Conditioning agent, system and method for landfill mineralization industrial sludge treatment

Abstract

The invention relates to the technical field of sludge treatment, and provides a conditioning agent, system and method for landfill mineralization industry sludge treatment, and the conditioning agent comprises an agent A and an agent B; the agent A comprises sodium hypochlorite, ferrous sulfate and nano titanium dioxide in a ratio of 1: 0.5: 1; the mass of the agent A is 2-5% of the mass of the sludge; the agent B is a polyaluminum chloride-chitosan composite flocculant; and the mass of the agent B is 1-2% of the mass of the sludge. The system comprises a cutter suction device, a conveying pipeline, a cyclone reactor and a plate-and-frame filter pressing device which are communicated in sequence. By means of the integrated and automatic sludge treatment process, reduction, harmlessness, environment-friendly and efficient treatment of the sludge is achieved, and remarkable technical advantages and economic benefits are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of sludge treatment, and in particular relates to a conditioning agent, system and method for treating landfill mineralization industrial sludge. Background Art

[0002] With the acceleration of industrialization, the amount of residual sludge generated by industrial wastewater treatment facilities has increased dramatically. Traditionally, these sludges are mainly disposed of by landfill. However, landfill treatment has significant disadvantages, especially at a time when environmental quality requirements are increasing. First, the landfilled sludge will emit an unpleasant odor during the natural decomposition process, which seriously affects the quality of life of surrounding residents. Secondly, the sludge contains a large amount of heavy metals and other harmful substances, which may penetrate into the soil and groundwater with rainwater, causing long-term negative impacts on the environment.

[0003] In view of these problems, some regions have begun to try to excavate sludge from landfills for the second time and treat it harmlessly by incineration. However, some areas of the landfill cannot be directly excavated by machinery, and the sludge needs to be dehydrated before incineration to save cost and time. Therefore, the dehydration method of suction-plate and frame filter pressing is adopted. However, in actual implementation, it is found that the sludge cake produced by plate and frame filter pressing often has a high moisture content (usually around 60-80%), which will cause difficulties in transportation, treatment and landfill. If the moisture content of the sludge cake is high, further drying treatment may be required, adding additional treatment steps and costs. The filtrate produced by the plate and frame filter pressing process needs to be recycled and treated, and often contains a large amount of organic matter, heavy metals, suspended solids and other pollutants, which increases the pressure of subsequent wastewater treatment. Improper filtrate treatment may lead to secondary pollution and increase the environmental risk of landfills.

[0004] Therefore, developing a technology that can efficiently remove pollutants from sludge, enhance the sludge dewatering effect, and facilitate the transportation and incineration of sludge has become a technical problem that urgently needs to be solved. Summary of the invention

[0005] In view of the above problems in the prior art, the present application proposes a conditioning agent, system and method for treating landfill mineralized industrial sludge.

[0006] In a first aspect, the present invention provides a conditioning agent for treating landfill mineralized industrial sludge, comprising: agent A and agent B;

[0007] The reagent A comprises sodium hypochlorite, ferrous sulfate and nano titanium dioxide in a ratio of 1:0.5:0.5-1; the mass of the reagent A is 2%-5% of the mass of the sludge;

[0008] The agent B is a polyaluminium chloride-chitosan composite flocculant; the mass of the agent B is 1%-2% of the mass of the sludge.

[0009] In a second aspect, the present invention provides a method for preparing a conditioning agent for treating landfill mineralized industrial sludge, wherein the conditioning agent comprises a polyaluminium chloride-chitosan composite flocculant; the method for preparing the polyaluminium chloride-chitosan composite flocculant comprises the following steps:

[0010] A chitosan solution with a mass concentration of 0.5%-2% is mixed with a polyaluminium chloride solution with a mass concentration of 20%-30%, and the pH value is controlled to be 4-7 at a temperature of 25°C-40°C to obtain a stable mixed solution; the mixed solution is spray-dried to obtain a solid powdery polyaluminium chloride-chitosan composite flocculant.

[0011] In the third aspect, the present invention proposes a system for treating mineralized industrial sludge in landfills, comprising a screw suction device, a conveying pipeline, a cyclone reactor and a plate and frame filter press device connected in sequence; the system is provided with a first dosing zone at one end close to the screw suction device for sucking sludge; the first dosing zone is used to add agent A to the sludge located in the first dosing zone, and the agent A includes sodium hypochlorite, ferrous sulfate and nano titanium dioxide in a ratio of 1:0.5:0.5-1; the screw suction device sucks and mixes the sludge and the agent A in the first dosing zone into the conveying pipeline; the conveying pipeline is used to convey the sludge sucked by the screw suction device to the cyclone reactor; a second dosing zone is provided at one end of the conveying pipeline close to the cyclone reactor; the second dosing zone is used to add agent B into the conveying pipeline; the agent B is a polyaluminum chloride-chitosan composite flocculant.

[0012] Furthermore, one end of the suction device for sucking sludge is provided with a stone-proof grille.

[0013] Furthermore, the mass of the agent A is 2%-5% of the mass of the sludge in the first dosing area.

[0014] Furthermore, the mass of the reagent B is 1%-2% of the mass of the sludge entering the cyclone reactor.

[0015] In a fourth aspect, the present invention provides a method for treating landfill mineralized industrial sludge, comprising the following steps:

[0016] The sludge to which the agent A is added is sucked into a conveying pipeline by a wringing suction device, so that the sludge and the agent A are fully mixed and reacted; the agent A comprises sodium hypochlorite, ferrous sulfate and nano titanium dioxide in a ratio of 1:0.5:0.5-1; the mass of the agent A is 2%-5% of the mass of the sludge;

[0017] The sludge fully mixed with the agent A is transported to the cyclone reactor by the transport pipeline, and the agent B prepared in advance is added into the cyclone reactor; the agent B is a polyaluminium chloride-chitosan composite flocculant; the mass of the agent B is 1%-2% of the mass of the sludge entering the cyclone reactor;

[0018] The sludge after being fully mixed and reacted with the agent B in the cyclone reactor is input into a plate-frame filter press device, and the plate-frame filter press device is used to dehydrate the sludge.

[0019] Furthermore, the mixing reaction time of the sludge and the reagent A is greater than or equal to 20 seconds.

[0020] Furthermore, the rotation speed of the cyclone reactor is 60-80 r / min, and the reaction time of the sludge and the agent B in the cyclone reactor is 30-60 seconds.

[0021] Furthermore, the preparation steps of the agent B include: mixing a chitosan solution with a mass concentration of 0.5%-2% with a polyaluminum chloride solution with a mass concentration of 20%-30%, controlling the pH value to 4-7 at a temperature of 25°C-40°C to obtain a stable mixed solution; spray drying the mixed solution to obtain a solid powdered polyaluminum chloride-chitosan composite flocculant.

[0022] The beneficial effects of the present invention include:

[0023] Efficient removal of pollutants: Through the action of two-stage conditioning agents, Agent A uses the strong oxidizing property of sodium hypochlorite and the catalytic effect of nano-titanium dioxide to effectively remove highly toxic organic pollutants and heavy metal pollutants in sludge. Agent B uses the flocculation effect of polyaluminium chloride and chitosan to enhance the particle aggregation of sludge and ensure the smooth progress of subsequent dehydration operations.

[0024] Enhanced sludge dewatering effect: This system combines chemical conditioning with mechanical filter pressing. Through the efficient flocculation effect of the cyclone reactor, the sludge particles are further agglomerated into larger flocs, effectively improving the dewatering efficiency of the plate and frame filter press, achieving high-dryness dehydration, and significantly reducing the sludge volume.

[0025] Reduce treatment costs: Through the integrated operation process, the equipment and processes required in the sludge treatment process are reduced, the operation steps are simplified, the work efficiency is improved, the energy consumption and the use of chemical agents are reduced, thereby effectively reducing the overall cost of sludge treatment.

[0026] Excellent environmental performance: The dehydrated liquid treated by this system has removed most of the toxic pollutants and can be discharged in compliance with the standards after being treated by a simple activated sludge method, which greatly reduces the difficulty and cost of wastewater treatment, meets environmental protection requirements, and reduces the impact on the environment.

[0027] Equipment protection and safety: Stone-proof grilles are set up to prevent larger stones or foreign objects from entering the suction device, protecting the normal operation of the equipment, avoiding equipment damage or blockage, and improving the safety and durability of the system.

[0028] Wide adaptability: The present invention is not only suitable for the treatment of industrial sludge containing high concentrations of toxic heavy metals or organic pollutants, but can also be used for conventional sludge treatment work, and has strong adaptability and broad application prospects.

[0029] In summary, the present invention achieves sludge reduction, harmlessness, environmental protection and high-efficiency treatment through an integrated and automated sludge treatment process, and has significant technical advantages and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The figure is a schematic diagram of the preparation process of the agent B of the conditioning agent of the present invention;

[0031] Figure 2 It is a schematic diagram of the structure of the system for treating landfill mineralized industrial sludge according to the present invention;

[0032] Figure 3 for Figure 2 Cross-section of the suction device of a system for treating landfill mineral industrial sludge.

[0033] In the figure, 1-suction device; 2-transport pipeline; 3-cyclone reactor; 4-plate and frame filter press; 5-stone-proof grid; 6-large circle of auger; 7-stone-moving and crushing shear plate; 8-knife arm; 9-round steel; 10-water outlet. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0035] The conditioning agent for treating landfill mineralization industrial sludge proposed by the present invention comprises: agent A and agent B;

[0036] Reagent A includes sodium hypochlorite, ferrous sulfate and nano titanium dioxide in a ratio of 1:0.5:1; the mass of reagent A is 2%-5% of the mass of sludge;

[0037] Agent B is a polyaluminium chloride-chitosan composite flocculant; the mass of agent B is 1%-2% of the mass of sludge.

[0038] Agent A uses nano-titanium dioxide to catalyze sodium hypochlorite to produce strong oxidizing substances such as active oxygen, which will oxidize the ferrous sulfate in the agent to ferric iron. The ferric iron will further oxidize substances such as carboxylic acids in the sludge to generate ferrous ions. This cycle of ferrous and ferric iron will further enhance the production of active oxygen substances by sodium hypochlorite, and quickly remove highly toxic organic matter such as aniline and polycyclic aromatic hydrocarbons in the sludge. At the same time, the addition of ferrous sulfate densifies the sludge particles, which is helpful for subsequent flocculation and dehydration operations. Agent B quickly flocculates the compacted sludge particles into larger flocs, which is beneficial for subsequent dehydration treatment.

[0039] like Figure 1 As shown, based on the same inventive concept, the present invention also proposes a method for preparing agent B, i.e., polyaluminium chloride-chitosan composite flocculant, comprising:

[0040] The chitosan is dissolved in 1%-2% acetic acid solution, and a chitosan solution with a concentration of 0.5%-2% is prepared at a stirring speed of 20-50r / min; polyaluminium chloride is dissolved in water, and a stirring speed of 50-80r / min is prepared to prepare a polyaluminium chloride solution with a concentration of 20%-30%; the chitosan solution and the polyaluminium chloride solution are mixed at a speed of 20-50r / min for 1-2 hours, and the pH value is controlled to be 4-7 at a temperature of 25°C-40°C to obtain a stable mixed solution; the mixed solution is spray-dried to obtain a solid powdery polyaluminium chloride-chitosan composite flocculant, which needs to be stored at low temperature and away from light.

[0041] like Figure 2 , Figure 3 As shown, based on the same inventive concept, the present invention also proposes a system for treating landfill mineralized industrial sludge, comprising a suction device 1, a conveying pipeline 2, a cyclone reactor 3 and a plate and frame filter press device 4 which are connected in sequence.

[0042] The system is equipped with a stone-proof grid 5 and a first dosing area at one end near the suction device 1 for sucking sludge; the first dosing area is an area set for sludge, which can be understood as a sludge stacking area or a sludge location, and agent A is added to the sludge in the first dosing area.

[0043] The conveying pipeline 2 is used to convey the sludge sucked by the twisting suction device 1 to the cyclone reactor 3; a second dosing area is provided at one end of the conveying pipeline 2 close to the cyclone reactor 3, and the second dosing area is used to add agent B into the conveying pipeline 2; agent B is a polyaluminum chloride-chitosan composite flocculant. The second dosing area can also be arranged on the cyclone reactor 3, so as to directly add agent B into the cyclone reactor 3. The cyclone reactor 3 is used to fully mix and react the sludge that is fully mixed with agent A with agent B, and then input the reacted sludge into the plate-frame filter press 4, and the plate-frame filter press 4 is used to dehydrate the sludge.

[0044] The winch suction device 1 comprises the following main components:

[0045] Large reamer circle 6: used for large-scale cutting in sludge to initially separate sludge from larger solid debris;

[0046] Stone-moving and crushing shear plate 7: used to crush and remove larger stones and gravel to ensure smooth operation of the suction operation;

[0047] Cutter arm 8 and round steel 9: used to support the reamer and provide rotation torque;

[0048] Water outlet 10: used to discharge the sludge that has undergone preliminary treatment into the conveying pipeline 2.

[0049] During operation, sludge is extracted from the screw suction device 1. The stone-proof grille 55 is arranged at the entrance of the screw suction device 1, and the aperture is 2-4 cm to prevent larger stones or debris from entering the device, thereby protecting the safe operation of the equipment.

[0050] The cutter suction device 1 may adopt existing technology, such as a stone-moving and stone-breaking equipment for a cutter suction dredger disclosed in publication number CN204112385U.

[0051] Based on the same inventive concept, the present invention also proposes a method for treating landfill mineralized industrial sludge, which is implemented using the above system and includes the following steps:

[0052] The sludge with the reagent A added is sucked into the conveying pipe 2 by the screw suction device 1, so that the sludge and the reagent A are fully mixed and reacted;

[0053] The sludge fully mixed with the reagent A is transported to the cyclone reactor 3 by using the transport pipeline 2, and the reagent B prepared in advance is added into the cyclone reactor 3;

[0054] The sludge after being fully mixed with the reagent B in the cyclone reactor 3 is input into the plate-frame filter press device 4, and the plate-frame filter press device 4 is used to dehydrate the sludge.

[0055] Specifically include:

[0056] The sludge is transported from the suction device 1 to the cyclone reactor 3 through the conveying pipeline 2. Ensure that the sludge and the reagent A are fully mixed and the reaction time is greater than 20s. The amount of reagent A added is 2%-5% of the sludge mass. The reagent A is mixed at a high speed during the suction process, and the highly toxic organic matter such as aniline and polycyclic aromatic hydrocarbons in the sludge is quickly removed through the catalytic effect of nano titanium dioxide and the strong oxidizing property of sodium hypochlorite. At the same time, the addition of ferrous sulfate makes the sludge particles dense, which is helpful for the subsequent flocculation and dehydration operations.

[0057] Afterwards, the sludge enters the cyclone reactor 3 through the conveying pipe 2. The speed of the reactor is set to 60-80r / min, and the contact reaction time is about 30-60s. At this stage, agent B is added in an amount of 1%-2% of the sludge mass to further promote the flocculation of sludge particles. Agent B is a polyaluminum chloride-chitosan composite flocculant (PAC-CTS), which is added at the connection between the conveying pipe 2 and the cyclone reactor 3. Through the efficient mixing action of the cyclone reactor 3, agent B quickly flocculates the compacted sludge particles into larger flocs, which is beneficial to the subsequent dehydration treatment.

[0058] The sludge treated by the cyclone reactor 3 enters the plate-frame filter press 4. The plate-frame filter press 4 can perform high-dryness dehydration treatment on the sludge to ensure that the volume of the sludge is significantly reduced. The conditioned sludge particles are dense, the floc structure is stable, and the dehydration efficiency is high. The pollutants in the dehydrated liquid finally discharged have been removed by the treatment of the reagent A and the reagent B, ensuring that it meets the discharge standards.

[0059] After the above system treatment, the water content of the sludge is significantly reduced, the final sludge volume is reduced, and the pollutants are effectively removed. The sludge dehydrated by the plate and frame filter press 4 can be used for further disposal, and the dehydrated liquid can meet the discharge standard after simple subsequent treatment. This method not only reduces the cost and complexity of sludge treatment, but also improves the treatment efficiency and has a good environmental protection effect.

[0060] Implementation case 1:

[0061] A large amount of mineralized sludge containing aniline is stored in an industrial landfill. The aniline concentration in the sludge is high and it is difficult to effectively remove it through conventional treatment technology. In order to meet environmental protection standards, the system of the present invention is used for treatment to effectively remove aniline from the sludge and achieve sludge reduction and harmlessness.

[0062] The mineralized sludge in the landfill is sucked into the system by a suction device 1, and the stone-proof grille 5 blocks larger stones and debris in the sludge to avoid damage to the equipment. During the suction process, agent A is added to the sludge to ensure that the contact reaction time between agent A and the sludge is greater than 20s. Agent A is composed of sodium hypochlorite, ferrous sulfate and nano-titanium dioxide in a ratio of 1:0.5:1, and the amount added is 3% of the sludge mass, wherein the ratio of nano-titanium dioxide can be any value between 0.5 and 1. Agent A is fully mixed with the sludge, sodium hypochlorite decomposes aniline through oxidation, nano-titanium dioxide catalyzes the reaction, and ferrous sulfate helps the sludge particles to be compacted. The conditioned sludge is transported to the cyclone reactor 3 through the conveying pipe 2. In the cyclone reactor 3, the speed is set to 70r / min, the sludge and agent A stay time is about 30s, and agent B is added to the sludge. Agent B is composed of a composite material of polyaluminum chloride and chitosan, and the amount added is 1% of the sludge mass. Through flocculation, the sludge particles aggregate into larger flocs, which are convenient for subsequent dehydration. The conditioned sludge is transported to the plate and frame filter press 4 for high-dryness dehydration, and the final moisture content is reduced to 40%, and the removal rate of pollutants such as aniline exceeds 95%. The dehydrated liquid can meet the discharge standards after simple treatment.

[0063] In this case, the system of the present invention was used to reduce the sludge volume by 60%, the removal rate of toxic organic matter such as aniline reached more than 95%, and the water content of the sludge was reduced to 40%. The whole process simplified the treatment process, greatly reduced the cost of sludge treatment, and achieved environmental protection emission standards.

[0064] Implementation case 2:

[0065] A large amount of industrial sludge containing heavy metals such as lead, cadmium, copper, etc. is stored in the landfill of a certain electroplating plant. These sludges pose a potential threat to the environment. Conventional treatment methods are difficult to effectively remove heavy metals in the sludge. It is necessary to use the system of the present invention for efficient reduction and harmless treatment.

[0066] The sludge is extracted from the landfill using a suction device 1, and large stones are prevented from entering the system through a stone-proof grille 5 to ensure the smooth progress of the treatment process. Agent A is added during the sludge suction process to ensure that the contact reaction time between agent A and the sludge is greater than 20s. Agent A is composed of sodium hypochlorite, ferrous sulfate and nano-titanium dioxide in a ratio of 1:0.5:1, and the amount added is 4% of the sludge mass. The oxidation of sodium hypochlorite and nano-titanium dioxide helps to dissolve and remove organic pollution in the sludge, while ferrous sulfate helps to capture heavy metal particles in the sludge through precipitation. The sludge after preliminary conditioning is transported to the cyclone reactor 3 through a conveying pipeline 2. In the cyclone reactor 3, the rotation speed is set to 80r / min, and the sludge and agent A stay for about 60s. Agent B is added, and agent B is composed of a composite material of polyaluminium chloride and chitosan, and the amount added is 1.5% of the sludge mass. The flocculation effect of the reagent B makes the heavy metals in the sludge closely combined with the particles to form larger flocs, which is conducive to the subsequent dehydration operation. After the sludge is treated by the cyclone reactor 3, it enters the plate and frame filter press 4 for dehydration. The moisture content of the dehydrated sludge is reduced to 35%, and the heavy metal removal rate reaches more than 90%. The heavy metal content in the dehydrated liquid is significantly reduced, and it meets the discharge standards after further treatment.

[0067] Through the system of the present invention, the volume of heavy metal-containing sludge is reduced by about 70%, the heavy metal removal rate reaches more than 90%, and the water content of the sludge is reduced to 35%. The system realizes efficient heavy metal removal and dehydration treatment, reduces the subsequent treatment cost of sludge, and meets the environmental protection discharge requirements.

[0068] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A conditioning agent for treating landfill mineralization industrial sludge, characterized in that: include: Medicine A and Medicine B; The reagent A comprises sodium hypochlorite, ferrous sulfate and nano titanium dioxide in a ratio of 1:0.5:0.5-1; the mass of the reagent A is 2%-5% of the mass of the sludge; The agent B is a polyaluminium chloride-chitosan composite flocculant; the mass of the agent B is 1%-2% of the mass of the sludge.

2. The conditioning agent according to claim 1, characterized in that The preparation method of the polyaluminium chloride-chitosan composite flocculant comprises the following steps: A chitosan solution with a mass concentration of 0.5%-2% is mixed with a polyaluminium chloride solution with a mass concentration of 20%-30%, and the pH value is controlled to be 4-7 at a temperature of 25°C-40°C to obtain a stable mixed solution; the mixed solution is spray-dried to obtain a solid powdery polyaluminium chloride-chitosan composite flocculant.

3. A system for treating landfill mineralized industrial sludge, characterized in that: The invention comprises a screw suction device, a conveying pipeline, a cyclone reactor and a plate-frame filter press device which are connected in sequence; the system is provided with a first dosing zone at one end close to the screw suction device for sucking sludge; the first dosing zone is used to add agent A to the sludge located in the first dosing zone, and the agent A comprises sodium hypochlorite, ferrous sulfate and nano titanium dioxide in a ratio of 1:0.5:0.5-1; the screw suction device sucks and mixes the sludge and the agent A in the first dosing zone into the conveying pipeline; the conveying pipeline is used to convey the sludge sucked by the screw suction device to the cyclone reactor; a second dosing zone is provided at one end of the conveying pipeline close to the cyclone reactor; the second dosing zone is used to add agent B into the conveying pipeline; the agent B is a polyaluminium chloride-chitosan composite flocculant.

4. The system for treating landfill mineralization industrial sludge according to claim 3, characterized in that: The end of the suction device for sucking sludge is provided with a stone-proof grille.

5. The system for treating landfill mineralization industrial sludge according to claim 3, characterized in that: The mass of the agent A is 2%-5% of the mass of the sludge in the first dosing zone.

6. The system for treating landfill mineralization industrial sludge according to claim 3, characterized in that: The mass of the reagent B is 1%-2% of the mass of the sludge entering the cyclone reactor.

7. A method for treating landfill mineralized industrial sludge, characterized in that: The following steps are involved: The sludge to which the agent A is added is sucked into a conveying pipeline by a wringing suction device, so that the sludge and the agent A are fully mixed and reacted; the agent A comprises sodium hypochlorite, ferrous sulfate and nano titanium dioxide in a ratio of 1:0.5:0.5-1; the mass of the agent A is 2%-5% of the mass of the sludge; The sludge fully mixed with the agent A is transported to the cyclone reactor by the transport pipeline, and the agent B prepared in advance is added into the cyclone reactor; the agent B is a polyaluminium chloride-chitosan composite flocculant; the mass of the agent B is 1%-2% of the mass of the sludge entering the cyclone reactor; The sludge after being fully mixed and reacted with the agent B in the cyclone reactor is input into a plate-frame filter press device, and the plate-frame filter press device is used to dehydrate the sludge.

8. The method for treating landfill mineralization industrial sludge according to claim 7, characterized in that: The mixing reaction time of the sludge and the reagent A is greater than or equal to 20 seconds.

9. The method for treating landfill mineralization industrial sludge according to claim 7, characterized in that: The rotation speed of the cyclone reactor is 60-80 r / min, and the reaction time of the sludge and the reagent B in the cyclone reactor is 30-60 seconds.

10. The method for treating landfill mineralization industrial sludge according to claim 7, characterized in that: The preparation steps of the agent B include: mixing a chitosan solution with a mass concentration of 0.5%-2% with a polyaluminium chloride solution with a mass concentration of 20%-30%, controlling the pH value to be 4-7 at a temperature of 25°C-40°C to obtain a stable mixed solution; spray drying the mixed solution to obtain a solid powdery polyaluminium chloride-chitosan composite flocculant.

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