Mobile toilet excrement resource fermentation agent, preparation method and application thereof

Abstract

The application relates to the field of environmental protection and excrement treatment technology, and discloses a mobile toilet excrement resourceization fermentation agent and a preparation method and application thereof, the fermentation agent is made of the following raw materials: taking a basic fermentation medium as a benchmark, the inoculation amount of Lactobacillus plantarum seed liquid and Bacillus subtilis seed liquid is 3.0%-5.0% and 4.0%-6.0%, and the anhydrous betaine is 1.5-2.5 g / 100 mL; the sodium citrate dihydrate accounts for 15.0%-20.0% in terms of the total magnesium molar amount consumed by light magnesium oxide; the total phosphorus and total magnesium molar ratio in the mixed powder of potassium dihydrogen phosphate and potassium hydrogen phosphate is 0.95-1.05:1; and the hydrophobic fumed silica accounts for 1.0%-2.0% of the total mass. The technical scheme of coupling of microbial fermentation acid production and magnesium oxide neutralization is adopted, so that the technical effect of in-situ generation of magnesium ammonium phosphate precipitate in an alkaline excrement environment is achieved.

Description

Technical Field

[0001] This invention relates to the field of environmental protection and sewage treatment technology, specifically to a mobile toilet sewage resource utilization fermentation agent, its preparation method, and its application. Background Technology

[0002] Portable toilets are widely used in outdoor locations lacking municipal sewer systems. Excrement accumulates rapidly within the storage tank. The urine within decomposes readily, producing large amounts of free ammonia. This causes the entire wastewater phase to quickly transform into a slightly alkaline system rich in high concentrations of ammonia nitrogen. This highly stressful microenvironment is the direct source of the strong odor emitted by portable toilets. Effective methods are needed to treat the high concentrations of foul-smelling wastewater in the storage tank in situ.

[0003] Currently, the treatment of this type of sewage typically involves adding physical adsorbents or conventional biodegradable microbial agents. Porous physical adsorbents such as activated carbon and zeolite can quickly capture dispersed odor molecules due to their abundant pore structure. This method shows good physical retention effects in the initial stages. Conventional microbial degradable agents rely on extracellular enzymes secreted by live bacteria to decompose residual organic matter in the sewage, thereby reducing the total amount of solid pollutants. Some solutions attempt to simply physically combine basic inorganic salt agents with dry bacterial powder. This approach aims to utilize the basic reaction characteristics of chemical reagents to assist in the subsequent biodegradation process.

[0004] The actual portable toilet system has an extremely high ammonia nitrogen load. The pore capacity of physical adsorption materials is fixed, and they quickly reach saturation and lose their adsorption function in the face of continuously released free ammonia. The alkaline, high-ammonia-nitrogen environment is highly biotoxic to conventional deodorizing microorganisms. The growth of externally applied live bacteria is severely inhibited in such extreme systems, and biodegradation almost stops. Simply mixing inorganic chemical agents with live bacteria powder presents serious inherent conflicts. High concentrations of inorganic salt mixtures create extremely high local osmotic pressure around the bacterial powder. This osmotic pressure directly destroys the structure of dormant cells, causing a large number of microorganisms to dehydrate and die before use. The magnesium source and mixed phosphates in the compound formula are highly hygroscopic. The porous, high-salt powder easily absorbs trace amounts of moisture during storage, causing deliquescence and clumping. The absorbed moisture not only hinders powder dispersion but also directly triggers premature and ineffective reactions of chemical precursors. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a mobile toilet waste resource utilization fermentation agent, its preparation method, and its application. This addresses the problems of existing mobile toilet waste treatment solutions where physical adsorption is easily saturated in alkaline, high-ammonia-nitrogen environments, microorganisms are easily inhibited by toxicity, and the simple combination of conventional inorganic chemical agents and live bacteria is prone to premature clumping and failure during storage due to local high osmotic stress and moisture absorption by porous powders.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a mobile toilet fecal resource recovery fermentation agent, which adopts the following technical solution:

[0008] A mobile toilet waste resource recovery fermentation agent, the fermentation agent is made from the following raw materials through fermentation and complexation processes: basic fermentation culture medium, Lactobacillus plantarum seed liquid, Bacillus subtilis seed liquid, anhydrous betaine, light magnesium oxide, sodium citrate dihydrate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, and hydrophobic fumed silica.

[0009] Furthermore, the following dosage relationships apply to all raw materials:

[0010] The basic fermentation medium uses deionized water as a solvent. Each liter of the basic fermentation medium consists of the following components and the remainder is deionized water: 15.0g to 25.0g glucose, 5.0g to 10.0g yeast extract, 5.0g to 10.0g peptone, 0.2g to 0.5g anhydrous magnesium sulfate, 0.05g to 0.1g manganese sulfate, and 1.0mL to 2.0mL Tween-80. The pH value is adjusted to 6.2 to 6.8 using hydrochloric acid solution or sodium hydroxide solution.

[0011] Based on the volume of the basic fermentation medium, the volume percentage of the inoculum of Lactobacillus plantarum seed liquid is 3.0% to 5.0%, the volume percentage of the inoculum of Bacillus subtilis seed liquid is 4.0% to 6.0%, and the dosage of anhydrous betaine is 1.5g to 2.5g per 100mL of the basic fermentation medium.

[0012] The total molar amount of magnesium in the light magnesium oxide consumed during fermentation does not include the molar amount of nutrient magnesium salts provided by anhydrous magnesium sulfate in the basic fermentation medium. The added molar amount of sodium citrate dihydrate accounts for 15.0% to 20.0% of the total molar amount of magnesium. The potassium dihydrogen phosphate and the dipotassium hydrogen phosphate form a solid mixed powder, and the ratio of the molar amount of total phosphorus to the molar amount of total magnesium in the solid mixed powder is 0.95 to 1.05:1.

[0013] The amount of hydrophobic fumed silica added accounts for 1.0% to 2.0% of the total mass of the prepared fermentation agent.

[0014] By employing the above technical solution, this invention couples microbial fermentation with a chemical precursor complexation process, enabling the fermentation agent to pre-contain water-soluble components capable of in-situ crystallization with ammonia nitrogen in the manure system, while simultaneously providing some protection for the survival of microorganisms in a high ammonia nitrogen environment. Specifically, during fermentation, *Lactobacillus plantarum* undergoes microaerobic metabolism in the fermentation medium and generates lactic acid, which leads to a decrease in the pH of the fermentation system. At this time, the added light magnesium oxide undergoes an acid-base neutralization reaction with the continuously generated lactic acid, generating water-soluble magnesium lactate. This process not only helps to relieve the feedback inhibition of microbial growth caused by lactic acid accumulation but also converts the insoluble magnesium oxide into a free magnesium ion precursor. In this reaction stage, light magnesium oxide mainly acts as a neutralizing agent, reacting with lactic acid to generate soluble magnesium lactate and water.

[0015] With the introduction of sodium citrate dihydrate, the system utilizes citrate ions to partially chelate free magnesium ions. Controlling the proportion of sodium citrate is primarily to prevent excessively rapid amorphous precipitation during subsequent addition of phosphate components, ensuring that a significant amount of magnesium and phosphorus components remain water-soluble within the fermenting agent powder during the subsequent concentration and drying processes. This relatively balanced chelation state also facilitates the gradual release of magnesium ions as the fermenting agent enters the actual manure environment and is diluted, due to changes in the complexation equilibrium.

[0016] Anhydrous betaine dissolved in the fermentation system enters the microbial cells as an osmotic pressure protectant. Under conditions of water evaporation and concentration, and subsequent contact with a high-salt manure environment, betaine can reduce the stress damage caused by high external osmotic pressure on the microorganisms, maintain the integrity of the cell membrane, and thus, to a certain extent, ensure the survival rate of Bacillus subtilis and Lactobacillus plantarum.

[0017] When the fermentation agent is added to the slightly alkaline sewage system of a portable toilet, characterized by high ammonia nitrogen levels, the water-soluble magnesium ions and mixed phosphate ions it carries are released. Under the slightly alkaline conditions of the sewage liquid phase, the free ammonia and ammonium ions in the system are in dynamic equilibrium. As the acid-base equilibrium shifts towards ammonium nitrogen, the released magnesium and phosphate ions combine with the ammonium ions, undergoing a crystallization precipitation reaction to form an insoluble magnesium ammonium phosphate solid phase. This process consumes the ammonia nitrogen in the liquid phase, reducing the material basis for ammonia volatilization and thus weakening the toxic inhibitory effect of high ammonia nitrogen on the decontamination microorganisms. From a chemical perspective, it mainly involves the combination of free magnesium ions, ammonium ions, and phosphate ions in a slightly alkaline aqueous environment, usually accompanied by several molecules of water of crystallization, to form an insoluble magnesium ammonium phosphate precipitate.

[0018] Simultaneously, the lactate, citrate, and mixed phosphate released along with the fermenting agent participate in the acid-base balance regulation of the manure liquid phase. Combined with the metabolic acid production after the resuscitation of *Lactobacillus plantarum*, this helps to lower the liquid phase pH from slightly alkaline to neutral, further reducing the proportion of free ammonia and limiting ammonia volatilization. Because hydrophobic fumed silica is added during the preparation of the fermenting agent powder, its hydrophobic groups adhere to the surface of the salt-containing fermentation material, hindering the infiltration of environmental moisture to a certain extent. This helps to mitigate the tendency of the fermenting agent to clump due to high salt and moisture absorption during storage.

[0019] Preferably, the physicochemical and biological properties of the raw material meet the following conditions:

[0020] The viable cell counts of both the *Lactobacillus plantarum* seed solution and the *Bacillus subtilis* seed solution are ≥1.0 × 10⁻⁶. 9 CFU / mL;

[0021] In the solid mixed powder, the molar ratio of potassium dihydrogen phosphate to potassium hydrogen phosphate is from 0.95:1.05 to 1.05:0.95;

[0022] The specific surface area of ​​the hydrophobic fumed silica is in the range of 100 m². 2 / g~200m 2 / g, carbon content ≥1.0%.

[0023] By employing the above technical solutions and limiting the molar ratio within the phosphate mixed powder, a slightly acidic to neutral buffer environment can be established during dissolution, reducing the risk of abnormal precipitation of effective ions caused by drastic local pH changes due to the addition of a single phosphate. Specifying the specific surface area and carbon content limits of silica ensures that its hydrophobic carbon groups are relatively uniformly dispersed within or on the surface of porous, high-salt powder particles, thus mitigating the deliquescence tendency of the fermentation agent product without significantly affecting the subsequent dissolution rate.

[0024] Preferably, the amount of the raw materials used is as follows:

[0025] Each liter of the basal fermentation medium consists of the following components and the remainder deionized water: 20.0 g glucose, 8.0 g yeast extract, 8.0 g peptone, 0.3 g anhydrous magnesium sulfate, 0.08 g manganese sulfate, 1.5 mL Tween-80, and the pH is adjusted to 6.5 using hydrochloric acid solution or sodium hydroxide solution.

[0026] Based on the volume of the basic fermentation medium, the volume percentage of the inoculum of Lactobacillus plantarum seed liquid is 4.0%, the volume percentage of the inoculum of Bacillus subtilis seed liquid is 5.0%, and the dosage of anhydrous betaine is 2.0g per 100mL of the basic fermentation medium.

[0027] The added sodium citrate dihydrate accounts for 18.0% of the total magnesium molar amount;

[0028] The ratio of the total phosphorus molar amount to the total magnesium molar amount in the solid mixed powder is 1:1, and the molar ratio of potassium dihydrogen phosphate to potassium hydrogen phosphate is 1:1.

[0029] The amount of hydrophobic fumed silica added accounts for 1.5% of the total mass of the prepared fermentation agent.

[0030] By adopting the above technical solution, setting the addition molar amount of sodium citrate to 18.0% of the total magnesium molar amount helps to balance the anti-precipitation requirements during the preparation period and the dissociation and release requirements during the application period. The equimolar ratio of mixed phosphates and magnesium source dosages is matched to ensure that the reaction ions released by the fermentation agent during the manure application stage are close to the theoretical stoichiometric ratio for the formation of magnesium ammonium phosphate crystals, reducing the residue of single ions and thus improving the ammonia nitrogen removal and total phosphorus retention efficiency during manure treatment.

[0031] Secondly, the present invention provides a method for preparing a mobile toilet fecal resource utilization fermentation agent, which adopts the following technical solution:

[0032] A method for preparing a fermentation agent for the resource utilization of feces from a portable toilet includes the following steps:

[0033] S1. After sterilizing and cooling the basic fermentation medium, inoculate it with Lactobacillus plantarum seed liquid for microaerobic fermentation; as lactic acid accumulates and the pH value decreases, add light magnesium oxide aqueous slurry to dynamically maintain the pH value of the fermentation system, record the actual consumption of the light magnesium oxide aqueous slurry, and calculate the total magnesium molar amount accordingly.

[0034] S2. After adding anhydrous betaine to the fermentation system and dissolving it, inoculate it with Bacillus subtilis seed liquid and introduce air to carry out aerobic symbiotic fermentation.

[0035] S3. After the symbiotic fermentation is completed, add sodium citrate dihydrate aqueous solution in proportion and stir to chelate.

[0036] S4. After chelation, add pre-mixed potassium dihydrogen phosphate and potassium hydrogen phosphate solid mixed powder to the fermentation system in proportion; after stirring and dissolving, immediately carry out a rapid cooling treatment to reduce the temperature of the entire fermentation liquid in a stepwise manner and maintain it between 10℃ and 15℃.

[0037] S5. The cooled whole liquid fermentation broth is dehydrated and concentrated under reduced pressure to form a concentrated salt slurry; then it is dried; finally, it is sent to a mechanical pulverizer and hydrophobic fumed silica is added at the same time to pulverize and mix together to obtain the final fermentation agent.

[0038] By employing the above technical solution, this invention combines fermentation with chemical complexation and quenching, enabling the coexistence of active microbial communities and high concentrations of water-soluble chemical precursors. During the fermentation stage, relying on the acid-producing characteristics of *Lactobacillus plantarum* and using continuously added light magnesium oxide as a neutralizing agent, the free lactic acid produced by metabolism is converted into readily water-soluble magnesium lactate. This operation maintains a suitable acid-base environment for microbial growth while simultaneously converting the externally introduced solid, insoluble magnesium source into a liquid-phase dissociated state.

[0039] Anhydrous betaine introduced into the fermentation system is actively absorbed and accumulated by microbial cells, which helps the cells to build a protective mechanism against the hypertonic environment during subsequent concentration and dehydration. After Bacillus subtilis is introduced, it utilizes the residual dissolved oxygen in the system for aerobic metabolism, forming a symbiotic fermentation state with Lactobacillus plantarum, enriching the complex microbial community structure of the fermentation broth for degrading organic matter in feces.

[0040] After symbiotic fermentation, a specific ratio of sodium citrate dihydrate solution is slowly added. The citrate ligands undergo a partial coordination reaction with free magnesium ions in the liquid phase, forming a soluble coordination complex. This reaction creates a certain steric hindrance effect on the free magnesium ions, reducing the probability of premature chemical precipitation when high-concentration phosphate is subsequently introduced.

[0041] After adding premixed phosphate solid powder, a step-by-step rapid cooling treatment is performed to quickly reduce the system temperature, thereby reducing ion migration and subsequent reaction rates. Under the combined effect of the aforementioned citrate partial complexation and the limited phosphate dissolution residence time, it helps to slow down the excessive nucleation and crystal growth of magnesium phosphate components before subsequent operations, thereby improving the retention level of effective magnesium phosphate components in the formulation.

[0042] The subsequent dehydration process directly targets the entire liquid-phase fermentation broth containing the microbial cells and all dissolved salts, avoiding the loss of effective solutes caused by conventional solid-liquid separation. The pre-treatment rapid cooling interruption effect helps reduce large-scale crystallization and deposition of salts during water evaporation and concentration. After dehydration and drying, the high-salt material is mixed with hydrophobic fumed silica during the mechanical pulverization stage. The silica particles adhere to the surface of the fermentation agent powder by mechanical force, reducing the surface energy of the product and, to some extent, preventing the wetting and penetration of moisture in the air, thus mitigating the moisture absorption and agglomeration of the salt-containing powder.

[0043] Preferably, in step S1, the microaerobic fermentation is carried out at 35℃~37℃; the specific pH control method is as follows: monitor the pH value of the fermentation broth, and when the pH value of the fermentation broth naturally decreases to between 4.0 and 4.2 due to lactic acid accumulation, start the peristaltic pump linked to the online pH sensor to add the light magnesium oxide aqueous slurry with a mass fraction of 10.0%~15.0%, dynamically maintaining the pH value of the fermentation system between 5.5 and 6.0; the microaerobic fermentation stage lasts for 12~16 hours, and the stirring speed is controlled between 100rpm and 150rpm; the total magnesium molar amount is calculated as the actual amount of magnesium element contained in the light magnesium oxide consumed, and the total magnesium molar amount does not include the amount of nutrient magnesium salts provided by anhydrous magnesium sulfate in the basic fermentation medium. In step S2, the aerobic symbiotic fermentation is carried out at 35℃~37℃ for 10~14 hours, and the aeration rate of the fermenter is adjusted to 0.5vvm~1.0vvm; in step S3, the temperature is maintained between 35℃~40℃, the mass fraction of the sodium citrate dihydrate aqueous solution is 20.0%, and it is slowly added to the fermenter at a rate of 50mL / min~100mL / min, and the mixture is stirred and chelated at a constant temperature for 40~50 minutes.

[0044] By adopting the above technical solutions and setting appropriate pH trigger thresholds and dynamic maintenance ranges, it is beneficial to achieve a dynamic balance between the lactic acid generation rate and the magnesium oxide aqueous slurry dissolution rate, reducing the impact of local pH fluctuations on the bacterial cells. Adjusting the aeration rate and isothermal conditions for aerobic symbiosis can promote the proliferation of Bacillus. Controlling the sodium citrate flow rate and chelation time helps the citrate ligands to be more uniformly dispersed in the liquid phase and to contact free magnesium ions.

[0045] Preferably, in step S4, the time for the solid mixed powder to be added and stirred to dissolve is limited to 9 to 11 minutes; the rapid cooling treatment specifically involves: introducing chilled water into the jacket of the fermenter and cooling it at a cooling rate of 2.0℃ / min to 3.0℃ / min.

[0046] By employing the above technical solution, the dissolution residence time of solid mixed phosphates is limited and rapid cooling is forced, utilizing the sudden temperature change to slow down the chemical reaction process within the fermentation system. The coordination between the dissolution sequence and the cooling rate prolongs the spontaneous nucleation time of magnesium ammonium phosphate precursors, helping to retain the water-soluble conversion activity of the active ingredients in the final solid powder.

[0047] Preferably, in step S5, the specific operation of dehydration and vacuum concentration is as follows: the whole liquid fermentation broth is directly transferred to a single-effect vacuum concentrator with a scraper and stirrer without solid-liquid separation, and dehydration is continuously carried out under the conditions of limiting the heating temperature of the broth to 35℃~40℃ and the working vacuum degree to -0.08MPa~-0.09MPa until the fermentation broth loses 60.0%~70.0% of its original moisture; the drying process is carried out until the total moisture content of the material is ≤5.0%, and is selected from the following method one or method two:

[0048] Method 1: Spread the concentrated salt slurry evenly into a vacuum conveyor belt dryer and set the heating plate temperature to 35℃~45℃ for drying;

[0049] Method 2: Transfer the concentrated salt slurry to a vacuum freeze dryer for freeze drying, control the cold trap temperature to -50℃, and the system vacuum degree to less than 10Pa.

[0050] By employing the above technical solutions, the heating temperature of the feed solution is limited to a range relatively tolerated by microorganisms, thus maintaining the cell structure of dormant live bacteria to a certain extent while removing moisture. The design with wall-scraping agitation prevents localized overheating of high-viscosity, salt-containing feed solutions at the heating wall surface. The selected vacuum conveyor drying or vacuum freeze-drying methods avoid significant heat damage during the deep dehydration stage, ensuring that the final product's moisture content meets the standards for pulverization and storage, which is beneficial for the uniform distribution of components in the compound formulation.

[0051] Thirdly, the present invention provides an application of a mobile toilet waste resource recovery fermentation agent in the treatment of mobile toilet waste, employing the following technical solution:

[0052] Application of a mobile toilet waste resource utilization fermentation agent in the treatment of mobile toilet waste.

[0053] When the above-mentioned fermentation agent is directly applied to the mobile toilet sewage treatment system using the above-mentioned technical solution, the water-soluble chemical precursors and functional microorganisms inside the fermentation agent work synergistically. After the fermentation agent is added to the sewage storage tank, magnesium lactate, sodium citrate, and phosphate buffers dissolve rapidly. The released lactate, citrate, and mixed phosphates jointly participate in the acid-base balance regulation of the sewage liquid phase. Combined with the metabolic acid production of Lactobacillus plantarum after its recovery, this helps to lower the pH value of the slightly alkaline sewage liquid phase back to the neutral range, further reducing the proportion of free ammonia and limiting ammonia volatilization.

[0054] The released magnesium ions combine with phosphate and ammonium ions to form a poorly soluble magnesium ammonium phosphate precipitate, stripping some nitrogen and phosphorus elements from the liquid phase and mitigating the inhibitory effect of high ammonia nitrogen on microorganisms. Under these conditions, the anhydrous betaine carried by the fermentation agent acts as an osmotic pressure protectant, maintaining the water balance of the free bacterial cells and promoting the revival and proliferation of *Lactobacillus plantarum* and *Bacillus subtilis* in the fecal liquid phase. They then rely on their secreted extracellular enzymes to biodegrade macromolecular organic matter in the fecal system. Through the dual effects of chemical crystallization and biodegradation, the bottom sediment is transformed into a mixture of nitrogen, phosphorus, and magnesium-rich inorganic crystals and biological residues, thereby achieving both wastewater reduction and resource utilization.

[0055] This invention provides a mobile toilet waste resource utilization fermentation agent, its preparation method, and its application. It has the following beneficial effects:

[0056] 1. This invention employs a technology that couples microbial fermentation for acid production with magnesium oxide neutralization. This process pre-contains a highly water-soluble magnesium ion precursor and mixed phosphates within the formulation, achieving the technical effect of in-situ generation of magnesium ammonium phosphate precipitate in a slightly alkaline fecal environment. Free ammonia molecules in the liquid phase are forcibly converted into ammonium ions and fixed during crystallization. Compared to conventional physical adsorption or single biodegradation technologies in the prior art, this invention overcomes the shortcomings of easily saturating the pores of physical adsorption under high ammonia nitrogen loads and severely inhibiting the growth of deodorizing microorganisms.

[0057] 2. This invention employs a technical solution combining anhydrous betaine osmotic pressure regulation, local chelation of citrate ions, and cooling quenching. Specific feeding and rapid cooling operations limit the early spontaneous binding of magnesium ions and phosphates, and construct a physiological protection mechanism for the internal microbial community against hyperosmotic stress, achieving the technical effect of stable coexistence of active microorganisms and supersaturated water-soluble inorganic precursors. Compared to existing technologies that simply dry-mix deodorizing bacteria with inorganic chemical agents, this invention overcomes the shortcomings of previous methods, such as the failure of spontaneous precipitation of inorganic ions during dehydration and mixing, and the large-scale death of dormant bacteria caused by the high-salt microenvironment.

[0058] 3. This invention employs a technical solution of incorporating hydrophobic fumed silica into the high-salt material after full-phase dehydration and concentration, and then pulverizing it together. The external particles adhere uniformly to the outside of the porous fermentation particles through mechanical force, appropriately reducing the surface energy of the product and achieving the technical effect of blocking environmental moisture penetration and preventing the high-salt powder from clumping. Compared to existing technologies that rely solely on conventional heat drying or ordinary packaging for moisture protection, this invention solves the problem of high-salt composite biological agents easily undergoing spontaneous deliquescence during long-term storage, leading to the inactivation of live bacteria. Attached Figure Description

[0059] Figure 1 This is a schematic diagram of the preparation method according to an embodiment of the present invention;

[0060] Figure 2 The figures show the test results of each group of fermentation agents in the test examples of the present invention after being introduced into a high ammonia nitrogen environment. (a) is a curve of the change of liquid phase free ammonia nitrogen concentration over time, and (b) is a bar chart of the dry weight of the solid phase recovered at the bottom after 60 minutes of reaction.

[0061] Figure 3 The figures show the test results of each group of fermentation agents in the simulated fermentation system of the test examples of the present invention. (a) is a curve of the absorbance (OD600) of suspended microorganisms changing with time, and (b) is a bar chart of COD removal rate and VS reduction rate after 120 hours of reaction. Detailed Implementation

[0062] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0063] The specifications of the main raw materials and reagents used in the following examples and comparative examples are as follows. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0064] The seed culture of *Lactobacillus plantarum*, with accession number CGMCC No. 18384, has a viable count greater than or equal to 1.0 × 10⁻⁶. 9 CFU / mL; Bacillus subtilis seed culture, preservation number CGMCC No. 17314, with a viable count greater than or equal to 1.0 × 10⁻⁶. 9 CFU / mL. The above strains were obtained through laboratory preservation or purchase.

[0065] Light magnesium oxide, with the molecular formula MgO, CAS number 1309-48-4, and a purity greater than or equal to 98.0%.

[0066] Anhydrous betaine, chemically known as N,N,N-trimethylglycine inner salt, has the molecular formula C5H. 11 NO2, CAS number 107-43-7, purity greater than or equal to 98.0%.

[0067] Sodium citrate dihydrate, chemically named 2-hydroxypropane-1,2,3-tricarboxylic acid trisodium salt dihydrate, with the molecular formula Na3C6H5O7·2H2O, CAS number 6132-04-3, and purity greater than or equal to 99.0%.

[0068] Potassium dihydrogen phosphate, molecular formula KH2PO4, CAS number 7778-77-0, analytical grade.

[0069] Dipotassium hydrogen phosphate, molecular formula K2HPO4, CAS number 7758-11-4, analytical grade.

[0070] Hydrophobic fumed silica, CAS number 68611-44-9, with a specific surface area ranging from 100 m². 2 / g~200m 2 / g, carbon content greater than or equal to 1.0%.

[0071] Preparation Example 1:

[0072] This preparation example provides a method for preparing a basic fermentation medium, including the following steps:

[0073] Take an appropriate amount of deionized water as a solvent, and add 20.0g of glucose, 8.0g of yeast extract, 8.0g of peptone, 0.3g of anhydrous magnesium sulfate, 0.08g of manganese sulfate, and 1.5mL of Tween-80 in sequence. Stir to dissolve and mix thoroughly. Adjust the pH to 6.5 using hydrochloric acid solution or sodium hydroxide solution, and then add deionized water to make up to 1L to obtain the basic fermentation medium.

[0074] Preparation Example 2:

[0075] This preparation example provides a method for preparing a basic fermentation medium, including the following steps:

[0076] Measure an appropriate amount of deionized water as a solvent, and add 15.0g of glucose, 5.0g of yeast extract, 5.0g of peptone, 0.2g of anhydrous magnesium sulfate, 0.05g of manganese sulfate, and 1.0mL of Tween-80 in sequence. Stir to fully dissolve and mix evenly. Adjust the pH value to 6.2 using hydrochloric acid solution or sodium hydroxide solution, and then add deionized water to make up to 1L to obtain the basic fermentation medium.

[0077] Preparation Example 3:

[0078] This preparation example provides a method for preparing a basic fermentation medium, including the following steps:

[0079] Measure an appropriate amount of deionized water as a solvent, and add 25.0g of glucose, 10.0g of yeast extract, 10.0g of peptone, 0.5g of anhydrous magnesium sulfate, 0.1g of manganese sulfate, and 2.0mL of Tween-80 in sequence. Stir to dissolve and mix thoroughly. Adjust the pH to 6.8 using hydrochloric acid solution or sodium hydroxide solution, and then add deionized water to make up to 1L to obtain the basic fermentation medium.

[0080] Example 1:

[0081] like Figure 1 As shown in the figure, this embodiment provides a method for preparing a mobile toilet fecal resource utilization fermentation agent, including the following steps:

[0082] S1. The basic fermentation medium prepared in Example 1 was placed in a fermenter with a jacketed temperature control and mechanical stirring. It was steam sterilized at 121°C for 15 minutes and then cooled to 36°C. 4.0% of the volume of the basic fermentation medium was inoculated with *Lactobacillus plantarum* seed liquid. Stirring was started and the speed was controlled at 120 rpm for microaerobic fermentation. The pH value of the fermentation broth was monitored. When the pH value of the fermentation broth naturally decreased to 4.1 due to lactic acid accumulation, a peristaltic pump linked to an online pH sensor was started to add a 12.0% (w / w) light magnesium oxide aqueous slurry. The flow rate was controlled to dynamically maintain the pH value of the fermentation system at 5.8. This stage of fermentation lasted for 14 hours. The total volume of light magnesium oxide aqueous slurry consumed was recorded, and the total molar amount of magnesium in the fermentation system was calculated based on the magnesium element in the added light magnesium oxide. The total molar amount of magnesium does not include the molar amount of nutrient magnesium salts provided by anhydrous magnesium sulfate in the basic fermentation medium.

[0083] S2. Add anhydrous betaine powder to the fermenter at a ratio of 2.0 g / 100 mL based on the volume of the basic fermentation medium, and maintain stirring for 15 minutes until completely dissolved; inoculate with Bacillus subtilis seed liquid at 5.0% of the volume of the basic fermentation medium; adjust the aeration rate of the fermenter to 0.8 vvm, and continue constant-temperature aerobic symbiotic fermentation at 36℃ for 12 hours.

[0084] S3. After the symbiotic fermentation is completed, maintain the jacket temperature of the fermenter at 38℃; prepare a 20.0% (w / w) aqueous solution of sodium citrate dihydrate; add the sodium citrate slowly to the fermenter at a rate of 75 mL / min, according to the proportion of the added sodium citrate molar amount to 18.0% of the total magnesium molar amount in the fermentation system (calculated as magnesium element); and chelate at a constant temperature for 45 minutes.

[0085] S4. After chelation, add pre-mixed potassium dihydrogen phosphate and dipotassium hydrogen phosphate solid powder to the fermenter at a uniform rate, with a total phosphorus to total magnesium molar ratio of 1:1. After the addition is completed and the mixture is stirred and dissolved for 10 minutes, immediately introduce chilled water into the jacket of the fermenter and gradually lower the temperature of the fermentation liquid in a stepwise manner at a cooling rate of 2.5℃ / min, maintaining it at 12℃.

[0086] S5. The cooled whole liquid fermentation broth is directly transferred to a single-effect vacuum concentrator with a scraper and agitator. Under the conditions of working vacuum of -0.085MPa and material heating temperature limited to 38℃, dehydration is continued until the fermentation broth loses 65.0% of its original water content, forming a concentrated salt slurry. The concentrated salt slurry is spread out and transferred to a vacuum conveyor dryer. The heating plate temperature is set to 40℃, and the material is dried until the total moisture content is less than or equal to 5.0%. The dried homogeneous solid material is fed into a mechanical pulverizer, and hydrophobic fumed silica is added and pulverized and mixed together until it accounts for 1.5% of the total mass of the final fermentation agent, thus obtaining the mobile toilet fecal resource utilization fermentation agent.

[0087] Example 2:

[0088] This embodiment provides a method for preparing a fermentation agent for the resource utilization of feces in a portable toilet, comprising the following steps:

[0089] S1. The basic fermentation medium prepared in Example 2 was placed in a fermenter with a jacketed temperature control and mechanical stirring. It was steam sterilized at 121°C for 20 minutes and then cooled to 35°C. 3.0% of the volume of the basic fermentation medium was inoculated with *Lactobacillus plantarum* seed liquid. Stirring was started and the speed was controlled at 100 rpm for microaerobic fermentation. The pH value of the fermentation broth was monitored. When the pH value of the fermentation broth naturally decreased to 4.0 due to lactic acid accumulation, a peristaltic pump linked to an online pH sensor was started to add 10.0% (w / w) of light magnesium oxide aqueous slurry. The flow rate was controlled to dynamically maintain the pH value of the fermentation system at 5.5. This stage of fermentation lasted for 12 hours. The total volume of light magnesium oxide aqueous slurry consumed was recorded, and the total molar amount of magnesium in the fermentation system was calculated based on the magnesium element in the added light magnesium oxide. The total molar amount of magnesium does not include the molar amount of nutrient magnesium salts provided by anhydrous magnesium sulfate in the basic fermentation medium.

[0090] S2. Add anhydrous betaine powder to the fermenter at a ratio of 1.5 g / 100 mL based on the volume of the basic fermentation medium, and maintain stirring for 20 minutes until completely dissolved; inoculate with Bacillus subtilis seed liquid at 4.0% of the volume of the basic fermentation medium; adjust the aeration rate of the fermenter to 0.5 vvm, and continue constant-temperature aerobic symbiotic fermentation at 35℃ for 10 hours.

[0091] S3. After the symbiotic fermentation is completed, maintain the jacket temperature of the fermenter at 35℃; prepare a 20.0% (w / w) aqueous solution of sodium citrate dihydrate; add the sodium citrate slowly to the fermenter at a rate of 50 mL / min, according to the proportion of the added sodium citrate molar amount to 15.0% of the total magnesium molar amount in the fermentation system (calculated as magnesium element); and chelate at a constant temperature for 40 minutes with stirring.

[0092] S4. After chelation, add pre-mixed potassium dihydrogen phosphate and dipotassium hydrogen phosphate solid powder to the fermenter at a uniform rate according to a total phosphorus to total magnesium molar ratio of 0.95:1, where the molar ratio of potassium dihydrogen phosphate to dipotassium hydrogen phosphate is 0.95:1.05. After the feeding is completed and the mixture is stirred and dissolved for 9 minutes, immediately introduce chilled water into the jacket of the fermenter and gradually lower the temperature of the fermentation liquid in the entire tank at a cooling rate of 2.0℃ / min, maintaining it at 10℃.

[0093] S5. The cooled whole-liquid fermentation broth is directly transferred to a single-effect vacuum concentrator with a scraper and agitator. Under the conditions of working vacuum of -0.08MPa and material heating temperature limited to 35℃, dehydration is continued until the fermentation broth loses 60.0% of its original water content, forming a concentrated salt slurry. The concentrated salt slurry is spread out and transferred to a vacuum conveyor dryer. The heating plate temperature is set to 35℃, and the material is dried until the total moisture content is less than or equal to 5.0%. The dried homogeneous solid material is fed into a mechanical pulverizer, and hydrophobic fumed silica is added and pulverized and mixed together, so that it accounts for 1.0% of the total mass of the final fermentation agent, thus obtaining the mobile toilet fecal resource utilization fermentation agent.

[0094] Example 3:

[0095] This embodiment provides a method for preparing a fermentation agent for the resource utilization of feces in a portable toilet, comprising the following steps:

[0096] S1. The basic fermentation medium prepared in Example 3 was placed in a fermenter with a jacketed temperature control and mechanical stirring. It was steam sterilized at 121°C for 15 minutes and then cooled to 37°C. 5.0% of the volume of the basic fermentation medium was inoculated with *Lactobacillus plantarum* seed liquid. Stirring was started and the speed was controlled at 150 rpm for microaerobic fermentation. The pH value of the fermentation broth was monitored. When the pH value of the fermentation broth naturally decreased to 4.2 due to lactic acid accumulation, a peristaltic pump linked to an online pH sensor was started to add a 15.0% (w / w) light magnesium oxide aqueous slurry. The flow rate was controlled to dynamically maintain the pH value of the fermentation system at 6.0. This stage of fermentation lasted for 16 hours. The total volume of light magnesium oxide aqueous slurry consumed was recorded, and the total molar amount of magnesium in the fermentation system was calculated based on the magnesium element in the added light magnesium oxide. The total molar amount of magnesium does not include the molar amount of nutrient magnesium salts provided by anhydrous magnesium sulfate in the basic fermentation medium.

[0097] S2. Add anhydrous betaine powder to the fermenter at a ratio of 2.5 g / 100 mL based on the volume of the basic fermentation medium, and maintain stirring for 15 minutes until completely dissolved; inoculate with Bacillus subtilis seed liquid at 6.0% of the volume of the basic fermentation medium; adjust the aeration rate of the fermenter to 1.0 vvm, and continue constant-temperature aerobic symbiotic fermentation at 37℃ for 14 hours.

[0098] S3. After the symbiotic fermentation is completed, maintain the jacket temperature of the fermenter at 40℃; prepare a 20.0% (w / w) aqueous solution of sodium citrate dihydrate; add the sodium citrate slowly to the fermenter at a rate of 100 mL / min, according to the proportion of the added sodium citrate molar amount to 20.0% of the total magnesium molar amount in the fermentation system (calculated as magnesium element); and chelate at a constant temperature for 50 minutes.

[0099] S4. After chelation, add pre-mixed potassium dihydrogen phosphate and dipotassium hydrogen phosphate solid powder to the fermenter at a uniform rate according to a total phosphorus to total magnesium molar ratio of 1.05:1, where the molar ratio of potassium dihydrogen phosphate to dipotassium hydrogen phosphate is 1.05:0.95. After the feeding is completed and the mixture is stirred and dissolved for 11 minutes, immediately introduce chilled water into the jacket of the fermenter and gradually lower the temperature of the fermentation liquid in the entire tank at a cooling rate of 3.0℃ / min, maintaining it at 15℃.

[0100] S5. The cooled whole-liquid fermentation broth is directly transferred to a single-effect vacuum concentrator with a scraper and agitator. Under the conditions of working vacuum of -0.09MPa and material heating temperature limited to 40℃, dehydration is continued until the fermentation broth loses 70.0% of its original water content, forming a concentrated salt slurry. The concentrated salt slurry is spread out and transferred to a vacuum conveyor dryer. The heating plate temperature is set to 45℃, and the material is dried until the total moisture content is less than or equal to 5.0%. The dried homogeneous solid material is fed into a mechanical pulverizer, and hydrophobic fumed silica is added and pulverized and mixed together until it accounts for 2.0% of the total mass of the final fermentation agent, thus obtaining the mobile toilet fecal resource utilization fermentation agent.

[0101] Example 4:

[0102] This embodiment provides a method for preparing a fermentation agent for the resource utilization of feces in a portable toilet, comprising the following steps:

[0103] S1. The basic fermentation medium prepared in Example 1 was placed in a fermenter with a jacketed temperature control and mechanical stirring. It was steam sterilized at 121°C for 15 minutes and then cooled to 36°C. 4.0% of the volume of the basic fermentation medium was inoculated with *Lactobacillus plantarum* seed liquid. Stirring was started and the speed was controlled at 120 rpm for microaerobic fermentation. The pH value of the fermentation broth was monitored. When the pH value of the fermentation broth naturally decreased to 4.1 due to lactic acid accumulation, a peristaltic pump linked to an online pH sensor was started to add a 12.0% (w / w) light magnesium oxide aqueous slurry. The flow rate was controlled to dynamically maintain the pH value of the fermentation system at 5.8. This stage of fermentation lasted for 14 hours. The total volume of light magnesium oxide aqueous slurry consumed was recorded, and the total molar amount of magnesium in the fermentation system was calculated based on the magnesium element in the added light magnesium oxide. The total molar amount of magnesium does not include the molar amount of nutrient magnesium salts provided by anhydrous magnesium sulfate in the basic fermentation medium.

[0104] S2. Add anhydrous betaine powder to the fermenter at a ratio of 2.0 g / 100 mL based on the volume of the basic fermentation medium, and maintain stirring for 15 minutes until completely dissolved; inoculate with Bacillus subtilis seed liquid at 5.0% of the volume of the basic fermentation medium; adjust the aeration rate of the fermenter to 0.8 vvm, and continue constant-temperature aerobic symbiotic fermentation at 36℃ for 12 hours.

[0105] S3. After the symbiotic fermentation is completed, maintain the jacket temperature of the fermenter at 38℃; prepare a 20.0% (w / w) aqueous solution of sodium citrate dihydrate; add the sodium citrate slowly to the fermenter at a rate of 75 mL / min, according to the proportion of the added sodium citrate molar amount to 18.0% of the total magnesium molar amount in the fermentation system (calculated as magnesium element); and chelate at a constant temperature for 45 minutes.

[0106] S4. After chelation, add pre-mixed potassium dihydrogen phosphate and dipotassium hydrogen phosphate solid powder to the fermenter at a uniform rate, with a total phosphorus to total magnesium molar ratio of 1:1. After the addition is completed and the mixture is stirred and dissolved for 10 minutes, immediately introduce chilled water into the jacket of the fermenter and gradually lower the temperature of the fermentation liquid in a stepwise manner at a cooling rate of 2.5℃ / min, maintaining it at 12℃.

[0107] S5. The cooled whole-liquid fermentation broth is directly transferred to a single-effect vacuum concentrator with a scraper and agitator. Under the conditions of working vacuum of -0.085MPa and material heating temperature limited to 38℃, dehydration is continued until the fermentation broth loses 65.0% of its original water content, forming a concentrated salt slurry. The concentrated salt slurry is then transferred to a vacuum freeze dryer for freeze drying. The cold trap temperature is set to -50℃, and the system vacuum is controlled to be less than 10Pa. The material is dried until the total moisture content is less than or equal to 5.0%. The dried homogeneous solid material is then fed into a mechanical pulverizer, and hydrophobic fumed silica is added and pulverized and mixed together until it accounts for 1.5% of the total mass of the final fermentation agent, thus obtaining the mobile toilet fecal resource utilization fermentation agent.

[0108] Comparative Example 1:

[0109] Compared with Example 1, the difference is that in step S5, the cooled whole liquid fermentation broth is first centrifuged to separate solid and liquid, the supernatant is discarded, and only the bottom solid concentrate is collected for subsequent drying and pulverizing operations. The rest are the same.

[0110] Comparative Example 2:

[0111] Compared with Example 1, the difference is that in step S3, sodium citrate dihydrate aqueous solution is not added and chelation treatment is not performed, but everything else is the same.

[0112] Comparative Example 3:

[0113] Compared with Example 1, the difference is that in step S3, the molar amount of sodium citrate dihydrate added accounts for 100.0% of the total molar amount of magnesium in the fermentation system, i.e., full stoichiometric chelation is performed, and the rest are the same.

[0114] Comparative Example 4:

[0115] Compared with Example 1, the difference is that in step S4, only potassium dihydrogen phosphate solid powder is added to provide the phosphorus source, and potassium dihydrogen phosphate is not added, while the rest are the same.

[0116] Comparative Example 5:

[0117] Compared with Example 1, the difference is that the addition of light magnesium oxide in step S1 is not performed, and the addition of sodium citrate in step S3 and the introduction of phosphate in step S4 are omitted; and after obtaining the dry powder in step S5, zeolite powder, a conventional physical adsorbent, with an equal mass to the dry powder is added and uniformly dry-mixed to form a conventional microbial-physical adsorbent compound formulation, all the other aspects are the same.

[0118] Test Example 1:

[0119] Test objective: This test case is used to investigate the effect of the synergistic effect of sodium citrate inhibitor and phosphate buffer on the water solubility retention rate of active ingredients and cell survival rate during the preparation stage.

[0120] Test steps:

[0121] 1. The experimental subjects were the dry powder of mobile toilet fecal resource utilization fermentation agent prepared in Examples 1 to 4 and Comparative Examples 1 to 5.

[0122] 2. Accurately weigh 5.00g of each group of fermentation agent dry powder samples and add them to a conical flask containing 100mL of neutral deionized water. Shake and extract at 150rpm for 30 minutes at 25℃ to fully dissolve and mix the water-soluble components.

[0123] 3. Transfer the extracted suspension to a centrifuge tube and centrifuge at 4000 rpm for 10 minutes to separate the supernatant from the bottom insoluble solid phase. Collect the supernatant as the test solution.

[0124] 4. The soluble magnesium content in the supernatant was determined using inductively coupled plasma optical emission spectrometry (ICP-OES), and the result was expressed as Mg. 2+ The retention rate of soluble magnesium was calculated based on the initial total feed amount for each group; simultaneously, the content of soluble orthophosphate in the supernatant was determined by ammonium molybdate spectrophotometry, and measured using PO4. 3- Calculate the retention rate of available phosphorus.

[0125] 5. Weigh out 1.00g of each group of fermentation agent dry powder, add 9mL of sterile physiological saline for serial dilution, and count the viable bacteria on the corresponding solid culture medium using the plate spread method, and record the total number of viable bacteria.

[0126] The test data is shown in Table 1:

[0127] Table 1: Results of test on retention rate of active ingredients and viable bacteria count of the formulation

[0128] Test object <![CDATA[Soluble magnesium retention rate (based on Mg 2+ calculated, %)]]> <![CDATA[Soluble orthophosphate retention rate (as PO4 3- , % by mass)]]> <![CDATA[Total viable count (×10 8 CFU / g)]]> Example 1 94.32 95.84 18.5 Example 2 92.15 93.41 15.2 Example 3 95.67 94.76 19.1 Example 4 93.28 92.93 16.8 Comparative Example 1 12.45 15.22 21.4 Comparative Example 2 21.53 24.89 11.3 Comparative Example 3 96.11 95.58 17.6 Comparative Example 4 18.36 20.67 8.5 Comparative Example 5 0.52 0.81 22.1

[0129] According to the data in Table 1, the soluble magnesium retention rate in Examples 1 to 4 was 92.15% to 95.67%, the soluble orthophosphate retention rate was 92.93% to 95.84%, and the total viable count was 15.2 × 10⁻⁶. 8 CFU / g up to 19.1×10 8 CFU / g. The results show that, under the preparation conditions of Examples 1 to 4, the soluble magnesium, soluble orthophosphate, and viable bacterial count in the formulation remained at high levels.

[0130] Compared to Examples 1 to 4, Comparative Example 1, which employed a centrifugal solid-liquid separation process, showed soluble magnesium retention of 12.45% and soluble orthophosphate retention of 15.22%, indicating that the solid-liquid separation process removes some of the magnesium and phosphorus components dissolved in the aqueous phase with the supernatant. Comparative Example 2, which did not include sodium citrate dihydrate, had soluble magnesium retention of 21.53% and soluble orthophosphate retention of 24.89%, lower than the Example group, indicating that the absence of sodium citrate inhibition treatment reduced the water-soluble retention level of magnesium and phosphorus components during the preparation process.

[0131] Comparative Example 4 used only dipotassium hydrogen phosphate as the phosphorus source, and its soluble magnesium retention rate and soluble orthophosphate retention rate were 18.36% and 20.67%, respectively, with a total viable count of 8.5 × 10⁻⁶. 8 The CFU / g was lower than that of the example group. This result indicates that the single phosphate system is not conducive to the retention of water solubility of magnesium phosphate components under the test conditions and has an adverse effect on the number of viable bacteria in the formulation.

[0132] Comparative Example 3 used sodium citrate dihydrate in its full stoichiometric ratio for complexation, and its soluble magnesium retention rate and soluble orthophosphate retention rate were 96.11% and 95.58%, respectively, which were close to those of the Example Group. This result indicates that increasing the amount of sodium citrate can enhance the water-soluble retention of magnesium and phosphorus components during the preparation stage; however, combined with subsequent test results, it is evident that excessive complexation will reduce the effective release of magnesium ions and the in-situ crystallization and deammoniation effect of magnesium ammonium phosphate during the application stage.

[0133] Comparative Example 5, as a conventional microbial-physical adsorbent compound formulation, had a low retention rate of soluble magnesium and soluble orthophosphate, with 0.52% and 0.81% respectively; its total viable count was 22.1 × 10⁻⁶. 8 The CFU / g indicates that this group mainly reflects the retention of live bacteria after the microbial carrier is compounded, and does not have the effective component retention characteristics brought about by the water-soluble magnesium phosphate precursor in the example group.

[0134] In summary, Examples 1 to 4 took into account the retention of soluble magnesium and soluble orthophosphate as well as the maintenance of viable bacterial count during the preparation stage. The comparative results showed that solid-liquid separation, lack of sodium citrate treatment, single phosphate system, and conventional physical adsorbent compounding process all affect the retention level of water-soluble active ingredients in the formulation.

[0135] Test Example 2:

[0136] Test objective: This test case is used to investigate the changes in liquid phase ammonia nitrogen concentration and the formation of bottom solid phase after the fermentation agent is added to a high ammonia nitrogen environment.

[0137] Test steps:

[0138] 1. The experimental subjects were the dry powder of mobile toilet fecal resource utilization fermentation agent prepared in Examples 1 to 4 and Comparative Examples 1 to 5.

[0139] 2. Prepare a simulated high ammonia nitrogen fermentation broth by adding urea, urease, and basic salt components to neutral deionized water. Incubate in a sealed container at 35°C until the urea is hydrolyzed, so that the initial ammonia nitrogen concentration in the liquid phase is NH4+. + The concentration of -N was approximately 2500 mg / L. The initial pH of the system was determined and then finely adjusted to 8.6 with dilute sodium hydroxide solution.

[0140] 3. Take 9 beakers with a capacity of 500mL, add 200mL of the prepared simulated high ammonia nitrogen fermentation broth to each, and place them on a constant temperature magnetic stirrer to maintain a stirring state of 200rpm; add 10.0g of the corresponding group of fermentation agent dry powder to each beaker, and use this as the zero point of reaction.

[0141] 4. At 5, 15, 30, and 60 minutes of reaction, 2 mL of the suspension was taken from each beaker and quickly filtered through a 0.45 μm microporous membrane. The ammonia nitrogen concentration in the filtrate was determined by Nessler's reagent spectrophotometry, and then analyzed with NH4+. + -N is used to record concentration data at different time points.

[0142] 5. After the reaction has proceeded for 60 minutes, stop the magnetic stirring and transfer all the remaining material in each beaker to the corresponding numbered centrifuge tube. Centrifuge at 3000 rpm for 10 minutes. Discard the supernatant and wash the bottom precipitate three times with deionized water. Place the washed precipitate in a vacuum drying oven at 45℃ and dry it to constant weight. Weigh and record the dry weight of the solid phase recovered at the bottom of the reaction system.

[0143] The test data is shown in Table 2:

[0144] Table 2: Simulated changes in ammonia nitrogen concentration in liquid phase of fecal waste and dry weight test results of bottom recovered solid phase

[0145] Test object 0 min (mg / L) 5 min (mg / L) 15 min (mg / L) 30 min (mg / L) 60 min (mg / L) Bottom recovered solid dry weight (g) Example 1 2512 1435 876 542 513 12.4 Example 2 2489 1502 912 588 551 11.9 Example 3 2505 1398 855 521 496 12.7 Example 4 2496 1466 891 563 528 12.1 Comparative Example 1 2510 2450 2411 2385 2360 3.2 Comparative Example 2 2495 2210 2155 2102 2088 10.5 Comparative Example 3 2508 2380 2265 2190 2150 4.5 Comparative Example 4 2502 2150 1980 1920 1895 9.8 Comparative Example 5 2515 1950 1880 1875 1870 10.3

[0146] Based on the data in Table 2, and combined with Figure 2 As shown, in Examples 1 to 4, after adding the simulated high-ammonia-nitrogen fermentation broth, the liquid-phase ammonia-nitrogen concentration decreased with increasing reaction time, ranging from 496 mg / L to 551 mg / L at 60 minutes; after the reaction, the dry weight of the bottom solid phase recovered was 11.9 g to 12.7 g. These results indicate that under the formulation conditions of Examples 1 to 4, after the fermentation agent was added to a high-ammonia-nitrogen environment, the liquid-phase ammonia-nitrogen concentration decreased, accompanied by the formation of bottom solid phase material.

[0147] Compared with Examples 1 to 4, Comparative Example 1 had an ammonia nitrogen concentration of 2360 mg / L at 60 minutes and a bottom solid phase dry weight of 3.2 g. These results indicate that after solid-liquid separation, Comparative Example 1 exhibited lower retention of water-soluble magnesium phosphorus precursors, and both the ammonia nitrogen reduction and bottom solid phase recovery were lower than those in the Example groups in a high ammonia nitrogen environment.

[0148] Comparative Example 2 showed an ammonia nitrogen concentration of 2088 mg / L at 60 minutes, with a bottom solid phase dry weight of 10.5 g. These results indicate that, without the addition of sodium citrate dihydrate for chelation treatment, the water solubility retention level of the magnesium-phosphorus components decreased during the preparation stage, and the decrease in liquid-phase ammonia nitrogen during the application stage was less significant than in the Example group.

[0149] Comparative Example 3 showed an ammonia nitrogen concentration of 2150 mg / L at 60 minutes, with a bottom solid phase dry weight of 4.5 g. These results indicate that while total stoichiometric sodium citrate complexation is beneficial for retaining soluble magnesium phosphate components during the preparation stage, under the test conditions, the decrease in liquid-phase ammonia nitrogen and the bottom solid phase recovery were lower in the application stage than in the Example group. This suggests that excessive complexation can affect magnesium ion release and subsequent magnesium ammonium phosphate solid phase formation.

[0150] Comparative Example 4 showed an ammonia nitrogen concentration of 1895 mg / L at 60 minutes, with a bottom solid phase dry weight of 9.8 g. These results indicate that when dipotassium hydrogen phosphate was used as the sole phosphorus source, the decrease in liquid-phase ammonia nitrogen and the bottom solid phase recovery were both lower than in the Example group, suggesting that the mixed phosphate system promotes the formation of magnesium ammonium phosphate solid phases at the application stage.

[0151] Comparative Example 5 showed an ammonia nitrogen concentration of 1870 mg / L at 60 minutes, with a bottom solid phase dry weight of 10.3 g. These results indicate that the conventional microbial-physical adsorbent combination formulation can reduce ammonia nitrogen concentration in the initial stage, but the change in ammonia nitrogen concentration is relatively small between 5 and 60 minutes, suggesting that its subsequent sustained ammonia nitrogen removal effect is lower than that of the Example group.

[0152] In summary, Examples 1 to 4 exhibited significant reductions in liquid-phase ammonia nitrogen and substantial recovery of the bottom solid phase in a simulated high-ammonia-nitrogen environment. These results are consistent with the reaction pathway by which the soluble magnesium phosphate precursor retained in the formulation participates in the formation of magnesium ammonium phosphate solid phases under alkaline high-ammonia-nitrogen conditions.

[0153] Test Example 3:

[0154] Test objective: This test case is used to investigate the effects of the fermentation agent on the changes in liquid phase pH and the amount of ammonia volatilization in a simulated highly alkaline manure environment.

[0155] Test steps:

[0156] 1. The experimental subjects were the dry powders of the starter culture prepared in Examples 1 to 4 and Comparative Examples 1 to 5.

[0157] 2. Prepare a simulated fecal culture medium containing a high concentration of urea and basic organic nutrients, add an appropriate amount of urease to carry out a pre-hydrolysis reaction, so that the initial pH of the reaction system reaches about 8.8, in order to simulate the liquid phase environment of the mobile toilet's fecal storage tank, which is highly alkaline and easily emits foul odors.

[0158] 3. Construct 9 fermentation reaction systems with headspace chambers and gas sampling / circulation interfaces. Each system was filled with 500 mL of pretreated simulated manure culture medium. An online pH glass electrode probe was immersed in the liquid phase and connected to a data acquisition system for continuous monitoring.

[0159] 4. Add 15.0g of the corresponding dry starter powder to each group of reaction systems, seal the reaction systems immediately, and carry out continuous reaction at a constant temperature of 35℃ for 72 hours. Record the liquid phase pH values ​​at hours 0, 12, 24, 48 and 72.

[0160] 5. During the reaction, headspace gas is introduced into the acidic absorbent at a constant flow rate for ammonia capture, and a high-precision electrochemical gas sensor is used to monitor the change in ammonia (NH3) concentration in the headspace chamber. After the 72-hour test cycle, the ammonia nitrogen content in the acidic absorbent is measured, and the cumulative NH3 volatilization mass during the entire cycle is calculated and recorded by combining the gas flow rate, sampling time and sensor concentration data.

[0161] The test data is shown in Table 3:

[0162] Table 3: Liquid phase pH self-degradation curve data and ammonia cumulative volatilization test results

[0163] Test object Initial pH (0h) 12h pH 24h pH 48h pH 72h pH <![CDATA[Cumulative NH3 volatilization mass (mg)]]> Example 1 8.82 7.84 7.41 7.22 7.15 13.5 Example 2 8.79 7.91 7.55 7.31 7.18 15.2 Example 3 8.85 7.88 7.46 7.25 7.11 12.8 Example 4 8.81 7.82 7.39 7.18 7.08 14.1 Comparative Example 1 8.80 8.75 8.68 8.61 8.55 215.4 Comparative Example 2 8.83 8.65 8.52 8.44 8.41 186.7 Comparative Example 3 8.81 8.71 8.65 8.58 8.52 204.3 Comparative Example 4 8.84 8.45 8.21 8.15 8.08 145.6 Comparative Example 5 8.82 8.52 8.48 8.46 8.45 168.2

[0164] According to the data in Table 3, during the 72-hour reaction period, the liquid phase pH of Examples 1 to 4 decreased from an initial 8.79 to 8.85 to 7.08 to 7.18, and the cumulative NH3 volatilization mass ranged from 12.8 mg to 15.2 mg. These results show that under the test conditions, after the fermentation agents corresponding to Examples 1 to 4 were introduced into a simulated highly alkaline manure environment, the pH of the reaction system showed a decreasing trend, while the cumulative NH3 volatilization mass remained at a low level.

[0165] Compared to Examples 1 to 4, Comparative Example 1 had a liquid phase pH of 8.55 and a cumulative NH3 volatilization mass of 215.4 mg after 72 hours. This result indicates that after solid-liquid separation, Comparative Example 1 exhibited a lower retention level of water-soluble chemical precursors in its formulation, and its effect on controlling liquid phase pH decline and NH3 volatilization under the test conditions was less significant than that of the Example groups.

[0166] Comparative Example 2 had a liquid phase pH of 8.41 after 72 hours, and the cumulative NH3 volatilization mass was 186.7 mg. This result indicates that, without the addition of sodium citrate dihydrate for chelation treatment, the water solubility retention level of the magnesium-phosphorus components was reduced during the preparation stage, and the effect of liquid phase pH adjustment and NH3 volatilization control during the application stage was lower than that of the Example group.

[0167] Comparative Example 3 had a liquid phase pH of 8.52 after 72 hours, and the cumulative NH3 volatilization mass was 204.3 mg. This result indicates that while the total stoichiometric sodium citrate complexation treatment is beneficial for the retention of soluble magnesium and phosphorus components during the preparation stage, under the test conditions, the release of magnesium ions and the fixation of ammonium ions during the application stage are affected, resulting in a lower liquid phase pH drop and less effective control of NH3 volatilization compared to the Example group.

[0168] Comparative Example 4, with a liquid phase pH of 8.08 after 72 hours, showed a cumulative NH3 volatilization mass of 145.6 mg. This result indicates that even when using dipotassium hydrogen phosphate as the sole phosphorus source, the reaction system remained slightly alkaline, and the cumulative NH3 volatilization mass was higher than in the Example group, suggesting that the mixed phosphate system promotes pH adjustment and ammonia volatilization control at the application end.

[0169] Comparative Example 5 had a liquid phase pH of 8.45 after 72 hours, and a cumulative NH3 volatilization mass of 168.2 mg. This result indicates that the conventional microbial-physical adsorbent combination formulation was less effective than the example group in controlling pH decline and NH3 volatilization under these test conditions.

[0170] In summary, Examples 1 to 4 exhibited a significant pH decrease trend in a simulated highly alkaline fecal environment, corresponding to a lower cumulative NH3 volatilization mass. This result is consistent with the action pathways of the water-soluble magnesium phosphate precursor in the formulation participating in ammonium nitrogen fixation and the organic acid salt buffer component participating in acid-base regulation.

[0171] Test Example 4:

[0172] Test objective: This test case is used to investigate the effects of the fermentation agent on microbial growth trend, COD removal rate and VS reduction rate in a high ammonia nitrogen simulated manure fermentation system.

[0173] Test steps:

[0174] 1. The experimental subjects were the dry powder of mobile toilet fecal resource utilization fermentation agent prepared in Examples 1 to 4 and Comparative Examples 1 to 5.

[0175] 2. Artificially prepare a simulated high-intensity manure fermentation broth containing high concentrations of urea, microcrystalline cellulose, and soluble starch. Adjust the initial ammonia nitrogen concentration of the system to NH4+. + The concentration of -N was approximately 2000 mg / L, and the initial chemical oxygen demand (COD) and total volatile solids (VS) of the system were determined.

[0176] 3. Take 9 1000mL shake flasks with breathable seals, put 400mL of the prepared simulated fermentation broth into each flask, add 10.0g of the corresponding group of fermentation agent dry powder, and place them in a constant temperature shaking incubator at 35℃ and 180rpm for incubation.

[0177] 4. At 0, 12, 24, 48 and 72 hours after inoculation, 5 mL of suspension was taken from each shake flask, centrifuged at 500 rpm for 3 minutes to remove large solid particles, and the absorbance (OD600) of the supernatant was measured at a wavelength of 600 nm. At the same time, a turbidity blank control containing the same chemical components but without live bacteria was set up to eliminate the interference of fine precipitate particles and colloidal substances on the OD600 reading, so as to reflect the growth trend of suspended free bacteria in the system.

[0178] 5. After 120 hours of fermentation, stop shaking, take samples to measure the COD concentration and residual VS mass at the reaction endpoint of each system, and calculate the COD removal rate and VS reduction rate after 120 hours based on the initial data.

[0179] The test data is shown in Table 4:

[0180] Table 4: Changes in microbial absorbance and organic matter degradation test results in the simulated fermentation system

[0181] Test object 0h OD600 12h OD600 24h OD600 48h OD600 72h OD600 COD removal rate (%) VS reduction rate (%) Example 1 0.25 0.86 2.12 2.85 3.14 69.4 56.1 Example 2 0.24 0.81 1.95 2.68 2.92 64.2 52.4 Example 3 0.26 0.94 2.27 2.91 3.28 72.5 59.3 Example 4 0.25 0.83 2.08 2.74 3.05 67.8 54.2 Comparative Example 1 0.23 0.36 0.41 0.62 0.86 22.1 17.5 Comparative Example 2 0.26 0.32 0.36 0.71 0.94 25.4 19.2 Comparative Example 3 0.24 0.45 0.52 0.82 1.15 29.3 23.6 Comparative Example 4 0.25 0.37 0.48 0.76 1.02 26.5 20.4 Comparative Example 5 0.25 0.14 0.11 0.16 0.19 11.2 8.5

[0182] Based on the data in Table 4, and combined with... Figure 3 As shown, the OD600 values ​​of Examples 1 to 4 increased with time during the cultivation process, ranging from 2.92 to 3.28 after 72 hours, and the COD removal rate from 120 hours to 64.2% to 72.5%, and the VS reduction rate from 52.4% to 59.3%. These results indicate that, under the test conditions, the fermentation agents corresponding to Examples 1 to 4 can maintain a high level of suspended microbial growth in a high-ammonia nitrogen simulated manure fermentation system, corresponding to high COD removal and VS reduction rates.

[0183] Compared with Examples 1 to 4, Comparative Example 1 had an OD600 value of 0.86, a COD removal rate of 22.1%, and a VS reduction rate of 17.5% after 72 hours. These results indicate that after solid-liquid separation, Comparative Example 1 had a lower retention level of water-soluble magnesium phosphate precursors in its formulation, and its promoting effect on suspended bacterial growth and organic matter degradation under the test conditions was lower than that of the Example group.

[0184] Comparative Example 2 had an OD600 value of 0.94, a COD removal rate of 25.4%, and a VS reduction rate of 19.2% after 72 hours. These results indicate that, without the addition of sodium citrate dihydrate for chelation treatment, the water solubility retention level of magnesium phosphate components was reduced during the preparation stage, and its promoting effect on cell growth and organic matter degradation in the simulated fermentation system during the application stage was lower than that of the Example group.

[0185] Comparative Example 3 had an OD600 value of 1.15, a COD removal rate of 29.3%, and a VS reduction rate of 23.6% after 72 hours. These results indicate that while the total stoichiometric sodium citrate complexation treatment is beneficial for the retention of soluble magnesium and phosphorus components during the preparation stage, under the conditions of this test, the release of magnesium ions and the fixation of ammonium nitrogen during the application stage were affected, resulting in lower levels of suspended bacterial growth and organic matter degradation compared to the Example group.

[0186] Comparative Example 4 had an OD600 value of 1.02, a COD removal rate of 26.5%, and a VS reduction rate of 20.4% after 72 hours. These results indicate that when dipotassium hydrogen phosphate is used as the sole phosphorus source, its promoting effect on cell growth and organic matter degradation in the high ammonia nitrogen fermentation system during the application stage is lower than that of the Example group, suggesting that the mixed phosphate system is beneficial for maintaining the reactivity of the magnesium-phosphorus precursor at the application stage.

[0187] Comparative Example 5 had an OD600 value of 0.19 after 72 hours, a COD removal rate of 11.2%, and a VS reduction rate of 8.5%. These results indicate that the conventional microbial-physical adsorbent combination formulation had a lower promoting effect on suspended bacterial growth, COD removal, and VS reduction under the test conditions compared to the Example group.

[0188] In summary, Examples 1 to 4 demonstrated high OD600 growth, COD removal rate, and VS reduction rate in the high ammonia nitrogen simulated manure fermentation system. These results are consistent with the mechanism by which the water-soluble magnesium phosphate precursor in the formulation participates in ammonia nitrogen fixation and, in conjunction with the available organic acid salt components, improves the microbial growth environment.

[0189] Test Example 5:

[0190] Test objective: This test case is used to investigate the effects of fermentation agents on ammonia nitrogen removal rate, total phosphorus retention rate, liquid phase viable bacteria titer, and solid waste reduction rate under simulated mobile toilet manure storage tank operating conditions.

[0191] Test steps:

[0192] 1. The mobile toilet fecal resource utilization fermentation agent dry powder prepared in Examples 1 to 4 and Comparative Examples 1 to 5 were selected as experimental subjects.

[0193] 2. Nine simulated mobile toilet manure storage tank reactors with a volume of 50L were constructed, and each was filled with 30L of real mixed manure substrate taken from public dry toilets. The initial ammonia nitrogen concentration, total phosphorus concentration and total solid mass of the mixed manure were measured and recorded.

[0194] 3. Add the corresponding group of fermentation agent dry powder evenly to each group of reactors at a dosage of 1.0g / 100mL of manure. Under the condition of ambient temperature fluctuation range of 20℃ to 30℃, conduct a natural open-air static simulation operation for 168 hours, i.e. 7 days.

[0195] 4. At the end of the 168th hour of the operating cycle, a full sample was taken from each reactor. 200 mL of the upper and middle layer mixture was taken, centrifuged, and filtered through a microporous membrane. The final concentrations of ammonia nitrogen and total phosphorus in the filtrate were determined by salicylic acid-hypochlorite spectrophotometry and ammonium molybdate spectrophotometry, respectively, and the liquid phase ammonia nitrogen removal rate was calculated. At the same time, the bottom solid phase in the reaction system was collected, dried, digested, and the phosphorus content retained in the solid phase was determined by ammonium molybdate spectrophotometry, and the total phosphorus retention rate was calculated. The total phosphorus retention rate was calculated as the ratio of the amount of phosphorus retained in the solid phase after the reaction to the sum of the initial phosphorus content of the manure and the exogenous phosphorus input of the fermentation agent.

[0196] 5. Simultaneously aspirate the intermediate layer solution, dilute it serially with physiological saline, spread it on nutrient agar plates, and incubate it at 37°C. Measure the titer of viable bacteria in the liquid phase at the reaction endpoint, and express the results as Log CFU / mL.

[0197] 6. Empty the liquid phase of each reactor, collect the bottom precipitate and undegraded residual solid phase, wash with water to remove water-soluble adhering substances, dry at 105℃ to constant weight, weigh and calculate the reduction rate of the final solid waste relative to the initial total solid phase mass.

[0198] The test data is shown in Table 5:

[0199] Table 5: Test data on the overall processing effect at the end of the 7th day of the simulation operation

[0200] Test object Ammonia nitrogen removal rate (%) Total phosphorus retention rate (%) Final viable cell titer (Log CFU / mL) Solid waste reduction rate (%) Example 1 78.4 91.2 8.6 61.5 Example 2 73.6 88.5 8.2 58.7 Example 3 81.2 94.3 9.1 65.2 Example 4 76.8 90.7 8.5 60.3 Comparative Example 1 14.5 11.2 4.3 16.8 Comparative Example 2 26.3 31.5 5.2 23.4 Comparative Example 3 18.7 45.6 6.1 28.9 Comparative Example 4 34.2 38.9 5.5 25.1 Comparative Example 5 12.8 9.4 3.8 12.5

[0201] According to the data in Table 5, the ammonia nitrogen removal rate of Examples 1 to 4 at the end of the 7th day of simulated operation was 73.6% to 81.2%, the total phosphorus retention rate was 88.5% to 94.3%, the final viable bacteria titer was 8.2 Log CFU / mL to 9.1 Log CFU / mL, and the solid waste reduction rate was 58.7% to 65.2%. These results show that, under the test conditions, the fermentation agents corresponding to Examples 1 to 4 have high ammonia nitrogen removal rates, total phosphorus retention rates, liquid phase viable bacteria titers, and solid waste reduction rates in real mixed manure substrates.

[0202] Compared with Examples 1 to 4, Comparative Example 1 showed an ammonia nitrogen removal rate of 14.5%, a total phosphorus retention rate of 11.2%, a final viable bacteria titer of 4.3 Log CFU / mL, and a solid waste reduction rate of 16.8%. These results indicate that after solid-liquid separation, Comparative Example 1 exhibited a lower retention level of water-soluble magnesium phosphorus precursors in its formulation, and its ammonia nitrogen removal, phosphorus retention, viable bacteria maintenance, and solid waste reduction indices were all lower than those of the Example groups during the simulated operating cycle.

[0203] Comparative Example 2 showed an ammonia nitrogen removal rate of 26.3%, a total phosphorus retention rate of 31.5%, a final viable bacteria titer of 5.2 LogCFU / mL, and a solid waste reduction rate of 23.4%. These results indicate that, without the addition of sodium citrate dihydrate for chelation treatment, the water solubility retention level of magnesium and phosphorus components decreased during the preparation stage, and the overall treatment indicators during the application stage were lower than those of the Example group.

[0204] Comparative Example 3 showed an ammonia nitrogen removal rate of 18.7%, a total phosphorus retention rate of 45.6%, a final viable bacteria titer of 6.1 LogCFU / mL, and a solid waste reduction rate of 28.9%. These results indicate that while the total stoichiometric sodium citrate complexation treatment is beneficial for the retention of soluble magnesium phosphate components during the preparation stage, the ammonia nitrogen removal rate and solid waste reduction rate were lower than those in the Example group during the simulated operating cycle. This result is consistent with the mechanism by which magnesium ion release and the formation of magnesium ammonium phosphate solid phases are limited under excessive complexation conditions.

[0205] Comparative Example 4 showed an ammonia nitrogen removal rate of 34.2%, a total phosphorus retention rate of 38.9%, a final viable bacteria titer of 5.5 LogCFU / mL, and a solid waste reduction rate of 25.1%. These results indicate that when using only dipotassium hydrogen phosphate as a single phosphorus source, the ammonia nitrogen removal, total phosphorus retention, viable bacteria maintenance, and solid waste reduction indices during the simulated operating cycle were lower than those in the Example Group, suggesting that the mixed phosphate system is beneficial for improving the overall treatment effect at the application end.

[0206] Comparative Example 5 showed an ammonia nitrogen removal rate of 12.8%, a total phosphorus retention rate of 9.4%, a final viable bacteria titer of 3.8 Log CFU / mL, and a solid waste reduction rate of 12.5%. These results indicate that the overall treatment performance of the conventional microbial-physical adsorbent combination formulation under these test conditions was lower than that of the Example group.

[0207] In summary, Examples 1 to 4, under simulated mobile toilet storage tank operating conditions, exhibited high ammonia nitrogen removal rates, total phosphorus retention rates, liquid-phase viable bacteria titers, and solid waste reduction rates. These results are consistent with the mechanism by which the water-soluble magnesium phosphorus precursor in the formulation participates in the solid-phase retention of ammonia nitrogen and phosphorus, and works in conjunction with the available organic acid salt components to maintain microbial activity.

[0208] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A mobile toilet waste resource utilization fermentation agent, characterized in that, The fermentation agent is made from the following raw materials through fermentation and complexation processes: basic fermentation culture medium, Lactobacillus plantarum seed liquid, Bacillus subtilis seed liquid, anhydrous betaine, light magnesium oxide, sodium citrate dihydrate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, and hydrophobic fumed silica. Furthermore, the following dosage relationships apply to all raw materials: The basic fermentation medium uses deionized water as a solvent. Each liter of the basic fermentation medium consists of the following components and the remainder is deionized water: 15.0g to 25.0g glucose, 5.0g to 10.0g yeast extract, 5.0g to 10.0g peptone, 0.2g to 0.5g anhydrous magnesium sulfate, 0.05g to 0.1g manganese sulfate, and 1.0mL to 2.0mL Tween-80. The pH value is adjusted to 6.2 to 6.8 using hydrochloric acid solution or sodium hydroxide solution. Based on the volume of the basic fermentation medium, the volume percentage of the inoculum of Lactobacillus plantarum seed liquid is 3.0% to 5.0%, the volume percentage of the inoculum of Bacillus subtilis seed liquid is 4.0% to 6.0%, and the dosage of anhydrous betaine is 1.5g to 2.5g per 100mL of the basic fermentation medium. The total molar amount of magnesium in the light magnesium oxide consumed during fermentation does not include the molar amount of nutrient magnesium salts provided by anhydrous magnesium sulfate in the basic fermentation medium. The added molar amount of sodium citrate dihydrate accounts for 15.0% to 20.0% of the total molar amount of magnesium. The potassium dihydrogen phosphate and the dipotassium hydrogen phosphate form a solid mixed powder, and the ratio of the molar amount of total phosphorus to the molar amount of total magnesium in the solid mixed powder is 0.95 to 1.05:

1. The amount of hydrophobic fumed silica added accounts for 1.0% to 2.0% of the total mass of the prepared fermentation agent.

2. The mobile toilet fecal resource utilization fermentation agent according to claim 1, characterized in that, The physicochemical and biological properties of the raw materials meet the following conditions: The viable cell counts of both the *Lactobacillus plantarum* seed solution and the *Bacillus subtilis* seed solution are ≥1.0 × 10⁻⁶. 9 CFU / mL; In the solid mixed powder, the molar ratio of potassium dihydrogen phosphate to potassium hydrogen phosphate is 0.95-1.05:1.05-0.95; The specific surface area of ​​the hydrophobic fumed silica is in the range of 100 m². 2 / g~200m 2 / g, carbon content ≥1.0%.

3. The mobile toilet fecal resource utilization fermentation agent according to claim 1, characterized in that, The dosage relationship of the raw materials is as follows: Each liter of the basal fermentation medium consists of the following components and the remainder deionized water: 20.0 g glucose, 8.0 g yeast extract, 8.0 g peptone, 0.3 g anhydrous magnesium sulfate, 0.08 g manganese sulfate, 1.5 mL Tween-80, and the pH is adjusted to 6.5 using hydrochloric acid solution or sodium hydroxide solution. Based on the volume of the basic fermentation medium, the volume percentage of the inoculum of Lactobacillus plantarum seed liquid is 4.0%, the volume percentage of the inoculum of Bacillus subtilis seed liquid is 5.0%, and the dosage of anhydrous betaine is 2.0g per 100mL of the basic fermentation medium. The added sodium citrate dihydrate accounts for 18.0% of the total magnesium molar amount; The ratio of the total phosphorus molar amount to the total magnesium molar amount in the solid mixed powder is 1:1, and the molar ratio of potassium dihydrogen phosphate to potassium hydrogen phosphate is 1:

1. The amount of hydrophobic fumed silica added accounts for 1.5% of the total mass of the prepared fermentation agent.

4. A method for preparing a mobile toilet fecal resource utilization fermentation agent as described in any one of claims 1-3, characterized in that, Includes the following steps: S1. After sterilizing and cooling the basic fermentation medium, inoculate it with Lactobacillus plantarum seed liquid for microaerobic fermentation; as lactic acid accumulates and the pH value decreases, add light magnesium oxide aqueous slurry to dynamically maintain the pH value of the fermentation system, record the amount of light magnesium oxide aqueous slurry consumed, and calculate the total amount of magnesium moles. S2. After adding anhydrous betaine to the fermentation system and dissolving it, inoculate it with Bacillus subtilis seed liquid and introduce air to carry out aerobic symbiotic fermentation. S3. After the symbiotic fermentation is completed, add sodium citrate dihydrate aqueous solution in proportion and stir to chelate. S4. After chelation, add a pre-mixed solid powder consisting of potassium dihydrogen phosphate and dipotassium hydrogen phosphate to the fermentation system in proportion; after stirring and dissolving, immediately carry out a rapid cooling treatment to gradually reduce the temperature of the entire fermentation liquid and maintain it between 10℃ and 15℃. S5. The cooled whole liquid fermentation broth is dehydrated and concentrated under reduced pressure to form a concentrated salt slurry; then it is dried; finally, it is sent to a mechanical pulverizer and hydrophobic fumed silica is added at the same time to pulverize and mix together to obtain the final fermentation agent.

5. The method for preparing the mobile toilet fecal resource utilization fermentation agent according to claim 4, characterized in that, In step S1, the microaerobic fermentation is carried out at 35℃~37℃; the specific pH control method is as follows: Monitor the pH value of the fermentation broth. When the pH value of the fermentation broth naturally decreases to between 4.0 and 4.2 due to lactic acid accumulation, start the peristaltic pump linked to the online pH sensor and add the light magnesium oxide aqueous slurry with a mass fraction of 10.0% to 15.0% to dynamically maintain the pH value of the fermentation system between 5.5 and 6.

0. The microaerobic fermentation stage lasts for 12 to 16 hours, and the stirring speed is controlled between 100 rpm and 150 rpm. The total magnesium molar amount is calculated as the amount of magnesium element contained in the actual consumed light magnesium oxide, and the total magnesium molar amount does not include the amount of nutrient magnesium salts provided by anhydrous magnesium sulfate in the basal fermentation medium.

6. The method for preparing the mobile toilet fecal resource utilization fermentation agent according to claim 4, characterized in that, In step S2, the aerobic symbiotic fermentation is carried out at 35℃~37℃ for 10~14 hours, and the aeration rate of the fermenter is adjusted to 0.5vvm~1.0vvm. In step S3, the temperature is maintained between 35°C and 40°C, the mass fraction of the sodium citrate dihydrate aqueous solution is 20.0%, and it is slowly added to the fermenter at a rate of 50 mL / min to 100 mL / min, and the mixture is stirred and chelated at a constant temperature for 40 to 50 minutes.

7. The method for preparing the mobile toilet fecal resource utilization fermentation agent according to claim 4, characterized in that, In step S4, the time for the solid mixed powder to be added and stirred to dissolve is limited to 9 to 11 minutes. The rapid cooling process specifically involves: introducing chilled water into the jacket of the fermenter and cooling it at a rate of 2.0℃ / min to 3.0℃ / min.

8. The method for preparing the mobile toilet fecal resource utilization fermentation agent according to claim 4, characterized in that, In step S5, the specific operations for dehydration and vacuum concentration are as follows: The entire liquid fermentation broth was directly transferred to a single-effect vacuum concentrator with a scraper and agitator without solid-liquid separation. Under the conditions of limiting the heating temperature of the broth to 35℃~40℃ and the working vacuum degree to -0.08MPa~-0.09MPa, dehydration was carried out until the fermentation broth lost 60.0%~70.0% of its original water content.

9. The method for preparing the mobile toilet fecal resource utilization fermentation agent according to claim 4, characterized in that, In step S5, the drying process is carried out until the total moisture content of the material is ≤5.0%, and is selected from either method one or method two: Method 1: Spread the concentrated salt slurry evenly into a vacuum conveyor belt dryer and set the heating plate temperature to 35℃~45℃ for drying; Method 2: Transfer the concentrated salt slurry to a vacuum freeze dryer for freeze drying, control the cold trap temperature to -50℃, and the system vacuum degree <10Pa.

10. The application of the mobile toilet waste resource utilization fermentation agent according to any one of claims 1-3 in the treatment of mobile toilet waste.

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