchased from Hubei Taihechang Biotechnology Co., Ltd.

[0070] Example 1

[0071] 1. Preparation of polymers

[0072] At room temperature, 8 g of polyvinylamine, 8 g of polyacrylamide, 8 g of poly (N-vinylformamide), 2.5 g of 1-vinyl-2-pyrrolidone, 1.6 g of hydrogen peroxide, and 1.4 g of N,N-methylenebisacrylamide were weighed respectively, added into a 250 ml three-necked flask, stirred continuously, and heated in a 75°C water bath for 3 hours to obtain 15.6 g of a high molecular polymer.

[0073] 2. Preparation of Tannic Acid-Fe 3+ Complex

[0074] At room temperature, 3 g of tannic acid was weighed to prepare a tannic acid solution, and 2 g of ferric chloride was added and stirred continuously. The reaction generated a black precipitate, which was allowed to settle and the supernatant was filtered out to obtain a black precipitate. The black precipitate was washed with ethanol to obtain 1.4 g of tannic acid-Fe 3+ Complex.

[0075] 3. Prepare a composite agent for sludge conditioning and dehydration.

[0076] At room temperature, 15.6 g of high molecular weight polymer and 1.4 g of tannic acid-Fe 3+ The complex is mixed with 0.5 g of thiourea to form a composite agent for sludge conditioning and dehydration.

[0077] Test Example 1

[0078] First, 1% calcium peroxide was added to the sludge as an oxidant and stirred for 10 minutes, and then the sludge conditioning and dehydration compound agent prepared in the above preparation example was added and stirred for 30 minutes to fully mix the compound agent with the sludge. Then, the stirred sludge was sent to a plate and frame filter press for filtration for 2 hours, and the pressure was maintained at 1.5-2Mpa.

[0079] Through observation and measurement, the capillary water absorption time of the sludge was reduced from 112.7s without conditioning to 13.2s, and the moisture content of the dehydrated mud cake was reduced to 58.7%.

[0080] Compared with the mud cake obtained by adding 1% calcium peroxide alone, the moisture content of the mud cake obtained in Example 1 is reduced by 82%. Compared with the mud cake without using the dehydration composite agent, the moisture content of the mud cake obtained in Example 1 is reduced by 79%. At the same time, the mud-water separation speed in Example 1 is also faster, and the sedimentation ratio SV30 value is 15%, while the SV30 value of the sludge using the conventional dehydration composite agent is 35%. Example 1 greatly saves the sludge sedimentation time.

[0081] Comparative Example 1

[0082] In the same sewage treatment plant, only high molecular weight polymer conditioner was added to the sludge of the same specifications and stirred for 30 minutes to fully mix the conditioner and the sludge.

[0083] The same filter press was used for filter pressing treatment in the same manner as in Example 1. The moisture content of the mud cake after dehydration was 76%, which was significantly worse than the effect of the dehydration composite agent in Example 1. The speed of mud-water separation was also slower than that of the sludge conditioning dehydration composite agent, and the sedimentation ratio SV30 was 24%.

[0084] Comparative Example 2

[0085] In the same sewage treatment plant, tannic acid-Fe was added to the sludge of the same specifications. 3+ Complex conditioner and stir for 30 minutes to fully mix the conditioner and sludge.

[0086] The same filter press was used as in Example 1. The moisture content of the dehydrated mud cake was 78%, which was significantly worse than the effect of using the dehydration compound agent. The speed of mud-water separation was also slower than that of the sludge conditioning dehydration compound agent, and the sedimentation ratio SV30 was 27%.

[0087] It can be seen from the above-mentioned Example 1, Test Example 1 and Comparative Examples 1-2 that the composite sludge conditioning and dehydration agent of the present invention is significantly superior to a single organic sludge conditioning agent in terms of deep dehydration and accelerating the separation of sludge and water. Therefore, the composite sludge conditioning and dehydration agent has a better application prospect.

[0088] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A sludge conditioning and dehydration composite agent, wherein: The compound medicine comprises: (1) a high molecular weight polymer comprising a copolymerization unit of 1-vinyl-2-pyrrolidone and a copolymerization unit comprising an alkenyl group and an amine group or an amide group; and (2) Tannic acid-inorganic salt complex.

2. The sludge conditioning and dehydration composite agent according to claim 1, wherein: The copolymerization unit containing alkenyl and amine or acylamino group is selected from vinylamine copolymerization unit, N-vinylformamide copolymerization unit, vinylacrylamide copolymerization unit, N,N-dimethylenebisacrylamide copolymerization unit or one or more combinations thereof.

3. The sludge conditioning and dehydration composite agent according to claim 1, wherein: The high molecular polymer comprises vinylamine copolymer units, N-vinyl formamide copolymer units and vinyl acrylamide copolymer units.

4. The sludge conditioning and dehydration composite agent according to claim 1, wherein: The tannic acid-inorganic salt complex includes a tannic acid-aluminum salt complex, a tannic acid-iron salt complex or a combination thereof.

5. The sludge conditioning and dehydration composite agent according to claim 1, wherein: The composite pharmaceutical preparation further comprises 1-vinyl-2-pyrrolidone.

6. The sludge conditioning and dehydration composite agent according to claim 1, wherein: The composite pharmaceutical composition further comprises an oxidizing agent.

7. The sludge conditioning and dehydration composite agent according to claim 6, wherein: The oxidizing agent includes hydrogen peroxide, peracetic acid, persulfate, calcium peroxide, ferrate, sodium hypochlorite or a combination thereof.

8. A method for preparing the sludge conditioning and dehydration composite agent according to any one of claims 1 to 7, the method comprising: (1) reacting 1-vinyl-2-pyrrolidone with a copolymer containing an alkenyl group and an amine group or an acylamino group to form a high molecular weight polymer; (2) contacting tannic acid with an inorganic salt to form the tannic acid-inorganic salt complex; and (3) Mixing the high molecular polymer and the tannic acid-inorganic salt complex to form a sludge conditioning and dehydration composite agent.

9. The method according to claim 8, wherein: The high molecular polymer is formed by reacting at 50-80° C. for 3-5 hours in the presence of an initiator and a cross-linking agent. Preferably, the initiator includes potassium persulfate, cerium sulfate, ammonium persulfate, hydrogen peroxide or a combination thereof; the cross-linking agent includes N,N-methylenebisacrylamide, divinylbenzene, diisocyanate or a combination thereof.

10. The method according to claim 9, wherein: Step (3) further comprises adding a stabilizer. Preferably, the stabilizer comprises isopropanol, thiourea, triethanolamine or a combination thereof.

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