Sludge drier

Abstract

The invention relates to a sludge drier, which has the main principle that water molecules are easier to escape and volatilize by degrading polyacrylamide in sludge, destroying hydrogen bonds on acylamino and breaking bridges for connecting sludge particles with the water molecules. Meanwhile, cell walls of hydrophilic bacteria can be broken, so that organic matters generated by the bacteria lose a water locking function, and the sludge drying speed is further increased.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental protection, and specifically relates to a sludge drying accelerator. Background Art

[0002] Sludge treatment is an important link in environmental protection. At present, there are many problems in the sludge treatment process.

[0003] First of all, in the prior art, sludge drying mainly dries the moisture in the sludge by strong heating, but the effect is not ideal. This will cause a large amount of energy consumption, increase costs, and at the same time cause volatile toxic substances in the sludge to escape into the air with water vapor. There is also a method of adding a large amount of lime to force the cell wall to break to achieve the purpose of drying the sludge. However, this will cause an increase in the amount of sludge. The main component of the sludge is diatomite, which still has utilization value. After adding a large amount of lime, the composition changes and the pH value changes, and it completely becomes solid waste. Summary of the Invention

[0004] In view of the above situation, in order to overcome the defects of the prior art, the present invention provides a sludge drying accelerator to at least partially solve the above technical problems.

[0005] The technical solution adopted by the present invention is as follows:

[0006] The present invention provides a sludge drying accelerator, comprising:

[0007] (1) Select one or more oxides of vanadium, titanium, chromium, manganese, iron, cobalt, nickel, copper, and zinc of the first transition series metals;

[0008] (2) Add sodium ethylenediaminetetraacetate and water;

[0009] (3) Add one of inorganic acids including sulfuric acid, hydrochloric acid, and phosphoric acid;

[0010] (4) Additionally add 2-5% of an organic acid, such as one or two of citric acid, tartaric acid, and fumaric acid;

[0011] (5) Keep at 80-95°C, stir for 2-4 hours, and then let it stand.

[0012] In an embodiment of the present invention, the sludge drying accelerator further comprises:

[0013] A. Add a sludge drying treatment agent to the remaining sludge and mix evenly;

[0014] B. Let it stand;

[0015] C. Press filter;

[0016] D. Dry to obtain a filter cake with a moisture content lower than 40%;

[0017] Among them, the sludge drying treatment agent described in step (1) is a combination of polyacrylamide and an iron-containing polymer coagulant, where the iron-containing polymer coagulant is selected from one or a combination of two or more of polyferric sulfate, polyaluminum ferric silicate, and Fenton-like catalysts.

[0018] In one embodiment of the present invention, the addition amount of polyacrylamide is 0.1-1.0% of the mass of dry sludge, and the addition amount of the iron-containing polymer coagulant, calculated by iron content, is 2-10% of the mass of dry sludge.

[0019] In one embodiment of the present invention, the sludge drying treatment agent is a combination of polyacrylamide and polyferric sulfate; or the sludge drying treatment agent is a combination of polyacrylamide and polyaluminum ferric silicate; or the sludge drying treatment agent is a combination of polyacrylamide and a Fenton-like catalyst; or the sludge drying treatment agent is a combination of polyacrylamide, polyferric sulfate and polyaluminum ferric silicate, where the mass ratio of polyferric sulfate to polyaluminum ferric silicate, calculated by iron content, is (1-7):1; or the sludge drying treatment agent is a combination of polyacrylamide, polyferric sulfate and a Fenton-like catalyst, where the mass ratio of polyferric sulfate to the Fenton-like catalyst, calculated by iron content, is (1-7):1.

[0020] In one embodiment of the present invention, the sludge drying treatment agent is a combination of polyacrylamide, polyferric sulfate and a Fenton-like catalyst, where the addition amount of polyacrylamide is 0.1-0.7% of the mass of dry sludge, the addition amount of polyferric sulfate, calculated by iron content, is 1-7% of the mass of dry sludge, and the addition amount of the Fenton-like catalyst is 1-3% of the mass of dry sludge.

[0021] In one embodiment of the present invention, the pressure filtration described in step C and the drying described in step D are carried out simultaneously.

[0022] In one embodiment of the present invention, the sludge drying treatment agent is a combination of polyacrylamide and an iron-containing polymer coagulant, where the iron-containing polymer coagulant is selected from one or a combination of two or more of polyferric sulfate, polyaluminum ferric silicate, and Fenton-like catalysts; the addition amount of polyacrylamide is 0.1-1.0% of the mass of dry sludge, and the addition amount of the iron-containing polymer coagulant, calculated by iron content, is 2-10% of the mass of dry sludge.

[0023] In one embodiment of the present invention, the sludge drying agent is a combination of polyacrylamide and polyferric sulfate; or the sludge drying agent is a combination of polyacrylamide and polyaluminum ferric silicate; or the sludge drying agent is a combination of polyacrylamide and a Fenton-like catalyst; or the sludge drying agent is a combination of polyacrylamide, polyferric sulfate and polyaluminum ferric silicate, wherein, based on the iron content, the mass ratio of polyferric sulfate to polyaluminum ferric silicate is (1-7):1; or the sludge drying agent is a combination of polyacrylamide, polyferric sulfate and a Fenton-like catalyst, wherein, based on the iron content, the mass ratio of polyferric sulfate to the Fenton-like catalyst is (1-7):1.

[0024] In one embodiment of the present invention, the sludge drying agent is a combination of polyacrylamide, polyferric sulfate and a Fenton-like catalyst, wherein the addition amount of polyacrylamide is 0.1-0.7% of the mass of dry sludge, the addition amount of polyferric sulfate is 1-7% of the mass of dry sludge based on the iron content, and the addition amount of the Fenton-like catalyst is 1-3% of the mass of dry sludge.

[0025] The beneficial effects of the technical solution of the present invention are as follows:

[0026] In the present invention, by degrading polyacrylamide in the sludge and breaking the hydrogen bonds on the amide group, the bridge connecting the diatomite particles and water molecules is broken, reducing the viscosity of the sludge and facilitating the escape and volatilization of water molecules.

[0027] The present invention can rupture the cell walls of hydrophilic bacteria, causing the organic matter produced by the bacteria to lose its water-locking function, and further accelerating the sludge drying speed.

[0028] The preparation method of the present invention is simple, the raw materials are easy to obtain, the cost is low, it will not cause secondary sludge, and the dried sludge still has utilization value.

[0029] The additional aspects and advantages of the present invention will be partly given in the following description, partly will become obvious from the following description, or will be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above-mentioned and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the following description of the embodiments in conjunction with the drawings, wherein:

[0031] Figure 1 It is a schematic diagram of the first method of a sludge drying accelerator proposed by an embodiment of the present invention;

[0032] Figure 2 It is a schematic diagram of the second method of a sludge drying accelerator proposed by an embodiment of the present invention. DETAILED DESCRIPTION

[0033] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0034] A sludge drying accelerator according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0035] As Figures 1 to 2 shown, an embodiment of the present invention provides a sludge drying accelerator, comprising:

[0036] (1) Select one or more oxides of vanadium, titanium, chromium, manganese, iron, cobalt, nickel, copper, and zinc of the first transition series metals;

[0037] (2) Add sodium ethylenediaminetetraacetate and water;

[0038] (3) Add an inorganic acid including one of sulfuric acid, hydrochloric acid, and phosphoric acid;

[0039] (4) Additionally add 2-5% of an organic acid, such as one or two of citric acid, tartaric acid, and fumaric acid;

[0040] (5) Maintain at 80-95 °C, stir for 2-4 hours, and then let it stand.

[0041] In the specific application of the embodiment of the present invention, metal ions in the drying accelerator are reduced to a low atomic valence, while the antioxidant is oxidized, thereby accelerating the oxidative scission and cell wall breaking of organic substances (such as high molecular polymers, bacteria, spores, etc.) in the sludge. The drying accelerator can accelerate the destruction of hydroperoxide bonds formed by the sludge film absorbing oxygen, and other unsaturated bonds directly polymerize, reducing the required amount of oxygen; the drying accelerator can absorb oxygen in the air, accelerate the hardening of the sludge surface film, help the formation of pores, and accelerate the volatilization of water in the sludge.

[0042] In one embodiment, the sludge drying accelerator further comprises:

[0043] A. Add a sludge drying treatment agent to the surplus sludge and mix evenly;

[0044] B. Let it stand;

[0045] C. Press filter;

[0046] D. Dry to obtain a filter cake with a moisture content lower than 40%;

[0047] Wherein, the sludge drying treatment agent in step (1) is a combination of polyacrylamide and an iron-containing high molecular coagulant, and the iron-containing high molecular coagulant is selected from one or a combination of two or more of polyferric sulfate, polyaluminum ferric silicate, and Fenton-like catalysts.

[0048] The pressure filtration in step C and the drying in step D are carried out simultaneously.

[0049] In the specific application of the embodiment of the present invention, polyacrylamide is a high molecular polymer, which mainly plays a flocculating role in sludge treatment. It can connect fine particles in the sludge together through adsorption bridging to form larger flocs, which helps the subsequent sludge separation process and makes the sludge easier to dehydrate during the pressure filtration and drying processes.

[0050] Polyferric sulfate will hydrolyze in aqueous solution to form a series of iron hydrolysis products. The hydrolysis products carry positive charges, which can neutralize the negative charges on the surface of sludge particles, reduce the electrostatic repulsion between sludge particles, and thus promote the aggregation of sludge particles. At the same time, the hydrolysis products of polyferric sulfate can also undergo complexation reactions with organic substances in the sludge, further enhancing the flocculation effect. For polyaluminum ferric silicate and Fenton-like catalysts, they have special treatment effects on certain components in the sludge in terms of redox reactions (Fenton-like reactions), which helps the dehydration of the sludge.

[0051] Step A: Mix the sludge drying agent with the surplus sludge

[0052] The sludge drying agent is evenly mixed into the surplus sludge to ensure that the agent can fully contact various components in the sludge. Polyacrylamide and iron-containing high molecular coagulants can then play their flocculating and coagulating roles, causing the solid particles in the sludge to aggregate and form larger aggregates, preparing for the subsequent treatment steps.

[0053] Step B: Standing

[0054] The standing process gives sufficient time for the particles in the sludge to aggregate and settle. During this process, the sludge particles after the action of the sludge drying agent will gradually settle to the bottom of the container, while the upper liquid is relatively clear, which helps to further separate the solid and liquid components in the sludge and improve the dehydration effect of the sludge.

[0055] Step C: Pressure filtration and Step D: Drying are carried out simultaneously

[0056] During the pressure filtration process, under the action of external pressure, the water in the sludge is forced to drain through the filter cloth. Since the previous treatment steps have caused the sludge particles to form larger aggregates and part of the water has been separated, the pressure filtration can more effectively remove the water at this time. Drying is carried out simultaneously, and hot air or other drying means can be used to further reduce the moisture content in the sludge. During the drying process, heat is transferred to the sludge to evaporate the water, while the pressure filtration continuously discharges the evaporated water. The two cooperate with each other to accelerate the sludge dehydration process, and finally a filter cake with a moisture content lower than 40% is obtained.

[0057] In one embodiment, the addition amount of polyacrylamide is 0.1-1.0% of the mass of dry sludge. Calculated by iron content, the addition amount of the iron-containing polymer coagulant is 2-10% of the mass of dry sludge; the sludge drying treatment agent is a combination of polyacrylamide and polyferric sulfate; or the sludge drying treatment agent is a combination of polyacrylamide and polyaluminum ferric silicate; or the sludge drying treatment agent is a combination of polyacrylamide and a Fenton-like catalyst; or the sludge drying treatment agent is a combination of polyacrylamide, polyferric sulfate and polyaluminum ferric silicate, wherein, calculated by iron content, the mass ratio of polyferric sulfate to polyaluminum ferric silicate is (1-7):1; or the sludge drying treatment agent is a combination of polyacrylamide, polyferric sulfate and a Fenton-like catalyst, wherein, calculated by iron content, the mass ratio of polyferric sulfate to the Fenton-like catalyst is (1-7):1.

[0058] In the specific application of the embodiment of the present invention, when it is used as a component of the sludge drying treatment agent, calculated by iron content, its addition amount is 2-10% of the mass of dry sludge. Polyferric sulfate will hydrolyze to form a large amount of iron in aqueous solution, which can carry out electro-neutralization with the negative charge on the surface of sludge particles. Since the surface of sludge particles usually carries negative charges and there is electrostatic repulsion between them, it is difficult to aggregate. The positively charged complex produced by the hydrolysis of PFS can neutralize this charge, reduce the repulsion between sludge particles, and thus promote the aggregation of particles.

[0059] Polyaluminum ferric silicate contains various elements such as aluminum, iron, and silicon. In sludge treatment, both aluminum ions and iron ions can play roles similar to those of polyferric sulfate in electro-neutralization and adsorption bridging. The silicate ion can increase the stability and adsorption performance of the coagulant through its interaction with other ions. When it is used in combination with polyacrylamide, it can synergistically improve the flocculation effect of sludge and make the sludge easier to handle during the drying process.

[0060] When combined with polyferric sulfate in a certain mass ratio (calculated by iron content as (1-7):1), PSAF and PFS can complement each other and optimize the coagulation effect on sludge particles. The aluminum ions and silicate ions in PSAF can make up for some deficiencies when PFS is used alone, improve the adaptability to different types of sludge, and make the water in the sludge easier to be separated. The Fenton-like catalyst has a special role in sludge drying treatment. It can generate strongly oxidizing free radicals (·OH) under certain conditions, which can decompose some organic substances in the sludge and change the structure and properties of the sludge.

[0061] Organic matter in sludge can affect the dewatering and drying performance of sludge. The Fenton-like catalyst reduces the viscosity of sludge by oxidizing and decomposing some organic matter, making sludge particles easier to be captured and aggregated by flocculants (such as polyacrylamide). When combined with polyferric sulfate in a certain mass ratio (1-7:1 based on iron content), the Fenton-like catalyst and polyferric sulfate can work synergistically. Polyferric sulfate is mainly responsible for electro-neutralization and adsorption bridging, while the Fenton-like catalyst starts from improving the structure of sludge organic matter to jointly improve the sludge drying efficiency.

[0062] When polyacrylamide is combined with iron-containing polymer coagulants (such as PFS, PSAF or Fenton-like catalyst), a synergistic effect can be exerted. The flocculation bridging effect of PAM cooperates with the electro-neutralization and adsorption bridging effects of iron-containing coagulants. For example, PAM can further connect the small flocs formed by iron-containing coagulants into larger flocs, and the iron-containing coagulants can change the charge state of sludge particles, making it easier for PAM to combine with sludge particles, which can more effectively improve the dewatering performance of sludge and accelerate the sludge drying process.

[0063] In various combinations (such as the combination of PAM with PFS and PSAF, the combination of PAM with PFS and Fenton-like catalyst), different components complement each other. According to the specific properties of sludge (such as organic matter content, particle size distribution, charge characteristics, etc.), the combination method and ratio can be adjusted to achieve the best sludge drying effect.

[0064] In one embodiment, the sludge drying treatment agent is a combination of polyacrylamide, polyferric sulfate and Fenton-like catalyst. Among them, the addition amount of polyacrylamide is 0.1-0.7% of the mass of dry sludge, the addition amount of polyferric sulfate is 1-7% of the mass of dry sludge based on iron content, and the addition amount of Fenton-like catalyst is 1-3% of the mass of dry sludge; the sludge drying treatment agent is a combination of polyacrylamide and iron-containing polymer coagulant. Among them, the iron-containing polymer coagulant is selected from one or more combinations of polyferric sulfate, polyaluminum ferric silicate and Fenton-like catalyst; the addition amount of polyacrylamide is 0.1-1.0% of the mass of dry sludge, and the addition amount of iron-containing polymer coagulant is 2-10% of the mass of dry sludge based on iron content.

[0065] In the specific application of the embodiments of the present invention, polyferric sulfate is an iron-containing coagulant. Based on iron content, when its addition amount in the first combination is 1-7% of the mass of dry sludge and in the second combination is 2-10% of the mass of dry sludge, it can play a coagulation role in the sludge system.

[0066] Polyferric sulfate undergoes hydrolysis reactions in water, generating a series of iron hydrolysis products, such as iron hydroxide colloids, etc. The hydrolysis products carry positive charges, while the surface of sludge particles often carries negative charges. According to the principle of charge neutralization, iron hydroxide colloids can adsorb and electro-neutralize with sludge particles, making the sludge particles lose stability and thus aggregate together. The coagulation effect synergizes with the flocculation effect of polyacrylamide. Polyferric sulfate initially causes the sludge particles to aggregate, forming smaller aggregates, and then polyacrylamide further flocculates these small aggregates into larger flocs, thereby improving the dewatering performance of the sludge.

[0067] The iron ions in polyferric sulfate have certain oxidizing properties. In the sludge system, it will undergo redox reactions with some reducing substances. For example, it will oxidize some of the organic matter in the sludge, changing the structure of the organic matter. The oxidation will break the macromolecular structure of the organic matter and decompose it into small-molecule substances, making the water in the sludge easier to release. At the same time, the oxidized organic matter will be more easily decomposed or volatilized during the subsequent drying process, which is beneficial to improving the efficiency of sludge drying.

[0068] When the Fenton-like catalyst is used as a component in the sludge drying treatment agent combination (the addition amount in the first combination is 1 - 3% of the dry sludge mass), it can catalyze the Fenton-like reaction, which is an advanced oxidation reaction based on iron ions (the Fenton-like catalyst contains iron elements) and hydrogen peroxide (present in the sludge system or a small amount can be added subsequently). This oxidation can break the complex structure of the organic matter and convert it into small-molecule organic matter or inorganic substances. For example, it can decompose long-chain aliphatic organic matter into short-chain fatty acids or carbon dioxide and water. In this way, the organic matter content in the sludge relatively decreases, and the binding force between water and solid substances weakens, which is beneficial to the drying and dewatering of the sludge.

[0069] When the Fenton-like catalyst is used as a type of iron-containing polymer coagulant (the iron-containing polymer coagulant mentioned in the second combination can be one or a combination of two or more of polyferric sulfate, polyaluminum ferric silicate, and the Fenton-like catalyst), it also has a coagulation effect similar to that of polyferric sulfate. The iron element in the Fenton-like catalyst can hydrolyze to form substances with coagulation effects such as iron hydroxide colloids under appropriate conditions, causing the sludge particles to aggregate through charge neutralization, adsorption bridging, etc., thereby improving the dewatering performance of the sludge and acting together with polyacrylamide to accelerate the sludge drying process.

[0070] When polyacrylamide, polyferric sulfate and Fenton-like catalyst (in the first combination) or polyacrylamide and iron-containing polymer coagulant (in the second combination) are used in combination, there is a synergistic effect between them. Polyferric sulfate or iron-containing polymer coagulant first makes sludge particles preliminarily aggregate through coagulation, changing the surface properties and charge state of sludge particles. Then polyacrylamide uses its flocculation effect to further flocculate these preliminarily aggregated particles into larger and more stable flocs. When there is a Fenton-like catalyst in the first combination, the Fenton-like catalyst decomposes organic matter through oxidation, further improving the properties of sludge, making the coagulation and flocculation effects of polyferric sulfate and polyacrylamide better.

[0071] When using only one agent alone, the ideal dehydration effect cannot be achieved. For example, when only using polyacrylamide, although it can flocculate sludge particles, it cannot effectively remove some moisture tightly bound to organic matter; while polyferric sulfate and Fenton-like catalyst can change the structure of organic matter and the properties of sludge particles through oxidation and coagulation, making this moisture easier to be released. Coupled with the flocculation effect of polyacrylamide, it can significantly improve the dehydration rate of sludge and accelerate the sludge drying process.

[0072] In one embodiment, the sludge drying treatment agent is a combination of polyacrylamide and polyferric sulfate; or the sludge drying treatment agent is a combination of polyacrylamide and polyaluminum ferric silicate; or the sludge drying treatment agent is a combination of polyacrylamide and Fenton-like catalyst; or the sludge drying treatment agent is a combination of polyacrylamide, polyferric sulfate and polyaluminum ferric silicate, wherein, based on the iron content, the mass ratio of polyferric sulfate to polyaluminum ferric silicate is (1-7):1; or the sludge drying treatment agent is a combination of polyacrylamide, polyferric sulfate and Fenton-like catalyst, wherein, based on the iron content, the mass ratio of polyferric sulfate to Fenton-like catalyst is (1-7):1; the sludge drying treatment agent is a combination of polyacrylamide, polyferric sulfate and Fenton-like catalyst, wherein the addition amount of polyacrylamide is 0.1-0.7% of the mass of dry sludge, based on the iron content, the addition amount of polyferric sulfate is 1-7% of the mass of dry sludge, and the addition amount of Fenton-like catalyst is 1-3% of the mass of dry sludge.

[0073] In the specific application of the embodiments of the present invention, polyaluminum ferric silicate has a unique three-dimensional network structure, which enables it to have a large specific surface area and can adsorb organic matter and suspended particles in sludge. At the same time, it can play the role of adsorption bridging like polyacrylamide, connecting multiple sludge particles together to form larger flocs. In this process, it can aggregate dispersed sludge particles, improve the dehydration performance of sludge, and is beneficial to the drying of sludge.

[0074] When used in combination with polyacrylamide, polymeric aluminum ferric silicate can complement PAM. PAM mainly acts through the adsorption bridging of long chains, while PSAF promotes the aggregation of sludge particles from multiple aspects by utilizing its unique structure and chemical properties. The combined action of the two can more effectively improve the sludge drying effect. After the organic matter in the sludge is oxidized, its structure and properties will change. Some complex organic matters will be decomposed into small molecule substances, which are easier to separate from the sludge, thereby reducing the organic matter content in the sludge and facilitating sludge drying. Through the oxidation reaction, the Fenton-like catalyst can change the surface properties of the sludge, such as reducing the viscosity of the sludge. After the sludge viscosity is reduced, water is more easily separated during the dehydration and drying process, improving the sludge drying efficiency.

[0075] When polyacrylamide is combined with polymeric ferric sulfate, the flocculation effect of PAM and the charge neutralization and enmeshment of PFS cooperate with each other. PAM preliminarily flocculates the sludge particles, and PFS further treats these flocs. Through charge neutralization and enmeshment, the sedimentation and dewatering performance of the sludge is better. For the combination of polyacrylamide and polymeric aluminum ferric silicate, the two play a synergistic role in adsorption bridging and improving the sludge structure. The long-chain adsorption bridging of PAM and the three-dimensional network structure adsorption of PSAF act synergistically to more effectively aggregate the sludge particles together and increase the sludge drying rate.

[0076] In the combination of polyacrylamide and the Fenton-like catalyst, the flocculation effect of PAM and the oxidation effect of the Fenton-like catalyst complement each other. PAM aggregates the sludge particles, and the Fenton-like catalyst oxidizes the organic matter therein, improving the dewatering performance of the sludge. When it comes to the combination of three agents, such as the combination of polyacrylamide, polymeric ferric sulfate and the Fenton-like catalyst, PAM first flocculates the sludge particles, PFS further treats them through charge neutralization and enmeshment, and the Fenton-like catalyst oxidizes the organic matter. The three are combined in a certain proportion to treat the sludge in different aspects to achieve the best drying effect.

[0077] For the combination containing polymeric ferric sulfate and polymeric aluminum ferric silicate, they are combined according to a certain mass ratio (the iron content is (1 - 7):1). At different ratios, the hydrolysis, polymerization and adsorption of the two are coordinated with each other. When working together with polyacrylamide, it can achieve efficient drying treatment for sludges with different properties. Similarly, when polymeric ferric sulfate and the Fenton-like catalyst are combined in a ratio of (1 - 7):1 (by iron content), the two work synergistically in aspects such as charge neutralization and redox, and cooperate with polyacrylamide to improve the sludge drying efficiency.

[0078] In the combined medicament, the dosage of each medicament is determined according to the properties of the sludge. For example, the dosage of polyacrylamide is 0.1-0.7% of the mass of the absolutely dry sludge, and this ratio ensures that it can effectively play a flocculation role without wasting the medicament.

[0079] The present invention can be operated by using the following examples:

[0080] Example 1:

[0081] Add this product to the sludge in the municipal sludge treatment plant, add an appropriate amount of water, stir evenly, filter by plate and frame extrusion, and let it stand.

[0082] Example 2:

[0083] Add this product to the printing and dyeing sludge, add an appropriate amount of water, stir evenly, pump out the accumulated water from the bottom of the sludge tank, and send it to the subsequent drying section.

[0084] Example 3:

[0085] Add this product to the incineration sludge of the chicken farm, add an appropriate amount of clean water, mix evenly, filter by plate and frame extrusion, and send it to the subsequent organic fertilizer forming machine.

[0086] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0087] The above describes the present invention and its implementation manners. This description is not restrictive. What is shown in the drawings is only one of the implementation manners of the present invention, and the actual structure is not limited thereto. Generally speaking, if those of ordinary skill in the art are inspired by it and, without departing from the gist of the present invention, design similar structural manners and embodiments to this technical solution without creative efforts, they shall fall within the protection scope of the present invention.

Claims

1. A sludge drying agent, characterized in that: include: (1) oxides of one or more of the first transition metals selected from vanadium, titanium, chromium, manganese, iron, cobalt, nickel, copper and zinc; (2) adding sodium edetate and water; (3) adding an inorganic acid including sulfuric acid, hydrochloric acid, or phosphoric acid; (4) adding 2-5% of an organic acid, such as one or two of citric acid, tartaric acid, and fumaric acid; (5) Maintain 80-95°C, stir for 2-4 hours, and let stand.

2. The sludge drying agent according to claim 1, characterized in that Also includes: A. Add sludge drying agent to the residual sludge and mix well; B. Let it stand; C. Filter pressing; D. Drying to obtain a filter cake with a moisture content of less than 40%; The sludge drying treatment agent in step (1) is a combination of polyacrylamide and an iron-containing polymer coagulant, wherein the iron-containing polymer coagulant is selected from one or a combination of two or more of polyferric sulfate, polyaluminium ferrosilicate and Fenton-like catalyst.

3. The sludge drying agent according to claim 2, characterized in that: The amount of polyacrylamide added is 0.1-1.0% of the mass of the absolute dry sludge. Calculated by iron content, the amount of iron-containing polymer coagulant added is 2-10% of the mass of the absolute dry sludge.

4. The sludge drying agent according to claim 2, characterized in that: The sludge drying treatment agent is a combination of polyacrylamide and polyferric sulfate; or the sludge drying treatment agent is a combination of polyacrylamide and polyaluminum ferric silicate; or the sludge drying treatment agent is a combination of polyacrylamide and a Fenton-like catalyst; or the sludge drying treatment agent is a combination of polyacrylamide, polyferric sulfate and polyaluminum ferric silicate, wherein, based on the iron content, the mass ratio of polyferric sulfate to polyaluminum ferric silicate is (1-7):1; or the sludge drying treatment agent is a combination of polyacrylamide, polyferric sulfate and a Fenton-like catalyst, wherein, based on the iron content, the mass ratio of polyferric sulfate to Fenton-like catalyst is (1-7):

1.

5. The sludge drying agent according to claim 4, characterized in that: The sludge drying treatment agent is a combination of polyacrylamide, polyferric sulfate and Fenton-like catalyst, wherein the amount of polyacrylamide added is 0.1-0.7% of the mass of the absolute dry sludge, based on the iron content, the amount of polyferric sulfate added is 1-7% of the mass of the absolute dry sludge, and the amount of Fenton-like catalyst added is 1-3% of the mass of the absolute dry sludge.

6. The sludge drying agent according to claim 2, characterized in that: The filtration described in step C and the drying described in step D are carried out simultaneously.

7. The sludge drying agent according to claim 2, characterized in that: The sludge drying treatment agent is a combination of polyacrylamide and an iron-containing polymer coagulant, wherein the iron-containing polymer coagulant is selected from one or a combination of more than two of polyferric sulfate, polyaluminum ferrosilicate, and Fenton-like catalysts; the amount of polyacrylamide added is 0.1-1.0% of the mass of the absolute dry sludge, and the amount of the iron-containing polymer coagulant added is 2-10% of the mass of the absolute dry sludge based on the iron content.

8. The sludge drying agent according to claim 2, characterized in that: The sludge drying treatment agent is a combination of polyacrylamide and polyferric sulfate; or the sludge drying treatment agent is a combination of polyacrylamide and polyaluminum ferric silicate; or the sludge drying treatment agent is a combination of polyacrylamide and a Fenton-like catalyst; or the sludge drying treatment agent is a combination of polyacrylamide, polyferric sulfate and polyaluminum ferric silicate, wherein, based on the iron content, the mass ratio of polyferric sulfate to polyaluminum ferric silicate is (1-7):1; or the sludge drying treatment agent is a combination of polyacrylamide, polyferric sulfate and a Fenton-like catalyst, wherein, based on the iron content, the mass ratio of polyferric sulfate to Fenton-like catalyst is (1-7):

1.

9. The sludge drying agent according to claim 2, characterized in that: The sludge drying treatment agent is a combination of polyacrylamide, polyferric sulfate and Fenton-like catalyst, wherein the amount of polyacrylamide added is 0.1-0.7% of the mass of the absolute dry sludge, based on the iron content, the amount of polyferric sulfate added is 1-7% of the mass of the absolute dry sludge, and the amount of Fenton-like catalyst added is 1-3% of the mass of the absolute dry sludge.

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