Organic fertilizer prepared based on sludge and preparation method thereof

Abstract

The invention discloses an organic fertilizer prepared based on sludge and a preparation method thereof. The organic fertilizer is prepared from the following raw materials in percentage by weight: 65-80% of municipal sludge; the organic waste accounts for 23%-30%; the biomass fermentation enzyme accounts for 5%-12%; the organic waste is prepared from 14-23% of waste generated in the traditional Chinese medicine production process, 6-12% of straw powder, 1-5% of mushroom residues, 6-13% of peanut shell powder, 8-14% of rice husks, 5-8% of plant wilt, 4-9% of kitchen waste peel, 2-6% of saw dust, 10-18% of a plastic rubber fiber fabric mixture and 12-20% of vinasse. Through preparation and use of the organic fertilizer, the soil structure can be effectively improved, the condition of soil hardening can be reduced, the effect of accelerating soil ripening is achieved for a newly-reclaimed farmland, the defects caused by directly adding municipal sludge into soil are overcome, and the economic benefit is increased. The pollution of heavy metals, pathogenic bacteria, parasitic ova, organic pollutants and odor in the municipal sludge to soil and environment is effectively prevented.

Description

Technical Field

[0001] The invention relates to the technical field of organic fertilizers, and in particular to an organic fertilizer prepared based on sludge and a preparation method thereof. Background Art

[0002] Nowadays, sewage treatment plants are found in every town, and the domestic sludge produced by sewage treatment plants is a headache for environmental protection departments, because the sludge is rich in organic matter, which is prone to produce stench, breed mosquitoes and flies, and pollute the environment.

[0003] At present, most of them are landfilled or incinerated, but landfilling takes up a lot of land and is easy to pollute surface water and groundwater. The cost of incinerating sludge is very high. After the careful research of technicians, domestic sludge can be turned into organic fertilizer after fermentation by microbial strains. It can be applied to trees, flowers, lawn grass and used as a substrate for tree container seedlings, all of which have a good growth response, and the physical, chemical and biological properties of the soil have been improved. Thus, the resource utilization of domestic sludge is completely realized.

[0004] Studies have shown that urban sludge contains a large amount of organic matter, nitrogen, phosphorus and other nutrients needed for plant growth. For a long time, most of the urban sludge has been directly applied to the planting site. However, if it is applied directly to the planting site without necessary treatment, it will not only fail to meet the plant's demand for nutrients, but its fertilizer effectiveness is low. If it is applied to the field without being composted by microorganisms, it will continue to decompose and generate heat, which may cause seedling burn. The microorganisms in the sludge may compete with crops for nutrients.

[0005] Since the composition of urban sewage sludge is relatively complex, the water content is high, and the treatment is difficult, the large amount of accumulated sewage sludge will not only occupy a large amount of land, but also the harmful components such as heavy metals, pathogens, parasite eggs, organic pollutants and odor will become a major hazard to urban environmental sanitation. Therefore, it is urgent to design an organic fertilizer prepared from sewage sludge and its preparation method to solve the above problems. Summary of the invention

[0006] The object of the present invention is to provide an organic fertilizer prepared based on sludge and a preparation method thereof, so as to solve the above-mentioned deficiencies in the prior art.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] An organic fertilizer prepared based on sewage sludge, which is made from the following raw materials in weight ratio:

[0009] Municipal sludge accounts for 65%-80%;

[0010] Organic waste accounts for 23%-30%;

[0011] Biomass fermentation enzymes account for 5%-12%;

[0012] The organic waste consists of 14-23% of waste generated in the production process of traditional Chinese medicine, 6-12% of straw powder, 1-5% of mushroom residue, 6-13% of peanut shell powder, 8-14% of rice husk, 5-8% of plant dead matter, 4-9% of kitchen waste peel, 2-6% of sawdust, 10-18% of plastic rubber fiber fabric mixture and 12-20% of wine lees;

[0013] The biomass fermentation enzyme consists of 10% polyvinyl alcohol degrading enzyme, 13% saccharifying enzyme, 8% pectinase, 12% glucose oxidase, 17% lipase, 8% bacillus subtilis, 8% bacillus stearothermophilus, 10% catalase and 14% cellulase.

[0014] Preferably, the waste generated during the production of the traditional Chinese medicine is concentrated and dried to control its moisture content to below 8%.

[0015] Preferably, the organic waste is processed by crushing, screening and grinding, and the powder of the organic waste is controlled below 100 μm. A linear screening method is used to evenly place the powder of the organic waste on a sieve and screen it through a sieve with a constant aperture.

[0016] Preferably, the biomass fermentation enzymes are added quantitatively and in fixed ratios by feeders, the number of feed pipes of the feeder is equal to the number of biomass fermentation enzymes, and the outlet diameter of each feed pipe of the feeder is determined according to the ratio of the biomass fermentation enzymes.

[0017] Preferably, the municipal sludge is pure sludge from which heavy metals and substances harmful to plant growth have been removed.

[0018] A method for preparing organic fertilizer based on sludge preparation comprises the following steps:

[0019] 1) Pretreatment of municipal sludge: The sludge is initially treated, such as screening and compression, to remove impurities and bulk materials;

[0020] 2) Adding the preparation: adding the organic waste and the biomass fermentation enzyme to the pretreated municipal sludge, and mixing them evenly to obtain a mixture;

[0021] 3) Adjustment of related parameters: adjust moisture, aeration and pH,

[0022] Add water to the mixture to adjust the humidity to a suitable level, usually 50%-60%. Moisture content: grab a handful of material, if watermarks are visible but no water is dripping, and it falls apart as soon as it hits the ground, ensure that air circulation is maintained inside the mixture;

[0023] 4) Composting: Pile the mixture on the composting site and turn it regularly to ensure uniform fermentation;

[0024] 5) Long-term storage and sorting: After the mixture is fermented, it will become stable. The mixture after long-term storage is crushed and sieved to remove large pieces of matter to obtain uniform powdered organic fertilizer;

[0025] 6) Packaging: Pack the prepared organic fertilizer according to specifications.

[0026] Preferably, in step 1), the municipal sludge with a higher moisture content is processed into dry sludge with a moisture content of 13%, which can be directly air-dried or crushed and dried using a drum dryer containing a hot air furnace and a crushing shaft, and the processed dry sludge is pulverized.

[0027] Preferably, in step 3), the pH value of the mixture is in the range of 6 to 9, and the pH value of the fermentation system is adjusted by adding acidic and alkaline substances such as hydrochloric acid, phosphoric acid and sodium hydroxide by acid-base adjustment method or buffer addition method; the buffer addition method stabilizes the pH value of the fermentation mixture by adding buffers such as phosphate buffer and bicarbonate buffer.

[0028] Preferably, in step 4), the fermentation temperature is controlled to be high temperature fermentation, medium temperature fermentation and low temperature fermentation.

[0029] High temperature fermentation: use ventilation and feeding methods, wait for the mixture to heat up to 63-70℃, and ferment at high temperature for 2-4 days;

[0030] Medium temperature fermentation: Use ventilation and feeding methods to reduce the temperature of the mixture to 40-50℃, ferment at controlled temperature for 2-3 days, turn the mixture over, and continue to ferment at controlled temperature for 2-4 days;

[0031] Low-temperature fermentation: Use ventilation and feeding methods to reduce the temperature of the mixture to 25-30℃, and ferment at controlled temperature for 4-6 days.

[0032] Preferably, in step 6), when making packages, the name, ingredients, and usage information of the organic fertilizer are indicated, and when making packages of the organic fertilizer, the package weight can be selected from 5Kg, 12Kg, 25Kg, and 40Kg.

[0033] In the above technical scheme, the present invention provides an organic fertilizer prepared based on sludge and a preparation method thereof. Through the preparation and use of the organic fertilizer, the soil structure can be effectively improved, the soil compaction can be reduced, and for newly reclaimed farmland, the effect of accelerating soil maturation can be achieved, and the disadvantages of directly adding urban sludge to the soil can be solved, and the heavy metals, pathogens, parasite eggs, organic pollutants and odor in the urban sludge can be effectively prevented from polluting the soil and the environment.

[0034] Since the preparation raw materials adopted in the present invention are mainly urban sludge and organic waste, the environmental pressure caused by sludge on the environment can be reduced to a certain extent, which is beneficial to the treatment of urban sludge.

[0035] Among the organic wastes of the present invention, the wastes and distiller's grains generated in the production process of traditional Chinese medicine account for a large proportion, which is particularly suitable for cities with relatively good development of traditional Chinese medicine and wine, and can accelerate the process of environmental waste resource treatment and achieve sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0037] Figure 1 The present invention provides a preparation flow chart of an organic fertilizer prepared based on sludge and a preparation method thereof. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0039] like Figure 1 As shown, an organic fertilizer prepared based on sludge provided in an embodiment of the present invention is made of raw materials with the following weight ratio:

[0040] Municipal sludge accounts for 65%-80%;

[0041] Organic waste accounts for 23%-30%;

[0042] Biomass fermentation enzymes account for 5%-12%;

[0043] Specifically, municipal sludge is pure sludge from which heavy metals and substances harmful to plant growth have been removed.

[0044] In this embodiment, the organic waste is composed of 14-23% of waste generated in the production process of traditional Chinese medicine, 6-12% of straw powder, 1-5% of mushroom residue, 6-13% of peanut shell powder, 8-14% of rice husk, 5-8% of plant dead matter, 4-9% of kitchen waste peel, 2-6% of sawdust, 10-18% of plastic rubber fiber fabric mixture and 12-20% of distiller's grains;

[0045] Specifically, the waste generated during the production of traditional Chinese medicine is concentrated and dried to control its moisture content below 8%;

[0046] Specifically, the organic waste is processed by crushing, screening and grinding, and the powder of the organic waste is controlled below 100 μm. A linear screening method is used to evenly place the powder of the organic waste on the screen and screen it through a screen with a constant aperture.

[0047] In this embodiment, the biomass fermentation enzymes consist of 10% polyvinyl alcohol degrading enzyme, 13% saccharifying enzyme, 8% pectinase, 12% glucose oxidase, 17% lipase, 8% Bacillus subtilis, 8% Bacillus stearothermophilus, 10% catalase and 14% cellulase;

[0048] Specifically, the biomass fermentation enzymes are added quantitatively and in fixed proportions through feeders, the number of feed pipes of the feeder is equal to the number of biomass fermentation enzymes, and the outlet diameter of each feed pipe of the feeder is determined according to the proportion of the biomass fermentation enzymes;

[0049] Polyvinyl alcohol degrading enzymes are a class of enzymes that can catalyze the biodegradation of polyvinyl alcohol (PVA), especially the degradation of organic waste such as plastic rubber fiber fabric mixtures. They mainly include the following: polyvinyl alcohol oxidase (secondary alcohol oxidase), which can catalyze the oxidation reaction of hydroxyl groups in polyvinyl alcohol molecules to generate hydrogen peroxide; polyvinyl alcohol dehydrogenase, which can catalyze the removal of hydrogen atoms in polyvinyl alcohol molecules to form ketone groups; diketone hydrolase (oxidative polyvinyl alcohol hydrolase), which can catalyze the hydrolysis reaction of ketone groups in polyvinyl alcohol molecules to generate hydroxyl groups.

[0050] Saccharifying enzyme can rapidly liquefy starch to generate low molecular weight dextrin, catalyze the hydrolysis of starch to produce beer, rice wine, sauce MSG and antibiotics, and can also be used in the production of glucose, maltose and dextrin. It can especially efficiently decompose organic wastes such as waste generated in the production process of traditional Chinese medicine and distiller's grains.

[0051] Pectinase, glucose oxidase and lipase as biocatalysts can play a positive role in the degradation of organic waste.

[0052] Bacillus subtilis can decompose plant residues and other organic waste, promote the decomposition cycle of organic matter in the soil, thereby improving soil texture and increasing nutrient utilization, while also promoting plant growth.

[0053] Bacillus stearothermophilus can use fat as a carbon source to decompose oil into organic acids, alcohols, ketones and other compounds.

[0054] Catalase works within the peroxisome within cells and can efficiently catalyze the decomposition reaction of hydrogen peroxide.

[0055] Cellulase is an enzyme that can decompose plant cellulose. It plays an important role in the treatment and resource utilization of organic waste. It has a good decomposition effect on straw powder, mushroom residue, peanut shell powder, rice husk and plant dead matter.

[0056] A method for preparing organic fertilizer based on sludge preparation comprises the following steps:

[0057] 1) Pretreatment of municipal sludge: The sludge is initially treated, such as screening and compression, to remove impurities and bulk materials;

[0058] Specifically, the municipal sludge with a high moisture content is processed into dry sludge with a moisture content of 13%, which can be directly air-dried or crushed and dried using a drum dryer containing a hot air furnace and a crushing shaft, and the processed dry sludge is pulverized.

[0059] 2) Adding the preparation: adding the organic waste and the biomass fermentation enzyme to the pretreated municipal sludge, and mixing them evenly to obtain a mixture;

[0060] 3) Adjustment of related parameters: adjust moisture, aeration and pH,

[0061] Add water to the mixture to adjust the humidity to a suitable level, usually 50%-60%. Moisture content: grab a handful of material, if watermarks are visible but no water is dripping, and it falls apart as soon as it hits the ground, ensure that air circulation is maintained inside the mixture;

[0062] Specifically, the pH value of the mixture is within the range of 6 to 9, and the pH value of the fermentation system is adjusted by adding acidic and alkaline substances such as hydrochloric acid, phosphoric acid and sodium hydroxide using an acid-base adjustment method or a buffer addition method; the buffer addition method stabilizes the pH value of the fermentation mixture by adding a buffer such as a phosphate buffer and a bicarbonate buffer.

[0063] 4) Composting: Pile the mixture on the composting site and turn it regularly to ensure uniform fermentation;

[0064] Specifically, the fermentation temperature is controlled as high temperature fermentation, medium temperature fermentation and low temperature fermentation.

[0065] High temperature fermentation: use ventilation and feeding methods, wait for the mixture to heat up to 63-70℃, and ferment at high temperature for 2-4 days;

[0066] Medium temperature fermentation: Use ventilation and feeding methods to reduce the temperature of the mixture to 40-50℃, ferment at controlled temperature for 2-3 days, turn the mixture over, and continue to ferment at controlled temperature for 2-4 days;

[0067] Low-temperature fermentation: Use ventilation and feeding methods to reduce the temperature of the mixture to 25-30℃, and ferment at controlled temperature for 4-6 days.

[0068] 5) Long-term storage and sorting: After the mixture is fermented, it will become stable. The mixture after long-term storage is crushed and sieved to remove large pieces of matter to obtain uniform powdered organic fertilizer;

[0069] 6) Packaging: Packing the prepared organic fertilizer according to specifications;

[0070] Specifically, when making packages, the name, ingredients, and usage information of the organic fertilizer are indicated. When making packages of the organic fertilizer, the package weight can be selected from 5Kg, 12Kg, 25Kg, and 40Kg.

[0071] Embodiment 1

[0072] An organic fertilizer prepared based on sewage sludge, which is made from the following raw materials in weight ratio:

[0073] Municipal sewage sludge accounts for 70%;

[0074] Organic waste accounts for 25%;

[0075] Biomass fermentation enzymes account for 5%.

[0076] The organic waste consists of 20% waste generated during the production of traditional Chinese medicine, 10% straw powder, 3% mushroom residue, 10% peanut shell powder, 10% rice husk, 7% plant dead matter, 5% kitchen waste peel, 4% sawdust, 15% plastic rubber fiber fabric mixture and 16% wine lees. The biomass fermentation enzymes consist of 10% polyvinyl alcohol degradation enzyme, 13% saccharifying enzyme, 8% pectinase, 12% glucose oxidase, 17% lipase, 8% Bacillus subtilis, 8% Bacillus stearothermophilus, 10% catalase and 14% cellulase.

[0077] The steps of a method for preparing organic fertilizer based on sludge are as follows: 1) pretreatment of municipal sludge; 2) addition of conditioning agent; 3) adjustment of relevant parameters: adjustment of moisture, aeration and pH; 4) composting and fermentation; 5) long-term storage and sorting; 6) packaging: packaging the prepared organic fertilizer according to specifications.

[0078] In order to verify the growth-promoting effect of the present invention on various crops, the following comparative experiments were conducted:

[0079] Two plots of land were selected and the same plants were planted respectively. One plot was fertilized with the organic fertilizer of the present invention and the other plot was fertilized with conventional livestock fertilizer. The following conclusions were drawn: the growth potential of the plants was lower than that of the livestock organic fertilizer in the early stage, but in the middle and late stages, the fertilizer efficiency of the sludge fermentation fertilizer increased significantly, the overall growth potential was about 4% higher than that of the plants planted with livestock fertilizer, and the total plant growth was 12%-18% higher than that of the plants planted with livestock organic fertilizer.

[0080] Embodiment 2

[0081] An organic fertilizer prepared based on sewage sludge, which is made from the following raw materials in weight ratio:

[0082] Municipal sewage sludge accounts for 65%;

[0083] Organic waste accounts for 30%;

[0084] Biomass fermentation enzymes account for 5%.

[0085] The organic waste consists of 20% waste generated during the production of traditional Chinese medicine, 10% straw powder, 3% mushroom residue, 10% peanut shell powder, 10% rice husk, 7% plant dead matter, 5% kitchen waste peel, 4% sawdust, 15% plastic rubber fiber fabric mixture and 16% wine lees. The biomass fermentation enzymes consist of 10% polyvinyl alcohol degradation enzyme, 13% saccharifying enzyme, 8% pectinase, 12% glucose oxidase, 17% lipase, 8% Bacillus subtilis, 8% Bacillus stearothermophilus, 10% catalase and 14% cellulase.

[0086] The steps of a method for preparing organic fertilizer based on sludge are as follows: 1) pretreatment of municipal sludge; 2) addition of conditioning agent; 3) adjustment of relevant parameters: adjustment of moisture, aeration and pH; 4) composting and fermentation; 5) long-term storage and sorting; 6) packaging: packaging the prepared organic fertilizer according to specifications.

[0087] In order to verify the growth-promoting effect of the present invention on various crops, the following comparative experiments were conducted:

[0088] Two plots of land were selected and the same plants were planted respectively. One plot was fertilized with the organic fertilizer of the present invention and the other plot was fertilized with conventional livestock fertilizer. The following conclusions were drawn: the growth potential of the plants was lower than that of the livestock organic fertilizer in the early stage, but in the middle and late stages, the fertilizer efficiency of the sludge fermentation fertilizer increased significantly, the overall growth potential was about 2% higher than that of the plants planted with livestock fertilizer, and the total plant growth was 8%-12% higher than that of the plants planted with livestock organic fertilizer.

[0089] Embodiment 3

[0090] An organic fertilizer prepared based on sewage sludge, which is made from the following raw materials in weight ratio:

[0091] Municipal sewage sludge accounts for 72%;

[0092] Organic waste accounts for 23%;

[0093] Biomass fermentation enzymes account for 5%.

[0094] The organic waste consists of 20% waste generated during the production of traditional Chinese medicine, 10% straw powder, 3% mushroom residue, 10% peanut shell powder, 10% rice husk, 7% plant dead matter, 5% kitchen waste peel, 4% sawdust, 15% plastic rubber fiber fabric mixture and 16% wine lees. The biomass fermentation enzymes consist of 10% polyvinyl alcohol degradation enzyme, 13% saccharifying enzyme, 8% pectinase, 12% glucose oxidase, 17% lipase, 8% Bacillus subtilis, 8% Bacillus stearothermophilus, 10% catalase and 14% cellulase.

[0095] The steps of a method for preparing organic fertilizer based on sludge are as follows: 1) pretreatment of municipal sludge; 2) addition of conditioning agent; 3) adjustment of relevant parameters: adjustment of moisture, aeration and pH; 4) composting and fermentation; 5) long-term storage and sorting; 6) packaging: packaging the prepared organic fertilizer according to specifications.

[0096] In order to verify the growth-promoting effect of the present invention on various crops, the following comparative experiments were conducted:

[0097] Two plots of land were selected and the same plants were planted respectively. One plot was fertilized with the organic fertilizer of the present invention and the other plot was fertilized with conventional livestock fertilizer. The following conclusions were drawn: the growth potential of the plants was lower than that of the livestock organic fertilizer in the early stage, but in the middle and late stages, the fertilizer efficiency of the sludge fermentation fertilizer increased significantly, the overall growth potential was about 2.5% higher than that of the plants planted with livestock fertilizer, and the total plant growth was 7%-11% higher than that of the plants planted with livestock organic fertilizer.

[0098] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. An organic fertilizer prepared based on sewage sludge, characterized in that: It is made of the following raw materials in the following weight ratio: Municipal sludge accounts for 65%-80%; Organic waste accounts for 23%-30%; Biomass fermentation enzymes account for 5%-12%; The organic waste consists of 14-23% of waste generated in the production process of traditional Chinese medicine, 6-12% of straw powder, 1-5% of mushroom residue, 6-13% of peanut shell powder, 8-14% of rice husk, 5-8% of plant dead matter, 4-9% of kitchen waste peel, 2-6% of sawdust, 10-18% of plastic rubber fiber fabric mixture and 12-20% of wine lees; The biomass fermentation enzyme consists of 10% polyvinyl alcohol degrading enzyme, 13% saccharifying enzyme, 8% pectinase, 12% glucose oxidase, 17% lipase, 8% bacillus subtilis, 8% bacillus stearothermophilus, 10% catalase and 14% cellulase.

2. An organic fertilizer prepared based on sewage sludge according to claim 1, characterized in that: The waste generated in the production process of the traditional Chinese medicine is concentrated and dried to control the moisture content below 8%.

3. An organic fertilizer prepared based on sewage sludge according to claim 1, characterized in that: The organic waste is processed by crushing, screening and grinding, and the powder of the organic waste is controlled below 100 μm. The powder of the organic waste is evenly placed on the screen by a linear screening method, and is screened through a screen with a constant aperture.

4. The organic fertilizer prepared based on sewage sludge according to claim 1, characterized in that: The biomass fermentation enzymes are added quantitatively and in fixed ratios through feeders. The number of feed pipes of the feeder is equal to the number of biomass fermentation enzymes. The outlet diameter of each feed pipe of the feeder is determined according to the ratio of the biomass fermentation enzymes.

5. The organic fertilizer prepared based on sewage sludge according to claim 1, characterized in that: The municipal sludge is pure sludge from which heavy metals and substances harmful to plant growth are removed.

6. A method for preparing organic fertilizer based on sludge, characterized in that: The following steps are involved: 1) Pretreatment of municipal sludge: The sludge is initially treated, such as screening and compression, to remove impurities and bulk materials; 2) Adding the preparation: adding the organic waste and the biomass fermentation enzyme to the pretreated municipal sludge, and mixing them evenly to obtain a mixture; 3) Adjustment of related parameters: adjust moisture, aeration and pH, Add water to the mixture to adjust the humidity to a suitable level, usually 50%-60%. Moisture content: grab a handful of material, if watermarks are visible but no water is dripping, and it falls apart as soon as it hits the ground, ensure that air circulation is maintained inside the mixture; 4) Composting: Pile the mixture on the composting site and turn it regularly to ensure uniform fermentation; 5) Long-term storage and sorting: After the mixture is fermented, it will become stable. The mixture after long-term storage is crushed and sieved to remove large pieces of matter to obtain uniform powdered organic fertilizer; 6) Packaging: Pack the prepared organic fertilizer according to specifications.

7. The method for preparing organic fertilizer based on sludge according to claim 6, characterized in that: In step 1), the municipal sludge with a high moisture content is processed into dry sludge with a moisture content of 13%, which can be directly air-dried or crushed and dried by a drum dryer containing a hot air furnace and a crushing shaft, and the processed dry sludge is crushed.

8. The method for preparing organic fertilizer based on sludge according to claim 6, characterized in that: In step 3), the pH value of the mixture is in the range of 6 to 9, and the pH value of the fermentation system is adjusted by adding acidic and alkaline substances such as hydrochloric acid, phosphoric acid and sodium hydroxide using an acid-base adjustment method or a buffer addition method; Buffer addition method, by adding buffers, such as phosphate buffer and bicarbonate buffer, to stabilize the pH value of the fermentation mixture.

9. The method for preparing organic fertilizer based on sludge according to claim 6, characterized in that: In step 4), the fermentation temperature is controlled to be high temperature fermentation, medium temperature fermentation and low temperature fermentation. High temperature fermentation: use ventilation and feeding methods, wait for the mixture to heat up to 63-70℃, and ferment at high temperature for 2-4 days; Medium temperature fermentation: Use ventilation and feeding methods to reduce the temperature of the mixture to 40-50℃, ferment at controlled temperature for 2-3 days, turn the mixture over, and continue to ferment at controlled temperature for 2-4 days; Low-temperature fermentation: Use ventilation and feeding methods to reduce the temperature of the mixture to 25-30℃, and ferment at controlled temperature for 4-6 days.

10. The method for preparing organic fertilizer based on sludge according to claim 6, characterized in that: In step 6), when making packages, the name, ingredients, and usage information of the organic fertilizer are indicated. When making packages of the organic fertilizer, the package weight can be selected from 5Kg, 12Kg, 25Kg, and 40Kg.

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