Sludge source plant stimulant as well as directional preparation method and application thereof

Abstract

The invention relates to the technical field of organic solid waste resourceful treatment, and discloses a sludge source plant stimulant and a directional preparation method and application thereof. The method comprises the following steps: (1) carrying out ultrasonic conditioning on activated sludge in an aerobic tank of an urban sewage plant to obtain an activated sludge raw material; and (2) performing different conversion treatments on the activated sludge raw material to directionally prepare the sludge source plant stimulant. The method provided by the invention not only can solve the problem of a large amount of sludge solid wastes after sewage treatment and anaerobic digestion treatment, but also can be used for directionally and efficiently preparing the high-value sludge source plant stimulant.

Description

Technical Field

[0001] The invention relates to the technical field of organic solid waste resource treatment, and in particular to a sludge-derived plant stimulant and a directional preparation method and application thereof. Background Art

[0002] As the demand for wastewater treatment increases, the amount of sludge generated by sewage treatment plants around the world is increasing. As an organic solid waste with complex composition and high water content, sludge can cause secondary pollution of groundwater and soil after rainwater erosion and leakage if it is not properly stabilized and reduced. At the same time, sludge is also a rich resource of carbon, nitrogen and phosphorus, containing polysaccharides, amino acids, humus and other substances that can be converted and utilized. Anaerobic digestion is one of the most widely used sludge resource technologies, which can achieve sludge stabilization and produce excellent gas fuel, but it also produces a large amount of digested sludge to be treated. Therefore, the development of sludge resource technology is of great significance to environmental protection and resource recycling.

[0003] As the population increases, the demand for food continues to rise, while extreme climate and frequent pests and diseases make it increasingly difficult to ensure the safety of crops. Although the application of inorganic fertilizers and pesticides can increase food production, it will lead to a decline in the quality of crops and pose potential health threats and soil risks. Therefore, it is particularly important to find resources that can replace traditional fertilizers to improve agricultural productivity. Non-toxic and harmless plant stimulants (including humic acid, protein hydrolysates, plant hormones, etc.) have therefore received great attention. Among them, plant hormones are the most important signaling molecules in plants, which can regulate plant signal transduction pathways, alleviate internal and external stimuli, and resist biotic and abiotic stresses.

[0004] Studies have found that sludge extracts contain plant stimulants, which have the potential to promote crop growth and resist pests, and can be used as liquid fertilizer. The development of sludge-derived plant stimulant production technology provides a new approach to solving the contradiction between rising food demand and global environmental degradation, and also brings opportunities for the resource utilization of organic solid waste. Currently, research is still in its infancy, and the plant hormones contained in it are not clearly identified, cannot be regulated, and cannot be effectively applied to crop production. It is urgent to provide a method that can prepare key plant hormone components through biological and chemical conversion technologies so that different types of sludge-derived plant stimulant products can be applied according to the state of the plant. Summary of the invention

[0005] The purpose of the present invention is to overcome the above problems existing in the prior art.

[0006] In order to achieve the above object, the first aspect of the present invention provides a method for directional preparation of sludge-derived plant stimulants, the method comprising the following steps:

[0007] (1) Ultrasonic conditioning is performed on the activated sludge in the aerobic tank of a municipal sewage plant to obtain activated sludge raw material;

[0008] (2) converting the activated sludge raw material to prepare sludge-derived plant stimulants in a targeted manner, specifically comprising:

[0009] S1. When the target sludge source plant stimulant is an auxin hormone, firstly adjusting the solid content of the activated sludge raw material to 5-20wt% to obtain a mixture I; then performing a first alkaline thermal hydrolysis on the mixture I to obtain the auxin hormone after separation;

[0010] S2. When the target sludge source plant stimulant is a jasmonic acid hormone, the solid content of the activated sludge raw material is first adjusted to 3-5wt% to obtain a mixture II; then the mixture II is subjected to semi-anaerobic digestion biological treatment to obtain a sludge with a solid content of 5-20wt% after solid-liquid separation, and then subjected to a second alkaline thermal hydrolysis to obtain a jasmonic acid hormone after separation;

[0011] The operation of the semi-anaerobic digestion biological treatment includes: hydrolyzing and acidifying the mixture II in an anaerobic digestion device at a temperature of 35-45° C. and a pH of 4.6-5.8 to obtain the sludge.

[0012] The second aspect of the present invention provides a sludge-derived plant stimulant prepared by the method described in the first aspect.

[0013] The third aspect of the present invention provides the use of the sludge-derived plant stimulant described in the second aspect in promoting plant growth and / or improving plant resistance.

[0014] The method provided by the invention can not only solve the problem of a large amount of sludge solid waste after sewage treatment and anaerobic digestion treatment, but also can be used to prepare high-value plant hormones in a directional manner.

[0015] The auxin-rich sludge plant stimulant prepared directionally by the present invention through different treatment methods can be used as a liquid fertilizer for promoting seedling germination and plant development after being diluted with water; the jasmonic acid-rich sludge plant stimulant prepared directionally can be used as a liquid fertilizer for resisting biological and non-biological adversities in the growth process of plants after being diluted with water.

[0016] In addition, the sludge-derived plant stimulant prepared by the present invention contains humic acid and exogenous nutrients such as carbon, nitrogen, phosphorus, potassium, and calcium, which helps plants maintain homeostasis in basic physiological and metabolic processes and improves the comprehensive performance of growth, development, and stress resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1The flowchart of the directional preparation of phytostimulants from sludge in Example 1;

[0018] Figure 2 is a graph showing changes in the total content of auxin-type plant hormones and the total content of jasmonic acid-type plant hormones of P1 before and after treatment in Example 1;

[0019] Figure 3 This is a graph showing the content of representative auxin substances in P1 in Example 1;

[0020] Figure 4 The content of representative jasmonic acid substances in P1 in Example 1;

[0021] Figure 5 The figure is a graph showing the changes in the total content of auxin-type plant hormones and the total content of jasmonic acid-type plant hormones of P3 before and after treatment in Example 2;

[0022] Figure 6 This is a graph showing the content of representative auxin substances in P3 in Example 2;

[0023] Figure 7 The figure is a graph showing the changes in the total content of auxin-type plant hormones and the total content of jasmonic acid-type plant hormones of P2 before and after treatment in Example 1;

[0024] Figure 8 This is a graph showing the content of representative auxin substances in P2 in Example 1;

[0025] Fig. 9 This is a graph showing the content of representative jasmonic acid substances in P2 in Example 1. DETAILED DESCRIPTION

[0026] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0027] As mentioned above, the first aspect of the present invention provides a method for directional preparation of sludge-derived plant stimulants, the method comprising the following steps:

[0028] (1) Ultrasonic conditioning is performed on the activated sludge in the aerobic tank of a municipal sewage plant to obtain activated sludge raw material;

[0029] (2) converting the activated sludge raw material to prepare sludge-derived plant stimulants in a targeted manner, specifically comprising:

[0030] S1. When the target sludge source plant stimulant is an auxin hormone, firstly adjusting the solid content of the activated sludge raw material to 5-20wt% to obtain a mixture I; then performing a first alkaline thermal hydrolysis on the mixture I to obtain the auxin hormone after separation;

[0031] S2. When the target sludge source plant stimulant is a jasmonic acid hormone, the solid content of the activated sludge raw material is first adjusted to 3-5wt% to obtain a mixture II; then the mixture II is subjected to semi-anaerobic digestion biological treatment to obtain a sludge with a solid content of 5-20wt% after solid-liquid separation, and then subjected to a second alkaline thermal hydrolysis to obtain a jasmonic acid hormone after separation;

[0032] The operation of the semi-anaerobic digestion biological treatment includes: hydrolyzing and acidifying the mixture II in an anaerobic digestion device at a temperature of 35-45° C. and a pH of 4.6-5.8 to obtain the sludge.

[0033] Preferably, the activated sludge in the aerobic tank of the municipal sewage plant has a dissolved oxygen of 3.5-4.5 mg / L and a COD load of 0.60-0.8 kg COD / m 3 ·d. Activated sludge in aerobic tanks of urban sewage plants.

[0034] Preferably, the method of the present invention further comprises: in step (1), before the ultrasonic conditioning, the activated sludge in the aerobic tank of the municipal sewage treatment plant is first settled for 24 hours and then filtered with a 20-mesh sieve to remove inorganic grit.

[0035] Preferably, in step (1), the conditions for the ultrasonic conditioning at least meet the following conditions: energy density is 0.1-0.2 W / mL, and the time is 3-6 min.

[0036] Preferably, the method of adjusting the solid content of the activated sludge raw material is at least one of adding water, sedimentation concentration, vacuum filtration, and plate and frame filter press.

[0037] According to a preferred specific embodiment, the method of the present invention further comprises: the first alkaline thermal hydrolysis and / or the second alkaline thermal hydrolysis is carried out in a thermal hydrolysis reactor, and the operation steps comprise: firstly adjusting the pH of the mixture I or the mixture II to 10-12, then heating to 45-55°C for low temperature maintenance for 8-13 minutes, then heating to 120-200°C for high temperature maintenance for 1-3 hours, and performing the separation after cooling.

[0038] Preferably, the cooling is to reduce the temperature to 20-30°C.

[0039] Preferably, the high temperature is maintained for 2 hours.

[0040] Preferably, the pH of the mixture I or the mixture II is adjusted by adding CaO, and the added amount is 10-15wt% of the dry weight of the sludge solids in the mixture I or the mixture II.

[0041] Preferably, the first alkaline thermal hydrolysis and / or the second alkaline thermal hydrolysis is carried out under stirring conditions at a rotation speed of 200-300 rpm, and the rotation direction of the stirrer is changed every 10-30 minutes to achieve the purpose of sufficient mixing.

[0042] Preferably, in step S2, the total time of the hydrolysis and the acidification is 3-8 days.

[0043] According to a preferred embodiment, in step S2, the operation of the semi-anaerobic digestion biological treatment includes: introducing nitrogen into an anaerobic digestion device with a stirring function for 2 minutes in advance to create an anaerobic state, and then placing the mixture II in the device, and hydrolyzing and acidifying at 35-45°C, and then performing the subsequent solid-liquid separation.

[0044] According to a preferred embodiment, the separation operation comprises: sequentially performing high-speed centrifugation and filtration on the product of the first alkaline thermal hydrolysis or the second alkaline thermal hydrolysis, and then taking the supernatant;

[0045] The rotation speed of the high-speed centrifugation is 7000-9000 rpm, the time is 9-15 min, and the average pore diameter of the filter membrane used in the filtration is 0.45 μm.

[0046] Preferably, the growth hormone contains indole-3-acetic acid.

[0047] Preferably, the growth hormone further contains at least one of L-tryptophan, indole, indole-3-lactic acid and indole-3-propionic acid.

[0048] Preferably, in the auxin hormone, the total content of auxin plant hormone is 10 4 -10 6 μg / L.

[0049] It should be noted that the total content of auxin plant hormones is the total content of auxin plant hormones including indole-3-acetic acid, L-tryptophan, indole, indole-3-lactic acid, and indole-3-propionic acid.

[0050] Preferably, the jasmonic acid hormone contains jasmonic acid, and the total content of jasmonic acid plant hormones in the jasmonic acid hormone is 10 3 -10 5 μg / L.

[0051] More preferably, the jasmonic acid hormone further contains oxypentenylcyclopentanebutyric acid and / or 12-oxo-phyto-dienoic acid.

[0052] As mentioned above, the second aspect of the present invention provides a sludge-derived plant stimulant prepared by the method described in the first aspect.

[0053] As mentioned above, the third aspect of the present invention provides the use of the sludge-derived plant stimulant described in the second aspect in promoting plant growth and / or improving plant resistance.

[0054] The present invention will be described in detail below by way of examples. In the following examples, unless otherwise specified, the raw materials are all commercially available.

[0055] Aerobic pool activated sludge from urban sewage treatment plants: taken from Shanghai Hongqiao Municipal Sewage Treatment Plant with dissolved oxygen of 3.5-4.5 mg / L and COD load of 0.8 kg COD / m 3 ·d. Activated sludge in aerobic tanks.

[0056] In the following examples, unless otherwise specified, the total volume of the thermal hydrolysis reactor is 3 L and the working volume is 2 L;

[0057] The total volume of the anaerobic digestion unit is 5L, and the working volume is 3L;

[0058] Example 1

[0059] This example is used to combine Figure 1 A preferred method for directional preparation of sludge-derived plant stimulants is provided, the method comprising the following steps:

[0060] (1) After the activated sludge in the aerobic tank of the municipal sewage plant is settled for 24 hours, it is filtered through a 20-mesh sieve to remove inorganic sand and gravel, and then ultrasonically conditioned for 3 minutes at an energy density of 0.1 W / mL to obtain an activated sludge raw material;

[0061] (2) converting the activated sludge raw material to prepare sludge-derived plant stimulants in a targeted manner, specifically comprising:

[0062] S1, using auxin hormones as target sludge source plant stimulants, first adjusting the solid content of the activated sludge raw material to 5wt%, to obtain a mixture I;

[0063] Then, 7.5 g of CaO was added to the mixture I, the pH was adjusted to 12, and then the mixture was transferred to a thermal hydrolysis reactor, stirring was started (the rotation speed was 200 rpm and the rotation direction of the stirrer was changed every 20 minutes), the temperature was heated to 50° C. and kept at low temperature for 10 minutes, and then heated to 120° C. and kept at high temperature for 2 hours to perform the first alkaline thermal hydrolysis, and after cooling to 25° C., the mixture was centrifuged at a rotation speed of 8000 rpm for 10 minutes, and then filtered using a filter membrane with an average pore diameter of 0.45 μm, and the supernatant was taken to obtain the auxin hormone, which was named P1;

[0064] S2, using jasmonic acid hormones as target sludge source plant stimulants, first adjusting the solid content of the activated sludge raw material to 3.12wt%, to obtain a mixture II;

[0065] Then, the mixture II was transferred to an anaerobic digestion device with a stirring function and nitrogen was introduced for 2 minutes to create an anaerobic state. Then, the mixture II was placed in the device and hydrolyzed and acidified at 37° C. for 8 days to perform semi-anaerobic digestion biological treatment. After solid-liquid separation to adjust the solid content, sludge with a solid content of 7.8 wt% was obtained, and CaO was added to adjust the pH to 12.

[0066] It was then transferred to a thermal hydrolysis reactor, stirring was started (the speed was 200 rpm and the rotation direction of the stirrer was changed every 20 minutes), the temperature was heated to 50°C and kept at low temperature for 10 minutes, and then heated to 120°C and kept at high temperature for 2 hours for a second alkaline thermal hydrolysis, cooled to 25°C and centrifuged at a speed of 8000 rpm for 10 minutes, and then filtered using a filter membrane with an average pore diameter of 0.45 μm, and the supernatant was taken to obtain jasmonic acid hormones, named P2.

[0067] Example 2

[0068] (1) The activated sludge in the aerobic tank of the municipal sewage plant was settled for 24 hours and then filtered through a 20-mesh sieve to remove inorganic sand and gravel, and then ultrasonically conditioned for 6 minutes at an energy density of 0.15 W / mL to obtain an activated sludge raw material;

[0069] (2) converting the activated sludge raw material to prepare sludge-derived plant stimulants in a targeted manner, specifically comprising:

[0070] S1. Using auxin hormones as target sludge source plant stimulants, the solid content of the activated sludge raw material is adjusted to 14 wt% by plate and frame filter pressing to obtain a mixture I;

[0071] Then, CaO was added to the mixture I, and the pH was adjusted to 12. The mixture was then transferred to a thermal hydrolysis reactor, and stirring was started (the rotation speed was 200 rpm and the rotation direction of the stirrer was changed every 20 minutes). The temperature was heated to 50°C and kept at low temperature for 10 minutes, and then heated to 160°C and kept at high temperature for 2 hours to perform the first alkaline thermal hydrolysis. After cooling to 25°C, the mixture was centrifuged at a rotation speed of 8000 rpm for 10 minutes, and then filtered using a filter membrane with an average pore diameter of 0.45 μm, and the supernatant was taken to obtain the auxin hormone, named P3.

[0072] Example 3

[0073] This embodiment is carried out in a similar manner to that of embodiment 1, except that in step (2), no low temperature maintenance operation is performed, specifically comprising:

[0074] (2) converting the activated sludge raw material to prepare sludge-derived plant stimulants in a targeted manner, specifically comprising:

[0075] S1, using auxin hormones as target sludge source plant stimulants, first adjusting the solid content of the activated sludge raw material to 5wt%, to obtain a mixture I;

[0076] Then, 7.5 g of CaO was added to the mixture I, the pH was adjusted to 12, and then the mixture was transferred to a thermal hydrolysis reactor, stirring was started (the rotation speed was 200 rpm and the rotation direction of the stirrer was changed every 20 minutes), the temperature was directly heated to 120° C. and maintained at high temperature for 2 hours to perform the first alkaline thermal hydrolysis, and after cooling to 25° C., the mixture was centrifuged at a rotation speed of 8000 rpm for 10 minutes, and then filtered using a filter membrane with an average pore diameter of 0.45 μm, and the supernatant was taken to obtain the auxin hormone, which was named P4;

[0077] S2, using jasmonic acid hormones as target sludge source plant stimulants, first adjusting the solid content of the activated sludge raw material to 3.12wt%, to obtain a mixture II;

[0078] Then, the mixture II was transferred to an anaerobic digestion device with a stirring function and nitrogen was introduced for 2 minutes to create an anaerobic state. Then, the mixture II was placed in the device and hydrolyzed and acidified at 37° C. for 8 days to perform semi-anaerobic digestion biological treatment. After solid-liquid separation to adjust the solid content, sludge with a solid content of 7.8 wt% was obtained, and CaO was added to adjust the pH to 12.

[0079] It was then transferred to a thermal hydrolysis reactor, and stirring was started (the speed was 200 rpm and the rotation direction of the stirrer was changed every 20 minutes). The temperature was directly heated to 120°C and maintained at high temperature for 2 hours for a second alkaline thermal hydrolysis. After cooling to 25°C, it was centrifuged at a speed of 8000 rpm for 10 minutes, and then filtered using a filter membrane with an average pore diameter of 0.45 μm. The supernatant was taken to obtain jasmonic acid hormones, named P5.

[0080] Comparative Example 1

[0081] This embodiment is carried out in a similar manner to that of embodiment 1, except that in step (1), ultrasonic conditioning is not performed, and specifically includes:

[0082] (1) The activated sludge in the aerobic tank of the municipal sewage plant is allowed to settle for 24 hours and then filtered through a 20-mesh sieve to remove inorganic sand and gravel, thereby obtaining an activated sludge raw material;

[0083] Finally, the auxin hormone (named P6) and jasmonic acid hormone (named P7) were obtained.

[0084] Test Example 1

[0085] Using the LC-MS / MS high-sensitivity platform and referring to the self-built database, the components of the growth hormones prepared in the above examples were quantitatively analyzed. The results are as follows:

[0086] For P1:

[0087] like Figure 2 As shown, compared with before treatment (i.e., mixture I in Example 1), in P1, the total content of auxin plant hormones increased significantly, from 15832.70 μg / L to 79341.10 μg / L, while the total content of jasmonic acid plant hormones did not change significantly, indicating that this method successfully prepared auxin hormones.

[0088] Among them, in P1, among the 17 auxins detected, the contents from high to low were L-tryptophan, indole-3-acetic acid, indole, indole-3-propionic acid, indole-3-lactic acid, indole-3-carboxaldehyde, oxidized indoleacetic acid, indole-3-carboxylic acid, tryptamine, indole-3-acrylic acid, indoleacetic acid-leucine, N-(3-indoleacetyl)-L-phenylalanine, indoleacetic acid-valine, indoleacetic acid-tryptophan, 3-indoleacetamide, indole-3-acetic acid methyl ester, and indoleacetic acid-glycine. Figure 3As shown, in P1, the content of L-tryptophan was 66109.20 μg / L, the content of indole-3-acetic acid was 6594.68 μg / L, the content of indole was 4936.38 μg / L, the content of indole-3-propionic acid was 1114.89 μg / L, and the content of indole-3-lactic acid was 140.70 μg / L.

[0089] Among them, in P1, the total content of jasmonic acid plant hormones detected was less than 150 μg / L, including oxypentenylcyclopentanebutyric acid and 12-oxo-phyto-dienoic acid, among which, e.g. Figure 4 As shown, in P1, the content of oxypentenylcyclopentanebutyric acid was 127.01 μg / L, and the content of 12-oxo-phyto-dienoic acid was 11.44 μg / L.

[0090] In addition, the obtained supernatant also contains 1.05g / L soluble total nitrogen, 1.30g / L humic acid, and 2.43g / L protein (in actual plant application, P1 can be used as a foliar fertilizer to promote growth after being prepared with water in a volume ratio of 1:30).

[0091] For P3:

[0092] A total of 22 auxins were detected. Figure 5 As shown, compared with before treatment (mixture I in Example 2), in P3, the total content of auxin plant hormones increased from 249.31 μg / L to 15619.14 μg / L, while the total content of jasmonic acid plant hormones changed little before and after treatment, indicating that this method successfully prepared auxin hormones.

[0093] Among them, in P3, the detected auxins are indole, L-tryptophan, indole-3-lactic acid, indole-3-acetic acid, oxidized indoleacetic acid, indole-3-carboxaldehyde, tryptamine, indole-3-propionic acid, indole-3-acrylic acid, indole-3-carboxylic acid, indoleacetic acid-aspartic acid, N-(3-indoleacetyl)-L-alanine, indole-3-butyric acid, indoleacetic acid-leucine, indoleacetic acid-dimethyl glutamate, indole-3-acetic acid methyl ester, indoleacetic acid-glutamic acid, 3-indoleacetamide, N-(3-indoleacetyl)-L-phenylalanine, indole-3-acetonitrile, indoleacetic acid-tryptophan and indoleacetic acid-phenylalanine methyl ester. Figure 6 As shown, the content of indole was 10528.71 μg / L, the content of L-tryptophan was 10528.74 μg / L, the content of indole-3-lactic acid was 4449.44 μg / L, the content of indole-3-acetic acid was 1063.27 μg / L, and the content of oxidized indoleacetic acid was 553.95 μg / L.

[0094] In addition, P3 also contains 5.92g / L soluble total nitrogen, 7.98g / L humic acid, 13.68g / L protein, 0.33g / L total potassium, and 0.38g / L total phosphorus (in actual plant application, P3 can be used as a foliar fertilizer to promote growth when mixed with water in a volume ratio of 1:20).

[0095] For P4:

[0096] Compared with before treatment (i.e., mixture I in Example 3), in P4, the total content of auxin plant hormones increased from 13354.40 μg / L to 27864.80 μg / L, while the total content of jasmonic acid plant hormones decreased, indicating that this method successfully prepared auxin hormones.

[0097] Among them, in P4, the contents of the 15 auxins detected were from high to low: L-tryptophan, indole, indole-3-acetic acid, indole-3-carboxaldehyde, indole-3-lactic acid, oxidized indoleacetic acid, tryptamine, indole-3-carboxylic acid, 3-indolepropionic acid, N-(3-indoleacetyl)-L-alanine, 3-indoleacetamide, indoleacetic acid-aspartic acid, indoleacetic acid-leucine, indole-3-acetonitrile, N-(3-indoleacetyl)-L-phenylalanine. Among them, the contents of the first four substances were 24531.80μg / L (L-tryptophan), 2740.10μg / L (indole), 253.50μg / L (indole-3-acetic acid), 113.5μg / L (indole-3-carboxaldehyde), and the contents of the remaining 11 substances were all lower than 100μg / L.

[0098] Among them, in P4, the total content of the four jasmonic acids detected was 77.60 μg / L, and the content of each substance was 29.50 μg / L for 12-hydroxyjasmonic acid, 27.10 μg / L for 12-oxo-phyto-dienoic acid, 18.70 μg / L for dihydrojasmonic acid, and 2.4 μg / L for jasmonic acid.

[0099] In addition, the obtained supernatant also contains 0.73g / L soluble total nitrogen, 3.98g / L humic acid, and 8.32g / L protein (in actual plant application, P4 can be used as a foliar fertilizer to promote growth after being prepared with water in a volume ratio of 1:15).

[0100] For P6:

[0101] Compared with before treatment (i.e., mixture I in comparative example 1), in P6, the total content of auxin plant hormones increased slightly, from 12974.60 μg / L to only 19846.40 μg / L, indicating that auxin hormones cannot be effectively prepared and have little practical application value.

[0102] Among them, in P6, the contents of the 15 auxins detected were from high to low: L-tryptophan, indole, tryptamine, indole-3-acetic acid, indole-3-carboxaldehyde, indole-3-carboxylic acid, indole-3-lactic acid, oxidized indoleacetic acid, 3-indolepropionic acid, N-(3-indoleacetyl)-L-alanine, 3-indoleacetamide, indoleacetic acid-aspartic acid, indoleacetic acid-leucine, indole-3-acetonitrile, N-(3-indoleacetyl)-L-phenylalanine. Among them, the contents of the first four substances were 17369.80μg / L (L-tryptophan), 2049.50μg / L (indole), 254.00μg / L (tryptamine), and 173.10μg / L (indole-3-acetic acid).

[0103] Test Example 2

[0104] Using the LC-MS / MS high-sensitivity platform and referring to the self-built database, the jasmonic acid hormones prepared in the above examples were quantitatively analyzed for components. The results are as follows:

[0105] For P2:

[0106] A total of 14 auxins and 3 jasmonic acids were detected in P2. Figure 7 As shown, compared with before treatment (mixture II in Example 1), the total content of jasmonic acid plant hormones increased significantly from 138.38 μg / L to 2657.77 μg / L, while the total content of auxin plant hormones decreased. Compared with P1, there was a significant increase in the type and content of jasmonic acid, indicating that this method successfully prepared jasmonic acid hormones.

[0107] Among them, Figure 8 As shown, in P2, the content of L-tryptophan in the detected auxin was 1665.33 μg / L, the content of indole-3-acetic acid was 353.22 μg / L, the content of indole-3-propionic acid was 304.96 μg / L, the content of indole was 139.47 μg / L, and the content of indole-3-lactic acid was 14.24 μg / L.

[0108] Among them, the total content of jasmonic acid plant hormones detected in P2 exceeded 2600 μg / L, including oxypentenylcyclopentanebutyric acid, 12-oxy-phyto-dienoic acid, and jasmonic acid, among which, e.g. Fig. 9 As shown, the content of oxypentenylcyclopentanebutyric acid was 2037.28 μg / L, the content of 12-oxo-phyto-dienoic acid was 491.48 μg / L, and the content of jasmonic acid was 129.01 μg / L.

[0109] In addition, P2 also contains 2.89g / L soluble total nitrogen, 1.47g / L humic acid, and 1.23g / L protein (in actual plant application, P2 can be used as an anti-pest foliar fertilizer after being mixed with water in a volume ratio of 1:20).

[0110] For P5:

[0111] A total of 13 auxins and 3 jasmonic acids were detected in P5. Compared with before treatment (Mixture II in Example 3), the total content of jasmonic acid plant hormones increased significantly from 203.38 μg / L to 1465.70 μg / L, while the total content of auxin plant hormones decreased. Compared with P4, the total content of jasmonic acid plant hormones was significantly improved, indicating that this method successfully prepared jasmonic acid hormones.

[0112] Among them, the content of L-tryptophan in the auxin detected in P5 was 2043.30 μg / L, the content of indole was 539.47 μg / L, the content of indole-3-acetic acid was 383.60 μg / L, the content of indole-3-propionic acid was 222.50 μg / L, and the content of indole-3-carboxaldehyde was 94.24 μg / L.

[0113] Among them, the jasmonic acid plant hormones detected in P5 include oxypentenylcyclopentanebutyric acid, 12-oxo-phyto-dienoic acid, and jasmonic acid, among which the content of oxypentenylcyclopentanebutyric acid is 1207.50 μg / L, the content of 12-oxo-phyto-dienoic acid is 209.40 μg / L, and the content of jasmonic acid is 48.80 μg / L.

[0114] In addition, P5 also contains 1.89g / L soluble total nitrogen, 5.98g / L humic acid, and 4.91g / L protein (in actual plant application, P5 can be used as an anti-pest foliar fertilizer after being mixed with water in a volume ratio of 1:10).

[0115] For P7:

[0116] Compared with before treatment (mixture II in comparative example 1), the total content of jasmonic acid plant hormones increased slightly, from 157.40 μg / L to 318.56 μg / L, indicating that the practical application value of jasmonic acid hormones prepared by this method is relatively small.

[0117] Among them, there are three types of jasmonic acid detected in P7, including oxypentenylcyclopentanebutyric acid, 12-oxy-phyto-dienoic acid, and jasmonic acid. Among them, the content of oxypentenylcyclopentanebutyric acid is 263.64μg / L, the content of 12-oxy-phyto-dienoic acid is 33.67μg / L, and the content of jasmonic acid is 21.25μg / L.

[0118] From the above, it can be seen that the method of the present invention can not only solve the problem of large amounts of sludge solid waste after sewage treatment and anaerobic digestion treatment, but also can use it to prepare high-value sludge-derived plant stimulants in a targeted and efficient manner, and apply different types of sludge-derived plant stimulants as appropriate according to the state of the plant, so as to achieve the effects of promoting plant growth and resisting external stress to improve plant resistance.

[0119] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for directional preparation of sludge-derived plant stimulants, characterized in that: The method comprises the following steps: (1) Ultrasonic conditioning is performed on the activated sludge in the aerobic tank of a municipal sewage plant to obtain activated sludge raw material; (2) converting the activated sludge raw material to prepare sludge-derived plant stimulants in a targeted manner, specifically comprising: S1. When the target sludge source plant stimulant is an auxin hormone, firstly adjusting the solid content of the activated sludge raw material to 5-20wt% to obtain a mixture I; then performing a first alkaline thermal hydrolysis on the mixture I to obtain the auxin hormone after separation; S2. When the target sludge source plant stimulant is a jasmonic acid hormone, the solid content of the activated sludge raw material is first adjusted to 3-5wt% to obtain a mixture II; then the mixture II is subjected to semi-anaerobic digestion biological treatment to obtain a sludge with a solid content of 5-20wt% after solid-liquid separation, and then subjected to a second alkaline thermal hydrolysis to obtain a jasmonic acid hormone after separation; The operation of the semi-anaerobic digestion biological treatment includes: hydrolyzing and acidifying the mixture II in an anaerobic digestion device at a temperature of 35-45° C. and a pH of 4.6-5.8 to obtain the sludge.

2. The method according to claim 1, characterized in that The method also includes: the first alkaline thermal hydrolysis and / or the second alkaline thermal hydrolysis is carried out in a thermal hydrolysis reactor, and the operation steps include: first adjusting the pH of the mixture I or the mixture II to 10-12, then heating to 45-55°C for low temperature maintenance for 8-13 minutes, then heating to 120-200°C for high temperature maintenance for 1-3 hours, and performing the separation after cooling.

3. The method according to claim 1 or 2, characterized in that: The activated sludge in the aerobic tank of the municipal sewage plant has a dissolved oxygen content of 3.5-4.5 mg / L and a COD load of 0.60-0.8 kg COD / m 3 ·d. Activated sludge in aerobic tanks of urban sewage plants.

4. The method according to claim 1 or 2, characterized in that: In step (1), the conditions for the ultrasonic conditioning at least meet the following requirements: energy density is 0.1-0.2 W / mL, and time is 3-6 min.

5. The method according to claim 1 or 2, characterized in that: In step S2, the total time of the hydrolysis and the acidification is 3-8 days.

6. The method according to claim 1 or 2, characterized in that: The separation operation includes: sequentially subjecting the product of the first alkaline thermal hydrolysis or the second alkaline thermal hydrolysis to high-speed centrifugation and filtration, and then taking the supernatant; The rotation speed of the high-speed centrifugation is 7000-9000 rpm, the time is 9-15 min, and the average pore diameter of the filter membrane used in the filtration is 0.45 μm.

7. The method according to claim 1 or 2, characterized in that: In the auxin hormone, the total content of auxin plant hormone is 10 4 -10 6 μg / L.

8. The method according to claim 1 or 2, characterized in that: The jasmonic acid hormone contains jasmonic acid, and in the jasmonic acid hormone, the total content of jasmonic acid plant hormone is 10 3 -10 5 μg / L.

9. The sludge-derived plant stimulant prepared by the method according to any one of claims 1 to 8.

10. Use of the sludge-derived plant stimulant according to claim 9 in promoting plant growth and / or improving plant resistance.

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