Preparation method of composite enzyme solidified sludge fly ash mixed material

Abstract

The present application relates to the technical field of road engineering material preparation, in particular to a preparation method of a composite enzyme solidified sludge fly ash mixed material, which comprises the following steps: sludge pretreatment, dewatering the sludge and then crushing and pulverizing it; fly ash pretreatment, screening the fly ash to a desired particle size; composite enzyme preparation, preparing a composite enzyme according to a desired mass ratio; mixing material preparation, mixing the pretreated sludge and fly ash and adding the composite enzyme, stirring uniformly to obtain a mixed material; and solidification reaction, solidifying the mixed material to obtain a final mixed material. The preparation method of the composite enzyme solidified sludge fly ash mixed material has the advantages of environmental protection and economy, excellent performance, convenient construction, resource saving, wide application and the like, and provides a new idea and solution for solving the treatment problem of sludge and fly ash and meeting the demand of roadbed engineering for high-performance materials.

Description

Technical Field

[0001] This invention relates to the field of road engineering material preparation technology, specifically a method for preparing a composite enzyme-cured sludge fly ash mixture. Background Technology

[0002] Sludge contains high levels of organic matter and moisture, while fly ash is rich in inorganic substances. Traditional treatment methods not only consume a large amount of land resources but may also cause secondary pollution to the environment. In recent years, research on the resource utilization of mixing sludge and fly ash has gradually increased, but the stability and strength of the mixed materials often fail to meet the requirements of roadbed engineering.

[0003] In current engineering construction, especially in road construction, the selection and application of subgrade materials directly affect the stability and service life of roads. Traditional subgrade materials, such as sand, gravel, and soil, are widely used, but given the increasing scarcity of resources and growing environmental pressures, finding new and sustainable subgrade materials has become a research hotspot in the industry. Sludge and fly ash, as two common industrial wastes, can not only help solve environmental pollution problems through their rational utilization, but also achieve effective resource conversion.

[0004] Sludge is a solid waste generated during wastewater treatment, rich in both organic and inorganic matter. However, its direct utilization faces numerous difficulties due to its high water content and unstable organic matter content. Fly ash, on the other hand, is fine particulate matter produced in industrial processes such as coal-fired plants, primarily composed of inorganic substances like silicates and aluminates. Mixing sludge and fly ash allows for the complementary use of these two wastes, reducing environmental pollution and lowering the cost of roadbed materials.

[0005] However, the direct application of sludge-fly ash mixtures also faces some challenges. First, the high organic matter content in sludge may lead to material degradation during long-term use, affecting the stability of the roadbed. Second, fly ash particles are small and easily dispersed, posing a potential threat to the environment and human health. Furthermore, the mechanical properties and water stability of sludge-fly ash mixtures must meet the requirements of roadbed engineering.

[0006] To address these issues, researchers have conducted extensive exploration and practice. In recent years, bio-enzyme technology has gained widespread attention in the field of waste treatment due to its high efficiency and environmental friendliness. As a biocatalyst, bio-enzymes can accelerate the rate of chemical reactions while producing little or no byproducts. Therefore, using composite enzymes to solidify sludge-fly ash mixtures has become a new research direction. Through the solidification effect of bio-composite enzymes, the organic matter in the sludge and the inorganic matter in the fly ash can undergo a chemical reaction to form a stable chemical bond structure, thereby improving the mechanical properties and durability of the material. Summary of the Invention

[0007] The purpose of this invention is to provide a method for preparing a composite enzyme-cured sludge fly ash mixture, so as to improve the strength and stability of the mixture and enable it to meet the application requirements of roadbed engineering.

[0008] To achieve the above objectives, the present invention provides the following technical solution.

[0009] A method for preparing a composite enzyme-cured sludge fly ash mixture includes the following steps:

[0010] Sludge pretreatment: After dewatering, the sludge is crushed and shredded.

[0011] Fly ash pretreatment: Screen the fly ash to the required particle size;

[0012] Compound enzyme preparation: The formula is prepared according to the required mass ratio to obtain the compound enzyme;

[0013] Mixture preparation: The pretreated sludge and fly ash are mixed, and compound enzymes are added and stirred evenly to obtain the mixture;

[0014] Curing reaction: The mixture is subjected to a curing reaction to obtain the final mixed material.

[0015] The specific steps for preparing the compound enzyme are as follows:

[0016] A composite enzyme was obtained by mixing cellulase, hemicellulase and protease in a mass ratio of 3:2:1.

[0017] After mixing, random sampling should be conducted to ensure that the activity of the compound enzyme is greater than 90%.

[0018] The specific steps for preparing the mixture are as follows;

[0019] Take sludge pretreatment granules and fly ash screenings at a mass ratio of 9:1 to 1:1, and put them into a mixer for mixing for 45 minutes;

[0020] Add 0.005% of the sludge mass of the compound enzyme to the mixer and stir for 20 minutes to obtain the mixture.

[0021] Among these requirements, the uniformity of the compound enzyme distribution must be greater than 95% in the test results.

[0022] The specific steps of the curing reaction are as follows:

[0023] The mixture is transferred to a constant temperature and humidity chamber for curing reaction. The curing temperature is set at 20-50℃, the curing humidity at 50-60%, and the curing reaction time at 36 hours, finally yielding the mixed material.

[0024] Preferably, the specific steps for sludge pretreatment are as follows:

[0025] The sludge is dewatered to keep its moisture content below 10%.

[0026] Use a crusher to crush the dewatered sludge, set the crushing time to 15 minutes, and ensure that the particle size of the sludge particles is less than 5 mm.

[0027] The crushed sludge particles are screened to remove sludge particles that do not meet the size requirements.

[0028] The sludge particles after screening were homogenized using a mixer for 30 minutes to obtain pretreated sludge particles.

[0029] Preferably, the specific steps for fly ash pretreatment are as follows:

[0030] The fly ash is sieved using a sieve to remove large impurities and unburned carbon particles, resulting in sieved fly ash.

[0031] The screen mesh size is 100μm;

[0032] The unburned carbon particle content is less than 0.5%.

[0033] Preferably, the dehydration process is carried out by hot air drying.

[0034] The hot air dryer operates at a temperature of 105-120℃ and lasts for 24-36 hours.

[0035] Preferably, the compound enzyme raw materials are mixed using a mixer for 10 minutes.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows.

[0037] Environmentally friendly and economical: Using composite enzymes as curing agents avoids the use of chemical agents in traditional chemical curing methods, reducing costs. In addition, the composite enzymes themselves are biodegradable and will not cause secondary pollution to the environment.

[0038] Excellent performance: Through the catalytic action of compound enzymes, organic matter in sludge and fly ash is decomposed and inorganic matter is transformed to form a stable solid structure. At the same time, the addition of compound enzymes can also improve the impermeability and durability of the mixed material, making it more suitable for roadbed engineering.

[0039] Convenient construction: The preparation and operation methods are simple and easy to realize industrial production. At the same time, the cured material has good construction performance and is easy to transport, lay and compact.

[0040] Resource conservation: Utilizing sludge and fly ash as waste materials not only solves their disposal problems but also saves land and raw material resources.

[0041] Wide range of applications: The sludge fly ash mixture of the present invention can be used not only in roadbed engineering, but also in other civil engineering fields, such as foundation treatment, embankment engineering, water conservancy engineering, etc., with a wide range of applications and good application prospects. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the preparation method steps provided by the present invention. Detailed Implementation

[0043] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0044] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connection" and "installation" should be interpreted broadly. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. Furthermore, "connection" can be a direct connection or an indirect connection through an intermediate medium. "Fixed" means that the devices are connected to each other and their relative positional relationship remains unchanged after the connection. The directional terms mentioned in the embodiments of the present invention, such as "inner," "outer," "top," and "bottom," are only for reference to the directions in the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of the present invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention.

[0045] In this embodiment of the invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0046] In this embodiment of the invention, "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 three cases: 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.

[0047] References to "one embodiment" or "some embodiments" as used in this specification mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in one or more embodiments of the invention. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including, but not limited to," unless otherwise specifically emphasized.

[0048] Please see Figure 1 This invention provides a method for preparing a composite enzyme-cured sludge fly ash mixture, specifically including the following steps:

[0049] Sludge pretreatment: After dewatering, the sludge is crushed and shredded.

[0050] Fly ash pretreatment: Screen the fly ash to the required particle size;

[0051] Compound enzyme preparation: The formula is prepared according to the required mass ratio to obtain the compound enzyme;

[0052] Mixture preparation: The pretreated sludge and fly ash are mixed, and compound enzymes are added and stirred evenly to obtain the mixture;

[0053] Curing reaction: The mixture is subjected to a curing reaction to obtain the final mixed material.

[0054] Specifically, the steps for sludge pretreatment are as follows:

[0055] The sludge is dewatered using a hot air dryer at a temperature of 105-120℃ for 24-36 hours to keep the sludge moisture content below 10%.

[0056] Use a crusher to crush the dewatered sludge, set the crushing time to 15 minutes, and ensure that the particle size of the sludge particles is less than 5 mm.

[0057] The crushed sludge particles are screened to remove sludge particles that do not meet the size requirements.

[0058] The sludge particles after screening were homogenized using a mixer for 30 minutes to obtain pretreated sludge particles.

[0059] Specifically, the steps for fly ash pretreatment are as follows:

[0060] The fly ash is sieved using a sieve to remove large impurities and unburned carbon particles, resulting in sieved fly ash.

[0061] The screen mesh size is 100μm;

[0062] The unburned carbon particle content is less than 0.5%.

[0063] Specifically, the steps for preparing the compound enzyme are as follows:

[0064] Cellulase, hemicellulase and protease in a mass ratio of 3:2:1 were added to a mixer and mixed for 10 minutes to obtain the complex enzyme.

[0065] After mixing, random sampling should be conducted to ensure that the activity of the compound enzyme is greater than 90%.

[0066] Specifically, the preparation steps for the mixture are as follows;

[0067] Take sludge pretreatment granules and fly ash screenings at a mass ratio of 9:1 to 1:1, and put them into a mixer for mixing for 45 minutes;

[0068] Add 0.005% of the sludge mass of the compound enzyme to the mixer and stir for 20 minutes to obtain the mixture.

[0069] Among these requirements, the uniformity of the compound enzyme distribution must be greater than 95%.

[0070] Specifically, the curing reaction involves the following steps:

[0071] The mixture is transferred to a constant temperature and humidity chamber for curing reaction. The curing temperature is set at 20-50℃, the curing humidity at 50-60%, and the curing reaction time at 36 hours, finally yielding the mixed material. Example

[0072] The sludge was dewatered for 24 hours using a hot air dryer at a drying temperature of 110℃, and the sludge moisture content was measured to be 9.5%. The dewatered sludge was then crushed for 15 minutes using a pulverizer to ensure that the particle size of the sludge particles was less than 5 mm. The crushed sludge particles were then screened to remove sludge particles that did not meet the size requirements. The screened sludge particles were then homogenized using a mixer for 30 minutes to obtain sludge pre-treated particles.

[0073] The fly ash was sieved using a 100μm sieve to remove large impurities and unburned carbon particles, resulting in fly ash sieve material. The content of unburned carbon particles in the fly ash sieve material was controlled to be less than 0.5%.

[0074] Cellulase, hemicellulase and protease in a mass ratio of 3:2:1 were used as raw materials for a composite enzyme. They were added to a mixer and mixed for 10 minutes to obtain a composite enzyme. After mixing, random sampling was performed, and the activity of the composite enzyme was 92%.

[0075] Sludge pretreatment granules and fly ash sieve material with a mass ratio of 2:1 were added to a mixer and mixed for 45 minutes. 0.005% of the sludge mass of the compound enzyme was added to the mixer and mixed for 20 minutes to obtain the mixture. The uniformity of compound enzyme distribution was 96%.

[0076] The mixture was transferred to a constant temperature and humidity chamber and cured for 36 hours under conditions of 30°C and 50% humidity to finally obtain mixture A. Example

[0077] The sludge was dewatered for 30 hours using a hot air dryer at a drying temperature of 115℃, and the sludge moisture content was measured to be 9.2%. The dewatered sludge was then crushed for 15 minutes using a pulverizer to ensure that the particle size of the sludge particles was less than 5 mm. The crushed sludge particles were then screened to remove sludge particles that did not meet the size requirements. The screened sludge particles were then homogenized using a mixer for 30 minutes to obtain sludge pre-treated particles.

[0078] The fly ash was sieved using a 100μm sieve to remove large impurities and unburned carbon particles, resulting in fly ash sieve material. The content of unburned carbon particles in the fly ash sieve material was controlled to be less than 0.5%.

[0079] Cellulase, hemicellulase and protease in a mass ratio of 3:2:1 were used as raw materials for a composite enzyme. They were added to a mixer and stirred for 10 minutes to obtain a composite enzyme. After mixing, random sampling was performed, and the activity of the composite enzyme was 91%.

[0080] Sludge pretreatment granules and fly ash sieve material with a mass ratio of 1:1 were added to a mixer and mixed for 45 minutes. 0.005% of the sludge mass of the compound enzyme was added to the mixer and mixed for 20 minutes to obtain the mixture. The uniformity of compound enzyme distribution was 97%.

[0081] The mixture was transferred to a constant temperature and humidity chamber and cured for 36 hours at 30°C and 60% humidity to finally obtain mixture B. Example

[0082] The sludge was dewatered for 33 hours using a hot air dryer at a drying temperature of 115℃, and the sludge moisture content was measured to be 8.9%. The dewatered sludge was then crushed for 15 minutes using a pulverizer to ensure that the particle size of the sludge particles was less than 5 mm. The crushed sludge particles were then screened to remove sludge particles that did not meet the size requirements. The screened sludge particles were then homogenized using a mixer for 30 minutes to obtain sludge pre-treated particles.

[0083] The fly ash was sieved using a 100μm sieve to remove large impurities and unburned carbon particles, resulting in fly ash sieve material. The content of unburned carbon particles in the fly ash sieve material was controlled to be less than 0.5%.

[0084] Cellulase, hemicellulase and protease in a mass ratio of 3:2:1 were used as raw materials for a composite enzyme. They were added to a mixer and mixed for 10 minutes to obtain a composite enzyme. After mixing, random sampling was performed, and the activity of the composite enzyme was 92%.

[0085] Sludge pretreatment granules and fly ash sieve material with a mass ratio of 3:1 were added to a mixer and mixed for 45 minutes. 0.005% of the sludge mass of the compound enzyme was added to the mixer and mixed for 20 minutes to obtain the mixture. The uniformity of compound enzyme distribution was 96%.

[0086] The mixture was transferred to a constant temperature and humidity chamber and cured for 36 hours at 35°C and 60% humidity to finally obtain mixed material C. Example

[0087] The sludge was dewatered at 120℃ for 35 hours using a hot air dryer, and the moisture content of the sludge was measured to be 8.4%. The dewatered sludge was then crushed for 15 minutes using a pulverizer to ensure that the particle size of the sludge particles was less than 5 mm. The crushed sludge particles were then screened to remove sludge particles that did not meet the size requirements. The screened sludge particles were then homogenized using a mixer for 30 minutes to obtain sludge pre-treated particles.

[0088] The fly ash was sieved using a 100μm sieve to remove large impurities and unburned carbon particles, resulting in fly ash sieve material. The content of unburned carbon particles in the fly ash sieve material was controlled to be less than 0.5%.

[0089] Cellulase, hemicellulase and protease in a mass ratio of 3:2:1 were used as raw materials for a composite enzyme. They were added to a mixer and mixed for 10 minutes to obtain a composite enzyme. After mixing, random sampling was performed, and the activity of the composite enzyme was 92%.

[0090] Sludge pretreatment granules and fly ash sieve material with a mass ratio of 5:1 were added to a mixer and mixed for 45 minutes. 0.005% of the sludge mass of the compound enzyme was added to the mixer and mixed for 20 minutes to obtain the mixture. The uniformity of compound enzyme distribution was 96%.

[0091] The mixture was transferred to a constant temperature and humidity chamber and cured for 36 hours at 40°C and 60% humidity to obtain the final mixture D. Example

[0092] The sludge was dewatered for 36 hours using a hot air dryer at a drying temperature of 110℃, and the sludge moisture content was measured to be 8.6%. The dewatered sludge was then crushed for 15 minutes using a pulverizer to ensure that the particle size of the sludge particles was less than 5 mm. The crushed sludge particles were then screened to remove sludge particles that did not meet the size requirements. The screened sludge particles were then homogenized for 30 minutes using a mixer to obtain sludge pre-treated particles.

[0093] The fly ash was sieved using a 100μm sieve to remove large impurities and unburned carbon particles, resulting in fly ash sieve material. The content of unburned carbon particles in the fly ash sieve material was controlled to be less than 0.5%.

[0094] Cellulase, hemicellulase and protease in a mass ratio of 3:2:1 were used as raw materials for a composite enzyme. They were added to a mixer and stirred for 10 minutes to obtain a composite enzyme. After mixing, random sampling was performed, and the activity of the composite enzyme was 93%.

[0095] Sludge pretreatment granules and fly ash sieve material with a mass ratio of 4:1 were added to a mixer and mixed for 45 minutes. 0.005% of the sludge mass of the compound enzyme was added to the mixer and mixed for 20 minutes to obtain the mixture. The uniformity of compound enzyme distribution was 96%.

[0096] The mixture was transferred to a constant temperature and humidity chamber and cured for 36 hours at 30°C and 50% humidity to finally obtain the mixed material E.

[0097] After the mixed material A prepared in Example 1 was naturally cured for 5 days, its performance was tested and found to have a load-bearing ratio of 55%, a compressive strength of 8 MPa, and good water stability.

[0098] After the mixed material B prepared in Example 2 was naturally cured for 7 days, its performance was tested and the load-bearing ratio was measured to be 60%, the compressive strength was 10 MPa, and the water stability was good.

[0099] After the mixed material C prepared in Example 3 was naturally cured for 5 days, its performance was tested and the load-bearing ratio was measured to be 57%, the compressive strength was 9 MPa, and the water stability was good.

[0100] After the mixed material D prepared in Example 4 was naturally cured for 7 days, its performance was tested and the load-bearing ratio was measured to be 59%, the compressive strength was 10 MPa, and the water stability was good.

[0101] After the mixed material E prepared in Example 5 was naturally cured for 3 days, its performance was tested. The results showed that its load-bearing ratio was 50%, its compressive strength was 7 MPa, and its water stability was good.

[0102] The performance test results of the mixed materials prepared by the above embodiments and each embodiment show that the preparation method provided by the present invention can prepare high-performance sludge and fly ash mixed materials under different conditions. At the same time, by adjusting the mixing ratio of sludge and fly ash, the amount of compound enzyme added, and the solidification reaction conditions, the performance and application effect of the material can be further optimized.

[0103] In summary, this invention proposes a method for preparing a composite enzyme-cured sludge-fly ash mixture. This method has advantages such as environmental friendliness, economy, excellent performance, convenient construction, and resource conservation. It provides a new approach and solution for solving the treatment problems of sludge and fly ash and addressing the demand for high-performance materials in roadbed engineering. Specifically, it has the following advantages:

[0104] Environmentally friendly and economical: Using composite enzymes as curing agents avoids the use of chemical agents in traditional chemical curing methods, reducing costs. In addition, the composite enzymes themselves are biodegradable and will not cause secondary pollution to the environment.

[0105] Excellent performance: Through the catalytic action of compound enzymes, organic matter in sludge and fly ash is decomposed and inorganic matter is transformed to form a stable solid structure. At the same time, the addition of compound enzymes can also improve the impermeability, durability and other properties of the mixed material, making it more suitable for roadbed engineering.

[0106] Convenient construction: The preparation and operation methods are simple and easy to realize industrial production. At the same time, the cured material has good construction performance and is easy to transport, lay and compact.

[0107] Resource conservation: The resource utilization of sludge and fly ash not only solves the problem of their treatment, but also saves land and raw material resources.

[0108] Wide range of applications: The sludge fly ash mixture of the present invention can be used not only in roadbed engineering, but also in other civil engineering fields, such as foundation treatment, embankment engineering, water conservancy engineering, etc., with a wide range of applications and good application prospects.

[0109] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

Claims

1. A method for preparing a composite enzyme-cured sludge-fly ash mixture, characterized in that: Specifically, the following steps are included: Sludge pretreatment: After dewatering, the sludge is crushed and shredded. Fly ash pretreatment: Screen the fly ash to the required particle size; Compound enzyme preparation: The formula is prepared according to the required mass ratio to obtain the compound enzyme; Preparation of mixture: The pretreated sludge and fly ash are mixed, and the compound enzyme is added. The mixture is stirred evenly to obtain the mixture. Curing reaction: The mixture is subjected to a curing reaction to finally obtain a mixed material; The specific steps for preparing the compound enzyme are as follows: A composite enzyme was obtained by mixing cellulase, hemicellulase and protease in a mass ratio of 3:2:

1. After mixing, random sampling should be conducted to ensure that the activity of the compound enzyme is greater than 90%. The specific steps for preparing the mixture are as follows; Take sludge pretreatment granules and fly ash screenings at a mass ratio of 9:1 to 1:1, and put them into a mixer for mixing for 45 minutes; Add 0.005% of the sludge mass of the compound enzyme to the mixer and stir for 20 minutes to obtain the mixture. Among these requirements, the uniformity of the compound enzyme distribution must be greater than 95% in the test results. The specific steps of the curing reaction are as follows: The mixture is transferred to a constant temperature and humidity chamber for curing reaction. The curing temperature is set at 20-50℃, the curing humidity at 50-60%, and the curing reaction time at 36h, finally obtaining the mixed material.

2. The method for preparing a composite enzyme-cured sludge fly ash mixture according to claim 1, characterized in that: The specific steps of the sludge pretreatment are as follows: The sludge is dewatered to keep its moisture content below 10%. Use a crusher to crush the dewatered sludge, set the crushing time to 15 minutes, and ensure that the particle size of the sludge particles is less than 5 mm. The crushed sludge particles are screened to remove sludge particles that do not meet the size requirements. The sludge particles after screening were homogenized using a mixer for 30 minutes to obtain pretreated sludge particles.

3. The preparation method of the composite enzyme-cured sludge fly ash mixture according to claim 2, characterized in that: The specific steps for fly ash pretreatment are as follows: The fly ash is sieved using a sieve to remove large impurities and unburned carbon particles, resulting in sieved fly ash. The screen mesh size is 100μm; The unburned carbon particle content is less than 0.5%.

4. The method for preparing a composite enzyme-cured sludge fly ash mixture according to claim 3, characterized in that: The dehydration process is carried out by hot air drying. The hot air dryer operates at a temperature of 105-120℃ and lasts for 24-36 hours.

5. The method for preparing a composite enzyme-cured sludge fly ash mixture according to claim 4, characterized in that: The compound enzyme raw materials were mixed using a mixer for 10 minutes.

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