A shallow sludge solidification process

Abstract

The invention discloses a shallow sludge solidification process, and relates to the field of sludge solidification. The shallow sludge solidification process comprises the following steps: S1, first adding a demulsifier to demulsify the shallow sludge, then adding a heavy metal capture agent, stirring to fully react, then adding biological strains to stir evenly, finally adding a coagulant and a flocculant, stirring and dispersing evenly to obtain the sludge after conditioning; wherein the coagulant comprises 30-50 parts by weight of polyaluminium chloride, 10-15 parts by weight of ferric chloride and 20-35 parts by weight of polyaluminium silicate iron; S2, dehydrating and drying the sludge after conditioning to obtain solidified soil. The solidified soil obtained by the solidification process of the present application has a stable structure and is not easy to crack and pulverize, which is conducive to promoting the healthy growth of plant roots.

Description

Technical Field

[0001] The invention relates to the field of sludge solidification, in particular to a shallow sludge solidification process. Background Art

[0002] River siltation will affect the normal operation of various functions such as flood control, drainage, water supply, and navigation. In order to ensure the normal operation of the river, it is necessary to regularly dredge the river, which will produce a large amount of dredged silt. However, after the large-scale dredged silt comes ashore, it is easy to cause secondary pollution to the surrounding environment, and the disposal of silt requires a large amount of urban construction land. Therefore, how to realize the resource utilization of dredged silt is a current research hotspot.

[0003] Among them, the reuse of dredged sludge includes planting soil, landfill soil, roadbed, etc. However, the most prominent feature of dredged sludge is its high water content. If dredged sludge is to be reused, it must be dehydrated and solidified.

[0004] At present, cement, lime and other curing agents are commonly used for dredged sludge solidification. However, the solidified soil obtained by cement and lime curing often has large shrinkage coefficient and temperature coefficient, which makes the solidified soil prone to cracking and powdering. When the easily powdered solidified soil is used as planting soil, it will affect the air permeability of the soil, which will not only inhibit the respiration of plant roots, but also greatly weaken the water and fertilizer absorption capacity of plant roots. Summary of the invention

[0005] In order to obtain a solidified soil that can promote the healthy growth of plant roots, the present application provides a shallow silt solidification process.

[0006] A shallow sludge solidification process provided in this application adopts the following technical solution:

[0007] A shallow sludge solidification process comprises the following steps:

[0008] S1, first add a demulsifier to demulsify the shallow sludge, then add a heavy metal capture agent, stir to react fully, then add the biological strain and stir evenly, finally add a coagulant and a flocculant, stir and disperse evenly to obtain the sludge after conditioning; wherein the coagulant includes 30-50 parts by weight of polyaluminium chloride, 10-15 parts by weight of ferric chloride and 20-35 parts by weight of polyaluminium ferric silicate;

[0009] S2. Dewatering and drying the conditioned sludge to obtain solidified soil.

[0010] Demulsification before adding heavy metal capture agent is beneficial to the removal efficiency of free heavy metals. Biological strains are added before adding coagulants and flocculants. Biological strains can decompose large molecular organic matter into substances that can be directly absorbed by plants, which is beneficial to reduce the number of fertilization times. The coagulant is a mixture of polyaluminum chloride, ferric chloride and polyaluminum ferrosilicate, which is not only beneficial to promote the separation of sludge and water, but also can synergistically form a stable skeleton, which can improve the structural stability of the solidified soil, making the solidified soil not easy to crack and powder, which is beneficial to promote the healthy growth of plant roots.

[0011] Optionally, the heavy metal capture agent includes an inorganic base and an organic heavy metal capture agent; when adding the heavy metal capture agent, the inorganic base is first added to adjust the pH of the sludge to 8-9, and then the organic heavy metal capture agent is added, and the amount of the organic heavy metal capture agent added is 2-5 times the heavy metal content in the lower layer of sludge.

[0012] Before adding the organic heavy metal scavenger, the pH of the sludge is adjusted to 8-9 with an inorganic base, which is beneficial to promote the combination of the organic heavy metal scavenger with the heavy metal ions and can improve the removal rate of free heavy metal ions.

[0013] Optionally, the heavy metal capture agent is modified vermicelli and sweet potato residue, and the preparation method of the modified vermicelli and sweet potato residue comprises the following steps:

[0014] S11, adding 20-30 parts by weight of vermicelli and sweet potato residue to 100 parts by weight of a sodium hydroxide solution with a mass fraction of 3-5%, then heating to 60-80°C, stirring and reacting for 2-4h, then adding 40-50 parts by weight of a 30-50% alcohol solution, 15-25 parts by weight of epichlorohydrin and 30-40 parts by weight of ethylenediamine, stirring and reacting at 90-100°C for 3-6h, centrifuging, washing the vermicelli and sweet potato residue with deionized water until neutral, and then drying to obtain pretreated vermicelli and sweet potato residue;

[0015] S12. Add 100 parts by weight of 3-5% sodium hydroxide solution and 50-60 parts by weight of 30-50% alcohol solution to 20-30 parts by weight of pretreated vermicelli and sweet potato residues, stir evenly, and slowly add 10-20 parts by weight of CS2 while stirring under nitrogen protection, then heat to 40-50°C and continue heating under reflux reaction for 1-2h, then cool to room temperature, add 1-2 parts by weight of alkyl glycoside and 5-10 parts by weight of 1% sodium polyacrylate, stir rapidly at a speed of 2000-3000r / min for 15-30min, and finally centrifuge, wash with deionized water until neutral, and then air-dry to obtain modified vermicelli and sweet potato residues.

[0016] The use of modified vermicelli and sweet potato residue as a heavy metal capture agent can omit the step of adjusting pH with sodium hydroxide, and at the same time improve the utilization rate of vermicelli and sweet potato residue waste. In addition, under the synergistic effect of alkyl glycoside and sodium polyacrylate, the adsorption efficiency and adsorption stability of modified vermicelli and sweet potato residue for heavy metal ions are effectively improved.

[0017] Optionally, the amount of modified vermicelli and sweet potato residue added is 3.5-5 times the heavy metal content in the lower layer sludge.

[0018] Optionally, a biological deodorant is also added in step S1. The biological deodorant is added before the coagulant is added, and the amount of the biological deodorant added is 1-5% of the content of the low-layer sludge.

[0019] The addition of biological deodorizers can improve the odor of solidified soil.

[0020] Optionally, the demulsifier is an AR emulsifier.

[0021] Optionally, the flocculant includes cationic polyacrylamide and quaternary ammonium salt, and the weight ratio of the cationic polyacrylamide to the quaternary ammonium salt is 1:(10-20).

[0022] The weight ratio of cationic polyacrylamide to quaternary ammonium salt is 1:(10-20), which can not only improve the mud-water separation effect of sludge, but also improve the stability of heavy metals and reduce the precipitation rate of heavy metals.

[0023] Optionally, the biological strains include ammonifying bacteria and photosynthetic bacteria.

[0024] Ammonia-forming bacteria can decompose nitrogen-containing organic matter into inorganic ammonia, which is beneficial for supplementing nitrogen sources for plant growth. The metabolites of photosynthetic bacteria can not only be directly absorbed by plants, but also become nutrients for the reproduction of other organisms, increasing the number of beneficial bacteria in the soil.

[0025] Optionally, the amount of the demulsifier added is 0.1-1% of the total amount of shallow sludge, the amount of the coagulant added is 10-20% of the solid content of the shallow sludge, and the amount of the flocculant added is 0.1-10% of the solid content of the shallow sludge.

[0026] In summary, the technical solution of this application includes at least the following beneficial effects:

[0027] (1) The sludge solidification process of the present application can improve the structural stability of the solidified soil, reduce the pulverization rate of the solidified soil, and promote the healthy growth of plant roots.

[0028] (2) The modified vermicelli residue of the present application is used as a heavy metal capture agent, which can omit the pH adjustment step and realize the reuse of the vermicelli residue waste. In addition, due to the addition of alkyl glycoside and sodium polyacrylate, the adsorption efficiency and adsorption stability of the modified vermicelli residue for heavy metals are improved, effectively reducing the content of free metal ions in the sludge and filtrate. DETAILED DESCRIPTION

[0029] The present application discloses a shallow sludge solidification process, comprising the following steps:

[0030] S1, first add a demulsifier to demulsify the shallow sludge, then add a heavy metal capture agent, stir to react fully, then add the biological strain and stir evenly, finally add a coagulant and a flocculant, stir and disperse evenly to obtain the sludge after conditioning; wherein the coagulant includes 30-50 parts by weight of polyaluminium chloride, 10-15 parts by weight of ferric chloride and 20-35 parts by weight of polyaluminium ferric silicate;

[0031] S2. Dewatering and drying the conditioned sludge to obtain solidified soil.

[0032] Among them, the demulsifier is AR type emulsifier, and the addition amount is 0.1-1% of the total amount of shallow sludge.

[0033] Heavy metal scavengers can be inorganic alkalis and organic heavy metal scavengers. Inorganic alkalis are used to adjust the pH value of sludge. The amount of organic heavy metal scavengers added is generally 2-5 times the heavy metal content in the lower layer of sludge. The role of organic heavy metal scavengers is to chelate heavy metal ions in the sludge. When used, inorganic alkalis are first used to adjust the pH of the sludge to 8-9, and then the organic heavy metal scavenger is added, which is beneficial to reduce the free metal ion content in the sludge and the water removed from the sludge.

[0034] Preferably, the heavy metal capture agent is modified sweet potato residue, and the amount of modified sweet potato residue added is 3.5-5 times the heavy metal content in the lower sludge. The preparation method of modified sweet potato residue includes the following steps:

[0035] S11, adding 20-30 parts by weight of vermicelli and sweet potato residue to 100 parts by weight of a sodium hydroxide solution with a mass fraction of 3-5%, then heating to 60-80°C, stirring and reacting for 2-4h, then adding 40-50 parts by weight of a 30-50% alcohol solution, 15-25 parts by weight of epichlorohydrin and 30-40 parts by weight of ethylenediamine, stirring and reacting at 90-100°C for 3-6h, centrifuging, washing the vermicelli and sweet potato residue with deionized water until neutral, and then drying to obtain pretreated vermicelli and sweet potato residue;

[0036] S12. Add 100 parts by weight of 3-5% sodium hydroxide solution and 50-60 parts by weight of 30-50% alcohol solution to 20-30 parts by weight of pretreated vermicelli and sweet potato residues, stir evenly, and slowly add 10-20 parts by weight of CS2 while stirring under nitrogen protection, then heat to 40-50°C and continue heating under reflux reaction for 1-2h, then cool to room temperature, add 1-2 parts by weight of alkyl glycoside and 5-10 parts by weight of 1% sodium polyacrylate, stir rapidly at a speed of 2000-3000r / min for 15-30min, and finally centrifuge, wash with deionized water until neutral, and then air-dry to obtain modified vermicelli and sweet potato residues.

[0037] The use of modified vermicelli and sweet potato residue as a heavy metal scavenger can omit the step of adjusting the pH using sodium hydroxide. At the same time, under the synergistic effect of alkyl glycoside and sodium polyacrylate, the adsorption efficiency and adsorption stability of modified vermicelli and sweet potato residue for heavy metal ions are effectively improved.

[0038] The main function of biological strains is to decompose macromolecular substances in sludge so that they can be effectively absorbed and utilized by plants, which can reduce the application of fertilizers. Preferably, the biological strains include ammonifying bacteria and photosynthetic bacteria. Ammonifying bacteria can decompose nitrogen-containing organic matter into inorganic ammonia, which is beneficial to supplement nitrogen sources for plant growth. The metabolites of photosynthetic bacteria can not only be directly absorbed by plants, but also become nutrients for the reproduction of other organisms, increasing the beneficial bacteria in the soil. Among them, the ratio of ammonifying bacteria to photosynthetic bacteria can be determined according to the needs of different plants.

[0039] The amount of coagulant added is 10-20% of the solid content of the shallow sludge. The coagulant includes 30-50 parts by weight of polyaluminium chloride, 10-15 parts by weight of ferric chloride and 20-35 parts by weight of polyaluminium ferric silicate. The synergistic cooperation of polyaluminium chloride, ferric chloride and polyaluminium ferric silicate forms a stable skeleton, which can improve the structural stability of the solidified soil and make the solidified soil less prone to cracking and powdering. When the solidified soil is used as planting soil, it can maintain good air permeability, so that the roots of the plants will not be short of oxygen, which is conducive to promoting the healthy growth of the plants.

[0040] The amount of flocculant added is 1-10% of the solid content of the shallow sludge. Among them, the flocculant can be selected from any one or a combination of cationic polyacrylamide and quaternary ammonium salt. In the present application, the flocculant is preferably a combination of cationic polyacrylamide and quaternary ammonium salt, and the weight ratio of cationic polyacrylamide to quaternary ammonium salt is 1: (10-20), which can not only improve the mud-water separation effect of the sludge, but also improve the stability of heavy metals and reduce the precipitation rate of heavy metals.

[0041] In addition, a biological deodorant can be added in step S1. The amount of the biological deodorant added is 1-5% of the content of the low-layer sludge. The biological deodorant is added before the coagulant is added, which is beneficial to the dispersion of the biological deodorant.

[0042] The following specific preparation examples, embodiments and comparative examples further illustrate the present application in detail, wherein the indicators of the sludge treated in each embodiment and comparative example are shown in Table 1 below.

[0043] Table 1 Silt index

[0044] Moisture content (%) Cadmium content (mg / L) Lead content (mg / L) pH 92 12.1 8.9 6-7

[0045] Preparation Example

[0046] Preparation Example 1

[0047] A modified vermicelli potato residue, the preparation method of which comprises the following steps:

[0048] S11, adding 20 kg of vermicelli and sweet potato residue to 100 kg of sodium hydroxide solution with a mass fraction of 3-5%, then heating to 70°C, stirring and reacting for 3 hours, then adding 40 kg of 30% alcohol solution by volume, 8 kg of epichlorohydrin and 30 kg of ethylenediamine, stirring and reacting at 90°C for 3 hours, centrifuging, washing the vermicelli and sweet potato residue with deionized water until neutral, and then drying to obtain pretreated vermicelli and sweet potato residue;

[0049] S12. Add 100 kg of 3-5% sodium hydroxide solution and 60 kg of 30% alcohol solution by weight to 20 kg of pretreated vermicelli residue. After stirring evenly, slowly add 10 kg of CS2 while stirring under nitrogen protection, then heat to 50 ° C and continue heating reflux reaction for 1.5 hours, then cool to room temperature, add 1 kg of alkyl glycoside and 8 kg of 1% sodium polyacrylate, stir rapidly at a speed of 2000 r / min for 20 minutes, and finally centrifuge, wash with deionized water until neutral, and then air-dry to obtain modified vermicelli residue.

[0050] Preparation Example 2

[0051] A modified vermicelli potato residue, which is different from Preparation Example 1 in that:

[0052] The alkyl glycoside was replaced by an equal amount of sodium dodecylbenzene sulfonate.

[0053] Preparation Example 3

[0054] A modified vermicelli potato residue, which is different from Preparation Example 1 in that:

[0055] Sodium polyacrylate is replaced by an equal amount of alkyl glycoside.

[0056] Example

[0057] Example 1

[0058] A shallow sludge solidification process comprises the following steps:

[0059] S1, add 0.25kg AR emulsifier to 500kg shallow sludge, stir and react for 30min, add 5wt% sodium hydroxide solution to adjust the pH to 8.5, then add 42g sodium dithiocarbamate, stir and react for 20min, then add 4g Bacillus subtilis and 8g cyanobacteria, stir evenly, finally add 6kg coagulant and 200g cationic polyacrylamide with a concentration of 0.1wt%, stir and disperse evenly to obtain the sludge after conditioning; wherein the coagulant includes 40kg polyaluminium chloride, 10kg ferric chloride and 28kg polyaluminium ferrosilicate;

[0060] S2. The sludge after conditioning is centrifugally dehydrated. The speed of the centrifuge is controlled at 10000r / min. The centrifugal time is 30min. After the water is separated, the solid residue is dried at 60°C for 1h to obtain solidified soil.

[0061] Example 2

[0062] A shallow sludge solidification process comprises the following steps:

[0063] S1, add 0.25kg AR emulsifier to 500kg shallow sludge, stir and react for 30min, then add 42g modified vermicelli potato residue obtained in Preparation Example 1, stir and react for 20min, then add 4g Bacillus subtilis and 8g cyanobacteria, stir evenly, finally add 6kg coagulant and 200g cationic polyacrylamide with a concentration of 0.1%, stir and disperse evenly to obtain the sludge after conditioning; wherein the coagulant includes 40kg polyaluminium chloride, 10kg ferric chloride and 28kg polyaluminium ferrosilicate;

[0064] S2. The sludge after conditioning is centrifugally dehydrated. The speed of the centrifuge is controlled at 10000r / min. The centrifugal time is 30min. After the water is separated, the solid residue is dried at 60°C for 1h to obtain solidified soil.

[0065] Example 3

[0066] A shallow sludge solidification process, which differs from Example 2 in that:

[0067] An equal amount of the modified sweet potato residue of vermicelli prepared in Preparation Example 2 was used to replace the modified sweet potato residue of vermicelli prepared in Preparation Example 1.

[0068] Example 4

[0069] A shallow sludge solidification process, which differs from Example 2 in that:

[0070] An equal amount of the modified sweet potato residue of vermicelli prepared in Preparation Example 3 was used to replace the modified sweet potato residue of vermicelli prepared in Preparation Example 1.

[0071] Example 5

[0072] A shallow sludge solidification process, which differs from Example 2 in that 200 g of 0.1 wt % cationic polyacrylamide is replaced by 200 g of 0.1 wt % polydimethyldiallylammonium chloride.

[0073] Example 6

[0074] A shallow sludge solidification process, which differs from Example 2 in that: 200g of cationic polyacrylamide with a concentration of 0.1wt% is replaced by 10g of cationic polyacrylamide with a concentration of 0.1wt% and 190g of polydimethyldiallylammonium chloride with a concentration of 0.1wt%.

[0075] Example 7

[0076] A shallow sludge solidification process, which differs from Example 2 in that: 200g of cationic polyacrylamide with a concentration of 0.1wt% is replaced by 100g of cationic polyacrylamide with a concentration of 0.1wt% and 100g of polydimethyldiallylammonium chloride with a concentration of 0.1wt%.

[0077] Comparative Example

[0078] Comparative Example 1

[0079] A shallow sludge solidification process, which differs from Example 1 in that:

[0080] The polyaluminium chloride in the coagulant is replaced by an equal amount of aluminium chloride.

[0081] Comparative Example 2

[0082] A shallow sludge solidification process, which differs from Example 1 in that:

[0083] The ferric chloride in the coagulant is replaced by an equal amount of aluminum chloride.

[0084] Comparative Example 3

[0085] A shallow sludge solidification process, which differs from Example 1 in that:

[0086] The polyaluminium ferric silicate in the coagulant is replaced by an equal amount of aluminium ferric silicate.

[0087] Performance test data

[0088] 1. Test of the filtrate separated by centrifugation

[0089] 1. SS content: Take 1000mL sample, filter, and then dry to constant weight to test the content of suspended matter.

[0090] 2. Cadmium and lead content: Pre-treat the filtrate with acid, then filter it and test the cadmium and lead content in the filtrate using ICP.

[0091] Table 2 Filtrate parameters

[0092] project Example 1 Example 2 Example 3 Example 4 Example 5 SS(mg / L) 286 274 281 279 368 Cadmium (mg / L) 1.36 0.56 0.78 0.86 0.89 Lead (mg / L) 0.99 0.42 0.63 0.67 0.85 project Example 6 Example 7 Comparative Example 1 Comparative Example 2 Comparative Example 3 SS(mg / L) 265 268 306 293 309 Cadmium (mg / L) 0.49 0.57 2.06 1.46 1.98 Lead (mg / L) 0.38 0.45 1.37 1.06 1.28

[0093] 2. Performance test of solidified soil

[0094] 1. Compressive strength: The filter residue after centrifugation was made into test pieces with a size of 50mm*100mm. After demoulding, it was cultured in a standard curing room for 7 days, and then the unconfined compressive strength of each experiment was tested.

[0095] 2. Cadmium and lead precipitation rate: Take 2g of solidified soil and put it in 100g of 0.1mol / L hydrochloric acid solution. After stirring for 2h, filter and take the filtrate to detect the cadmium and lead content in the filtrate.

[0096] 3. Pulverization rate: Take an equal amount of solidified soil with a particle size range of 30-40 mesh and put it into a mold as the sample to be tested, then use a sample weighing 5 kg to press for 5 days. After 5 days, the proportion of solidified soil with a particle size less than 45 mesh is sieved out, and this proportion is taken as the pulverization rate.

[0097] Table 3 Solidified soil parameters

[0098]

[0099]

[0100] Combining Example 1 with Example 2 and the data in Table 2-3, it can be seen that when modified vermicelli and sweet potato residue is used as a heavy metal capture agent, not only can the pH adjustment step be omitted, but the removal rate of free heavy metals can also be effectively improved. At the same time, the heavy metals in the solid soil are stable and not easy to precipitate.

[0101] Combining Example 2-4 with the data in Table 2-3, it can be seen that the high adsorption efficiency and adsorption stability of modified vermicelli and potato residue for heavy metal ions are obtained by the synergistic effect of alkyl glycoside and sodium polyacrylate.

[0102] Combining Example 2 with Examples 5-7 and the data in Table 2-3, it can be seen that the flocculant is a combination of cationic polyacrylamide and quaternary ammonium salt, and the weight ratio of cationic polyacrylamide to quaternary ammonium salt is 1: (10-20), which can not only improve the mud-water separation effect of the sludge, but also improve the stability of heavy metals and reduce the precipitation rate of heavy metals.

[0103] Application Examples

[0104] The solidified soils of Examples 1-7 and Comparative Examples 1-3 were sieved to separate solidified soils with mesh sizes ranging from 30 to 50, and the sieved solidified soils were used to plant sunflowers, cultured under the same environmental conditions for 60 days, and the number of dead sunflowers in each application example and the number of sunflowers with rotten roots among the dead sunflowers were counted. The solidified soils used in each application example and the number of dead sunflowers and the number of rotten roots are shown in Table 4 below.

[0105] Table 4

[0106]

[0107] By comparing Application Examples 1-7 with Application Examples 8-10, it can be seen that the solidified soil produced by the process claimed in the present application is more conducive to promoting the healthy development of the roots of sunflowers.

[0108] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed. However, as long as it is within the scope of the claims of the present application, it shall be protected by the patent law.

Claims

1. A shallow sludge solidification process, characterized in that: The following steps are involved: S1, first add demulsifier to demulsify shallow sludge, then add heavy metal capture agent, stir to react fully, then add biological strains and stir evenly, finally add coagulant and flocculant, stir and disperse evenly to obtain tempered sludge; wherein the coagulant includes 30-50 parts by weight of polyaluminium chloride, 10-15 parts by weight of ferric chloride and 20-35 parts by weight of polyaluminium ferric silicate; S2, dehydrate and dry the tempered sludge to obtain solidified soil; The heavy metal capture agent is modified sweet potato residue, and the amount of the modified sweet potato residue added is 3.5-5 times the heavy metal content in the shallow sludge; the preparation method of the modified sweet potato residue comprises the following steps: S11, adding 20-30 parts by weight of sweet potato residue to 100 parts by weight of sodium hydroxide solution with a mass fraction of 3-5%, then heating to 60-80°C, stirring and reacting for 2-4h, then adding 40-50 parts by weight of alcohol solution with a volume fraction of 30-50%, 15-25 parts by weight of epichlorohydrin and 30-40 parts by weight of ethylenediamine, stirring and reacting at 90-100°C for 3-6h, centrifuging, washing the sweet potato residue with deionized water until it is neutral, and then drying to obtain pretreated sweet potato residue; S12, add 100 parts by weight of 3-5% sodium hydroxide solution and 50-60 parts by weight of 30-50% alcohol solution to 20-30 parts by weight of pretreated vermicelli residue, stir evenly, slowly add 10-20 parts by weight of CS2 while stirring under nitrogen protection, then heat to 40-50°C and continue heating under reflux for 1-2h, then cool to room temperature, add 1-2 parts by weight of alkyl glycoside and 5-10 parts by weight of 1% sodium polyacrylate, stir rapidly at a speed of 2000-3000r / min for 15-30min, finally centrifuge, wash with deionized water until neutral, and then air-dry to obtain modified vermicelli residue.

2. A shallow sludge solidification process according to claim 1, characterized in that: In step S1, a biological deodorant is also added before the coagulant is added, and the amount of the biological deodorant added is 1-5% of the shallow sludge content.

3. A shallow sludge solidification process according to claim 1, characterized in that: The demulsifier is an AR emulsifier.

4. A shallow sludge solidification process according to claim 1, characterized in that: The flocculant comprises cationic polyacrylamide and quaternary ammonium salt, and the weight ratio of the cationic polyacrylamide to the quaternary ammonium salt is 1:(10-20).

5. A shallow sludge solidification process according to claim 1, characterized in that: The biological strains include ammonifying bacteria and photosynthetic bacteria.

6. A shallow sludge solidification process according to claim 1, characterized in that: The amount of the demulsifier added is 0.1-1% of the total amount of shallow sludge, the amount of the coagulant added is 10-20% of the solid content of the shallow sludge, and the amount of the flocculant added is 0.1-10% of the solid content of the shallow sludge.

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