Sludge organic dewatering agent and sludge dewatering process

Abstract

The present application provides a kind of sludge organic dewatering agent and sludge dewatering process, the component of sludge organic dewatering agent described in the present application is dimethyl diallyl ammonium chloride: acryloyloxyethyl trimethyl ammonium chloride: polyamine=2:3:5 according to mass fraction ratio, when carrying out sludge dewatering, sludge stabilizer is added to sludge and is fully stirred with sludge, the addition amount of sludge stabilizer is 20%~40% of absolute dry mud amount;Sludge obtained in the above step is added with the organic dewatering agent, so that the concentration of organic dewatering agent in sludge is 0.02%~0.25%, and pressure filtration dewatering is carried out using plate and frame filter press, the special monomer and molecular structure in the component of the organic dewatering agent used in the present application act on sludge, form fine and solid small flocs, the solid small flocs are beneficial to form dewatering channel in filter pressing process and do not coat water, at the same time, interstitial water in sludge is squeezed out under the action of special positive charge group, reduce the specific resistance in sludge dewatering process, which is beneficial to dewatering.

Description

Technical Field

[0001] The invention belongs to the technical field of sludge dewatering treatment, relates to a sludge machine dewatering agent and a process for dewatering sludge using the machine dewatering agent, and specifically relates to a sludge organic dewatering agent and a sludge dewatering process. Background Art

[0002] When municipal sludge is not properly treated and disposed of, it directly causes secondary pollution to underground soil, water bodies and the atmosphere, which not only reduces the effective treatment capacity of the sewage treatment system, but also poses a serious threat to the ecological environment and human activities. Due to the characteristics of sludge, the following problems exist in the sludge treatment and disposal process:

[0003] On the one hand, the incoming sludge contains approximately 85% water, making it difficult for the water within the microbial cells to break through the walls and evaporate during the drying process. On the other hand, the incoming sludge is affected by the addition of flocculants and other chemicals during the dehydration process, which often changes the sludge's properties to a "viscous" semi-solid, semi-liquid state. This leads to unstable and inefficient drying processes.

[0004] During the heat exchange drying process, sludge emits odors to varying degrees, affecting the production workshop and factory environment, and posing environmental risks to the company. Since the dried sludge carries odors, the resource recycling and reuse industry of dried sludge is interrupted, such as in red brick factories and replacing low-calorific value and inferior coal for combustion in furnaces, resulting in waste of resources.

[0005] The fuel heating method is used to evaporate the water in the sludge, which is inefficient, costly and difficult to maintain.

[0006] For example, patent document CN108947202A discloses a composite thermal drying system and method for sludge, which utilizes the greenhouse effect of a transparent drying greenhouse and the waste steam heat from a power plant as an auxiliary heat source for drying. Although this method improves the dehydration efficiency of sludge drying to a certain extent, it suffers from problems such as limited drying capacity, low drying efficiency, and the volatilization and overflow of fermentation odors. In addition, the process design fails to take into account the extremely cold local climate, resulting in shutdown during the entire heating period.

[0007] Patent document CN217535795U discloses a device for drying sludge using a drying box. The device can remove moisture from the sludge inside the sludge box, so that the sludge can be dried quickly. However, since the device uses electricity for heating, the energy consumption during the sludge drying process is high. In addition, since the sludge entering the sewage treatment plant has a high water content and high viscosity, the patent solution has poor strip cutting operation after sludge drying, resulting in low drying efficiency.

[0008] With the substantial increase in sludge treatment volume, the use of a single drying greenhouse or drying box for sludge drying can no longer meet the needs of sludge drying treatment.

[0009] In order to achieve the "reduction, stabilization, harmlessness and resource utilization" of municipal sludge treatment, it is necessary to propose a new sludge drying treatment solution. Summary of the Invention

[0010] In order to achieve the goal of "reduction, stabilization, harmlessness and resource utilization" of municipal sludge treatment, the present invention provides a sludge organic dehydrating agent on the one hand and a sludge dehydration method on the other hand. The present invention is specifically as follows:

[0011] In a first aspect, the present invention provides a sludge organic dehydrating agent, wherein the mass fraction ratio of the components of the organic dehydrating agent is dimethyldiallylammonium chloride: acryloyloxyethyltrimethylammonium chloride: polyamine = 2:3:5, and the allowable error of the mass fraction ratio is ≤±10%.

[0012] The preparation method of the organic dehydrating agent comprises the following steps: mixing dimethyldiallylammonium chloride, acryloyloxyethyltrimethylammonium chloride and polyamine according to the product component ratio, heating to above 48 DEG C, fully melting and mixing, drying, crushing and granulating to obtain the organic dehydrating agent dry powder.

[0013] The main chemical component of the organic dehydrating agent provided in this application is a characteristic cationic water-soluble high molecular weight polymer, which appears as white powder and is a colorless, transparent to pale white liquid after dissolution. The organic dehydrating agent is a medium- and low-molecular-weight organic substance, a cationic mixture, with a volume density of approximately 600 kg / m3, a pH value of approximately 6-7 in a 0.1% deionized water solution, and an aqueous solution viscosity (0.3% tap water, 20°C) of approximately 300 mPa.s, showing good water solubility.

[0014] The organic dehydrating agent of this invention is a high-molecular-weight polymer. As a drying agent in the sludge dehydration process, it significantly reduces the moisture content of the sludge compared to traditional PAM flocculants. It can fully or partially replace inorganic flocculants and conditioning agents such as polyferric chloride, polyaluminum chloride, and lime used in the dehydration process, achieving true sludge reduction. It also reduces the inorganic content of the sludge and the salt content of the filtrate, lowering the conductivity of the total treated water without changing the water's acidity or alkalinity. This eliminates the "sugar core" of the sludge cake, reduces its moisture content, facilitates resource utilization through sludge composting and incineration, reduces water conductivity, and improves the operating environment of sewage treatment plants.

[0015] In a second aspect, the present application also provides a sludge dewatering process, comprising the following steps:

[0016] First, the stabilizer is sampled to adjust the sludge properties so that the chemical properties of the sludge material tend to be stable and the same. The specific process is as follows:

[0017] S1: adding the sludge stabilizer to the sludge and stirring the sludge thoroughly. The amount of the sludge stabilizer added is 20% to 40% of the absolute dry sludge amount.

[0018] The sludge stabilizer comprises, by mass fraction, 10 parts of magnesium carbonate, 20 parts of calcium carbonate, 10 parts of aluminum sulfate, 20 parts of potassium carbonate, 20 parts of aluminum oxide, and 20 parts of calcium oxide.

[0019] In this application, after adding the stabilizer to the sludge, the organic dehydrating agent is added to the sludge, specifically as follows:

[0020] S2. Add the organic dehydrating agent to the sludge obtained in S1, so that the concentration of the organic dehydrating agent in the sludge liquid is 0.02% to 0.25%.

[0021] S3, passing the sludge to which the organic dehydrating agent is added into a plate and frame filter press for filter pressing and dehydration treatment.

[0022] The present application also provides another method for dehydrating sludge using the organic dehydrating agent, specifically:

[0023] S1. Add organic dehydrating agent to the sludge to make the concentration of organic dehydrating agent in the sludge 0.02% to 0.25%.

[0024] S2. The sludge to which the organic dehydrating agent is added is passed into a plate and frame filter press for filter pressing and dehydration treatment.

[0025] As a preferred technical solution of the second aspect of the present invention, the configuration method of the organic dehydrating agent before adding it to the sludge is: adding the organic dehydrating agent powder and granules to clean water at 15-30°C, and continuously stirring and dissolving the organic dehydrating agent powder and granules to dissolve the organic dehydrating agent powder and granules into a 0.25% to 0.50% storage aqueous solution.

[0026] As a preferred technical solution of the second aspect of the present invention, when the stored aqueous solution is added to the sludge, it must be diluted online with water 5 to 10 times and then metered into the sludge.

[0027] It should be noted that the organic dehydrating agent of the present application should be used as soon as possible after dissolution, and the storage time should not exceed 24 hours; pay attention to the quality of the water used for dissolution, use clean water for dissolution, if the pH value of the water used for dissolution is too acidic / alkaline, the water hardness is high, the SS content is high, the COD content is high, the microorganisms are high, the residual chlorine is high, and the water temperature is too high, it will affect the dissolution and use effect of the product; if it is dissolved manually, the powder particles will be evenly scattered in the water during dissolution, and adding the material too quickly will easily cause agglomeration, and avoid miscibility with the anionic flocculant.

[0028] As a preferred technical solution of the second aspect of the present invention, after dehydration using the sludge dehydrating agent, the sludge to which the organic dehydrating agent is added is passed into a plate and frame filter press for filter pressing and dehydration treatment.

[0029] As a preferred technical solution of the second aspect of the present invention, the device for adding the organic dehydrating agent to the sludge is a positive displacement dosing pump. More preferably, the positive displacement dosing pump is a screw pump. The use of a positive displacement dosing pump prevents the polymer chains from being damaged by mechanical shear forces. The organic dehydrating agent can be added continuously or in batches.

[0030] The outstanding technical effects of this application are:

[0031] 1. The special monomers and molecular structures in the organic dehydrating agent used in this application react with the sludge to form fine, compact flocs. These compact flocs facilitate the formation of dehydration channels during the filtration process and do not encapsulate water. At the same time, interstitial water in the sludge is squeezed out by the special positively charged groups, reducing the specific resistance of the sludge dehydration process. After the addition of the agent, the sludge is rapidly and continuously dehydrated under the action of gravity and pressure using dehydration equipment, achieving solid-liquid separation, reducing the sludge moisture content, and achieving true volume reduction. Furthermore, since the organic dehydrating agent completely or partially replaces the inorganic flocculant, it can reduce filtrate conductivity, improve sewage treatment plant operating conditions, and is particularly beneficial in reducing anaerobic reaction calcification and scaling in water treatment flow areas.

[0032] 2. The sludge dewatering process adopted in this application uses the stabilizer and organic dehydrating agent of this application. During sludge filter pressing, there is no need to add lime iron salts and sludge conditioners for sludge conditioning. Only one agent needs to be added for direct sludge filter pressing. The dosage is small, the cost is low, and the effect is good. The moisture content of the sludge filter cake is about 60%, it does not stick to the filter cloth and does not clog the filter cloth, the water quality is not sticky, and it is easy to filter.

[0033] 3. The organic dehydrating agent of the present application is solid, with high dehydration efficiency and low dosage. The addition amount is 0.1% to 0.5%. The moisture content of sludge with high moisture content can be reduced to 60% after filter pressing and dehydration. After the organic dehydrating agent of the present application is used to dehydrate the sludge, the sludge volume is small, the increase ratio of dry sludge compared to the traditional lime method is lower, the subsequent treatment cost is low, and the treatment efficiency is increased. The sludge skeleton structure of the organic dehydrating agent of the present application will undergo a hydration gel reaction during the later disposal process to form a rigid structure with a certain strength, so that the mud cake has the characteristics of long-term stability and reduced subsequent continuous water loss. The components in the organic dehydrating agent of the present application are more environmentally friendly, the preparation process is simple, and the lime component in the traditional sludge conditioner is avoided. It overcomes technical defects such as large dosage, serious wear and corrosion to equipment, and potential harm to the environment. Its performance is compared with existing sludge adjusters and traditional sludge conditioners, and has extremely strong technical advantages.

[0034] 4. The technical features of the organic dehydrating agent of this application are: ① Pure organic green technology, achieving "zero" addition of lime, "zero" addition of iron salts, and "zero" addition of aluminum salts; it does not change the organic matter content and properties of the mud cake, which is conducive to the resource utilization of sludge composting or incineration, turning waste into resources; and achieving true sludge reduction. ② Safe and friendly, the product is biodegradable, non-corrosive, non-irritating, and safe to operate; it does not change the acidity and alkalinity of the sludge and filtrate; it completely changes the harsh on-site environment caused by the addition of lime; it completely eliminates the corrosion caused by the acidity and alkalinity of iron salts, aluminum salts, and lime to the equipment, as well as the additional salt introduced by the water supply system; it can be used alone or in combination with other flocculants and dehydrating agents, and a variety of application solutions can be derived according to customer needs and on-site conditions. ③ Efficient and easy to use, the liquid product is metered and added using a dosing pump, eliminating the need for complex and expensive dosing equipment, and achieving fully automated dosing; it significantly improves the efficiency of the plate and frame filter press in treating sludge; it reduces the cost of sludge transportation, processing, and disposal; the small amount used reduces the operating intensity of employees. DETAILED DESCRIPTION

[0035] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the description and claims of this application are intended to cover non-exclusive inclusions.

[0037] The "range" disclosed in this application is defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of a particular range. The range defined in this way can be inclusive or exclusive of the end values ​​and can be arbitrarily combined, i.e., any lower limit can be combined with any upper limit to form a range. In this application, unless otherwise specified, the numerical range "ab" represents an abbreviation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" have been listed herein, and "0-5" is just an abbreviation of these numerical combinations. In addition, when stating that a parameter is 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.

[0038] The applicants of this invention are engaged in research on sludge drying technology. In practice, they have discovered that, with sludge containing approximately 85% water entering the plant, the water within the microbial cells is difficult to break through the walls and evaporate during the drying process. Furthermore, the addition of flocculants and other chemicals during the dehydration process often causes the sludge to become "viscous," a semi-solid, semi-liquid state. This results in unstable and inefficient drying processes. During the heat exchange drying process, the sludge emits varying degrees of odor, impacting the production workshop and plant environment and posing environmental risks to the company. The odor carried by the dried sludge has disrupted the recycling and reuse of the dried sludge.

[0039] The applicant previously used ferrous sulfate and hydrogen peroxide to pre-treat sludge dewatering. However, they discovered that the reaction between the sludge and the reagents in the conditioning tank generated a large amount of foam, which was prone to overflow and environmental pollution. Furthermore, the high-pressure diaphragm plate-and-frame filter press dewatering system suffered from unstable operation, large fluctuations in the moisture content of the mud cake, and severe sticking to the filter cloth, preventing it from automatically dislodging. This resulted in the inability of one person to work normally, forcing a temporary assistant to perform manual unloading, which increased the workload for the sludge workers.

[0040] When adding ferrous sulfate and hydrogen peroxide, the high-pressure diaphragm plate and frame filter cloth was severely corroded. The filter cloth broke after only three months of use, causing mud to leak from the system. The filtrate containing mud was discharged into the sewage station, resulting in an increase in the cost of sewage treatment desludging agents.

[0041] The process involves adding ferrous sulfate and hydrogen peroxide. Ferrous sulfate is acidic and contains iron ions, while hydrogen peroxide is a strong oxidant. During the use of diluted sludge while circulating filter press water in the system, the wastewater revealed excessive iron ions, becoming turbid and concentrated, and the pH value continuously dropped to around 3, becoming acidic. Upon entering the sewage treatment plant, the system generated excessive foaming that was difficult to control, and also caused clogging of the membrane system, requiring frequent membrane cleaning. This low pH increased wastewater conditioning costs and inhibited the normal growth of bacteria in the anaerobic and biochemical systems of the sewage treatment plant, significantly impacting the sewage treatment system.

[0042] Due to the large amount of reagents added, the material storage area on site is large and messy, and the workload of personnel addition also increases accordingly.

[0043] In view of the problems encountered in existing sludge drying technologies, and to achieve the "reduction, stabilization, harmlessness, and resource utilization" of sludge drying, the inventors of this application have proposed a sludge organic dehydrating agent, a method for preparing the sludge organic dehydrating agent, and a method for treating sludge and wastewater using the sludge organic dehydrating agent. The applicants of this application will illustrate the proposed sludge organic dehydrating agent, a method for preparing the sludge organic dehydrating agent, and a method for treating sludge and wastewater using the sludge organic dehydrating agent through specific embodiments.

[0044] In a first aspect, a method for preparing an organic dehydrating agent and the prepared organic dehydrating agent.

[0045] Dimethyldiallylammonium chloride: acryloyloxyethyltrimethylammonium chloride: polyamine were uniformly mixed in a mass fraction ratio of 2:3:5, heated to above 48°C for full melting and mixing, dried, crushed and granulated to obtain a bulk density of 600 kg / m 3 of white powder.

[0046] It should be noted that the mass fraction ratio of the components of the organic dehydrating agent described in this application is dimethyldiallyl ammonium chloride: acryloyloxyethyltrimethylammonium chloride: polyamine = 2:3:5, and the allowable error of the mass fraction ratio is ≤±10%. For example, the mass fraction of dimethyldiallyl ammonium chloride can be 1.8~2.2; the mass fraction of acryloyloxyethyltrimethylammonium chloride can be 2.7~3.3, and the mass fraction of polyamine can be 4.5~5.5.

[0047] Second, the configuration of the organic dehydrating agent dilution solution,

[0048] Add the prepared organic dehydrating agent powder to clean water at 15-30℃ and stir continuously to dissolve it into a 0.25% to 0.50% storage aqueous solution.

[0049] The obtained storage aqueous solution is diluted online with 5 to 10 times of water and then stored for use. The storage time shall not exceed 24 hours.

[0050] Finally, the sludge is dehydrated using an organic dehydrating agent solution, specifically:

[0051] S1. Add a sludge stabilizer to the sludge and stir it thoroughly. The amount of the sludge stabilizer added is 20% to 40% of the absolute dry sludge. The composition of the sludge stabilizer is a mixture of 10 parts by mass of magnesium carbonate, 20 parts by mass of calcium carbonate, 10 parts by mass of aluminum sulfate, 20 parts by mass of potassium carbonate, 20 parts by mass of aluminum oxide, and 20 parts by mass of calcium oxide.

[0052] S2. Add the obtained organic dehydrating agent dilution solution to the sludge obtained in S1 by using a metering screw pump to add the solution to the sludge so that the concentration of the solution is 0.02% to 0.25% and the amount of the organic dehydrating agent active ingredient added is 25 kg.

[0053] S3. The sludge treated in step S2 is passed through a plate and frame filter press for filtration, and the moisture content of the mud cake is tested. The chemical composition of the filtrate after dehydration of the sludge is tested. The test items include salt content, conductivity, COD value, ammonia nitrogen value and iron content.

[0054] In the examples, the salt content, conductivity, COD value, ammonia nitrogen value and iron content of the filtered water after sludge dehydration are tested to illustrate that the present invention is an environmentally friendly dehydrating agent compared with the prior art, and the dehydration effect of the present invention is illustrated by testing the moisture content of the mud cake.

[0055] The sludge in the following examples is derived from the sludge randomly mixed from the Ningxia Hongsibao Sewage Treatment Plant, Qingtongxia Sewage Treatment Plant, the First Sewage Treatment Plant, the Second Sewage Treatment Plant, and the Third Sewage Treatment Plant, and the sludge has a moisture content of 85%.

[0056] Below, the present invention is described through specific embodiments, which are as follows:

[0057] Example 1.1

[0058] Method for preparing organic dehydrating agent and organic dehydrating agent:

[0059] According to the mass fraction, 20 parts of dimethyldiallylammonium chloride, 30 parts of acryloyloxyethyltrimethylammonium chloride and 50 parts of polyamine were uniformly mixed and heated to 50 ° C and reacted for 30 minutes. After the reaction, the material was dried and crushed and granulated to obtain a bulk density of 600 kg / m 3 of white powder.

[0060] Example 1.2

[0061] Preparation of organic dehydrating agent dilution solution:

[0062] Add the organic dehydrating agent powder to clean water at 22-27°C and stir continuously to dissolve it. Dissolve the organic dehydrating agent powder into a 0.35% storage water solution.

[0063] The obtained storage aqueous solution is diluted online with water 8 times and then stored for use. The storage time shall not exceed 24 hours.

[0064] Example 1.3

[0065] Sludge dewatering process:

[0066] Dehydration was performed using the organic dehydrating agent dilution solution prepared in Example 1.2.

[0067] S1. Add 400 kg of sludge stabilizer to 12 tons of sludge with a moisture content of 85% and stir thoroughly. The amount of sludge stabilizer added is 22% of the absolute dry sludge.

[0068] The sludge stabilizer comprises a mixture of 10 parts by mass of magnesium carbonate, 20 parts by mass of calcium carbonate, 10 parts by mass of aluminum sulfate, 20 parts by mass of potassium carbonate, 20 parts by mass of aluminum oxide, and 20 parts by mass of calcium oxide.

[0069] S2. Using a metering screw pump, add the organic dehydrating agent dilution obtained in Example 1.2 to the sludge obtained in S1. The amount of the organic dehydrating agent active ingredient added is 250 kg, so that the concentration of the solution is 0.25%.

[0070] S3. The sludge treated in step S2 was passed through a plate and frame filter press for filtration. The moisture content of the sludge cake was tested to be 60%, as shown in Table 1. The chemical composition of the filtrate after dehydration of the sludge was tested, and the test results showed a salt content of 5655 mg / L, a conductivity of 8.09 ms / cm, a COD value of 1156 mg / L, and an ammonia nitrogen value of 190 mg / L. No iron was detected in the sludge. As shown in Table 2.

[0071] Example 2.1

[0072] Method for preparing organic dehydrating agent and organic dehydrating agent:

[0073] According to the mass fraction, 18 parts of dimethyldiallylammonium chloride, 32 parts of acryloyloxyethyltrimethylammonium chloride and 50 parts of polyamine were uniformly mixed and heated to 50 ° C and reacted for 30 minutes. After the reaction, the material was dried and crushed and granulated to obtain a bulk density of 600 kg / m 3 of white powder.

[0074] Example 2.2

[0075] Preparation of organic dehydrating agent dilution solution:

[0076] Add the organic dehydrating agent powder to clean water at 15-22℃ and stir continuously to dissolve it. Dissolve the organic dehydrating agent powder into a 0.25% storage water solution.

[0077] The obtained storage aqueous solution is diluted online with 5 times of water and then stored for use. The storage time shall not exceed 24 hours.

[0078] Example 2.3

[0079] Sludge dewatering process:

[0080] Dehydration was performed using the organic dehydrating agent dilution solution prepared in Example 2.2.

[0081] S1. Add 720 kg of sludge stabilizer to 12 tons of sludge with a moisture content of 85% and stir thoroughly. The amount of sludge stabilizer added is 40% of the absolute dry sludge.

[0082] The sludge stabilizer comprises a mixture of 10 parts by mass of magnesium carbonate, 20 parts by mass of calcium carbonate, 10 parts by mass of aluminum sulfate, 20 parts by mass of potassium carbonate, 20 parts by mass of aluminum oxide, and 20 parts by mass of calcium oxide.

[0083] S2. Using a metering screw pump, add the organic dehydrating agent dilution obtained in Example 2.2 to the sludge obtained in S1. The amount of the organic dehydrating agent active ingredient added is 250 kg, so that the concentration of the solution is 0.25%.

[0084] S3. The sludge treated in step S2 was passed through a plate and frame filter press for filtration. The moisture content of the sludge cake was tested to be 62%, as shown in Table 1. The chemical composition of the filtrate after dehydration of the sludge was tested, and the test results showed a salt content of 5622 mg / L, a conductivity of 8.05 ms / cm, a COD value of 1157 mg / L, and an ammonia nitrogen value of 191 mg / L. No iron was detected in the sludge. As shown in Table 2.

[0085] Example 3.1

[0086] Method for preparing organic dehydrating agent and organic dehydrating agent:

[0087] According to the mass fraction, 22 parts of dimethyldiallylammonium chloride, 27 parts of acryloyloxyethyltrimethylammonium chloride and 51 parts of polyamine were uniformly mixed and heated to 50°C and reacted for 30 minutes. After the reaction, the material was dried and crushed and granulated to obtain a bulk density of 600 kg / m 3 of white powder.

[0088] Example 3.2

[0089] Preparation of organic dehydrating agent dilution solution:

[0090] Add the organic dehydrating agent powder to clean water at 27-30℃ and stir continuously to dissolve it. Dissolve the organic dehydrating agent powder into a 0.5% storage water solution.

[0091] The obtained storage aqueous solution is diluted online with 10 times of water and then stored for use. The storage time shall not exceed 24 hours.

[0092] Example 3.3

[0093] Sludge dewatering process:

[0094] Dehydration was performed using the organic dehydrating agent dilution solution prepared in Example 3.2.

[0095] S1. Add 720 kg of sludge stabilizer to 12 tons of sludge with a moisture content of 85% and stir thoroughly. The amount of sludge stabilizer added is 40% of the absolute dry sludge.

[0096] The sludge stabilizer comprises a mixture of 10 parts by mass of magnesium carbonate, 20 parts by mass of calcium carbonate, 10 parts by mass of aluminum sulfate, 20 parts by mass of potassium carbonate, 20 parts by mass of aluminum oxide, and 20 parts by mass of calcium oxide.

[0097] S2. Using a metering screw pump, add the organic dehydrating agent dilution obtained in Example 3.2 to the sludge obtained in S1. The amount of the organic dehydrating agent active ingredient added is 250 kg, so that the concentration of the solution is 0.25%.

[0098] S3. The sludge treated in step S2 was passed through a plate and frame filter press for filtration. The moisture content of the sludge cake was tested to be 61%, as shown in Table 1. The chemical composition of the filtrate after dehydration of the sludge was tested, and the test results showed a salt content of 5699 mg / L, a conductivity of 8.09 ms / cm, a COD value of 1150 mg / L, and an ammonia nitrogen value of 190 mg / L. No iron was detected in the sludge. As shown in Table 2.

[0099] Example 4.1

[0100] Method for preparing organic dehydrating agent and organic dehydrating agent:

[0101] According to the mass fraction, 18 parts of dimethyldiallylammonium chloride, 27 parts of acryloyloxyethyltrimethylammonium chloride and 55 parts of polyamine were uniformly mixed and heated to 50 ° C and reacted for 30 minutes. After the reaction, the material was dried and crushed and granulated to obtain a bulk density of 600 kg / m 3 of white powder.

[0102] Example 4.2

[0103] Preparation of organic dehydrating agent dilution solution:

[0104] Add the organic dehydrating agent powder to clean water at 22-27°C and stir continuously to dissolve it. Dissolve the organic dehydrating agent powder into a 0.35% storage water solution.

[0105] The obtained storage aqueous solution is diluted online with water 8 times and then stored for use. The storage time shall not exceed 24 hours.

[0106] Example 4.3

[0107] Sludge dewatering process:

[0108] Dehydration was performed using the organic dehydrating agent dilution solution prepared in Example 3.2.

[0109] S1. Add 400 kg of sludge stabilizer to 12 tons of sludge with a moisture content of 85% and stir thoroughly. The amount of sludge stabilizer added is 22% of the absolute dry sludge.

[0110] The sludge stabilizer comprises a mixture of 10 parts by mass of magnesium carbonate, 20 parts by mass of calcium carbonate, 10 parts by mass of aluminum sulfate, 20 parts by mass of potassium carbonate, 20 parts by mass of aluminum oxide, and 20 parts by mass of calcium oxide.

[0111] S2. Using a metering screw pump, add the organic dehydrating agent dilution obtained in Example 4.2 to the sludge obtained in S1. The amount of the organic dehydrating agent active ingredient added is 200 kg, so that the concentration of the solution is 0.2%.

[0112] S3. The sludge treated in step S2 was passed through a plate and frame filter press for filtration. The moisture content of the sludge cake was tested to be 62%, as shown in Table 1. The chemical composition of the filtrate after dehydration of the sludge was tested, and the test results showed a salt content of 5631 mg / L, a conductivity of 8.12 ms / cm, a COD value of 1184 mg / L, and an ammonia nitrogen value of 195 mg / L. No iron was detected in the sludge. As shown in Table 2.

[0113] Example 5.1

[0114] Method for preparing organic dehydrating agent and organic dehydrating agent:

[0115] According to the mass fraction, 22 parts of dimethyldiallylammonium chloride, 33 parts of acryloyloxyethyltrimethylammonium chloride and 45 parts of polyamine were uniformly mixed and heated to 50 ° C and reacted for 30 minutes. After the reaction, the material was dried, crushed and granulated to obtain a bulk density of 600 kg / m 3 of white powder.

[0116] Example 5.2

[0117] Preparation of organic dehydrating agent dilution solution:

[0118] Add the organic dehydrating agent powder to clean water at 22-27°C and stir continuously to dissolve it. Dissolve the organic dehydrating agent powder into a 0.35% storage water solution.

[0119] The obtained storage aqueous solution is diluted online with water 8 times and then stored for use. The storage time shall not exceed 24 hours.

[0120] Example 5.3

[0121] Sludge dewatering process:

[0122] Dehydration was performed using the organic dehydrating agent dilution solution prepared in Example 3.2.

[0123] S1. Add 400 kg of sludge stabilizer to 12 tons of sludge with a moisture content of 85% and stir thoroughly. The amount of sludge stabilizer added is 22% of the absolute dry sludge.

[0124] The sludge stabilizer comprises a mixture of 10 parts by mass of magnesium carbonate, 20 parts by mass of calcium carbonate, 10 parts by mass of aluminum sulfate, 20 parts by mass of potassium carbonate, 20 parts by mass of aluminum oxide, and 20 parts by mass of calcium oxide.

[0125] S2. Using a metering screw pump, add the organic dehydrating agent dilution obtained in Example 5.2 to the sludge obtained in S1. The amount of the organic dehydrating agent active ingredient added is 23 kg, so that the concentration of the solution is 0.02%.

[0126] S3. The sludge treated in step S2 was passed through a plate and frame filter press for filter press treatment. The moisture content of the mud cake was tested to be 68%. The chemical composition of the filtrate after dehydration was tested. The test results showed a salt content of 5632 mg / L, a conductivity of 8.04 ms / cm, a COD value of 1152 mg / L, and an ammonia nitrogen value of 197 mg / L. No iron was detected in the sludge. See Table 2 for details.

[0127] Example 6.1

[0128] Method for preparing organic dehydrating agent and organic dehydrating agent:

[0129] According to the mass fraction, 20 parts of dimethyldiallylammonium chloride, 30 parts of acryloyloxyethyltrimethylammonium chloride and 50 parts of polyamine were uniformly mixed and heated to 50 ° C and reacted for 30 minutes. After the reaction, the material was dried and crushed and granulated to obtain a bulk density of 600 kg / m 3 of white powder.

[0130] Example 6.2

[0131] Preparation of organic dehydrating agent dilution solution:

[0132] Add the organic dehydrating agent powder to clean water at 22-27°C and stir continuously to dissolve it. Dissolve the organic dehydrating agent powder into a 0.35% storage water solution.

[0133] The obtained storage aqueous solution is diluted online with water 8 times and then stored for use. The storage time shall not exceed 24 hours.

[0134] Example 6.3

[0135] Sludge dewatering process:

[0136] Dehydration process using organic dehydrating agent

[0137] S1. Use a metering screw pump to add the diluted organic dehydrating agent obtained in Example 6.2 to 12 tons of sludge with a moisture content of 85%. The amount of the organic dehydrating agent active ingredient added is 250 kg, so that the concentration of the solution is 0.25%.

[0138] S2. The sludge treated in step S1 was passed through a plate and frame filter press for filtration. The moisture content of the sludge cake was tested to be 68%, as shown in Table 1. The chemical composition of the filtrate after dehydration was tested, and the test results showed a salt content of 12640 mg / L, a conductivity of 9.0 ms / cm, a COD value of 4276 mg / L, an ammonia nitrogen value of 506 mg / L, and an iron content of 24.2 mg / L, as shown in Table 2.

[0139] Comparative Example 1

[0140] Ferrous sulfate + hydrogen peroxide dehydration process

[0141] S1. Add 550 kg of ferrous sulfate to 8 tons of sludge with a moisture content of 85% and stir thoroughly.

[0142] S2. Add 400 kg of hydrogen peroxide to the sludge obtained in S1, and mix the hydrogen peroxide and the sludge thoroughly.

[0143] S3. The sludge treated in step S2 was passed through a plate and frame filter press for filtration. The moisture content of the sludge cake was tested to be 62%, as shown in Table 1. The chemical composition of the filtrate after dehydration of the sludge was tested, and the test results showed a salt content of 25902 mg / L, a conductivity of 13.53 ms / cm, a COD value of 2956 mg / L, an ammonia nitrogen value of 891 mg / L, and an iron content of 3218 mg / L, as shown in Table 2.

[0144] Table 1 Comparative table of dehydration effects of various embodiments and comparative examples

[0145]

[0146] Table 2 Chemical composition of the filtered water after sludge dehydration

[0147]

[0148] It can be seen from Example 1.3, Example 6.3 and Comparative Example 1 that when treating sludge with a moisture content of 85%, the method of Example 1 has lower cost and higher dehydration efficiency. In addition, when using the method of Example 1, the chemical composition of the filtered water after sludge dehydration does not contain iron, and the salt content, conductivity, COD value and ammonia nitrogen value are much lower than those of Example 6.3 and Comparative Example 1.

[0149] It can be seen that the dehydration agent and dehydration method used in this application have lower dehydration cost, higher dehydration efficiency, and are more environmentally friendly.

[0150] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A sludge dewatering process, characterized in that: The following steps are involved: S1. Add a sludge stabilizer to the sludge and stir the sludge thoroughly. The amount of the sludge stabilizer added is 20% to 40% of the absolute dry sludge amount. S2. Add an organic dehydrating agent to the sludge obtained in S1, so that the concentration of the organic dehydrating agent in the sludge liquid is 0.02% to 0.25%; S3, the addition of the organic dehydrating agent sludge is passed into a plate and frame filter press for dehydration treatment; The sludge stabilizer comprises, by mass fraction, 10 parts of magnesium carbonate, 20 parts of calcium carbonate, 10 parts of aluminum sulfate, 20 parts of potassium carbonate, 20 parts of aluminum oxide, and 20 parts of calcium oxide; The components of the organic dehydrating agent have a mass fraction ratio of dimethyldiallylammonium chloride:acryloyloxyethyltrimethylammonium chloride:polyamine of 2:3:5, and the allowable error of the mass fraction ratio is ≤±10%. The preparation method of the organic dehydrating agent is specifically as follows: dimethyldiallylammonium chloride, acryloyloxyethyltrimethylammonium chloride, and polyamine are mixed according to the product component ratio, heated to above 48° C., and fully melted and mixed, followed by drying, crushing, and granulating to obtain an organic dehydrating agent dry powder; The method for preparing the organic dehydrating agent before adding it to the sludge is as follows: adding the organic dehydrating agent powder to clean water at 15-30°C, and continuously stirring and dissolving the organic dehydrating agent powder to dissolve it into a 0.25% to 0.50% storage water solution.

2. The sludge dewatering process according to claim 1, wherein: Before being added to the sludge, the stored aqueous solution is diluted online with water 5 to 10 times and then added to the sludge.

3. The sludge dewatering process according to claim 1, wherein: The device for adding the organic dehydrating agent into the sludge is a volumetric dosing pump.

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