Oil refining concentrated sludge stabilization method

Abstract

The invention relates to an oil refining concentrated sludge stabilization method which comprises the following steps: mixing oil refining concentrated sludge with a treating agent under an acidic condition, and carrying out heating treatment to obtain a treated material, wherein the water content of the oil refining concentrated sludge is 98-98.5 wt%, the content of total suspended solids is 15-20 g / L, and the content of volatile suspended solids is 10-15 g / L; the treating agent is obtained by pretreating the ammoximation wastewater. The treatment agent obtained after the ammoximation wastewater is pretreated is used for treating the oil refining concentrated sludge, the organic matter content of the sludge and the water content of a mud cake can be remarkably reduced, great stabilization treatment of the oil refining concentrated sludge is achieved, and meanwhile resource utilization of the ammoximation wastewater is achieved.

Description

Technical Field

[0001] The present invention relates to a method for stabilizing concentrated sludge from an oil refinery. Background Art

[0002] my country's sewage treatment plants generally use activated sludge technology. In the process of treating sewage, a large amount of biochemical excess sludge is produced. Biochemical excess sludge contains a large number of toxic and harmful substances such as microorganisms, viruses, and parasites. Before being discharged into the environment, it needs to be reduced to reduce environmental pollution. At present, the general method of treating biochemical excess sludge is: concentration - conditioning - dehydration - transportation. The water content of the transported sludge is relatively high (generally between 80% and 85%), the sludge is large in volume, and the content of viruses and bacteria is high, which increases the cost of subsequent disposal of the sludge (such as landfill and incineration).

[0003] Sludge thermal hydrolysis technology can dissolve microbial flocs, break cell structures, and hydrolyze organic macromolecules such as proteins, polysaccharides, and lipids, thereby reducing the solid content in the sludge. At the same time, thermal hydrolysis can also lead to reduced viscosity of sludge particles and changes in the water distribution characteristics in the sludge, thereby improving the dehydration capacity of the sludge. CN102718384A discloses a sludge alkali-catalyzed thermal hydrolysis treatment method, which uses a method of adding alkaline substances to the sludge to improve the sludge hydrolysis efficiency, which helps to quickly break sludge cells and quickly hydrolyze organic matter. However, this method has very high requirements on the material of the reactor, and can cause scaling, limiting the long-term operation of the reactor. Therefore, it is necessary to develop an economically feasible biochemical sludge reduction technology to significantly reduce the volume of excess sludge and reduce harm to the environment. Summary of the invention

[0004] The purpose of the present invention is to provide a method for stabilizing concentrated refinery sludge, so as to achieve substantial stabilization of concentrated refinery sludge.

[0005] In order to achieve the above object, the present disclosure provides a method for stabilizing oil refinery concentrated sludge, the method comprising:

[0006] Under acidic conditions, the oil refinery concentrated sludge is mixed with a treatment agent and subjected to heating treatment to obtain a treated material;

[0007] The water content of the oil refinery concentrated sludge is 98-98.5% by weight, the total solid suspended matter content is 15-20 g / L, and the volatile suspended matter content is 10-15 g / L; the treatment agent is obtained by pre-treating the ammoximation wastewater.

[0008] Optionally, the preparation step of the treatment agent includes:

[0009] Concentrating the ammoximation wastewater to obtain concentrated materials;

[0010] A coagulant is added to the concentrated material for sedimentation, and the sediment is removed to obtain the treatment agent.

[0011] Optionally, the pH value of the ammoximation wastewater is 12-13.

[0012] Optionally, the concentration conditions include: -0.07 MPa to -0.08 MPa, a temperature of 60 to 95° C., and a concentration multiple of 20 to 70 times, preferably 30 to 60 times.

[0013] Optionally, the sedimentation conditions include: pH value of 6 to 8, time of 15 to 120 min;

[0014] Preferably, the sedimentation conditions include: pH value of 6.5-7, and time of 30-60 minutes.

[0015] Optionally, based on the volume of the concentrated material, the amount of the coagulant is 20 to 80 mg / L, preferably 40 to 60 mg / L;

[0016] The coagulant is an aluminum salt, preferably aluminum sulfate and / or aluminum chloride.

[0017] Optionally, the acidic conditions include: a pH value of 3 to 7, preferably 4.5 to 6.5.

[0018] Optionally, based on the volume of the refined concentrated sludge, the dosage of the treatment agent is 10 to 30 mL / L, preferably 15 to 25 mL / L.

[0019] Optionally, the conditions of the heating treatment include: a temperature of 80 to 160° C. and a time of 30 to 360 min;

[0020] Preferably, the conditions of the heating treatment include: a temperature of 90 to 140° C. and a time of 60 to 120 min.

[0021] Optionally, the method further comprises:

[0022] The treated material is subjected to solid-liquid separation to obtain a liquid phase material and a solid phase material;

[0023] The liquid phase material is sent to a front-end sewage treatment device.

[0024] Through the above technical scheme, the present invention uses the treatment agent obtained by pre-treating the ammonia oxime wastewater to treat the refined concentrated sludge, which can significantly reduce the organic matter content and the water content of the mud cake in the sludge, achieve a significant stabilization treatment of the refined concentrated sludge, and at the same time realize the resource utilization of the ammonia oxime wastewater.

[0025] Other features and advantages of the present disclosure will be described in detail in the following detailed description. DETAILED DESCRIPTION

[0026] The specific embodiments of the present disclosure are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure, and are not used to limit the present disclosure.

[0027] The present disclosure provides a method for stabilizing oil refinery concentrated sludge, the method comprising:

[0028] Under acidic conditions, the oil refinery concentrated sludge is mixed with a treatment agent and subjected to heating treatment to obtain a treated material;

[0029] The water content of the oil refinery concentrated sludge is 98-98.5% by weight, the total solid suspended matter content is 15-20 g / L, and the volatile suspended matter content is 10-15 g / L; the treatment agent is obtained by pre-treating the ammoximation wastewater.

[0030] According to the present disclosure, the oil refinery concentrated sludge refers to solid, semi-solid and liquid wastes generated during sewage treatment, mainly the activated sludge discharged from the concentration tank in the activated sludge system, and the pH value can be 7.1-7.7. The disclosed method is particularly suitable for oil refinery concentrated sludge with a high suspended matter content. Specifically, the water content of the oil refinery concentrated sludge is 98-98.5% by weight, the total solid suspended matter (SS) content is 15-20g / L, the volatile suspended matter (VSS) content is 10-15g / L, and the VSS / SS is 67-75% by weight. The use of the treatment agent can effectively remove organic matter in the oil refinery concentrated sludge, reduce the water content of the mud cake, and the treated material has a higher BOD5 / COD.

[0031] According to the present disclosure, the material obtained by appropriately pre-treating the ammoximation wastewater can be used as a treatment agent for oil refinery concentrated sludge. In one embodiment, the preparation steps of the treatment agent include:

[0032] Concentrating the ammoximation wastewater to obtain concentrated materials;

[0033] A coagulant is added to the concentrated material for sedimentation, and the sediment is removed to obtain the treatment agent.

[0034] The ammoximation wastewater refers to wastewater generated by the process of preparing cyclohexanone oxime from cyclohexanone in the caprolactam production process. The present disclosure has no special requirements on the components and properties of the ammoximation wastewater, and is widely applicable to various caprolactam production wastewaters. For example, the COD of the ammoximation wastewater may be 2000-12000 mg / L, the BOD5 / COD may be 0-0.01, and the peroxide content may be 6120 mg / L-9171 mg / L.

[0035] In a preferred embodiment, the pH value of the ammoximation wastewater is 12 to 13, and the treatment agent obtained by using alkaline ammoximation wastewater as a raw material is particularly suitable for treating oil refinery concentrated sludge. At this time, the method may also include adjusting the pH value of the ammoximation wastewater to 12 to 13 using a pH adjuster before concentrating. The pH adjuster may be, for example, sodium hydroxide, potassium hydroxide, etc.

[0036] Among them, the concentration can adopt the means commonly used in the art for increasing the concentration of substances in wastewater, such as evaporation concentration. The concentration conditions enable the concentrated material to reach an appropriate degree of concentration, avoiding adverse effects on subsequent utilization due to excessive salt content in the wastewater. Specifically, the concentration conditions may include: a pressure of -0.07MPa to -0.08MPa, a temperature of 60 to 95°C, and a concentration multiple of 20 to 70 times, preferably 30 to 60 times. The concentrated material generally contains flocs, and there is no need to separate the concentrated material into solids and liquids, and the sedimentation is directly performed.

[0037] The sedimentation conditions may include: pH value of 6 to 8, and time of 15 to 120 min. Preferably, the sedimentation conditions include: pH value of 6.5 to 7, and time of 30 to 60 min.

[0038] Wherein, based on the volume of the concentrated material, the dosage of the coagulant can be 20-80 mg / L, preferably 40-60 mg / L. In one embodiment, the coagulant is an aluminum salt, and the use of aluminum salt as a coagulant does not introduce additional impurity ions and is conducive to improving the sedimentation effect; preferably, the aluminum salt is aluminum sulfate and / or aluminum chloride.

[0039] The sediment is generally flocculent, and the clear liquid obtained after removing the sediment is the treating agent. Specifically, the method for removing the sediment can be, for example, filtration, centrifugation, etc.

[0040] In this embodiment, the treatment agent for treating the concentrated sludge of oil refinery can be obtained by concentrating and settling the ammoximation wastewater and removing the sediment, thereby realizing the resource utilization of the ammoximation wastewater. The properties of the treatment agent include: COD of 53140mg / L to 132850mg / L, and BOD5 / COD of 0 to 0.01.

[0041] According to the present disclosure, the acidic conditions may include a pH value of 3 to 7, preferably 4.5 to 6.5.

[0042] According to the present disclosure, the treatment agent can achieve excellent treatment effects when used in a relatively small amount. Specifically, based on the volume of the refined concentrated sludge, the amount of the treatment agent can be 10 to 30 mL / L, preferably 15 to 25 mL / L.

[0043] Compared with the traditional sludge thermal hydrolysis technology, the heating treatment disclosed in the present invention can be carried out under milder conditions. Specifically, the heating treatment conditions may include: a temperature of 80 to 160°C and a time of 30 to 360 minutes; preferably, the heating treatment conditions include: a temperature of 90 to 140°C and a time of 60 to 120 minutes.

[0044] According to the present disclosure, the organic matter content and water content of the treated material are greatly reduced, and the material has good biodegradability. The liquid phase material after solid-liquid separation can be returned to the front-end sewage treatment device, thereby effectively reducing the sludge discharge. In one embodiment, the method also includes solid-liquid separation of the treated material to obtain liquid phase material and solid phase material; sending the liquid phase material to the front-end sewage treatment device, preferably adjusting the pH value of the liquid phase material to 6.8-7.2 and then sending it to the front-end sewage treatment device. Among them, the front-end sewage treatment device refers to a device for treating domestic sewage and / or industrial sewage, and the oil refinery concentrated sludge is the back-end product of the front-end sewage treatment device. Specifically, the COD of the liquid phase material can be 11000mg / L-12000mg / L, and the BOD5 / COD can be 0.5-0.7. The water content of the solid phase material can be 56-60% by weight, and subsequent treatment such as landfill can be performed as needed.

[0045] The present invention discloses treating the oil refinery concentrated sludge with a treatment agent obtained by pre-treating the ammoximation wastewater, which can significantly reduce the organic matter content and the water content of the mud cake in the sludge, achieve a substantial stabilization treatment of the oil refinery concentrated sludge, and at the same time realize the resource utilization of the ammoximation wastewater.

[0046] The present disclosure is further illustrated by the following examples, but is not intended to limit the present disclosure.

[0047] In the following examples, the source of the ammoximation wastewater is wastewater taken from an industrial site, with a COD of 2625 mg / L, a BOD5 / COD of 0.01, and a peroxide content of 6171 mg / L. The source of the refinery concentrated sludge is the refinery concentrated sludge produced by industrial wastewater of a refinery enterprise, with a pH value of 7.1, a water content of 98.39% by weight, a total suspended solids (SS) content of 16.1 g / L, a volatile suspended solids (VSS) content of 11.6 g / L, and a VSS / SS of 72% by weight.

[0048] COD analysis method: HJ 828-2017 Determination of chemical oxygen demand in water quality - dichromate method.

[0049] BOD5 analysis method: HJ 505-2009 Water quality - Determination of five-day biochemical oxygen demand (BOD5) - Dilution and inoculation method.

[0050] Organic matter content analysis method: CJT221-2005 Urban sewage treatment plant sludge inspection method.

[0051] Analysis method of moisture content of mud cake: CJT221-2005 Inspection method of sludge from urban sewage treatment plants.

[0052] Organic matter removal rate = (1-sludge VSS after treatment / sludge VSS before treatment) × 100%

[0053] Sludge reduction rate = (1-sludge mass after treatment / sludge mass before treatment) × 100%

[0054] Example 1

[0055] Take 600mL of ammoximation wastewater, keep the pH value of the wastewater at 12, evaporate and concentrate at 95°C and a pressure of -0.08MPa. After concentrating 30 times, a concentrated material is obtained. An aluminum sulfate solution (concentration of 1000mg / L) is added to the concentrated material. Based on the volume of the concentrated material, an aluminum sulfate amount of 50mg / L is used. The solution is allowed to settle for 45min at a pH of 6.9. The sediment is removed by filtration, and the clear liquid is taken to obtain the treatment agent of the present embodiment (COD is 67200mg / L, BOD5 / COD is 0).

[0056] The pH value of the refined concentrated sludge was adjusted to 5.5, and the above-mentioned treatment agent was added for heating treatment. Based on the volume of the refined concentrated sludge, the amount of the treatment agent was 15 mL / L, the temperature of the heating treatment was 140°C, and the time was 60 min. After the treatment was completed, the treated material was taken to test the organic matter removal rate, and the water content and sludge reduction rate of the solid phase material, i.e. the mud cake, were calculated after solid-liquid separation. The BOD5 / COD of the liquid phase material, i.e. the supernatant, was tested. After the pH value of the supernatant was adjusted to 7, it could be sent back to the front-end sewage treatment device. The results are listed in Table 1.

[0057] Example 2

[0058] Take 600mL of ammoximation wastewater, keep the pH value of the wastewater at 12, evaporate and concentrate at 95°C and a pressure of -0.08MPa. After concentrating 40 times, a concentrated material is obtained. An aluminum sulfate solution (concentration of 1000mg / L) is added to the concentrated material. Based on the volume of the concentrated material, an aluminum sulfate amount of 40mg / L is used. The solution is allowed to settle for 50min at a pH of 7.5. The sediment is removed by filtration, and the clear liquid is taken to obtain the treatment agent of the present embodiment (COD is 90400mg / L, BOD5 / COD is 0).

[0059] The pH value of the refined concentrated sludge was adjusted to 6.5, and the above-mentioned treatment agent was added for heating treatment. Based on the volume of the refined concentrated sludge, the amount of treatment agent was 18mL / L, the temperature of the heating treatment was 130℃, and the time was 60min. After the treatment was completed, the treated material was taken to test the organic matter removal rate, and the moisture content of the mud cake and the sludge reduction rate were calculated after solid-liquid separation. The BOD5 / COD of the supernatant was tested, and the supernatant could be sent back to the front-end sewage treatment device after the pH value was adjusted to 6.8. The results are listed in Table 1.

[0060] Example 3

[0061] Take 600mL of ammoximation wastewater, keep the pH value of the wastewater at 12, evaporate and concentrate at 85°C and a pressure of -0.09MPa. After concentrating 50 times, a concentrated material is obtained. An aluminum sulfate solution (concentration of 1000mg / L) is added to the concentrated material. Based on the volume of the concentrated material, an aluminum sulfate amount of 60mg / L is used. The solution is allowed to settle for 60min at a pH of 6.5. The sediment is removed by filtration, and the clear liquid is taken to obtain the treatment agent of the present embodiment (COD is 115000mg / L, BOD5 / COD is 0).

[0062] The pH value of the refined concentrated sludge was adjusted to 4.5, and the above-mentioned treatment agent was added for heating treatment. Based on the volume of the refined concentrated sludge, the amount of the treatment agent was 25 mL / L, the temperature of the heating treatment was 90°C, and the time was 100 min. After the treatment was completed, the treated material was taken to test the organic matter removal rate, and the moisture content of the mud cake and the sludge reduction rate were calculated after solid-liquid separation. The BOD5 / COD of the supernatant was tested, and the supernatant could be sent back to the front-end sewage treatment device after the pH value was adjusted to 7. The results are listed in Table 1.

[0063] Example 4

[0064] The refined concentrated sludge was treated according to the method of Example 1, except that the amount of the treatment agent used was 10 mL / L based on the volume of the refined concentrated sludge.

[0065] After the treatment is completed, the treated material is taken to test the organic matter removal rate, the moisture content of the mud cake and the sludge reduction rate are calculated after solid-liquid separation, and the BOD5 / COD of the supernatant is tested. After the pH value of the supernatant is adjusted to 7.2, it can be sent back to the front-end sewage treatment device. The results are listed in Table 1.

[0066] Example 5

[0067] The refined concentrated sludge was treated according to the method of Example 1, except that the amount of the treatment agent used was 30 mL / L based on the volume of the refined concentrated sludge.

[0068] After the treatment is completed, the treated material is taken to test the organic matter removal rate, the moisture content of the mud cake and the sludge reduction rate are calculated after solid-liquid separation, and the BOD5 / COD of the supernatant is tested. The supernatant can be sent back to the front-end sewage treatment device after the pH value is adjusted to 7. The results are listed in Table 1.

[0069] Example 6

[0070] The refined concentrated sludge was treated according to the method of Example 1, except that the pH value of the refined concentrated sludge was adjusted to 7, the temperature of the heating treatment was 150° C., and the time was 300 min.

[0071] After the treatment is completed, the treated material is taken to test the organic matter removal rate, the moisture content of the mud cake and the sludge reduction rate are calculated after solid-liquid separation, and the BOD5 / COD of the supernatant is tested. The supernatant can be sent back to the front-end sewage treatment device after the pH value is adjusted to 7. The results are listed in Table 1.

[0072] Comparative Example 1

[0073] Take 600mL of ammoximation wastewater, keep the pH value of the wastewater at 12, evaporate and concentrate at 95°C and a pressure of -0.08MPa. After concentrating 30 times, a concentrated material is obtained. The concentrated material is filtered to remove the floccules and then an aluminum sulfate solution (concentration of 1000mg / L) is added. Based on the volume of the filtered clear liquid, the amount of aluminum sulfate is 50mg / L. The solution is allowed to settle for 45min at a pH of 6.9, and the sediment is removed by filtration. The clear liquid is taken to obtain the treatment agent of this comparative example (COD is 71100mg / L, BOD5 / COD is 0).

[0074] The pH value of the oil refinery concentrated sludge was adjusted to 5.5, and the above-mentioned treatment agent was added for heating treatment. Based on the volume of the oil refinery concentrated sludge, the amount of the treatment agent was 15 mL / L, the temperature of the heating treatment was 140°C, and the time was 60 min. After the treatment was completed, the treated material was taken to test the organic matter removal rate, and the moisture content of the mud cake and the sludge reduction rate were calculated after solid-liquid separation. The BOD5 / COD of the supernatant was tested, and the results are listed in Table 1.

[0075] Comparative Example 2

[0076] Take 600 mL of ammonia oxime wastewater, keep the pH value of the wastewater at 12, and evaporate and concentrate it at 95°C and a pressure of -0.08 MPa. After concentrating it 30 times, a concentrated material is obtained. After filtering the concentrated material to remove flocs, the clear liquid is taken to obtain the treatment agent of this comparative example (COD is 75800 mg / L, BOD5 / COD is 0).

[0077] The pH value of the oil refinery concentrated sludge was adjusted to 5.5, and the above-mentioned treatment agent was added for heating treatment. Based on the volume of the oil refinery concentrated sludge, the amount of the treatment agent was 15 mL / L, the temperature of the heating treatment was 140°C, and the time was 60 min. After the treatment was completed, the treated material was taken to test the organic matter removal rate, and the moisture content of the mud cake and the sludge reduction rate were calculated after solid-liquid separation. The BOD5 / COD of the supernatant was tested, and the results are listed in Table 1.

[0078] Comparative Example 3

[0079] In this comparative example, hydrogen peroxide with a concentration of 27 wt % was used as the treating agent.

[0080] The pH value of the oil refinery concentrated sludge was adjusted to 5.5, and the above-mentioned treatment agent was added for heating treatment. Based on the volume of the oil refinery concentrated sludge, the amount of the treatment agent was 15 mL / L, the temperature of the heating treatment was 140°C, and the time was 60 min. After the treatment was completed, the treated material was taken to test the organic matter removal rate, and the moisture content of the mud cake and the sludge reduction rate were calculated after solid-liquid separation. The BOD5 / COD of the supernatant was tested, and the results are listed in Table 1.

[0081] Comparative Example 4

[0082] Take 600 mL of ammoximation wastewater, keep the pH value of the wastewater at 12, do not concentrate it, directly add aluminum sulfate, based on the volume of the wastewater, the amount of aluminum sulfate is 50 mg / L, and settle for 45 minutes under the condition of pH 6.9. Filter to remove the sediment, and take the clear liquid to obtain the treatment agent of this comparative example.

[0083] The pH value of the biochemical excess sludge was adjusted to 5.5, and the above-mentioned treatment agent was added for heating treatment. Based on the volume of the biochemical excess sludge, the amount of the treatment agent was 15 mL / L, the temperature of the heating treatment was 140°C, and the time was 60 min. After the treatment was completed, the treated material was taken to test the organic matter removal rate, and the moisture content of the mud cake and the sludge reduction rate were calculated after solid-liquid separation. The BOD5 / COD of the supernatant was tested, and the results are listed in Table 1.

[0084] Comparative Example 5

[0085] Take 600 mL of ammonia oxime wastewater, keep the pH value of the wastewater at 12, evaporate and concentrate at 95°C and a pressure of -0.08 MPa. After concentrating 30 times, a concentrated material is obtained. The concentrated material is filtered to remove flocs and then aluminum sulfate is added. Based on the volume of the filtered clear liquid, the amount of aluminum sulfate is 50 mg / L. The solution is allowed to settle for 45 minutes at a pH value of 6.9, and the sediment is removed by filtration. The clear liquid is taken to obtain the treating agent of this comparative example.

[0086] The pH value of the biochemical excess sludge was adjusted to 8, and the above-mentioned treatment agent was added for heating treatment. Based on the volume of the biochemical excess sludge, the amount of the treatment agent was 15 mL / L, the temperature of the heating treatment was 140°C, and the time was 60 min. After the treatment was completed, the treated material was taken to test the organic matter removal rate, and the moisture content of the mud cake and the sludge reduction rate were calculated after solid-liquid separation. The BOD5 / COD of the supernatant was tested, and the results are listed in Table 1.

[0087] Table 1

[0088]

[0089]

[0090] As can be seen from Table 1, the method disclosed in the present invention is used to treat the refined concentrated sludge, with a high organic matter removal rate, a low mud cake moisture content, and a high sludge reduction rate. At the same time, the treated liquid material has a high BOD5 / COD value and can be returned to the front-end sewage treatment. The moisture content of the solid material is less than 60% by weight, and can be sanitarily landfilled according to the requirements of GB / T23485-2009 standard, thereby effectively reducing the output of refined concentrated sludge.

[0091] The preferred embodiments of the present disclosure are described in detail above; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0092] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0093] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for stabilizing oil refinery concentrated sludge, characterized in that: The method includes: Under acidic conditions, the oil refinery concentrated sludge is mixed with a treatment agent and subjected to heating treatment to obtain a treated material; The water content of the oil refinery concentrated sludge is 98-98.5% by weight, the total solid suspended matter content is 15-20 g / L, and the volatile suspended matter content is 10-15 g / L; the treatment agent is obtained by pre-treating the ammoximation wastewater.

2. The method according to claim 1, wherein: The preparation steps of the treatment agent include: Concentrating the ammoximation wastewater to obtain concentrated materials; A coagulant is added to the concentrated material for sedimentation, and the sediment is removed to obtain the treatment agent.

3. The method according to claim 2, wherein: The pH value of the ammoximation wastewater is 12-13.

4. The method according to claim 2, wherein: The concentration conditions include: a pressure of -0.07 MPa to -0.08 MPa, a temperature of 60 to 95° C., and a concentration multiple of 20 to 70 times, preferably 30 to 60 times.

5. The method according to claim 2, wherein: The sedimentation conditions include: pH value of 6 to 8, time of 15 to 120 minutes; Preferably, the sedimentation conditions include: pH value of 6.5-7, and time of 30-60 minutes.

6. The method according to claim 2, wherein: Based on the volume of the concentrated material, the dosage of the coagulant is 20 to 80 mg / L, preferably 40 to 60 mg / L; The coagulant is an aluminum salt, preferably, the aluminum salt is aluminum sulfate and / or aluminum chloride.

7. The method according to claim 1, wherein: The acidic conditions include: a pH value of 3 to 7, preferably 4.5 to 6.

5.

8. The method according to claim 1, wherein: Based on the volume of the refined concentrated sludge, the dosage of the treatment agent is 10 to 30 mL / L, preferably 15 to 25 mL / L.

9. The method according to claim 1, wherein: The conditions of the heating treatment include: a temperature of 80 to 160° C. and a time of 30 to 360 min; Preferably, the conditions of the heating treatment include: a temperature of 90 to 140° C. and a time of 60 to 120 min.

10. The method according to claim 1, wherein: The method further includes: The treated material is subjected to solid-liquid separation to obtain a liquid phase material and a solid phase material; The liquid phase material is sent to a front-end sewage treatment device.

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