Method for synchronously realizing heavy metal passivation, ammonia reduction and nitrogen conservation through ultrahigh-temperature aerobic composting, and used strain and fungicide

Abstract

The invention discloses a method for synchronously realizing heavy metal passivation, ammonia reduction and nitrogen conservation through ultrahigh-temperature aerobic composting as well as a bacterial strain and a microbial agent used in the method, and belongs to the technical field of microorganisms and functional application thereof. According to the method, compost thermophilic bacillus WY1, thermoactinomycetes F2 and a composite conditioner are added into compost raw materials, and rapid degradation of organic matters, passivation of heavy metal activity, reduction of ammonia release amount and fixation of nitrogen are achieved under the ultrahigh-temperature aerobic condition of 60-80 DEG C. The method is beneficial to promoting the synergistic effect among different high-temperature strains and the stability of the number of effective strains in the fermentation process, improves the fermentation efficiency, solves the problems of serious odor pollution, large nitrogen loss and high heavy metal activity in traditional compost, has the advantages of high efficiency, environmental protection and low cost, and has wide application prospects. The method is suitable for resourceful treatment of livestock and poultry manure, sludge and other organic wastes.

Description

Technical Field

[0001] The present invention relates to the technical field of microorganisms and their functionalized applications, and particularly to a method, a strain and a microbial agent for synchronously achieving heavy metal passivation, ammonia reduction and nitrogen preservation through ultra-high temperature aerobic composting, which are applicable to the harmless treatment and resource utilization of organic wastes such as livestock and poultry manure, municipal sludge, and food waste. Background Art

[0002] Composting is an important method for treating organic solid wastes (such as livestock and poultry manure, agricultural straws, kitchen wastes, etc.). By the action of microorganisms, organic substances are converted into stable humus, which can not only reduce the pollution of wastes, but also produce valuable organic fertilizers. However, there are the following problems in the traditional composting process: 1. Serious nitrogen loss: Ammonia (NH3) volatilization and nitrification-denitrification during composting lead to a large amount of nitrogen loss. Especially during the high-temperature period (>50°C) of composting, ammonia volatilization intensifies, and the total nitrogen loss can reach 30%-50%, reducing the fertilizer efficiency of compost products. 2. Odor emission: Odor components such as ammonia, hydrogen sulfide (H2S), and volatile organic acids generated during composting pose significant hazards to the environment and human health. 3. Insufficient microbial activity: Ordinary mesophilic microbial agents are easily inactivated during the high-temperature period, resulting in incomplete degradation of organic substances and an extended composting cycle. 4. Heavy metals such as copper, zinc, and cadmium are often contained in organic wastes (such as livestock and poultry manure), and are easily left in an active form during composting, leading to environmental risks during subsequent agricultural use. Most current traditional compostings add single microbial agents or adsorbents, and at the same time have the following problems: 1. The high-temperature resistance of microbial agents is poor, and they cannot continuously act during the high-temperature period of composting; 2. The conditioner has a single function (only adjusting C / N or adsorbing ammonia), lacking a synergistic mechanism; 3. The combined control effect on nitrogen retention and ammonia emission reduction is insufficient; 4. The heavy metal passivation effect is not ideal. Therefore, there is an urgent need for an efficient and environmentally friendly composting product and method to solve the above problems.

[0003] By introducing ultra-thermophilic bacteria in the present invention, the composting temperature is maintained above 75°C for 3-5 days and above 65°C for 8-10 days by using their metabolic heat production. Coupled with the synergistic effect of Streptomyces thermophilus, the following significant advantages are shown: 1. Accelerate the degradation of organic matter, and the fermentation cycle is shortened to 20-25 days; 2. The high-temperature environment inhibits the activity of ammonia-producing bacteria, and the NH3 emission reduction rate reaches 20%-30%; 3. Promote the conversion of nitrogen to stable forms such as amino sugars, and the total nitrogen retention rate is increased to more than 80%. At the same time, this technology can also synchronously achieve pathogen inactivation and heavy metal passivation. Therefore, the application of the ultra-high temperature composting technology of the present invention is expected to greatly reduce the formation of ammonia and ammonium ions during composting, thereby significantly reducing composting nitrogen loss, and also achieving the effects of heavy metal passivation and shortening the composting cycle. Summary of the Invention

[0004] The primary objective of the present invention is to provide a method for synergistically reducing nitrogen loss and ammonia emissions in composting by using hyperthermophilic functional bacterial agents and conditioners, so as to solve the problems of serious nitrogen loss, large ammonia emissions, unsatisfactory heavy metal passivation, and long composting cycle in traditional composting processes.

[0005] This method optimizes nitrogen retention and ammonia control in the composting process, reduces the biological activity of heavy metals, and improves the efficiency and quality of composting through the efficient degradation ability of hyperthermophilic bacterial agents and the physicochemical effects of conditioners. Hyperthermophilic bacteria accelerate the decomposition of organic matter under high-temperature conditions, while conditioners reduce nitrogen loss and ammonia emissions by adsorbing and adjusting the C / N ratio. The synergistic effect of the two can not only improve the composting efficiency, effectively control heavy metals, reduce the activity of heavy metals, but also reduce environmental pollution. Through the metabolic activities of hyperthermophilic bacteria and the adsorption of conditioners, nitrogen in the compost is retained, heavy metals are effectively controlled, and finally high-quality organic fertilizers are formed. The conditioner adsorbs ammonia, while hyperthermophilic bacteria reduce ammonia production by rapidly decomposing organic matter, thus significantly reducing ammonia emissions during the composting process.

[0006] To achieve the above objective, the present invention adopts the following technical solutions:

[0007] A method for simultaneously achieving heavy metal passivation, ammonia reduction, and nitrogen preservation in ultra-high temperature aerobic composting,

[0008] Composting treatment is carried out using a hyperthermophilic functional bacterial agent, and the hyperthermophilic functional bacterial agent includes: Thermaerobacter composti WY1 with a preservation number of CCTCC NO: M 2025621 and Streptomycete sp. F2 with a preservation number of CCTCC NO: M 2014465, which are compounded.

[0009] The hyperthermophilic functional bacterial agent is composed of a mixed fermentation broth of Thermaerobacter composti WY1 and Streptomycete sp. F2;

[0010] The fermentation broth of Thermaerobacter composti WY1 is obtained by shaking culture at 180 - 200 rpm on a shaker at 70 - 75 °C for 2 - 3 days in a nutrient broth liquid medium;

[0011] The fermentation broth of Streptomycete sp. F2 is obtained by shaking culture at 180 - 200 rpm on a shaker at 40 - 45 °C for 3 - 5 days in a spore-producing medium.

[0012] Furthermore,

[0013] The hyperthermophilic functional bacterial agent is compounded from the fermentation broths of Thermaerobacter composti WY1 and Streptomycete sp. F2 in a volume ratio of 1 - 2:1, and the viable count of each strain's fermentation broth in the compound bacterial agent is ≥ 1×10 8CFU·mL -1 ; The inoculation amount of the hyperthermophilic functional bacterium agent is 1-2% of the mass of the compost heap.

[0014] Furthermore,

[0015] A composite conditioner is also added during composting. The composite conditioner includes: at least one of calcium superphosphate or potassium dihydrogen phosphate, biochar, and zeolite powder; preferably: the biochar is 40-60 mesh, the zeolite powder is 80-100 mesh, and both calcium superphosphate or potassium dihydrogen phosphate are of analytical purity.

[0016] The method specifically includes the following steps:

[0017] (a) Mix the organic waste with a carbon source conditioner (sawdust and rice husk) to obtain compost raw materials, adjust the moisture content to 55-65%, and the C / N ratio to 20-30;

[0018] (b) Add a composite conditioner to the compost raw materials, including:

[0019] i. Adsorbent: Zeolite powder and biochar are compounded at a ratio of 1:(1-2), and the addition amount is 3%-8%;

[0020] ii. Acidic additive: Calcium superphosphate or potassium dihydrogen phosphate, and the addition amount is 0.5%-1.5%;

[0021] (c) Inoculate the hyperthermophilic functional bacterium agent.

[0022] The specific condition parameters during composting are: aerobic composting fermentation is carried out in a 100L compost fermentation tank for 21d; the oxygen supply ventilation volume is set to 0.5-0.8L min -1 kg -1 , stop for 20-30min every 10-15min of ventilation; stir once a day in the first 7 days of composting, stir every 3 days from 8d to 15d of composting, the rotation speed is 20 - 30rpm, each time for 20-30min, and do not stir in the later stage.

[0023] The organic waste involved in the present invention includes: at least one of livestock and poultry manure, food waste, and municipal sludge.

[0024] The second object of the present invention is to provide a Thermaerobacter composti WY1, with the preservation number of CCTCC NO: M 2025621.

[0025] The third object of the present invention is to provide a hyperthermophilic functional bacterial agent, which comprises Thermaerobacter composti WY1 with the preservation number of CCTCC NO: M 2025621 and streptomycete sp F2 with the preservation number of CCTCC NO: M 2014465, which are compounded.

[0026] Further, the hyperthermophilic functional bacterial agent is compounded by the fermentation broth of Thermaerobacter composti WY1 and streptomycete sp F2 according to a volume ratio of 1-2:1, and the viable count of the fermentation broth of each strain in the compound bacterial agent is ≥ 1×10 8 CFU·mL -1 .

[0027] The R & D process of the present invention is as follows:

[0028] 1. Directional breeding of hyperthermophilic functional bacterial agent

[0029] Screen strains that can withstand high temperatures and efficiently degrade organic matter to promote rapid temperature rise of compost, shorten the composting maturity time, significantly reduce ammonia emissions during composting, reduce the bioavailability of heavy metals, and improve the quality of compost.

[0030] 2. Selection and proportioning of compound conditioner

[0031] Select conditioners with high adsorption and buffering capacities, such as zeolite, bentonite, biochar, etc., to adsorb ammonia and other volatile organic compounds generated during composting. The compound conditioner mainly includes: biochar (adsorbing NH3, catalyzing the oxidation of H2S to elemental sulfur, reducing the emission of toxic gases), zeolite (fixing NH4 + ), superphosphate (providing PO4 3- to generate magnesium ammonium phosphate), reducing nitrogen loss through multiple channels.

[0032] 3. Optimization of composting process

[0033] 4. Return the composted clinker to the raw material, and improve the composting efficiency and quality by introducing active microorganisms, optimizing the composting environment and accelerating the composting process.

[0034] The technical solution specifically includes the following steps:

[0035] 1. Preparation of hyperthermophilic functional bacterial agent

[0036] The hyperthermophilic functional bacterial agent is composed of the fermentation broth of Thermaerobacter composti WY1 and streptomycete sp F2 mixed according to a volume ratio of 1:1.

[0037] The fermentation product of Thermaerobacter compostophilus WY1 is obtained by culturing in a nutrient broth liquid medium on a shaker at 75 °C with a shaking speed of 180 - 200 rpm for 2 - 3 days to obtain a liquid fermentation product.

[0038] The fermentation product of Streptomyces thermophilus F2 is obtained by culturing in a spore-producing medium on a shaker at 40 - 45 °C with a shaking speed of 180 - 200 rpm for 3 - 5 days to obtain a liquid fermentation product.

[0039] 2. Preparation of composite conditioner

[0040] Carbon source conditioner: Sawdust and rice husk are selected to adjust the initial C / N ratio of the compost pile to 20 - 30:1;

[0041] Adsorbent: Zeolite and biochar are compounded at a ratio of 1:2, and the total addition amount is 3% - 8%;

[0042] Acidic additive: Superphosphate (addition amount 0.5% - 1.5%), reducing the pH of the compost pile to 6.5 - 7.5 to inhibit ammonia volatilization.

[0043] 3. Optimization of composting process

[0044] An aerobic composting fermentation test is carried out in a 100 L composting fermentation tank for 21 days. Forced oxygen supply is carried out through a vortex air pump, and the ventilation volume is set to 0.5 - 0.8 L min -1· kg -1 , and every 10 - 15 minutes of ventilation, it stops for 20 - 30 minutes. Stirring is carried out once a day in the first 7 days of composting, and the stirrer is turned on every 3 days from the 8th day to the 15th day of composting, with a rotation speed of 20 - 30 rpm and each time for 20 - 30 minutes, and no stirring in the later stage. Gas samples are collected once every 1 day, and solid compost samples are collected on the 0th, 3rd, 6th, 9th, 12th, 15th, 18th, and 21st days. When sampling, first start the stirrer to mix for 30 minutes, and then take about 500 g of samples from the upper, middle, and lower sampling ports respectively, and mix them evenly. And divide the taken samples into 2 parts, one part is stored in a 4 °C refrigerator, and the other part is air-dried, ground, and passed through a 1 mm sieve for later use.

[0045] The innovation points of this patent application are mainly reflected in the following aspects:

[0046] 1. Innovative combination of hyperthermophilic functional bacterial agents

[0047] Specificity of strains: Thermaerobacter compostophilus WY1 was independently screened and combined with Actinomyces thermophilus F2 for application in composting. The two act synergistically in the medium and high temperature environment, significantly enhancing the decomposition efficiency of organic matter. At the same time, through the regulation of bacterial metabolism, the generation of ammonia is reduced, and the biological activity of heavy metals is decreased.

[0048] High-temperature adaptability: Most traditional composting inoculants are adapted to medium temperatures (40 - 60°C), while the inoculant of this application is designed specifically for the synergistic effect in the medium- and high-temperature stages, breaking through the limitation of high temperature on microbial activity and shortening the composting cycle.

[0049] 2. Multifunctional Synergistic Design of Composite Conditioner

[0050] Adsorption - Chemical Fixation Dual Mechanism: Adopt a composite formula of biochar (adsorbing ammonia), zeolite powder (ion-exchanging and fixing nitrogen), and superphosphate (acidifying to inhibit ammonia volatilization). Through the triple effects of physical adsorption, chemical fixation, and pH adjustment, synchronously reduce nitrogen loss (the total nitrogen retention rate is increased by 15 - 20%) and the emissions of hydrogen sulfide and ammonia (emission reduction by 20 - 30%).

[0051] Targeted Adaptation to the High-temperature Stage: The components of the conditioner are selected to match the activity of the high-temperature inoculant. For example, superphosphate releases acidic substances at high temperatures, effectively inhibiting ammonia volatilization caused by the alkaline environment.

[0052] 3. Synergistic Optimization of Nitrogen Retention and Ammonia Control in the High-temperature Stage

[0053] Solution to the Contradictory Problem: Although the high-temperature stage of traditional composting accelerates decomposition, it is accompanied by high nitrogen loss and ammonia release. The method of this invention, through the synchronous addition of inoculant and conditioner, not only maintains the efficient degradation of organic matter in the high-temperature stage but also instantaneously fixes the released ammonia with the conditioner, breaking through the nitrogen retention bottleneck of high-temperature composting.

[0054] 4. Improvement of Comprehensive Efficiency

[0055] Multi-objective Synergistic Enhancement: While shortening the composting cycle, it takes into account nitrogen retention, ammonia emission reduction, and the degradation efficiency of organic matter, solving the contradiction between "rapid composting" and "nutrient loss" in traditional technologies.

[0056] Double Benefits for Environment and Economy: By reducing nitrogen loss, it reduces the subsequent fertilizer supplementation cost; by ammonia emission reduction, it reduces the load on treatment facilities; by passivating heavy metals, it reduces crop accumulation, having significant environmental and economic benefits.

[0057] 5. Integrated Innovation of Technical Path

[0058] Combination of Biology and Physicochemistry: Deeply integrate the biodegradation ability of hyperthermophilic bacteria and the physicochemical functions of the conditioner to form an integrated technical path of "biological promotion of decomposition + instant nitrogen fixation and ammonia locking", which is different from the conventional schemes of single biological or chemical means.

[0059] Beneficial Effects of the Invention

[0060] 1. Reduction of Nitrogen Loss: Through the synergistic effect of hyperthermophilic functional inoculant and conditioner, significantly reduce ammonia emissions during composting and nitrogen loss during the composting process.

[0061] 2. Improve composting efficiency: The high degradation ability of thermophilic bacteria agents shortens the composting cycle and improves the quality and stability of compost products.

[0062] 3. Environmentally friendly: This method is simple to operate, can passivate heavy metals, is suitable for large-scale application, and has significant environmental and economic benefits.

[0063] The preservation information of the strains used in the present invention is as follows:

[0064] The compost thermophilic aerobacterium of the present invention is named Thermaerobacter composti WY1, the preservation unit: China Center for Type Culture Collection, the preservation number is CCTCC NO: M 2025621, the preservation time is March 31, 2025, and the address: Wuhan University, Wuhan, China.

[0065] The thermophilic Streptomyces of the present invention is named Streptomycete sp.F2, the preservation unit: China Center for Type Culture Collection, the preservation number is CCTCC NO: M 2014465, the preservation time is October 10, 2014, and the address: Wuhan University, Wuhan, China. This strain has been publicly disclosed. Description of the drawings

[0066] Figure 1 : The cell morphology of strain WY1;

[0067] Figure 2 : Phylogenetic analysis of strain WY1;

[0068] Figure 3 : Temperature changes during the ultra-high temperature composting process of different experimental groups;

[0069] Figure 4 : Changes in ammonia release during the ultra-high temperature composting process of different experimental groups;

[0070] Figure 5 : Seed germination index of compost products after ultra-high temperature composting of different experimental groups;

[0071] Figure 6 : Relative passivation rate of heavy metals after ultra-high temperature composting. Specific implementation manners

[0072] The following implementation manners are intended to further illustrate the present invention rather than limit the present invention.

[0073] Example 1: Isolation and identification of hyperthermophilic strains

[0074] (1) Screening and molecular identification of hyperthermophilic strains

[0075] A hyperthermophilic strain (named WY1) was screened from compost samples during the high-temperature period through continuous heat acclimation. The cell morphology of this strain was observed (see Figure 1 ) and phylogenetic analysis was carried out (see Figure 2 ). The bacterial cells are Gram-positive, rod-shaped, and form spores after growing to the stationary phase. The spores are round and strictly aerobic. This strain was preliminarily identified as Thermaerobacter Composti.

[0076] (2) Determination of the growth performance of Thermaerobacter Composti WY1

[0077] In order to better apply it to the ultra-high temperature composting experiment, the growth performance of this strain at different temperatures was determined under laboratory conditions. The results showed that the optimal growth temperature of this strain in the medium was 75 °C, and the highest growth temperature was 82 °C.

[0078] (3) Determination of the tolerance of Thermaerobacter Composti WY1 and Streptomyces thermophilus F2 to various heavy metals

[0079] The activated Thermaerobacter Composti WY1 and Streptomyces thermophilus F2 were respectively inoculated into fresh nutrient broth liquid medium and sporulation medium supplemented with different concentrations of K2Cr2O7, CdCl2, ZnSO4·7H2O, MnSO4·H2O, CuSO4·5H2O, Pb(NO3)2 and CoCl3. The medium without adding any heavy metals and only inoculating Thermaerobacter Composti WY1 and Streptomyces thermophilus F2 was used as the control. Each treatment had 3 replicates and was cultured at 75 °C and 45 °C for 2 - 3 d. The minimum inhibitory concentration (MIC) of each metal was evaluated according to the growth of Thermaerobacter Composti WY1 and Streptomyces thermophilus F2 in the shake flask. The minimum inhibitory concentrations of different heavy metals on Thermaerobacter Composti WY1 and Streptomyces thermophilus F2 are shown in Table 1. The two strains have a certain tolerance to common heavy metals.

[0080] Table 1 Minimum inhibitory concentrations of different heavy metals on WY1 and F2

[0081]

[0082] Example 2: Preparation of hyperthermophilic functional bacterial agent

[0083] Thermaerobacter Composti WY1 was inoculated into nutrient broth medium and cultured in a shake flask at a culture temperature of 75 °C for 2 - 3 d to obtain a bacterial solution with a viable count of 2.0×10 8 CFU·mL -1 .

[0084] Nutrient broth medium: Beef extract 3 g / L; Peptone 10 g / L; Sodium chloride 5 g / L; Agar 20 g / L; pH 7.0 - 7.2.

[0085] Inoculate Thermostreptomyces sp. F2 into the spore - producing medium and perform shake - flask culture at a culture temperature of 45 °C, shaking culture at 200 rpm for 4 d to obtain a bacterial solution with a viable cell count of 2.0×10 8 CFU·mL -1 of the bacterial suspension.

[0086] Streptomyces spore - producing medium: Yeast extract 2.0%; Soluble starch 2.0%; Maltose 5.0%; Cobalt chloride hexahydrate 0.00025%; pH 7.2 - 7.4.

[0087] Mix the bacterial suspensions of Thermophilic Aerobacter WY1 and Thermostreptomyces sp. F2 in a volume ratio of 1:1 to obtain a composite hyperthermophilic bacterial agent, and the viable cell count of each strain in the composite bacterial agent ≥ 1.0×10 8 CFU·mL -1 .

[0088] Example 3: Preparation of composite conditioner

[0089] The adsorbents zeolite and biochar are compounded at a ratio of 1:2, and the total addition amount is 5%; Acidic additive: Superphosphate (addition amount 1.0%) to reduce the pH of the compost pile to 7.0 and inhibit ammonia volatilization.

[0090] Example 4: Application of hyperthermophilic functional bacterial agent and composite conditioner in livestock and poultry manure composting

[0091] 1. Experimental design

[0092] Mix pig manure, sawdust and rice husk with water evenly, adjust the C / N ratio to be between 20 and 30, and the moisture content to be about 60% to obtain compost raw materials. Then mix the compost raw materials and the composite conditioner evenly at a mass ratio of 8:1 to obtain compost mixed materials. Add the compost mixed materials into a 100 - L compost reactor (using the fermentation tank in the utility model with the application number 202322464098.3) for aerobic composting fermentation test. The physicochemical properties of the compost raw materials are shown in Table 2. When starting the compost reaction for the first time, add the hyperthermophilic functional bacterial agent, and the addition ratio is 2.0% of the mass of the compost mixed materials, and make it mix evenly with the material to be treated; Start the ultra - high - temperature composting, set the fermentation time to 21 d, perform forced oxygen supply through a vortex air pump in the compost reactor, and set the ventilation volume to 0.5 L min -1· kg -1, Ventilate for 10 min and stop for 30 min. Stir once a day in the first 7 days of composting, and stir every 3 days from the 8th day to the 15th day of composting at a rotation speed of 20 rpm for 30 min each time. Do not stir in the later stage. Collect gas samples once every 1 day, and collect solid compost samples on the 0th, 3rd, 6th, 9th, 12th, 15th, 18th, and 21st days. When sampling, first start the stirrer to mix for 30 min, and then take about 500 g of samples from the upper, middle, and lower sampling ports respectively and mix them evenly. Divide the collected samples into two parts, one part is stored in a refrigerator at 4 °C, and the other part is air-dried, ground, and passed through a 1 mm sieve for standby. After the composting is completed, the compost product is taken out from the composting box, which is the organic fertilizer, and a part can be used as the return mixing material.

[0093] After the composting reaction enters the continuous operation stage, the ultra-high temperature composting clinker can also be returned to the compost mixing material, and the return mixing ratio is 10% - 15% of the mass of the compost mixing material (the main purpose of adding return materials, that is, the already decomposed compost or partially decomposed materials, to the ultra-high temperature composting is to improve the composting efficiency and quality by introducing active microorganisms, optimizing the composting environment, and accelerating the decomposition process).

[0094] 2. Experimental grouping

[0095] The CK group is the control group, without adding microbial agents and composite conditioners to the compost; in the experimental T1 group, no microbial agents are added to the compost, only composite conditioners are added; in the experimental T2 group, the fermentation broth of Thermoactinomyces sp. F2 (concentration about 2.0×10 8 CFU·mL -1 approx.) and composite conditioners are added to the compost; in the experimental T3 group, the fermentation broth of Thermaerobacter sp. WY1 (concentration about 2.0×10 8 CFU·mL -1 approx.) and composite conditioners are added to the compost; in the experimental T4 group, ultra-thermophilic functional microbial agents (total concentration of two kinds of bacteria about 2.0×10 8 CFU·mL -1 approx.) and composite conditioners are added to the compost. The addition amount of microbial agents is 2% in all groups.

[0096] Table 2 Physicochemical properties of compost raw materials

[0097]

[0098] 3. Experimental results

[0099] 1) Temperature change

[0100] Such as Figure 3As shown, all treatments in the composting process went through four stages: the heating period, the high-temperature period, the cooling period, and the maturity period. In the experimental groups T3 and T4 inoculated with Thermophilic Aerobic Bacterium WY1, the temperature increased rapidly to the highest temperatures of 75.4 °C and 78.2 °C on the 4th day and the 3rd day respectively, and the high-temperature period above 55 °C lasted for 10 days and 12 days respectively. In the experimental group T2 inoculated with Streptomyces thermophilus F2, the temperature rose to the highest temperature of 65.6 °C on the 5th day, and the high-temperature period at 55 °C lasted for 7 days. The CK and T1 groups without inoculants had a slower temperature increase. The highest temperatures reached on the 7th day were 58.7 °C and 58.0 °C respectively, and the high-temperature period above 55 °C only lasted for 5 days. Thus, it can be seen that the experimental groups with the addition of hyperthermophilic bacterium agents can promote the compost pile to enter the high-temperature period in advance and extend the duration of the high-temperature period. The hyperthermophilic bacterium agents accelerated the decomposition of organic matter in the compost pile, released a large amount of heat at the same time, promoted the composting system to quickly enter the high-temperature period, and accelerated the composting process.

[0101] 2) Ammonia release

[0102] The NH3 release amounts of each treatment group are as Figure 4 shown. The peaks of NH3 release amounts during composting in the experimental groups T3 and T4 with the addition of hyperthermophilic bacterium agents appeared on the 3rd day, and the maximum NH3 release values were 45.7 ppm and 37.5 ppm respectively. For the CK and T1 treatments without bacterium agents, the peaks of NH3 release were on the 7th day, which were 65.6 ppm and 50.7 ppm respectively. During the whole composting process, compared with the control group, the experimental groups with the addition of microbial bacterium agents and composite conditioner effectively reduced the volatilization of ammonia. The maximum NH3 release amounts of the experimental groups T1, T2, T3, and T4 were reduced by 14.9%, 9.2%, 19.9%, and 28.1% respectively compared with the CK group.

[0103] 3) Total nitrogen content

[0104] As shown in Table 3, after 21 days of composting fermentation, the control treatment (CK) had the largest total nitrogen loss, reaching 26.02%. The order of total nitrogen loss was CK > T1 > T2 > T3 > T4. This shows that the experimental groups with the addition of bacterium agents and conditioner had significantly better nitrogen retention effects than the control group, and the nitrogen retention effect was the best when both bacterium agents and conditioner were added, reducing by 24.48% compared with the control (P < 0.05).

[0105] Table 3 Changes in total nitrogen content (%) of each treatment before and after composting

[0106]

[0107] 4) Seed germination index

[0108] The seed germination index is an important biological index for evaluating the maturity of compost. According to the NY / T 525 - 2021 standard, when GI ≥ 70%, it is considered that the compost product reaches the maturity level and has no obvious toxic effect on plants. ByFigure 5 It can be seen that as the composting progresses, the seed germination index (GI) of different treatment groups shows a gradually increasing trend throughout the composting process. At 9 days of composting, the GI values of the experimental groups T2, T3, and T4 with added inoculants reached 76.4%, 96.5%, and 104.6% respectively, all exceeding 70%, indicating that the composting had basically reached the mature level. At the end of composting, the GI values of the experimental groups T2, T3, and T4 reached 105.3%, 112.5%, and 121.2% respectively, which shows that adding microbial inoculants to the compost can accelerate the composting of the pile. In particular, the composting speed of the experimental group T4 with added hyperthermophilic functional inoculant was the fastest, significantly shortening the composting cycle and improving the degree of compost maturity.

[0109] 5) Relative passivation rate of ultra-high temperature composting

[0110] Compared with the control CK, the ultra-high temperature composting with added hyperthermophilic functional inoculant and composite conditioner reduced the distribution rates of exchangeable and reducible forms of copper and zinc, and increased the distribution rates of oxidizable and residual forms. From this, the relative passivation rates of heavy metals copper and zinc ( Figure 6 ) can be calculated, that is, the difference between the effective state distribution rate of heavy metals before composting and the effective state distribution rate after composting, divided by the effective state distribution rate of heavy metals before composting, and then multiplied by 100%. The results show that the treatment of experimental group T4, that is, adding hyperthermophilic functional inoculant and composite conditioner to the compost, improved the passivation efficiency of heavy metals copper and zinc.

Claims

1. A method for simultaneously achieving heavy metal passivation, ammonia reduction and nitrogen conservation by ultra-high temperature aerobic composting, characterized in that: The super thermophilic functional bacterial agent is used for composting treatment, wherein the super thermophilic functional bacterial agent comprises: a compound of Thermaerobacter composti WY1 with a preservation number of CCTCC NO: M 2025621 and a compound of Streptomycete sp. F2 with a preservation number of CCTCC NO: M 2014465.

2. The method according to claim 1, characterized in that The hyperthermophilic functional bacterial agent is composed of a mixture of fermentation broths of composting thermophilic Aerobacillus WY1 and thermophilic Streptomyces F2; The fermentation liquid of the composting thermophilic aerobacter WY1 was obtained by shaking and culturing in a nutrient broth liquid medium at 70-75°C and 180-200 rpm for 2-3 days; The fermentation broth of thermophilic Streptomyces F2 is obtained by culturing in a spore-forming medium at 40-45° C. and 180-200 rpm shaking on a shaker for 3-5 days.

3. The method according to claim 1, characterized in that The super thermophilic functional bacterial agent is prepared by compounding the fermentation broth of compost thermophilic Aerobacillus WY1 and thermophilic Streptomyces F2 in a volume ratio of 1-2:1, and the number of viable bacteria in the fermentation broth of each strain in the composite bacterial agent is ≥1×10 8 CFU·mL -1 The inoculation amount of the hyperthermophilic functional bacterial agent is 1-2% of the mass of the pile.

4. The method according to claim 1, 2 or 3, characterized in that: A composite conditioner is also added during composting, and the composite conditioner includes: at least one of superphosphate or potassium dihydrogen phosphate, biochar, and zeolite powder; preferably: biochar 40-60 mesh, zeolite powder 80-100 mesh, superphosphate or potassium dihydrogen phosphate are all analytically pure.

5. The method according to any one of claims 1 to 4, characterized in that: The following steps are involved: (a) mixing organic waste with a carbon source conditioner to obtain a composting raw material, adjusting the moisture content to 55-65% and the C / N ratio to 20-30; (b) Adding a composite conditioner to the compost raw material comprises: i. Adsorbent: zeolite powder and biochar are mixed in a ratio of 1: (1-2), and the addition amount is 3%-8%; ii. Acidic additives: superphosphate or potassium dihydrogen phosphate, added in an amount of 0.5%-1.5%; (c) Inoculation of hyperthermophilic functional bacteria.

6. The method according to claim 5, characterized in that Composting parameters: 21 days of aerobic composting in a 100L composting tank; oxygen supply and ventilation rate set at 0.5-0.8L min -1 kg -1 , ventilate for 10-15 minutes, stop for 20-30 minutes; start stirring once a day for the first 7 days of composting, and start stirring every 3 days for 8-15 days of composting, with a speed of 20-30rpm, each time for 20-30 minutes, and no stirring in the later period.

7. The method according to claim 5, characterized in that Organic waste includes at least one of livestock and poultry manure, food waste and municipal sludge.

8. A composting Thermaerobacter composti WY1, with a preservation number of CCTCC NO: M2025621.

9. A hyperthermophilic functional bacterial agent, characterized in that: The hyperthermophilic functional bacterial agent comprises: a compound of Thermaerobacter composti WY1 with a preservation number of CCTCCNO: M 2025621 and a compound of Streptomycete sp. F2 with a preservation number of CCTCCNO: M 2014465.

10. The bacterial agent according to claim 9, characterized in that The super thermophilic functional bacterial agent is prepared by compounding the fermentation broth of compost thermophilic Aerobacillus WY1 and thermophilic Streptomyces F2 in a volume ratio of 1-2:1, and the number of viable bacteria in the fermentation broth of each strain in the composite bacterial agent is ≥1×10 8 CFU·mL -1 .

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