Method for simultaneously realizing harmless treatment and resource utilization of silkworm excrement and cocoon cooking wastewater

Abstract

The application discloses a method for realizing harmless treatment and resource utilization of silkworm excrement and cocoon boiling wastewater simultaneously, which comprises the following steps: mixing the silkworm excrement and cocoon boiling wastewater according to a certain proportion, separating the silkworm excrement residue and the silkworm excrement water extract after heat preservation treatment, mixing the silkworm excrement with garden soil, inoculating chlorella in the water extract, and separating after culture, and using the algal cells to prepare composite aquatic feed.The advantages of the method are as follows: the method can effectively prevent the pollution of silkworm excrement, cocoon boiling wastewater and other wastes of the sericulture industry to the environment, and can transform the resource advantage into economic advantage, which is of great significance to the in-depth development of the sericulture industry chain and the formation of the circular economy mode, and is beneficial to environmental protection.In addition, the silkworm excrement fertilizer can significantly promote the growth of vegetables, the aquatic feed can significantly improve the growth rate and survival rate of aquatic animals such as fish, and the method has the characteristics of high conversion efficiency, good product effect, simple operation and the like, and is easy to realize industrialized production.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of environmental protection and resource comprehensive utilization, and relates to a comprehensive utilization method of silkworm breeding waste, in particular to a method for simultaneously realizing harmless treatment and resource utilization of silkworm manure and cocoon boiling wastewater. BACKGROUND

[0002] Theoretically, silkworm manure refers to the excrement of silkworms after eating mulberry leaves, but in actual production, the excrement of silkworms is usually collected together with residual mulberry leaves and silkworm seat padding. The silkworm manure contains a large amount of nucleopolyhedrosis virus, plasmid polyhedrosis virus, Beauveria bassiana, microsporidium, and aspergillus spores and other pathogens, which have strong pathogenicity and infectivity and are one of the main sources of infection and prevalence of silkworm diseases in silkworm areas. With the rapid development of the sericulture industry and the increasing production, the improper disposal of silkworm manure has led to a large area of silkworm disease outbreak in some silkworm areas, causing significant economic losses to sericulturists, increasing the risk and instability of sericulturists in engaging in the sericulture industry, reducing the production enthusiasm of sericulturists, and being not conducive to the sustainable development of the sericulture industry. Therefore, the prevention and control of silkworm manure pollution has become the first priority for the sustainable, healthy and stable development of the sericulture industry. However, the current utilization of silkworm manure is mostly in the shallow state of agricultural use, mainly as agricultural fertilizer. How to effectively control the spread of pathogens in silkworm manure and environmental pollution and help sericulturists find an effective and simple method for the prevention and control of silkworm manure pollution and resource utilization is an urgent need to purify the silkworm breeding environment, reduce the risk of silkworm breeding, and increase the income of sericulturists.

[0003] Reeling enterprises are large consumers of water and wastewater discharges, and a large amount of organic wastewater with medium and high concentrations is generated in the production processes such as cocoon boiling and silk reeling, and the main pollutants include sericin protein, pupa protein, pigment and fatty acid, etc.

[0004] Fully exploring the multiple functions of silkworm manure and silk reeling wastewater, correctly grasping the development direction of diversified development and utilization of silkworm manure and silk reeling wastewater resources, understanding the relationship between them and the traditional sericulture industry, establishing a diversified development and utilization mode of silkworm manure and silk reeling wastewater, and building a technology system suitable for the diversified development and utilization of silkworm manure and silk reeling wastewater resources can not only promote the further diversified development and utilization of silkworm manure and silk reeling wastewater resources, but also produce a strong driving force for the development of the sericulture industry. SUMMARY

[0005] The technical problem solved is to overcome the shortcomings of the prior art and obtain a method for effectively, high-value-added and comprehensive utilization of silkworm breeding waste. In view of this, the present application provides a method for simultaneously realizing harmless treatment and resource utilization of silkworm manure and cocoon boiling wastewater.

[0006] Technical scheme: The method for simultaneously realizing harmless treatment and resource utilization of silkworm manure and cocoon boiling wastewater comprises the following steps:

[0007] S1, mixing silkworm excrement and cocoon cooking wastewater at a mass g: volume mL ratio of 1:5-1:50, stirring uniformly, and then incubating at 80-90°C for 1-6 hours, and then cooling to room temperature;

[0008] S2, using a spiral extruder to extrude the mixture obtained in S1 to obtain silkworm excrement filter residue and silkworm excrement water extract;

[0009] S3, detecting pathogenic bacteria in the silkworm excrement filter residue and silkworm excrement water extract obtained in S2;

[0010] S4, mixing the silkworm excrement filter residue collected in S2 with vegetable garden soil at a mass ratio of 1:1-1:2, and using the mixture to plant vegetables;

[0011] S5, inoculating Chlorella into the silkworm excrement water extract collected in S2, at an inoculation density of 10 4 -10 5 cells / mL, culturing at a temperature of 25°C and under a light intensity of 3000 lux, and obtaining Chlorella culture solution after culturing for 3-5 days;

[0012] S6, separating the Chlorella culture solution collected in S5 into algae and water, using the algae to prepare composite aquatic feed, and directly discharging the separated water into natural water bodies.

[0013] Preferably, the total nitrogen content of the cocoon cooking wastewater in S1 is 203.2±4.48 mg / L, the total phosphorus content is 18.2±0.11 mg / L, the COD content is 2535.0±4.48 mg / L, and the temperature is 90-100°C. The silkworm excrement is the excrement of domestic silkworms, or the excrement, leftover mulberry leaves, and silkworm seat padding.

[0014] Preferably, the rotation speed of the spiral extruder in S2 is 50-100 r / min, and the extrusion gap is 1-2 mm.

[0015] Preferably, the plate colony counting method or polymerase chain reaction is used to detect pathogenic bacteria in S3.

[0016] Preferably, the Chlorella in S5 is Chlorella pyrenoidosa, Chlorella sorokiniana, or Chlorella vulgaris.

[0017] Preferably, the composite aquatic feed in S6 includes, in terms of mass fractions, 20-25 parts of algae cells, 20-25 parts of fish meal, 15-20 parts of soybean meal, 15-20 parts of corn meal, 10-15 parts of silkworm chrysalis powder, and 1-2 parts of composite vitamins.

[0018] Preferably, the composite vitamins include, in terms of mass fractions, B 12 20-25 parts, C 50-60 parts, and E 20-30 parts.

[0019] Preferably, the pathogenic bacteria detection rate is less than 2.0%.

[0020] Preferably, the plant height increase rate is higher than 37%.

[0021] Preferably, the aquatic animal mortality rate is less than 0.5%, the average daily growth rate of aquatic animals is higher than 0.3%, and the aquatic animal morbidity rate is less than 1.8%.

[0022] The principle of the method for simultaneously achieving harmless treatment and resource utilization of silkworm excrement and cocoon boiling wastewater provided by the present application is as follows: (1) The 90-100℃ cocoon boiling wastewater is mixed with silkworm excrement to kill pathogenic bacteria in the silkworm excrement while preparing silkworm excrement water extract, thereby reducing the risk of environmental pollution caused by pathogenic bacteria in use. Moreover, this step can be directly completed at the silkworm breeding household, thereby reducing the cost of intermediate processes such as collection, transportation and storage of silkworm excrement and the risk of leakage and diffusion caused by the intermediate processes. (2) The total phosphorus content in the cocoon boiling wastewater is only 18.2±0.11 mg / L, which is far lower than the demand of microalgae for phosphorus source. After mixing with silkworm excrement, the phosphorus content in the silkworm excrement water extract can be significantly increased, the nitrogen and phosphorus ratio can be improved, and the obtained silkworm excrement water extract is more suitable as a culture solution for microalgae, thereby solving the technical problems such as high cost and large water consumption in the process of microalgae cultivation. (3) The valuable resources such as carbon, nitrogen and phosphorus in the silkworm excrement and cocoon boiling wastewater are converted by microalgae, and the obtained microalgae biomass is developed as aquatic feed, thereby improving the resource utilization efficiency of silkworm excrement and cocoon boiling wastewater, reducing the pollution to the environment, and widening the diversified utilization channels of by-products of the sericulture industry. (4) After pathogenic bacteria detection, the obtained silkworm excrement filter residue is developed as a compound fertilizer, which not only optimizes the fertility of the silkworm excrement filter residue, but also greatly reduces the risk of pathogenic bacteria transmission caused by the application of silkworm excrement organic fertilizer. Therefore, compared with the prior art, the technical process provided by the present application has obvious economic, social and environmental benefits, has great industrialization application prospect, and can be widely applied in many silkworm breeding households.

[0023] Beneficial effects: (1) The method provided by the present application can not only effectively control the transmission and environmental pollution of pathogenic bacteria in silkworm excrement and reduce the pollution of silkworm excrement to the environment, but also can significantly reduce the content of environmental pollutants such as nitrogen and phosphorus in silkworm excrement and cocoon boiling wastewater, meet the diversified development and utilization demand of silkworm excrement and cocoon boiling wastewater, and improve the comprehensive economic benefit of silkworm production. (2) The method can significantly reduce the content of total nitrogen, total phosphorus and COD in silkworm excrement and cocoon boiling wastewater, which not only helps to avoid the eutrophication hazard of silkworm excrement and cocoon boiling wastewater to rivers, lakes and other water bodies, realizes the resource utilization of silkworm industry waste, but also purifies the silkworm breeding environment and improves the income of silkworm farmers. (3) The method has strong practicability and is easy to realize industrialization and other characteristics, which not only can save a large amount of water resources and nutrient salts, but also can greatly reduce the production cost of microalgae large-scale cultivation, which is conducive to the industrialization process of microalgae cultivation. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a process schematic diagram of a method for simultaneously realizing harmless treatment and resource utilization of silkworm excrement and cocoon boiling wastewater. DETAILED DESCRIPTION

[0025] The following examples further illustrate the content of the present application, but should not be construed as limiting the present application. Modifications and replacements made to the method, steps or conditions of the present application without departing from the spirit and essence of the present application shall fall within the scope of the present application. If not specifically indicated, the technical means used in the examples are conventional means well known to those skilled in the art.

[0026] Examples 1-9

[0027] The method for simultaneously realizing harmless treatment and resource utilization of silkworm excrement and cocoon boiling wastewater comprises the following steps:

[0028] S1, mixing silkworm excrement and cocoon boiling wastewater according to a mass (g): volume (mL) ratio of 1:5-1:50, stirring uniformly, then incubating at 80-90℃ for 1-6 hours, and then cooling to room temperature;

[0029] S2, using a spiral extruder to extrude the mixture obtained in S1 to obtain silkworm excrement residue and silkworm excrement water extract;

[0030] S3, detecting pathogenic bacteria in the silkworm excrement residue and silkworm excrement water extract obtained in S2;

[0031] S4, mixing the silkworm excrement residue collected in S2 with vegetable garden soil according to a mass ratio of 1:1-1:2, and using for planting vegetables;

[0032] S5, inoculating Chlorella into the silkworm excrement water extract collected in S2, with an inoculation density of 10 4 -10 5 cells / mL, a culture temperature of 25℃, and a light intensity of 3000 lux, and obtaining Chlorella culture solution after 3-5 days of culture;

[0033] S6, separating the Chlorella culture solution collected in S5 into algae and water, using the algae for preparing composite aquatic feed, and directly discharging the separated water into natural water bodies.

[0034] In S2, the rotation speed of the spiral extruder is 50-100 r / min, and the strip gap is 1-2 mm. In S5, the Chlorella is Chlorella vulgaris, Chlorella protothecoides or ordinary Chlorella. In S6, the composite aquatic feed comprises, in terms of mass fraction: 20-25 parts of Chlorella cells, 20-25 parts of fish meal, 15-20 parts of soybean meal, 15-20 parts of corn meal, 10-15 parts of silkworm chrysalis powder, and 1-2 parts of composite vitamins. The composite vitamins comprise, in terms of mass fraction: 0.5-1 part of B 1220-25 servings, C 50-60 servings, E 20-30 servings.

[0035] The above important parameters and corresponding test results are shown in Table 1.

[0036] Compare with Example 1

[0037] (1) Mix silkworm excrement and tap water at a ratio of 1:15 (w / v)(g / mL) and let stand at room temperature for 4 hours.

[0038] (2) The mixture of silkworm excrement and tap water obtained in (1) was squeezed using a screw extruder (speed of 100r / min, gap of extruder bars of 2mm) to obtain silkworm excrement filter residue and silkworm excrement water extract respectively.

[0039] (3) The pathogens in the silkworm excrement filter residue and silkworm excrement water extract obtained in (2) were detected by plate count and polymerase chain reaction (PCR);

[0040] (4) The silkworm excrement filter residue obtained in (2) is mixed with garden soil at a ratio of 1:1.5 (w / w) and then used to plant water spinach;

[0041] (5) Inoculate Chlorella sorokinensis into the silkworm excrement water extract obtained in step (2), analyze the microalgae growth characteristics, and obtain Chlorella culture medium;

[0042] (6) The Chlorella culture medium obtained in (5) was subjected to algae-water separation to develop a compound aquatic feed, the formula of which is shown in Table 1.

[0043] (7) Using microalgal biomass as an indicator, analyze the growth status and transformation capacity of microalgae in this comparative scheme (Table 1).

[0044] (8) The effect of using the increase in water spinach plant height compared with the control group was evaluated by the amount of increase in plant height compared with the control group (Table 1).

[0045] (9) Grass carp were fed with the aquatic feed developed in this comparative example for 60 days. The effects of the developed aquatic feed were compared with the mortality rate, average daily growth rate and morbidity rate as indicators (Table 1).

[0046] Comparative Example 2

[0047] (1) Take the wastewater from the silk reeling factory and cool it to room temperature;

[0048] (2) Pathogen detection was performed on cocoon boiling wastewater using plate count and polymerase chain reaction (PCR) methods;

[0049] (3) Chlorella sorokin was inoculated into cocoon boiling wastewater, and the microalgae growth characteristics were analyzed to obtain Chlorella culture medium.

[0050] (4) The Chlorella culture solution obtained in (3) is subjected to algae water separation to develop a compound aquatic feed, and the formula is shown in Table 1;

[0051] (5) Taking the microalgae biomass as an index, the growth state and conversion capacity of the microalgae in the scheme of the present comparative example are analyzed (Table 1);

[0052] (6) The aquatic feed developed in the present comparative example is used to feed grass carp for 60 days, and the mortality rate, average daily growth rate and incidence rate are taken as indexes to compare the effect of the developed aquatic feed (Table 1).

[0053]

[0054]

[0055]

Claims

1. A method for simultaneously achieving harmless treatment and resource utilization of silkworm excrement and cocoon cooking wastewater, characterized in that, The method comprises the following steps: S1, mixing silkworm excrement and cocoon cooking wastewater at a mass g: volume mL ratio of 1:5-1:50, stirring uniformly, and then incubating at 80-90 DEG C for 1-6 hours, and then cooling to room temperature; S2, using a spiral extruder to extrude the mixture obtained in S1 to obtain silkworm excrement filter residue and silkworm excrement water extract; S3, detecting pathogenic bacteria in the silkworm excrement filter residue and silkworm excrement water extract obtained in S2; S4, mixing the silkworm excrement filter residue collected in S2 with vegetable garden soil at a mass ratio of 1:1-1:2, and using the mixture to plant vegetables; S5, inoculate Chlorella into the collected silk worm excrement water extract in S2, the inoculation density is 10 4 -10 5 cells / mL, the culture temperature is 25℃, the light intensity is 3000 lux, and the Chlorella culture solution is obtained after 3-5 days of culture. S6, separating algae from the Chlorella vulgaris culture solution collected in S5, using the algal body to prepare a composite aquatic feed, and directly discharging the separated water into a natural water body.

2. The method for simultaneously realizing harmless treatment and resource utilization of silkworm excrement and cocoon cooking wastewater according to claim 1, characterized in that, The total nitrogen content of the cocoon cooking wastewater in S1 is 203.2±4.48 mg / L, the total phosphorus content is 18.2±0.11 mg / L, the COD content is 2535.0±4.48 mg / L, and the temperature is 90-100 DEG C.

3. The method for simultaneously realizing harmless treatment and resource utilization of silkworm excrement and cocoon cooking wastewater according to claim 1, characterized in that, The rotation speed of the spiral extruder in S2 is 50-100 r / min, and the strip gap is 1-2 mm.

4. The method for harmless treatment and resource utilization of silkworm excrement and cocoon cooking wastewater according to claim 1, characterized in that, The plate colony counting method or polymerase chain reaction is used to detect pathogenic bacteria in S3.

5. The method for harmless treatment and resource utilization of silkworm excrement and cocoon cooking wastewater according to claim 1, characterized in that, The Chlorella vulgaris in S5 is Chlorella pyrenoidosa, Chlorella sorokiniana or Chlorella vulgaris.

6. The method for harmless treatment and resource utilization of silkworm excrement and cocoon cooking wastewater according to claim 1, characterized in that, The composite aquatic feed in S6 comprises, by mass fraction, 20-25 parts of algal cells, 20-25 parts of fish meal, 15-20 parts of soybean meal, 15-20 parts of corn meal, 10-15 parts of silkworm chrysalis powder, and 1-2 parts of composite vitamins.

7. The method according to claim 6, wherein the method is characterized in that, The compound vitamin comprises, in mass fraction, B 12 20-25 parts of C, 50-60 parts of E, and 20-30 parts.

8. The method for harmless treatment and resource utilization of silkworm excrement and cocoon cooking wastewater according to claim 1, characterized in that, The detection rate of pathogenic bacteria is lower than 2.0%.

9. The method for simultaneously realizing harmless treatment and resource utilization of silkworm excrement and cocoon cooking wastewater according to claim 1, characterized in that, The plant height increase rate is higher than 37%.

10. The method for harmless treatment and resource utilization of silkworm excrement and cocoon cooking wastewater according to claim 1, characterized in that, The mortality rate of aquatic animals is lower than 0.5%, the average daily growth rate of aquatic animals is higher than 0.3%, and the incidence rate of aquatic animals is lower than 1.8%.

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