Sewage treatment composite agent and preparation method thereof

Abstract

The invention belongs to the technical field of sewage treatment, and provides a sewage treatment composite agent and a preparation method thereof.The sewage treatment composite agent is prepared from, by mass, 30-40 parts of polyaluminum chloride, 2-5 parts of polyacrylamide, 15-25 parts of polyferric sulfate, 5-10 parts of hydrogen peroxide, 10-15 parts of sodium hydroxide, 8-12 parts of aluminum sulfate and 0.5-1 part of defoaming agent; by combining multiple formula components of the polyaluminum chloride, the polyferric sulfate and the aluminum sulfate, the capability of removing suspended solids, colloidal substances and heavy metal ions in sewage can be remarkably enhanced by utilizing the synergistic effect of different components, and the formed flocculating constituent is high in density and high in settling velocity, so that the sewage treatment efficiency is favorably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, in particular to a sewage treatment composite agent and a preparation method thereof. Background Art

[0002] With the acceleration of industrialization and urbanization, the total amount of sewage discharge continues to increase, the water quality components are becoming more complex, and the requirements for sewage treatment technology and reagents are becoming increasingly stringent; the existing sewage treatment methods mainly include physical methods, chemical methods and biological methods, and the composite reagents in the chemical method are more widely used. Traditional sewage treatment composite reagents usually rely on a single component or a combination of fewer components.

[0003] However, many traditional sewage treatment compound agents only have a single function. For example, common single flocculants, such as early aluminum sulfate or polyaluminum chloride single agents, are mainly limited to flocculating and settling suspended particles and colloidal substances in sewage. When faced with sewage with complex components, such single flocculants cannot effectively treat other pollutants such as difficult-to-degrade organic matter and heavy metal ions in sewage. Taking printing and dyeing wastewater as an example, the wastewater not only contains a large number of suspended dye particles, but also contains many organic compounds that are difficult to biodegrade. After treatment with only a single flocculant, although some suspended particles can be removed, the chemical oxygen demand (COD) in the wastewater remains high and cannot meet the discharge standards. Although some traditional compound agents try to combine multiple components, the synergistic effect is not good. For example, some compound agents that simply mix flocculants and oxidants, due to the lack of in-depth research on the reaction conditions and action mechanisms of each component, in actual applications, flocculants and oxidants cannot give full play to their respective advantages and promote each other. In this case, the flocculation process may be interfered by the oxidant, resulting in unstable flocculation effect, and the oxidation efficiency of the oxidant is also difficult to be effectively improved.

[0004] In the flocculation process, traditional technologies often face the problem of poor floc performance. The flocs formed by traditional agents often have a slow sedimentation rate, which not only prolongs the sewage treatment time, reduces the treatment efficiency, but also increases the treatment cost. The floc structure is loose and is easily broken in the subsequent solid-liquid separation process, causing some suspended matter to return to the treated water and affect the water quality. In urban sewage treatment plants, when using a combination of traditional flocculants and coagulants, the effluent from the sedimentation tank is often turbid, which is caused by the loose floc structure and poor sedimentation performance.

[0005] To this end, those skilled in the art have proposed a sewage treatment composite agent and a preparation method thereof, aiming to effectively improve the sewage treatment capacity, shorten the sewage treatment cycle, and make the formed floccules easier to settle and separate. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a sewage treatment composite agent and a preparation method thereof to solve the problems raised in the background technology.

[0007] According to the first aspect of the present disclosure, a composite agent for sewage treatment and a preparation method thereof are proposed, which includes the following components, calculated by mass: 30-40 parts of polyaluminium chloride, 2-5 parts of polyacrylamide, 15-25 parts of polyferric sulfate, 5-10 parts of hydrogen peroxide, 10-15 parts of sodium hydroxide, 8-12 parts of aluminium sulfate and 0.5-1 part of defoaming agent.

[0008] Preferably, the following components are included, calculated by mass: 30 parts of polyaluminium chloride, 5 parts of polyacrylamide, 15 parts of polyferric sulfate, 10 parts of hydrogen peroxide, 10 parts of sodium hydroxide, 8 parts of aluminium sulfate and 1 part of defoaming agent.

[0009] According to a second aspect of the present disclosure, a method for preparing a composite agent for sewage treatment is provided, which is applied in the first aspect and comprises the following steps:

[0010] S1, pouring polyaluminium chloride, polyferric sulfate and aluminium sulfate solid raw materials into a grinder at the same time, performing a grinding operation, and after the grinding is completed, screening the mixture through an 80-mesh sieve to remove larger particles that are not fully ground, to obtain a solid mixture;

[0011] S2. Slowly add sodium hydroxide solid into water while gently stirring with a stirring rod until the sodium hydroxide is completely dissolved to prepare a 10% sodium hydroxide solution;

[0012] S3, slowly adding 10% sodium hydroxide solution to the screened solid mixed material, during the adding process, continuously stirring the mixed material, and controlling the pH value at 9-10 to obtain a mixed system;

[0013] S4, slowly adding polyacrylamide into water, stirring continuously at a low speed of 50 rpm for 1-2 hours to fully dissolve the polyacrylamide, and preparing a 0.1% polyacrylamide solution;

[0014] S5. While maintaining stirring, uniformly add the polyacrylamide solution to the mixed system, continue stirring for 5-10 minutes after the addition, then uniformly add the 30% hydrogen peroxide solution to the mixed system, and continue stirring for 15-20 minutes to allow the hydrogen peroxide to fully participate in the reaction to obtain a multi-component mixed system;

[0015] S6. Slowly add the defoamer into the multi-component mixed system, and continue stirring at a speed of 100-150 rpm for 30 minutes to evenly disperse the defoamer in the mixed solution to obtain a uniform suspension;

[0016] S7. Atomize the suspension into fine droplets, and quickly evaporate the water under the action of hot air flow to form a light yellow granular finished product.

[0017] Preferably, in step S4, when preparing the polyacrylamide solution, the solution is stirred to prevent agglomeration. When agglomerations occur, stirring is stopped in time, the agglomerated materials are removed, and the stirring speed and mode are readjusted until the solution is uniform and agglomerates are free.

[0018] Preferably, the defoaming agent is a polyether defoaming agent.

[0019] Preferably, the suspension is spray-dried to obtain a light yellow granular finished product with a moisture content of ≤5%. During the spray-drying process, the air inlet temperature is 150-200°C and the air outlet temperature is 80-120°C.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention combines multiple formula components of polyaluminium chloride, polyferric sulfate and aluminium sulfate, and can utilize the synergistic effect between different components to significantly enhance the removal capacity of suspended matter, colloidal substances and heavy metal ions in sewage. The formed flocs have high density and fast sedimentation rate, which helps to improve the sewage treatment efficiency.

[0022] 2. The present invention uses multiple ingredients and the strong oxidizing ability of hydrogen peroxide. The formula can achieve a higher water purification effect in a shorter time, and through a diversified combination of agents, the formula can effectively reduce the secondary pollution that may be generated during the treatment process. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a flow chart of the preparation method of the sewage treatment composite agent. DETAILED DESCRIPTION

[0024] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0025] As attached Figure 1 As shown:

[0026] Embodiment 1: The present invention provides a composite agent for sewage treatment, which comprises the following components by weight: 35 parts of polyaluminium chloride, 3 parts of polyacrylamide, 20 parts of polyferric sulfate, 7 parts of hydrogen peroxide, 12 parts of sodium hydroxide, 10 parts of aluminium sulfate and 0.8 parts of defoaming agent.

[0027] Embodiment 2: The present invention provides a composite agent for sewage treatment, which comprises the following components by weight: 30 parts of polyaluminium chloride, 5 parts of polyacrylamide, 15 parts of polyferric sulfate, 10 parts of hydrogen peroxide, 10 parts of sodium hydroxide, 8 parts of aluminium sulfate and 1 part of defoaming agent.

[0028] Embodiment 3: The present invention provides a composite agent for sewage treatment, which comprises the following components by weight: 40 parts of polyaluminium chloride, 2 parts of polyacrylamide, 25 parts of polyferric sulfate, 5 parts of hydrogen peroxide, 15 parts of sodium hydroxide, 12 parts of aluminium sulfate and 0.5 parts of defoaming agent.

[0029] Experimental Example: In three groups of 10-liter sewage samples, the sewage treatment composite agent formulations of Example 1, Example 2 and Example 3 were respectively tested, and the results are shown in the following table:

[0030]

[0031] As shown in the table above, Example 1 shows a good treatment effect, but the treatment time is long and the COD removal rate is relatively low; Example 2 performs best in suspended solids removal rate, COD removal rate and treatment time, indicating that it is the optimal formula; Example 3 has a medium suspended solids removal rate and COD removal rate, but the treatment time is the longest and the pH is high. In summary, Example 2 provides the best sewage treatment effect, which is the optimal formula ratio.

[0032] Embodiment 4: The present invention also provides a method for preparing a sewage treatment composite agent, comprising the following steps:

[0033] S1. Pour the solid raw materials of polyaluminium chloride, polyferric sulfate and aluminium sulfate into the grinder at the same time and perform grinding operation for 15-30 minutes to fully refine the raw material particles. The refined particles can contact and play a role more fully in the subsequent mixing and reaction process, significantly improving the performance of the composite agent; after grinding, screen the mixture through an 80-mesh screen, pour the mixture slowly and evenly on the screen, and gently push it with a soft tool to ensure that the material can pass through the screen smoothly. The screen can effectively remove large particles that are not fully ground, ensure the uniformity of the particle size of the mixture, make the subsequent reaction more stable and efficient, and remove large particles that are not fully ground by screening to obtain a solid mixture.

[0034] S2. Slowly add sodium hydroxide solid to water, and quickly stir gently with a stirring rod to promote the dissolution of sodium hydroxide. When the sodium hydroxide is completely dissolved, prepare a 10% sodium hydroxide solution; the dissolution process of sodium hydroxide will release heat violently, and the solution temperature will increase significantly, so be extra careful when operating to avoid burns. If conditions permit, the liquid preparation container can be placed in a cold water bath to assist in heat dissipation and ensure that the dissolution process is safe and smooth. Continue stirring until the sodium hydroxide is completely dissolved to obtain a uniform and transparent 10% sodium hydroxide solution.

[0035] S3. Slowly add 10% sodium hydroxide solution to the screened solid mixed material. During the addition process, continuously stir the mixed material at a speed of 80-120 rpm, and control the pH value at 9-10 to obtain a mixed system. This pH range is crucial for the subsequent synergistic reaction between multiple components, which can ensure that the reaction proceeds in the expected direction and improve the treatment effect of the composite agent.

[0036] S4. Slowly add polyacrylamide into water, and stir continuously at a low speed of 50 rpm for 1-2 hours to fully dissolve the polyacrylamide to prepare a 0.1% polyacrylamide solution. When preparing the polyacrylamide solution, make sure that the solution is free of lumps during the stirring process. If lumps appear, stop stirring in time, remove the lumps, and readjust the stirring speed and method until the solution is uniform and free of lumps.

[0037] S5. While maintaining stirring, uniformly add the prepared 0.1% polyacrylamide solution to the mixed system, continue stirring at a speed of 80-120rmp for 5-10 minutes, then uniformly add 30% hydrogen peroxide solution to the mixed system, and continue stirring for 15-20 minutes to allow hydrogen peroxide to fully participate in the reaction to obtain a multi-component mixed system; hydrogen peroxide will produce hydroxyl radicals under alkaline conditions, which can enhance the oxidation of pollutants in sewage, decompose difficult-to-degrade organic matter, etc., and further enhance the treatment capacity of the composite agent.

[0038] S6. Slowly add the polyether defoamer to the multi-component mixed system, and continue stirring at a speed of 100-150 rpm for 30 minutes to evenly disperse the defoamer in the mixed liquid, effectively eliminate the foam that may be generated in the mixed system, and thus obtain a uniform suspension.

[0039] S7. Atomize the suspension into fine droplets, and quickly evaporate the water under the action of hot air flow to form a light yellow granular finished product. The suspension is spray-dried to obtain a light yellow granular finished product with a moisture content of ≤5%. During the spray-drying process, the inlet air temperature is 150-200℃ and the outlet air temperature is 80-120℃. The inlet air temperature can promote the rapid evaporation of water. The atomization process needs to ensure that the droplet size is uniform, so that the water evaporation is more uniform and efficient.

[0040] The multi-core flocculant formed by polyaluminium chloride + polyferric sulfate + aluminium sulfate is used as a gradient charge neutralization system. Hydrogen peroxide produces hydroxyl radicals under alkaline conditions to strengthen oxidative decolorization. Polyacrylamide adopts a post-addition process to avoid molecular chain degradation. Sodium hydroxide has the dual functions of pH adjustment and coagulant. By compounding multiple agents such as polyaluminium chloride, polyferric sulfate and aluminium sulfate, a synergistic effect can be achieved to enhance the ability to remove pollutants in sewage. This composite agent can effectively precipitate and flocculate suspended matter and colloidal substances in sewage, thereby improving the efficiency of sewage treatment.

[0041] Importantly, it should be noted that the construction and arrangement of the present application shown in a plurality of different exemplary embodiments are only exemplary. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible (e.g., the size, scale, structure, shape and proportion of various elements and parameter values ​​(e.g., temperature, pressure, etc.), installation arrangement, use of materials, color, directional changes, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in the application. For example, the element shown as integrally formed can be composed of multiple parts or elements, the position of the element can be inverted or otherwise changed, and the nature or number or position of the discrete element can be changed or changed. Therefore, all such modifications are intended to be included in the scope of the present invention. The order or sequence of any process or method steps can be changed or reordered according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure described herein that performs the function, and is not only structurally equivalent but also equivalent structure. Without departing from the scope of the present invention, other replacements, modifications, changes and omissions can be made in the design, operating conditions and arrangement of the exemplary embodiments. Therefore, the invention is not limited to a specific embodiment, but extends to numerous modifications still falling within the scope of the appended claims.

[0042] Additionally, in order to provide a concise description of exemplary embodiments, all features of an actual embodiment (ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those that are not relevant to implementing the invention) may not be described.

[0043] It should be understood that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but for those of ordinary skill having the benefit of this disclosure, without undue experimentation, the development effort will be a routine task of design, fabrication, and production.

[0044] 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 preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A composite agent for sewage treatment, characterized in that: Calculated by weight, the composition includes: 30-40 parts of polyaluminium chloride, 2-5 parts of polyacrylamide, 15-25 parts of polyferric sulfate, 5-10 parts of hydrogen peroxide, 10-15 parts of sodium hydroxide, 8-12 parts of aluminium sulfate and 0.5-1 part of defoaming agent.

2. A sewage treatment composite agent as claimed in claim 1, characterized in that: Calculated by weight, the composition includes: 30 parts of polyaluminium chloride, 5 parts of polyacrylamide, 15 parts of polyferric sulfate, 10 parts of hydrogen peroxide, 10 parts of sodium hydroxide, 8 parts of aluminium sulfate and 1 part of defoaming agent.

3. A method for preparing a composite sewage treatment agent, applied to a composite sewage treatment agent as claimed in claim 1-2, characterized in that: The following steps are involved: S1, pouring polyaluminium chloride, polyferric sulfate and aluminium sulfate solid raw materials into a grinder at the same time, performing a grinding operation, and after the grinding is completed, screening the mixture through an 80-mesh sieve to remove larger particles that are not fully ground, to obtain a solid mixture; S2. Slowly add sodium hydroxide solid into water while gently stirring with a stirring rod until the sodium hydroxide is completely dissolved to prepare a 10% sodium hydroxide solution; S3, slowly adding 10% sodium hydroxide solution to the screened solid mixed material, during the adding process, continuously stirring the mixed material, and controlling the pH value at 9-10 to obtain a mixed system; S4, slowly adding polyacrylamide into water, stirring continuously at a low speed of 50 rpm for 1-2 hours to fully dissolve the polyacrylamide, and preparing a 0.1% polyacrylamide solution; S5. While maintaining stirring, uniformly add the polyacrylamide solution to the mixed system, continue stirring for 5-10 minutes after the addition, then uniformly add the 30% hydrogen peroxide solution to the mixed system, and continue stirring for 15-20 minutes to allow the hydrogen peroxide to fully participate in the reaction to obtain a multi-component mixed system; S6. Slowly add the defoamer into the multi-component mixed system, and continue stirring at a speed of 100-150 rpm for 30 minutes to evenly disperse the defoamer in the mixed solution to obtain a uniform suspension; S7. Atomize the suspension into fine droplets, and quickly evaporate the water under the action of hot air flow to form a light yellow granular finished product.

4. A method for preparing a composite sewage treatment agent as claimed in claim 3, characterized in that: In step S4, when preparing the polyacrylamide solution, the solution is stirred to prevent agglomeration. When agglomerates appear, stirring is stopped in time, the agglomerated materials are removed, and the stirring speed and mode are readjusted until the solution is uniform and agglomerates are not formed.

5. The method for preparing a composite agent for sewage treatment as claimed in claim 3, characterized in that: The defoaming agent is a polyether defoaming agent.

6. The method for preparing a composite agent for sewage treatment according to claim 3, characterized in that: The suspension is passed through a spray drying device to obtain a light yellow granular finished product with a moisture content of ≤5%. During the spray drying process, the air inlet temperature is 150-200°C and the air outlet temperature is 80-120°C.

Images