A method of processing end sludge in industrial wastewater and sludge fuel

Abstract

The application provides a method for treating end sludge in industrial wastewater, which comprises the following steps: stirring the end sludge in the industrial wastewater and keeping the temperature at 25-45 DEG C; adding a compound conditioning agent into the end sludge and controlling the stirring speed at 100-200 r / min, and reacting for 20-40 min to obtain reaction sludge; filtering and dewatering the reaction sludge to obtain dewatered sludge cake; crushing the dewatered sludge cake, uniformly mixing the dewatered sludge cake with a combustion aid, and then compressing and forming to obtain sludge fuel. Through the optimization of the specific conditioning agent and the treatment process parameters of the end sludge, the application realizes efficient dewatering and resource utilization of the end sludge, converts the dewatered end sludge into fuel with a certain calorific value, realizes the resource utilization of the end sludge, and solves the defects of poor dewatering effect and difficult fuelization in the related art.

Description

Technical Field

[0001] This application relates to the field of industrial wastewater treatment technology, and in particular to a method for treating end-of-pipe sludge in industrial wastewater and sludge fuel. Background Technology

[0002] The treatment of industrial wastewater generates a large amount of end-of-pipe sludge. This sludge has a high water content (usually 80%-95%), large volume, and contains pollutants such as heavy metals and organic matter. Improper treatment can cause secondary pollution. Currently, the main methods for end-of-pipe sludge treatment include landfill, incineration, and resource utilization. However, landfill occupies a large amount of land resources, while incineration requires additional energy and easily produces harmful gases.

[0003] Dewatering of sludge at the end of the treatment process is crucial. Conventional dewatering methods, such as plate and frame filter presses and centrifugal dewatering, have poor dewatering effects, leaving sludge with a moisture content still above 60%, which is detrimental to subsequent treatment. To improve dewatering efficiency, conditioning agents such as polyaluminum chloride and polyacrylamide are usually added. However, the conditioning effect of a single conditioning agent is limited, making it difficult to simultaneously achieve efficient dewatering and sludge modification for fuel production. Therefore, developing a treatment method that can simultaneously achieve efficient sludge dewatering and fuel production is of significant practical importance. Summary of the Invention

[0004] This application aims to at least partially solve one of the technical problems in the related art. This application proposes a method for treating end-of-pipe sludge from industrial wastewater. Through the optimization of specific conditioning agents and end-of-pipe sludge treatment process parameters, the method achieves efficient dewatering and resource utilization of end-of-pipe sludge, converting the dewatered end-of-pipe sludge into fuel with a certain calorific value, thereby realizing the resource utilization of end-of-pipe sludge.

[0005] According to an embodiment of the first aspect of this application, a method for treating terminal sludge in industrial wastewater is provided, comprising the following steps: Stir the end-stage sludge in the industrial wastewater treatment process and maintain the temperature at 25-45℃; Add a compound conditioner to the terminal sludge and control the stirring rate to 100-200 r / min, react for 20-40 min to obtain the reacted sludge; The reacted sludge is dewatered by filter pressing to obtain dewatered sludge cake; the dewatered sludge cake is crushed and mixed evenly with a binder and combustion aid, and then pressed into shape to obtain sludge fuel.

[0006] In some embodiments, based on the dry weight of the end sludge, the compound conditioning agent comprises 8%-15% pH adjuster, 5%-10% inert aggregate, and 0.1%-0.3% flocculant by weight percentage.

[0007] In some embodiments, the pH adjuster includes quicklime.

[0008] In some embodiments, the inert aggregate includes fly ash.

[0009] In some embodiments, the flocculant includes polyacrylamide.

[0010] In some embodiments, the filtration pressure during the dewatering process of the reacted sludge is 0.8-1.2 MPa, and the filtration time is 30-60 min.

[0011] In some embodiments, the binding and combustion aid comprises straw powder, with the weight percentage of the dehydrated sludge cake being 3%-5% based on the dehydrated sludge cake.

[0012] In some embodiments, the dewatered sludge cake is crushed, mixed evenly with the binder and combustion aid, and then pressed into shape under conditions of 100-120°C and 1.5-2.0 MPa.

[0013] In some embodiments, the calorific value of the sludge fuel is 1200-1800 kcal / kg, and the compressive strength is greater than 5 MPa.

[0014] According to an embodiment of the second aspect of this application, a sludge fuel is provided, obtained by the method described in any of the above embodiments, which can be used directly for combustion in industrial boilers or as an auxiliary fuel for biomass fuels.

[0015] The method for dewatering and fueling sludge at the end of industrial wastewater treatment in this application has the following beneficial effects: Significant dewatering effect: Through the synergistic effect of compound conditioning agents and the optimization of process parameters, the moisture content of dewatered sludge cake can be reduced to below 40%, which is 20%-30% higher than that of conventional methods, greatly reducing the volume of end sludge and lowering subsequent disposal costs; Resource utilization: Dewatered sludge cake can be converted into fuel with a calorific value of 1200-1800 kcal / kg, which can replace part of fossil fuels, reduce energy consumption and carbon emissions, and has good economic and environmental benefits. The process is simple and easy to operate: the entire process does not require complex equipment, the process parameters are easy to control, and it is suitable for industrial application. Good pollutant control effect: pH adjuster and inert aggregate can adsorb heavy metals and organic matter in sludge, reduce the environmental risk of sludge, and make the emission of harmful gases during the combustion of sludge fuel meet environmental protection standards.

[0016] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0017] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a flowchart of a method for treating end-of-pipe sludge in industrial wastewater according to an embodiment of this application. Detailed Implementation

[0018] Embodiments of this application are described in detail below. Examples of these embodiments are illustrated 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 with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. Rather, this application includes all variations, modifications, and equivalents falling within the spirit and scope of the appended claims.

[0019] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0020] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0021] According to an embodiment of the first aspect of this application, a method for treating terminal sludge in industrial wastewater is provided, such as... Figure 1 As shown, it includes the following steps: S1: Stir the end-of-pipe sludge in the industrial wastewater and maintain the temperature at 25-45℃; S2: Add compound conditioner to the end sludge and control the stirring rate to 100-200 r / min. React for 20-40 min to obtain reacted sludge. S3: The reaction sludge is dewatered by filter pressing to obtain dewatered sludge cake; the dewatered sludge cake is crushed and mixed evenly with a binder and combustion aid, and then pressed into shape to obtain sludge fuel.

[0022] In step S1, the sludge from the treated industrial wastewater is placed in a mixing tank, stirred evenly, and its moisture content and dry weight are confirmed. The sludge in the example industrial wastewater treatment typically has a moisture content of 80%-95%, a large volume, and contains pollutants such as heavy metals and organic matter. In this step, the sludge is stirred evenly while its temperature is controlled at 25-45℃. This process serves as pretreatment of the sludge, ensuring good uniformity and reactivity, preparing it for the addition of a compound conditioner to the pretreated sludge in step S2.

[0023] In S2, a compound conditioning agent is added to the pretreated end sludge. Based on the dry weight of the end sludge, the compound conditioning agent includes 8%-15% pH adjuster, 5%-10% inert aggregate, and 0.1%-0.3% flocculant by weight percentage.

[0024] For example, the pH adjuster includes quicklime, which can lower the pH value of sludge, disrupt the colloidal structure of sludge, and release bound water; wherein the amount of pH adjuster added is 8%, 9%, 10%, 11%, 12%, 13%, 14%, or 15%. In some embodiments, the inert aggregate includes fly ash, which, as an inert aggregate, can adsorb moisture and pollutants in sludge and increase the calorific value of sludge; wherein the amount of inert aggregate added is 5%, 6%, 7%, 8%, 9%, or 10%. In some embodiments, the flocculant includes polyacrylamide, which can promote the flocculation of sludge particles, increase the floc size, and improve the dewatering rate; wherein the amount of flocculant added is 0.1%, 0.2%, or 0.3%. In this embodiment, the synergistic effect of the three compound conditioners increases the sludge dewatering rate by 20%-30% compared to a single conditioner, and the moisture content of the dewatered sludge can be reduced to below 40%.

[0025] In this process, a compound conditioner is added to the end-of-pipe sludge, and the stirring rate is controlled at 100-200 r / min. The reaction is carried out for 20-40 minutes to obtain reacted sludge. By controlling parameters such as sludge reaction temperature, stirring rate, and reaction time, the conditioner and sludge are ensured to react fully, thereby improving dewatering efficiency. The reaction temperature of 25-45℃ ensures the activity of the conditioner while avoiding energy waste; the stirring rate of 100-200 r / min ensures uniform mixing of the conditioner and sludge, preventing incomplete local reactions.

[0026] In step S3, the reacting sludge is dewatered by filter pressing to obtain a dewatered sludge cake. For example, the filter pressing pressure during the dewatering process is 0.8-1.2 MPa, and the pressing time is 30-60 min. The filter pressing pressure of 0.8-1.2 MPa in this process can ensure the dewatering effect while preventing damage to the filter cloth.

[0027] The binder and combustion aid includes straw powder, based on dehydrated sludge cake, with the dehydrated sludge cake accounting for 3%-5% by weight. By adding straw powder as a binder and combustion aid, and controlling the molding temperature and pressure, the sludge fuel has good strength and combustion performance. After the dehydrated sludge cake is crushed and mixed evenly with the binder and combustion aid, it is pressed into shape under conditions of 100-120℃ and 1.5-2.0MPa. The calorific value of the molded sludge fuel can reach 1200-1800 kcal / kg, the compressive strength is greater than 5MPa, and it is not easily broken. It can be directly used for combustion in industrial boilers or as auxiliary fuel for biomass fuels, realizing the resource utilization of sludge and reducing solid waste disposal costs.

[0028] According to an embodiment of the second aspect of this application, a sludge fuel is provided, obtained using the method in any of the above embodiments, which can be used directly for combustion in industrial boilers or as an auxiliary fuel for biomass fuel.

[0029] To facilitate a further understanding of this application, the solutions described below are further described in conjunction with embodiments. Those skilled in the art will understand that the examples described in this application are only a portion of the examples, and any other suitable specific examples are within the scope of this application.

[0030] Example 1 This embodiment proposes a method for treating end-of-pipe sludge from industrial wastewater, comprising the following steps: Take end-of-pipe sludge (90% moisture content, 100 kg dry weight) from a chemical plant's industrial wastewater treatment plant, place it in a mixing tank, stir evenly, and control the sludge temperature at 25°C. Add a compound conditioning agent to the sludge, comprising 8 kg quicklime (8% of the sludge dry weight), 5 kg fly ash (5% of the sludge dry weight), and 0.1 kg polyacrylamide (0.1% of the sludge dry weight). After addition, stir at a rate of 100 r / min for 20 min. Feed the reacted sludge into a plate and frame filter press and filter under 0.8 MPa pressure for 30 min to obtain dewatered sludge cake, with a moisture content of 38%. Crush the dewatered sludge cake, add 3% straw powder (by weight of the sludge cake), mix evenly, and then feed it into a molding machine. Press and mold it at 100°C and 1.5 MPa to obtain sludge fuel blocks. The fuel block was tested and found to have a calorific value of 1200 kcal / kg and a compressive strength of 5.2 MPa.

[0031] Example 2 This embodiment proposes a method for treating end-of-pipe sludge from industrial wastewater, comprising the following steps: Take end-of-pipe sludge (85% moisture content, 100 kg dry weight) from a dyeing and printing enterprise's industrial wastewater treatment plant, place it in a mixing tank, stir evenly, and control the sludge temperature at 35℃. Add a compound conditioning agent to the sludge: 12 kg quicklime (12% of the sludge dry weight), 8 kg fly ash (8% of the sludge dry weight), and 0.2 kg polyacrylamide (0.2% of the sludge dry weight). After addition, stir at a rate of 150 r / min for 30 min. Feed the reacted sludge into a plate and frame filter press and filter under 1.0 MPa pressure for 45 min to obtain dewatered sludge cake, with a moisture content of 32%. Crush the dewatered sludge cake, add 4% straw powder (by weight of the sludge cake), mix evenly, and feed it into a molding machine. Press and mold it at 110℃ and 1.8 MPa to obtain sludge fuel. The fuel block was tested and found to have a calorific value of 1500 kcal / kg and a compressive strength of 6.5 MPa.

[0032] Example 3 This embodiment proposes a method for treating end-of-pipe sludge from industrial wastewater, comprising the following steps: Take end-of-pipe sludge (92% moisture content, 100 kg dry weight) from a paper mill's industrial wastewater treatment plant, place it in a mixing tank, stir evenly, and control the sludge temperature at 45℃. Add a compound conditioning agent to the sludge: 15 kg quicklime (15% of the sludge dry weight), 10 kg fly ash (10% of the sludge dry weight), and 0.3 kg polyacrylamide (0.3% of the sludge dry weight). After addition, stir at a rate of 200 r / min for 40 min. Feed the reacted sludge into a plate and frame filter press and filter under 1.2 MPa pressure for 60 min to obtain dewatered sludge cake, with a moisture content of 30%. Crush the dewatered sludge cake, add 5% straw powder (by weight of the sludge cake), mix evenly, and feed it into a molding machine. Press and mold under 120℃ and 2.0 MPa conditions to obtain sludge fuel. The fuel block was tested and found to have a calorific value of 1800 kcal / kg and a compressive strength of 7.0 MPa.

[0033] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0034] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A method for treating end-of-pipe sludge from industrial wastewater, characterized in that, Includes the following steps: Stir the end-stage sludge in the industrial wastewater treatment process and maintain the temperature at 25-45℃; Add a compound conditioner to the terminal sludge and control the stirring rate to 100-200 r / min, react for 20-40 min to obtain the reacted sludge; The reacted sludge is dewatered by filter pressing to obtain dewatered sludge cake; the dewatered sludge cake is crushed and mixed evenly with a binder and combustion aid, and then pressed into shape to obtain sludge fuel.

2. The method according to claim 1, characterized in that, Based on the dry weight of the terminal sludge, the compound conditioning agent comprises 8%-15% pH adjuster, 5%-10% inert aggregate, and 0.1%-0.3% flocculant by weight percentage.

3. The method according to claim 2, characterized in that, The pH adjuster includes quicklime.

4. The method according to claim 2, characterized in that, The inert aggregate includes fly ash.

5. The method according to claim 2, characterized in that, The flocculant includes polyacrylamide.

6. The method according to any one of claims 1-5, characterized in that, The filtration pressure during the dewatering process of the reacted sludge is 0.8-1.2 MPa, and the filtration time is 30-60 min.

7. The method according to claim 6, characterized in that, The binding and combustion aid includes straw powder, with the dehydrated sludge cake as a base, and the weight percentage of the dehydrated sludge cake is 3%-5%.

8. The method according to claim 6, characterized in that, After the dehydrated sludge cake is crushed, it is mixed evenly with the binder and combustion aid and then pressed into shape under the conditions of temperature 100-120℃ and pressure 1.5-2.0MPa.

9. The method according to claim 1, characterized in that, The calorific value of the sludge fuel is 1200-1800 kcal / kg, and the compressive strength is greater than 5 MPa.

10. A sludge fuel, characterized in that, The product obtained by any one of the methods described in claims 1-9 can be used directly for combustion in industrial boilers or as an auxiliary fuel for biomass fuels.

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