Method for preparing cattle bed padding from cow dung

Abstract

The invention belongs to the technical field of bioengineering, and particularly relates to a method for preparing a cattle bed padding by using cow dung, which comprises the following steps: step 1, preparing a padding matrix by using fresh cow dung; step 2, preparing modified straw-rice husk; step 3, preparing a modified charcoal-zeolite compound; step 4, mixing and fermenting a padding matrix, the modified straw-rice husk, the modified charcoal-zeolite compound, coconut fiber, wheat bran, monopotassium phosphate and a complex microbial inoculant according to a mass ratio of (45-55): (10-20): (5-15): (15-25): (3-7): (1-2): (2-3); 5, a ferric sulfate-silicon dioxide solution and a chitosan-tea polyphenol solution are sequentially sprayed on the surface; by means of physical dehydration, chemical activation, biological fermentation, functional composite design and the like, the technical bottlenecks in the prior art are broken through in the three dimensions of safety, functionality and economy, and closed-loop utilization of cow breeding waste is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of bioengineering, and in particular relates to a method for preparing cow mattress material by utilizing cow dung. Background Art

[0002] In-situ fermentation bed farming technology utilizes the basic theories of microbiology, ecology and fermentation engineering. A certain thickness of organic bedding is laid in the cowshed, and active functional microorganisms are used as carriers of matter and energy. Animal manure and urine waste are degraded and consumed through the growth and reproduction of powerful and active beneficial functional bacteria, while achieving the goal of pollution-free and zero-emission farming. This farming technology is a new type of environmentally friendly ecological farming technology.

[0003] Currently, the following materials are commonly used for bedding for cattle: 1) Traditional bedding materials such as sawdust, wood chips, sand, and straw. Although sawdust and wood chips have good water absorption, their costs continue to rise, and there is a risk of fungal contamination (such as Aspergillus flavus). Although sand has good drainage, it is easy to compact, which can easily increase the rate of hoof damage to cattle and is difficult to separate from manure. Straw is low in cost but has poor water absorption and is prone to mildew. It needs to be frequently replaced and has high maintenance costs. 2) Manure recycling bedding is made by separating the solid and liquid parts of cow dung and briefly composting the solid part for use as bedding. However, during the preparation process, there may be problems such as incomplete pathogen inactivation (such as residual E. coli and Salmonella) and insufficient dehydration, resulting in damp bedding and bacterial growth. 3) Using residues from biogas projects as bedding still has problems such as severe fiber structure damage, poor water absorption, and enrichment of heavy metals (such as copper and zinc).

[0004] Therefore, providing a new method for preparing cow mattress material using cow dung as raw material has become an urgent problem to be solved. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides a method for preparing cow mattress material using cow dung, which specifically comprises the following steps:

[0006] Step 1: Take fresh cow dung with a moisture content of ≥80%, filter it through a sieve with a pore size of 3-5 mm to remove large particles of impurities, and then filter it with a filter press until the filter cake has a moisture content of 55-65%. The filter cake is mixed with wood ash at a mass ratio of 20:1 to obtain a bedding matrix;

[0007] Step 2: Mix the crop straw and rice husk, dry them at 50-60° C. to constant weight, crush them through a 40-50 mesh sieve, mix the powder with an alkaline solution, stir them at 70-80° C. and 120-150 rpm for 2-2.5 hours, filter, remove the filtrate, wash the residue with clean water until the pH of the washing solution is ≤7.8, then mix the residue with an enzymatic hydrolyzate, stir them at 40-50° C. and 150-180 rpm for 1-1.5 hours, filter, remove the filtrate, and dry the residue at 45-50° C. to a moisture content of ≤12% to obtain a modified straw-rice husk.

[0008] Preferably, the crop straw is one or more of corn straw, rice straw, wheat straw, sorghum straw, barley straw and oat straw. Most preferably, the crop straw is corn straw.

[0009] Preferably, the mass ratio of the crop straw, rice husk, alkaline solution and enzymatic hydrolyzate is (1-3):(1-3):(8-24):(8-24).

[0010] Preferably, the alkaline solution is a potassium hydroxide solution with a mass fraction of 8-10% or a sodium hydroxide solution with a mass fraction of 8-10%.

[0011] Preferably, the enzymatic hydrolysis solution comprises cellulase, hemicellulase, pectinase, xylanase and water in a mass ratio of 3:1:1:1000.

[0012] Step 3: The biochar, attapulgite and zeolite are mixed and crushed, passed through a 60-70 mesh sieve, and then mixed with an organic acid solution, ultrasonicated at 50-60° C. and 30-40 kHz for 20-30 minutes, filtered, the filtrate is removed, and the filter residue is dried at 100-120° C. to constant weight to obtain a modified biochar-zeolite composite.

[0013] Preferably, the mass ratio of the biochar, attapulgite, zeolite and organic acid solution is 2:1:1:16.

[0014] Preferably, the organic acid solution is a citric acid solution with a mass fraction of 8-10% or an acetic acid solution with a volume fraction of 10-12%.

[0015] Step 4: Mix the bedding matrix, modified straw-rice husk, modified biochar-zeolite composite, coconut shell fiber, wheat bran, potassium dihydrogen phosphate and EM bacterial agent in a mass ratio of (45-55):(10-20):(5-15):(15-25):(3-7):(1-2):(2-3), adjust the pH to 6.8-7.2 with sodium carbonate, ferment at a humidity of 67-70% and 50-70°C for 4-5 days, and after fermentation, dry the fermented material at 60-65°C to a moisture content of ≤12% to obtain the initial bedding product.

[0016] Preferably, the mass ratio of the bedding matrix, modified straw-rice husk, modified biochar-zeolite composite, coconut shell fiber, wheat bran, potassium dihydrogen phosphate and EM bacterial agent is 50:15:10:20:5:1:2.

[0017] Preferably, the compost is turned once every 5-6 hours within 0-24 hours after the start of fermentation; within 24-72 hours after the start of fermentation, the compost is turned once every 10-12 hours; and after 72 hours from the start of fermentation, the compost is turned once every 22-24 hours.

[0018] Step 5: Spray ferric sulfate-silicon dioxide solution on the surface of the initial bedding material, the spraying amount is 2-3% of the initial bedding material quality, and then spray chitosan-tea polyphenol solution on the surface, the spraying amount is 3-4% of the initial bedding material quality after natural drying, and then naturally dry to obtain cattle mattress material.

[0019] Preferably, the ferric sulfate-silicon dioxide solution comprises ferric sulfate, nano-silicon dioxide and water in a mass ratio of 3:1:1000.

[0020] Preferably, the chitosan-tea polyphenol solution comprises chitosan, tea polyphenol, acetic acid and water in a ratio of 2g:1g:4mL:100mL.

[0021] The present invention has the following advantages:

[0022] (1) The present invention adopts EM microbial agents in combination with staged compost turning and fermentation to ensure the thorough killing of pathogens such as bacteria, viruses and parasites. Modified biochar-zeolite composites are added to inhibit the reproduction of microorganisms by adsorbing ammonia in the cowshed, significantly improving the sanitation and safety of bedding, reducing the incidence of mastitis in dairy cows, and avoiding the incomplete killing of pathogens caused by the existing bedding composting temperature not meeting the standard or the composting time being insufficient.

[0023] (2) The present invention uses sodium hydroxide solution to destroy the lignin-cellulose composite structure, and cellulase and hemicellulase further depolymerize the fibers, thereby increasing the porosity of the straw and rice husk and the liquid absorption rate of the bedding. Coconut shell fiber is then added to enhance the tensile strength of the bedding, thereby extending the service life of the bedding and avoiding the problem of low liquid absorption rate of unmodified straw.

[0024] (3) The present invention uses citric acid to activate biochar, zeolite and attapulgite to enhance ammonia adsorption capacity. Zeolite and attapulgite form ion exchange channels, lock ammonium ions, and significantly reduce the amount of ammonia released. Spraying ferric sulfate-silicon dioxide solution solidifies free ammonia, and spraying chitosan-tea polyphenol solution reduces the activity of urea-decomposing bacteria, thereby solving the problem of urea in feces and urine being quickly decomposed into ammonia, resulting in excessive ammonia concentration in the cowshed.

[0025] (4) The present invention adds wood ash to cow dung, uses an alkaline environment to precipitate heavy metal ions, and after biochar, zeolite and attapulgite are loaded with citric acid, the heavy metals are chelated with citric acid to reduce the risk of heavy metal residues in the bedding.

[0026] (5) The present invention uses cow dung as the main material to replace commercial electrical materials, uses coconut shell fiber to replace commercial fiber, and modifies and utilizes straw and rice husk to reduce the cost of agricultural waste treatment. DETAILED DESCRIPTION

[0027] The following is a clear and complete description of the technical solutions in the embodiments of the invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0028] Example 1

[0029] Step 1: Take fresh cow dung with a moisture content of 80% or more, filter it through a 4 mm pore size sieve to remove large particles of impurities, and then filter it with a filter press until the filter cake has a moisture content of 60%. The filter cake is mixed with plant ash at a mass ratio of 20:1 to obtain a bedding matrix;

[0030] Step 2: Mix corn stalks and rice husks, dry them at 55°C to constant weight, crush them through a 45-mesh sieve, mix the powder with a 10% sodium hydroxide solution, stir at 75°C and 150rpm for 2h, filter, remove the filtrate, wash the residue with clean water until the pH of the washing solution is ≤7.8, then mix the residue with an enzymatic hydrolyzate, stir at 45°C and 180rpm for 1h, filter, remove the filtrate, and dry the residue at 45°C to a moisture content of ≤12% to obtain a modified straw-rice husk. The mass ratio of the corn stalks, rice husks, 10% sodium hydroxide and enzymatic hydrolyzate is 3:2:20:20. The enzymatic hydrolyzate includes cellulase, hemicellulase, pectinase, xylanase and water in a mass ratio of 3:1:1:1000.

[0031] Step 3: The biochar, attapulgite, and zeolite were mixed and ground, passed through a 65-mesh sieve, and then mixed with a 10% by mass citric acid solution. The mixture was ultrasonically treated at 55°C and 40kHz for 30 minutes, filtered, the filtrate was removed, and the residue was dried at 110°C to constant weight to obtain a modified biochar-zeolite composite. The mass ratio of the biochar, attapulgite, zeolite, and organic acid solution was 2:1:1:16.

[0032] Step 4: Mix the bedding matrix, modified straw-rice husk, modified biochar-zeolite composite, coconut shell fiber, wheat bran, potassium dihydrogen phosphate and EM bacterial agent in a mass ratio of 50:15:10:20:5:1:2, adjust the pH to 6.8-7.2 with sodium carbonate, ferment at 68% humidity and 60°C for 5 days, turn the pile once every 5-6 hours within 0-24 hours after the start of fermentation; turn the pile once every 10-12 hours within 24-72 hours after the start of fermentation; turn the pile once every 22-24 hours after 72 hours from the start of fermentation. After fermentation is completed, dry the fermented material at 60°C to a moisture content of ≤12% to obtain the initial bedding product.

[0033] Step 5: Spray an iron sulfate-silicon dioxide solution on the surface of the initial bedding material in an amount of 3% of the initial bedding material quality. After natural drying, spray a chitosan-tea polyphenol solution in an amount of 4% of the initial bedding material quality. After natural drying, the cattle bedding material is obtained. The iron sulfate-silicon dioxide solution includes iron sulfate, nano-silicon dioxide and water in a mass ratio of 3:1:1000. The chitosan-tea polyphenol solution includes chitosan, tea polyphenols, acetic acid and water in a ratio of 2g:1g:4mL:100mL.

[0034] Test Example 1

[0035] 1. Sample Preparation

[0036] Experimental group: The cow mattress material was prepared according to the method of Example 1.

[0037] Control group 1: traditional compost bedding prepared according to steps 1 and 4 of Example 1 (after solid-liquid separation of cow dung in step 1, no modified straw-rice husk, modified biochar-zeolite composite and coconut shell fiber were added, and composting and fermentation were directly carried out according to step 4).

[0038] Control group 2: sawdust livestock bedding produced by Shijiazhuang Xueli Agricultural Products Co., Ltd.

[0039] Refer to GB / T 13091-2018 "Detection of Salmonella in Feed"

[0040] 10 g of bedding sample was added to 90 mL of sterile saline and shaken for 30 min. The supernatant was collected and inoculated into Salmonella and Escherichia coli selective culture media, respectively. The colonies were counted (CFU / g) after incubation at 37°C for 48 h. The results are shown in Table 1.

[0041] Table 1

[0042] Experimental group Control group 1 Control group 2 Safety limit Escherichia coli Not detected <![CDATA[2.1×10 3 ]]> <![CDATA[8.7×10 2 ]]> <![CDATA[≤1×10 3 ]]> salmonella Not detected <![CDATA[1.5×10 2 ]]> Not detected Not to be detected Total colony count <![CDATA[4.2×10 2 ]]> <![CDATA[3.8×10 4 ]]> <![CDATA[1.1×10 5 ]]> <![CDATA[≤1×10 4 ]]>

[0043] Test Example 2

[0044] 1. Liquid absorption rate determination

[0045] Take 10g of dry bedding sample, weigh it accurately and record it as W0, soak it in deionized water for 30min, take it out and drain it for 1min, weigh it accurately and record it as W t , calculate the liquid absorption rate and drainage rate, and the results are shown in Table 2.

[0046] Liquid absorption rate = (W t -W0) / W0×100%.

[0047] Drainage rate: Apply 10kPa pressure (simulating the weight of cattle) to the saturated bedding, and the weight of the bedding after drainage is recorded as W G , calculate the drainage rate:

[0048] Liquid retention rate = (W t -W G ) / (W t -W0)×100%.

[0049] 2. Natural drying rate test

[0050] The saturated water-absorbing pad was placed in an environment of 25°C / 70% humidity and the water evaporation rate was recorded for 24 hours. The results are shown in Table 2.

[0051] 3. Compressive strength test

[0052] The gasket was pressed into a Φ50 mm × 20 mm cylinder using a universal material testing machine (ISO 604 standard) at a compression rate of 5 mm / min. The stress value at 50% deformation was recorded. The results are shown in Table 2.

[0053] Table 2

[0054] Experimental group Control group 1 Control group 2 Liquid absorption rate (%) 386±12 152±9 95±5 Drainage rate (%) 78.3±3.1 42.6±2.8 35.2±2.5 24h drying rate (%) 85.7±2.4 61.3±3.7 48.9±3.0 Compressive strength (kPa) 18.7±0.8 6.2±0.5 >100(hardened)

[0055] Test Example 3

[0056] 1. Simulate cowshed environment

[0057] In the closed cabin (1m 3 ) with 5 cm thick bedding, temperature 25±1℃, and humidity 70%.

[0058] Add 200 mL of simulated cow urine (urea solution, nitrogen content 1.5 g / L) every day.

[0059] 2. Ammonia monitoring

[0060] The indigo blue spectrophotometric method (GB / T 18204.25) was used to collect gas in the chamber every 12 hours and continuously monitor for 72 hours. The results are shown in Table 3.

[0061] Table 3

[0062]

[0063] Test Example 4

[0064] 1. Heavy metal detection

[0065] According to GB 13078-2017 "Feed Hygiene Standard"

[0066] After microwave digestion of the samples, the heavy metal content was determined by ICP-MS. The results are shown in Table 4.

[0067] 2. Service life verification

[0068] Bedding (20 cm thick) was laid in a dairy farm, and the time when compaction and mildew first appeared was recorded. The results are shown in Table 4.

[0069] Table 4

[0070] Experimental group Control group 1 Standard limit Copper (mg / kg) 8.3±0.7 42.5±3.1 ≤50 Zinc (mg / kg) 62.1±4.2 187.3±10.8 ≤150 Cadmium (mg / kg) Not detected 0.8±0.1 ≤1 Average service life 28-32 days 10-15 days -

[0071] As shown in Tables 1-4, no Escherichia coli or Salmonella was detected in the cattle bedding material prepared by the present invention, indicating that the cattle bedding material prepared by the present invention is highly safe and basically does not contain pathogens.

[0072] The cow bedding material prepared by the present invention has good water absorption (386%), drainage (78.3%) and drying efficiency (85.7% water loss in 24 hours), can quickly absorb feces and urine to prevent surface moisture, can quickly drain water when the cow lies on it to keep the upper layer of the bedding dry, and then the remaining water quickly evaporates to keep the cowshed dry.

[0073] The cow mattress material prepared by the present invention can volatilize ammonia efficiently, and the ammonia release amount is only 83.6 mg / m 3 , 44% lower than the standard limit.

[0074] The service life of the cow mattress material prepared by the present invention is significantly prolonged, with continuous use of more than 28 days, thereby reducing the subsequent maintenance cost.

[0075] The cow mattress material prepared by the present invention has extremely low heavy metal residues, and the zinc residue is only 1 / 3 of that in the control group 1, which is far below the safety limit.

[0076] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a mattress for cattle using cow dung, characterized in that: The following steps are involved: Step 1: fresh cow dung is filtered and pressed until the filter cake has a moisture content of 55-65%, and the filter cake is mixed with plant ash to obtain a bedding matrix; Step 2: drying and crushing the crop straw and rice husk, mixing the powder with an alkaline solution, filtering, removing the filtrate, mixing the filter residue with an enzymatic hydrolysis solution, filtering, removing the filtrate, and drying the filter residue to a moisture content of ≤12% to obtain a modified straw-rice husk; Step 3: The biochar, attapulgite and zeolite are mixed and crushed, then mixed and soaked with an organic acid solution, filtered, the filtrate is removed, and the filter residue is dried to a constant weight to obtain a modified biochar-zeolite composite; Step 4: mix the litter matrix, modified straw-rice husk, modified biochar-zeolite composite, coconut shell fiber, wheat bran, potassium dihydrogen phosphate and composite microbial agent according to the mass ratio. (45-55):(10-20):(5-15):(15-25):(3-7):(1-2):(2-3) and mixed, and the pH was adjusted to 6.8-7.

2. After fermentation for 4-5 days, the fermented material was dried to a moisture content of ≤12% to obtain the initial bedding product; Step 5: spraying ferric sulfate-silicon dioxide solution and chitosan-tea polyphenol solution on the surface of the primary bedding material in sequence and drying it naturally to obtain the cattle bedding material.

2. The method for preparing a mattress for cattle using cow dung according to claim 1, characterized in that: The mass ratio of the crop straw, rice husk, alkaline solution and enzymatic hydrolyzate in step 2 is (1-3):(1-3):(8-24):(8-24).

3. The method for preparing a mattress material for cattle using cow dung according to claim 1, characterized in that: The alkaline solution in step 2 is a potassium hydroxide solution with a mass fraction of 8-10% or a sodium hydroxide solution with a mass fraction of 8-10%. The enzymatic hydrolysis solution includes cellulase, hemicellulase, pectinase, xylanase and water in a mass ratio of 3:1:1:1000.

4. The method for preparing a mattress material for cattle using cow dung according to claim 1, characterized in that: The mass ratio of the biochar, attapulgite, zeolite and organic acid solution in step three is 2:1:1:

16.

5. The method for preparing a cow mattress material using cow dung according to claim 1, characterized in that: The organic acid solution in step 3 is a citric acid solution with a mass fraction of 8-10% or an acetic acid solution with a volume fraction of 10-12%.

6. The method for preparing a mattress for cattle using cow dung according to claim 1, characterized in that: The mass ratio of the bedding matrix, modified straw-rice husk, modified biochar-zeolite composite, coconut shell fiber, wheat bran, potassium dihydrogen phosphate and composite bacterial agent in step 4 is 50:15:10:20:5:1:

2.

7. The method for preparing a cow mattress material using cow dung according to claim 1, characterized in that: In step 4, within 0-24 hours after the start of fermentation, the pile is turned over once every 5-6 hours; within 24-72 hours after the start of fermentation, the pile is turned over once every 10-12 hours; after 72 hours after the start of fermentation, the pile is turned over once every 22-24 hours.

8. The method for preparing a cow mattress material using cow dung according to claim 1, characterized in that: The ferrous sulfate-silicon dioxide solution in step five includes ferrous sulfate, nano-silicon dioxide and water in a mass ratio of 3:1:1000; the chitosan-tea polyphenol solution includes chitosan, tea polyphenol, acetic acid and water in a ratio of 2g:1g:4mL:100mL.

9. The method for preparing a mattress for cattle using cow dung according to claim 1, characterized in that: In step 5, the spraying amount of the ferric sulfate-silicon dioxide solution is 2-3% of the initial quality of the bedding, and the spraying amount of the chitosan-tea polyphenol solution is 3-4% of the initial quality of the bedding.

10. Cattle mattress material prepared by the method according to any one of claims 1 to 9.

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